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Sample records for high-resolution ct scans

  1. A wire scanning based method for geometric calibration of high resolution CT system

    NASA Astrophysics Data System (ADS)

    Jiang, Ruijie; Li, Guang; Gu, Ning; Chen, Gong; Luo, Shouhua

    2015-03-01

    This paper is about geometric calibration of the high resolution CT (Computed Tomography) system. Geometric calibration refers to the estimation of a set of parameters that describe the geometry of the CT system. Such parameters are so important that a little error of them will degrade the reconstruction images seriously, so more accurate geometric parameters are needed in the higher-resolution CT systems. But conventional calibration methods are not accurate enough for the current high resolution CT system whose resolution can reach sub-micrometer or even tens of nanometers. In this paper, we propose a new calibration method which has higher accuracy and it is based on the optimization theory. The superiority of this method is that we build a new cost function which sets up a relationship between the geometrical parameters and the binary reconstruction image of a thin wire. When the geometrical parameters are accurate, the cost function reaches its maximum value. In the experiment, we scanned a thin wire as the calibration data and a thin bamboo stick as the validation data to verify the correctness of the proposed method. Comparing with the image reconstructed with the geometric parameters calculated by using the conventional calibration method, the image reconstructed with the parameters calculated by our method has less geometric artifacts, so it can verify that our method can get more accurate geometric calibration parameters. Although we calculated only one geometric parameter in this paper, the geometric artifacts are still eliminated significantly. And this method can be easily generalized to all the geometrical parameters calibration in fan-beam or cone-beam CT systems.

  2. High resolution extremity CT for biomechanics modeling

    SciTech Connect

    Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

    1995-09-23

    With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling.

  3. High Resolution Scanning Reflectarray Antenna

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R. (Inventor); Miranda, Felix A. (Inventor)

    2000-01-01

    The present invention provides a High Resolution Scanning Reflectarray Antenna (HRSRA) for the purpose of tracking ground terminals and space craft communication applications. The present invention provides an alternative to using gimbaled parabolic dish antennas and direct radiating phased arrays. When compared to a gimbaled parabolic dish, the HRSRA offers the advantages of vibration free steering without incurring appreciable cost or prime power penalties. In addition, it offers full beam steering at a fraction of the cost of direct radiating arrays and is more efficient.

  4. 102 Bronchiectasis: Localization and Characteristics, Identified by Using a High Resolution CT Scan in Adults With Common Variable Immunodeficiency

    PubMed Central

    Mendoza, Laura; Segura Mendez, Nora Hilda; Flores, Francisco; Campos Romero, Freya Helena; Guillén, Nelva

    2012-01-01

    Background The common variable Immunodeficiency (CVID) is the second cause of primary immunodeficiency. The bronchiectasis are the most frequent structural pulmonary alterations in CVID, which have been principally described in pediatric population, finding the presence of the same ones in 50% of the cases, nevertheless exists inssuficient information about the location and characteristics as type and distribution of the bronchiectasis; in adult population, less information exists still on this matter. High resolution CT scan is valuable for detection of bronchiectasis and may alter treatment of these patients. Objective The purpose of this study was to determine the presence of bronchiectasis, their characteristics and most frequent location using a high resolution CT scan in adults with diagnosis of CVID. Methods This was a cohort study whit 15 adult subjects whit the diagnosis of CVID, who underwent a chest high-resolution computed tomography scan, previous signature of a letter of informed consent and with the approval of the committee of ethics and investigation (F-2011-3601-21). Results We studied all the subjects (n = 15) whit CVID, finding the presence of bronquiectasias in 73% of the subjects with CVID, 82% was a women and 8% males. The most frequent location was in the left lung in 46% of the cases and 45 bilateral %, with only 9% of location in right lung. These were more frequent in the lower lobe in 42, 17% in top lobe and l6% diffuse, the rest of them were brought like diffuse, bibasal or parahiliar. In one patient we found the presence of a left apical cavitation and only one was brought by presence of pulmonary diffuse fibrosis. Conclusions There was realized a search of bronchiectasis and their characteristics in subjects with CVID disorders, the incidence of bronchiectasis is higher in our poblation (82%) than in the rest (50% described in other pubiclations). The most affected lung was the left in the lower lobe. The most frequent type of

  5. Computer-aided mesenteric small vessel segmentation on high-resolution 3D contrast-enhanced CT angiography scans

    NASA Astrophysics Data System (ADS)

    Zhang, Weidong; Liu, Jiamin; Yao, Jianhua; Nguyen, Tan; Louie, Adeline; Wank, Stephen; Summers, Ronald M.

    2012-03-01

    Segmentation of the mesenteric vasculature has important applications for evaluation of the small bowel. In particular, it may be useful for small bowel path reconstruction and precise localization of small bowel tumors such as carcinoid. Segmentation of the mesenteric vasculature is very challenging, even for manual labeling, because of the low contrast and tortuosity of the small blood vessels. Many vessel segmentation methods have been proposed. However, most of them are designed for segmenting large vessels. We propose a semi-automated method to extract the mesenteric vasculature on contrast-enhanced abdominal CT scans. First, the internal abdominal region of the body is automatically identified. Second, the major vascular branches are segmented using a multi-linear vessel tracing method. Third, small mesenteric vessels are segmented using multi-view multi-scale vesselness enhancement filters. The method is insensitive to image contrast, variations of vessel shape and small occlusions due to overlapping. The method could automatically detect mesenteric vessels with diameters as small as 1 mm. Compared with the standard-of-reference manually labeled by an expert radiologist, the segmentation accuracy (recall rate) for the whole mesenteric vasculature was 82.3% with a 3.6% false positive rate.

  6. CT Scans

    MedlinePlus

    ... cross-sectional pictures of your body. Doctors use CT scans to look for Broken bones Cancers Blood clots Signs of heart disease Internal bleeding During a CT scan, you lie still on a table. The table ...

  7. Reconstructing high-resolution climate using CT scanning of unsectioned stalagmites: A case study identifying the mid-Holocene onset of the Mediterranean climate in southern Iberia

    NASA Astrophysics Data System (ADS)

    Walczak, Izabela W.; Baldini, James U. L.; Baldini, Lisa M.; McDermott, Frank; Marsden, Stuart; Standish, Christopher D.; Richards, David A.; Andreo, Bartolomé; Slater, Jonathan

    2015-11-01

    The forcing mechanisms responsible for the mid-Holocene onset of the Mediterranean-type climate in south-western Europe are currently unclear, but understanding these is critical for accurate climate projections under future greenhouse gas warming. Additionally, regional studies that present conflicting patterns for the onset and advancement of Mediterranean climatic conditions complicate definitively ascribing causality. Here, we use a new high resolution stalagmite density record obtained non-destructively using Computed Tomography (CT scanning) to reconstruct southern Iberian climate between 9.3 and 2.9 ka BP. We suggest that stalagmite density can be used as a water-excess proxy, with lower densities associated with more variable drip rates, possibly reflecting increased seasonality consistent with expectations from previous studies of speleothem textures and crystal fabrics. Our results reveal an early Holocene humid interval and mid-Holocene year-round aridity that preceded the onset of Mediterranean climate at 5.3 ka BP in southern Iberia. Using this new dataset combined with previously published results, we link the gradual advancement of the Mediterranean climate to the southward migration of the North Atlantic Subtropical High induced by an orbitally driven decrease in Northern Hemisphere insolation. Future anthropogenic warming could result in a reversal of this trend, a northward migration of the North Atlantic Subtropical High, and a return to year-round aridity in south-western Europe.

  8. High resolution CT of Meckel's cave.

    PubMed

    Chui, M; Tucker, W; Hudson, A; Bayer, N

    1985-01-01

    High resolution CT of the parasellar region was carried out in 50 patients studied for suspected pituitary microadenoma, but who showed normal pituitary gland or microadenoma on CT. This control group of patients all showed an ellipsoid low-density area in the posterior parasellar region. Knowledge of the gross anatomy and correlation with metrizamide cisternography suggest that the low density region represents Meckel's cave, rather than just the trigeminal ganglion alone. Though there is considerable variation in the size of Meckel's cave in different patients as well as the two sides of the same patient, the rather constant ellipsoid configuration of the cave in normal subjects will aid in diagnosing small pathological lesions, thereby obviating more invasive cisternography via the transovale or lumbar route. Patients with "idiopathic" tic douloureux do not show a Meckel's cave significantly different from the control group.

  9. Head CT scan

    MedlinePlus

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... conditions: Birth (congenital) defect of the head or brain Brain infection Brain tumor Buildup of fluid inside ...

  10. High resolution obtained by photoelectric scanning techniques.

    NASA Technical Reports Server (NTRS)

    Hall, J. S.

    1972-01-01

    Several applications of linear scanning of different types of objects are described; examples include double stars, satellites, the Red Spot of Jupiter and a landing site on the moon. This technique allows one to achieve a gain of about an order of magnitude in resolution over conventional photoelectric techniques; it is also effective in providing sufficient data for removing background effects and for the application of deconvolution procedures. Brief consideration is given to two-dimensional scanning, either at the telescope or of electronographic images in the laboratory. It is suggested that some of the techniques described should be given serious consideration for space applications.

  11. CT Scan

    MedlinePlus

    ... exposing your baby to radiation. Reactions to contrast material In certain cases, your doctor may recommend you ... for a few hours before your scan Contrast material A special dye called a contrast material is ...

  12. Abdominal CT scan

    MedlinePlus

    Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... 2016:chap 133. Radiologyinfo.org. Computed tomography (CT) - abdomen and pelvis. Updated June 16, 2016. www.radiologyinfo. ...

  13. Leg CT scan

    MedlinePlus

    CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... scanners can perform the exam without stopping.) A computer creates separate images of the body area, called ...

  14. Arm CT scan

    MedlinePlus

    CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... scanners can perform the exam without stopping.) A computer creates separate images of the arm area, called ...

  15. LandScan 2013 High Resolution Global Population Data Set

    SciTech Connect

    2014-07-01

    The LandScan data set is a worldwide population database compiled on a 30"x30" latitude/longitude grid. Census counts (at sub-national level) were apportioned to each grid cell based on likelihood coefficients, which are based on land cover, slope, road proximity, high-resolution imagery, and other data sets. The LandScan data set was developed as part of Oak Ridge National Laboratory (ORNL) Global Population Project for estimating ambient populations at risk.

  16. High-resolution low-dose scanning transmission electron microscopy.

    PubMed

    Buban, James P; Ramasse, Quentin; Gipson, Bryant; Browning, Nigel D; Stahlberg, Henning

    2010-01-01

    During the past two decades instrumentation in scanning transmission electron microscopy (STEM) has pushed toward higher intensity electron probes to increase the signal-to-noise ratio of recorded images. While this is suitable for robust specimens, biological specimens require a much reduced electron dose for high-resolution imaging. We describe here protocols for low-dose STEM image recording with a conventional field-emission gun STEM, while maintaining the high-resolution capability of the instrument. Our findings show that a combination of reduced pixel dwell time and reduced gun current can achieve radiation doses comparable to low-dose TEM.

  17. Lumbar spine CT scan

    MedlinePlus

    CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... stopping.) A computer creates separate images of the spine area, called slices. These images can be stored, ...

  18. Tuning and scanning control system for high resolution alexandrite lasers

    NASA Technical Reports Server (NTRS)

    Smith, James C.; Schwemmer, Geary K.

    1988-01-01

    An alexandrite laser is spectrally narrowed and tuned by the use of three optical elements. Each element provides a successively higher degree of spectral resolution. The digitally controlled tuning and scanning control servo system simultaneously positions all three optical elements to provide continuous high resolution laser spectral tuning. The user may select manual, single, or continuous modes of automated scanning of ranges up to 3.00/cm and at scan rates up to 3.85/cm/min. Scanning over an extended range of up to 9.999/cm may be achieved if the highest resolution optic is removed from the system. The control system is also capable of being remotely operated by another computer or controller via standard RS-232 serial data link.

  19. Cardiac CT Scan

    MedlinePlus

    ... CT Scan Related Topics Aneurysm Coronary Calcium Scan Coronary Heart Disease Heart Attack Pulmonary Embolism Send a link to ... imaging test can help doctors detect or evaluate coronary heart disease, calcium buildup in the coronary arteries, problems with ...

  20. High resolution digital holography based on the point source scanning

    NASA Astrophysics Data System (ADS)

    Wang, Minchao; Wang, Dayong; Rong, Lu; Wang, Yunxin; Wang, Fengpeng; Lin, Qiaowen

    2016-10-01

    Digital holographic microscopy has been widely used for the imaging of micro-objects and biological samples. Lensless in-line digital holographic microscopy is capable of wide field-of-view imaging. However the spatial resolution of the reconstructed images is limited by the pixel size of the detector. The relative position shift between the sample and the detector can effectively improve the resolution in the traditional sub-pixel shifting method, but it requires a high precision of translation stage. To overcome this problem, we propose a method based on the point source scanning to realize sub-pixel shifting. High precision sub-pixel shifting is achieved easily by using the geometric between point source and detector. Through moving the point source, multiple holograms with sub-pixel shifts are captured. These holograms are merged together to obtained a high resolution hologram by a synthesizing algorithm. Then, the high resolution reconstructed image of the object can be obtained by the angular spectrum algorithm. The feasibility of the proposed method is demonstrated by simulation and experiments. A USAF resolution test target was used as the object. Compared with the traditional digital holography, a higher resolution reconstructed image is obtained by our method. The proposed method has the advantages of simple recording setup and lower precision requirement of the translation stage. It can achieve the wide field-of-view and high resolution imaging.

  1. High Resolution X-Ray Micro-CT of Ultra-Thin Wall Space Components

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Rauser, R. W.; Bowman, Randy R.; Bonacuse, Peter; Martin, Richard E.; Locci, I. E.; Kelley, M.

    2012-01-01

    A high resolution micro-CT system has been assembled and is being used to provide optimal characterization for ultra-thin wall space components. The Glenn Research Center NDE Sciences Team, using this CT system, has assumed the role of inspection vendor for the Advanced Stirling Convertor (ASC) project at NASA. This article will discuss many aspects of the development of the CT scanning for this type of component, including CT system overview; inspection requirements; process development, software utilized and developed to visualize, process, and analyze results; calibration sample development; results on actual samples; correlation with optical/SEM characterization; CT modeling; and development of automatic flaw recognition software. Keywords: Nondestructive Evaluation, NDE, Computed Tomography, Imaging, X-ray, Metallic Components, Thin Wall Inspection

  2. High resolution X-ray CT for advanced electronics packaging

    NASA Astrophysics Data System (ADS)

    Oppermann, M.; Zerna, T.

    2017-02-01

    Advanced electronics packaging is a challenge for non-destructive Testing (NDT). More, smaller and mostly hidden interconnects dominate modern electronics components and systems. To solve the demands of customers to get products with a high functionality by low volume, weight and price (e.g. mobile phones, personal medical monitoring systems) often the designers use System-in-Package solutions (SiP). The non-destructive testing of such devices is a big challenge. So our paper will impart fundamentals and applications for non-destructive evaluation of inner structures of electronics packaging for quality assurance and reliability investigations with a focus on X-ray methods, especially on high resolution X-ray computed tomography (CT).

  3. Low-dose high-resolution CT of lung parenchyma

    SciTech Connect

    Zwirewich, C.V.; Mayo, J.R.; Mueller, N.L. )

    1991-08-01

    To evaluate the efficacy of low-dose high-resolution computed tomography (HRCT) in the assessment of lung parenchyma, three observers reviewed the scans of 31 patients. The 1.5-mm-collimation, 2-second, 120-kVp scans were obtained at 20 and 200 mA at selected identical levels in the chest. The observers evaluated the visualization of normal pulmonary anatomy, various parenchymal abnormalities and their distribution, and artifacts. The low-dose and conventional scans were equivalent in the evaluation of vessels, lobar and segmental bronchi, and anatomy of secondary pulmonary lobules, and in characterizing the extent and distribution of reticulation, honeycomb cysts, and thickened interlobular septa. The low-dose technique failed to demonstrate ground-glass opacity in two of 10 cases (20%) and emphysema in one of nine cases (11%), in which they were evident but subtle on the high-dose scans. These differences were not statistically significant. Linear streak artifact was more prominent on images acquired with the low-dose technique, but the two techniques were judged equally diagnostic in 97% of cases. The authors conclude that HRCT images acquired at 20 mA yield anatomic information equivalent to that obtained with 200-mA scans in the majority of patients, without significant loss of spatial resolution or image degradation due to linear streak artifact.

  4. Thoracic spine CT scan

    MedlinePlus

    ... Narrowing of the spine ( spinal stenosis ) Scoliosis Tumor Risks Risks of CT scans include: Exposure to radiation ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  5. Pediatric CT Scans

    Cancer.gov

    The Radiation Epidemiology Branch and collaborators have initiated a retrospective cohort study to evaluate the relationship between radiation exposure from CT scans conducted during childhood and adolescence and the subsequent development of cancer.

  6. A new high-resolution computed tomography (CT) segmentation method for trabecular bone architectural analysis.

    PubMed

    Scherf, Heike; Tilgner, Rico

    2009-09-01

    In the last decade, high-resolution computed tomography (CT) and microcomputed tomography (micro-CT) have been increasingly used in anthropological studies and as a complement to traditional histological techniques. This is due in large part to the ability of CT techniques to nondestructively extract three-dimensional representations of bone structures. Despite prior studies employing CT techniques, no completely reliable method of bone segmentation has been established. Accurate preprocessing of digital data is crucial for measurement accuracy, especially when subtle structures such as trabecular bone are investigated. The research presented here is a new, reproducible, accurate, and fully automated computerized segmentation method for high-resolution CT datasets of fossil and recent cancellous bone: the Ray Casting Algorithm (RCA). We compare this technique with commonly used methods of image thresholding (i.e., the half-maximum height protocol and the automatic, adaptive iterative thresholding procedure). While the quality of the input images is crucial for conventional image segmentation, the RCA method is robust regarding the signal to noise ratio, beam hardening, ring artifacts, and blurriness. Tests with data of extant and fossil material demonstrate the superior quality of RCA compared with conventional thresholding procedures, and emphasize the need for careful consideration of optimal CT scanning parameters.

  7. High-resolution fully vectorial scanning Kerr magnetometer.

    PubMed

    Flajšman, Lukáš; Urbánek, Michal; Křižáková, Viola; Vaňatka, Marek; Turčan, Igor; Šikola, Tomáš

    2016-05-01

    We report on the development of a high-resolution scanning magnetometer, which fully exploits the vectorial nature of the magneto-optical Kerr effect. The three-dimensional nature of magnetization is at the basis of many micromagnetic phenomena and from these data, we can fully characterize magnetization processes of nanostructures in static and dynamic regimes. Our scanning Kerr magnetometer uses a high numerical aperture microscope objective where the incident light beam can be deterministically deviated from the objective symmetry axis, therefore, both in-plane (via the longitudinal Kerr effect) and out-of-plane (via the polar Kerr effect) components of the magnetization vector may be detected. These components are then separated by exploiting the symmetries of the polar and longitudinal Kerr effects. From four consecutive measurements, we are able to directly obtain the three orthogonal components of the magnetization vector with a resolution of 600 nm. Performance of the apparatus is demonstrated by a measurement of 3D magnetization vector maps showing out-of-plane domains and in-plane domain walls in an yttrium-iron-garnet film and on a study of magnetization reversal in a 4-μm-wide magnetic disk.

  8. High resolution helium ion scanning microscopy of the rat kidney.

    PubMed

    Rice, William L; Van Hoek, Alfred N; Păunescu, Teodor G; Huynh, Chuong; Goetze, Bernhard; Singh, Bipin; Scipioni, Larry; Stern, Lewis A; Brown, Dennis

    2013-01-01

    Helium ion scanning microscopy is a novel imaging technology with the potential to provide sub-nanometer resolution images of uncoated biological tissues. So far, however, it has been used mainly in materials science applications. Here, we took advantage of helium ion microscopy to explore the epithelium of the rat kidney with unsurpassed image quality and detail. In addition, we evaluated different tissue preparation methods for their ability to preserve tissue architecture. We found that high contrast, high resolution imaging of the renal tubule surface is possible with a relatively simple processing procedure that consists of transcardial perfusion with aldehyde fixatives, vibratome tissue sectioning, tissue dehydration with graded methanol solutions and careful critical point drying. Coupled with the helium ion system, fine details such as membrane texture and membranous nanoprojections on the glomerular podocytes were visualized, and pores within the filtration slit diaphragm could be seen in much greater detail than in previous scanning EM studies. In the collecting duct, the extensive and striking apical microplicae of the intercalated cells were imaged without the shrunken or distorted appearance that is typical with conventional sample processing and scanning electron microscopy. Membrane depressions visible on principal cells suggest possible endo- or exocytotic events, and central cilia on these cells were imaged with remarkable preservation and clarity. We also demonstrate the use of colloidal gold probes for highlighting specific cell-surface proteins and find that 15 nm gold labels are practical and easily distinguishable, indicating that external labels of various sizes can be used to detect multiple targets in the same tissue. We conclude that this technology represents a technical breakthrough in imaging the topographical ultrastructure of animal tissues. Its use in future studies should allow the study of fine cellular details and provide

  9. Prolactin-secreting pituitary microadenomas: inaccuracy of high-resolution CT imaging

    SciTech Connect

    Davis, P.C.; Hoffman, J.C. Jr.; Tindall, G.T.; Braun, I.F.

    1985-01-01

    Computed tomographic (CT) and surgical findings were correlated retrospectively in 51 patients with preoperative diagnoses of prolactin-secreting pituitary microadenomas. Thirty-nine had microadenomas at surgery. Twenty-three had identifiable discrete lesions. Of these, 21 had microadenomas and two did not; these two groups could not be distinguished reliably. Six patients with proven microadenomas had normal CT scans. Focal hypodense lesions, sellar floor erosion, infundibulum displacement, gland height greater than 8 mm, and an abnormal diaphragma sellae configuration are neither sensitive nor specific findings or microadenoma. A significant number of patients with proven microadenomas has few or none of these abnormalities. Thus, recognition of prolactin microadenoma may not be possible by CT alone, even with high-resolution direct coronal imaging.

  10. High-Resolution Underwater Mapping Using Side-Scan Sonar.

    PubMed

    Burguera, Antoni; Oliver, Gabriel

    2016-01-01

    The goal of this study is to generate high-resolution sea floor maps using a Side-Scan Sonar(SSS). This is achieved by explicitly taking into account the SSS operation as follows. First, the raw sensor data is corrected by means of a physics-based SSS model. Second, the data is projected to the sea-floor. The errors involved in this projection are thoroughfully analysed. Third, a probabilistic SSS model is defined and used to estimate the probability of each sea-floor region to be observed. This probabilistic information is then used to weight the contribution of each SSS measurement to the map. Because of these models, arbitrary map resolutions can be achieved, even beyond the sensor resolution. Finally, a geometric map building method is presented and combined with the probabilistic approach. The resulting map is composed of two layers. The echo intensity layer holds the most likely echo intensities at each point in the sea-floor. The probabilistic layer contains information about how confident can the user or the higher control layers be about the echo intensity layer data. Experimental results have been conducted in a large subsea region.

  11. High-Resolution Underwater Mapping Using Side-Scan Sonar

    PubMed Central

    2016-01-01

    The goal of this study is to generate high-resolution sea floor maps using a Side-Scan Sonar(SSS). This is achieved by explicitly taking into account the SSS operation as follows. First, the raw sensor data is corrected by means of a physics-based SSS model. Second, the data is projected to the sea-floor. The errors involved in this projection are thoroughfully analysed. Third, a probabilistic SSS model is defined and used to estimate the probability of each sea-floor region to be observed. This probabilistic information is then used to weight the contribution of each SSS measurement to the map. Because of these models, arbitrary map resolutions can be achieved, even beyond the sensor resolution. Finally, a geometric map building method is presented and combined with the probabilistic approach. The resulting map is composed of two layers. The echo intensity layer holds the most likely echo intensities at each point in the sea-floor. The probabilistic layer contains information about how confident can the user or the higher control layers be about the echo intensity layer data. Experimental results have been conducted in a large subsea region. PMID:26821379

  12. Why is high resolution computerized tomography scanning used in evaluating the lungs?

    PubMed Central

    Graves, W. A.; Collins, J. D.; Miller, T. Q.

    1989-01-01

    High resolution computerized tomography scans have been used for medical and legal purposes to evaluate patients with a history of exposure to asbestos. Some investigators argue that high resolution scanning provides a better image of the lungs than routine computerized tomography. A review of the literature shows that although high resolution scanning displays the lymphatics in the lung, it offers no new useful diagnostic information. The authors conclude that no real advantage is attained with high resolution scanning of the lung and that pathology of disease can be determined decisively only by histology. Images Figure 1 Figure 2A Figure 2B Figure 3 Figure 4 PMID:2681799

  13. Accurate Coregistration between Ultra-High-Resolution Micro-SPECT and Circular Cone-Beam Micro-CT Scanners.

    PubMed

    Ji, Changguo; van der Have, Frans; Gratama van Andel, Hugo; Ramakers, Ruud; Beekman, Freek

    2010-01-01

    Introduction. Spatially registering SPECT with CT makes it possible to anatomically localize SPECT tracers. In this study, an accurate method for the coregistration of ultra-high-resolution SPECT volumes and multiple cone-beam CT volumes is developed and validated, which does not require markers during animal scanning. Methods. Transferable animal beds were developed with an accurate mounting interface. Simple calibration phantoms make it possible to obtain both the spatial transformation matrix for stitching multiple CT scans of different parts of the animal and to register SPECT and CT. The spatial transformation for image coregistration is calculated once using Horn's matching algorithm. Animal images can then be coregistered without using markers. Results. For mouse-sized objects, average coregistration errors between SPECT and CT in X, Y, and Z directions are within 0.04 mm, 0.10 mm, and 0.19 mm, respectively. For rat-sized objects, these numbers are 0.22 mm, 0.14 mm, and 0.28 mm. Average 3D coregistration errors were within 0.24 mm and 0.42 mm for mouse and rat imaging, respectively. Conclusion. Extending the field-of-view of cone-beam CT by stitching is improved by prior registration of the CT volumes. The accuracy of registration between SPECT and CT is typically better than the image resolution of current ultra-high-resolution SPECT.

  14. Ultra-high resolution flat-panel volume CT: fundamental principles, design architecture, and system characterization.

    PubMed

    Gupta, Rajiv; Grasruck, Michael; Suess, Christoph; Bartling, Soenke H; Schmidt, Bernhard; Stierstorfer, Karl; Popescu, Stefan; Brady, Tom; Flohr, Thomas

    2006-06-01

    Digital flat-panel-based volume CT (VCT) represents a unique design capable of ultra-high spatial resolution, direct volumetric imaging, and dynamic CT scanning. This innovation, when fully developed, has the promise of opening a unique window on human anatomy and physiology. For example, the volumetric coverage offered by this technology enables us to observe the perfusion of an entire organ, such as the brain, liver, or kidney, tomographically (e.g., after a transplant or ischemic event). By virtue of its higher resolution, one can directly visualize the trabecular structure of bone. This paper describes the basic design architecture of VCT. Three key technical challenges, viz., scatter correction, dynamic range extension, and temporal resolution improvement, must be addressed for successful implementation of a VCT scanner. How these issues are solved in a VCT prototype and the modifications necessary to enable ultra-high resolution volumetric scanning are described. The fundamental principles of scatter correction and dose reduction are illustrated with the help of an actual prototype. The image quality metrics of this prototype are characterized and compared with a multi-detector CT (MDCT).

  15. LandScan 2011 High Resolution Global Population Data Set

    SciTech Connect

    2012-11-19

    The LandScan data set is a worldwide population database compiled on a 30" x 30" latitude/longitude grid. Census counts (at sub-national level) were apportioned to each grid cell based on likelihood coefficients, which are based on proximity to roads, slope, land cover, nighttime lights, and other data sets. LandScan 2001 has been developed as part of Oak Ridge National Laboratory (ORNL) Global Population Project for estimating ambient population risk.

  16. LandScan 2007 High Resolution Global Population Data Set

    SciTech Connect

    2008-01-01

    The LandScan data set is a worldwide population database compiled on a 30" x 30" latitude/longitude grid. Census counts (at sub-national level) were apportioned to each grid cell based on likelihood coefficients, which are based on proximity to roads, slope, land cover, nighttime lights, and other data sets. LandScan 2001 has been developed as part of Oak Ridge National Laboratory (ORNL) Global Population Project for estimating ambient population risk.

  17. LandScan 2010 High Resolution Global Population Data Set

    SciTech Connect

    2010-07-01

    The LandScan data set is a worldwide population database compiled on a 30" x 30" latitude/longitude grid. Census counts (at sub-national level) were apportioned to each grid cell based on likelihood coefficients, which are based on proximity to roads, slope, land cover, nighttime lights, and other data sets. LandScan 2001 has been developed as part of Oak Ridge National Laboratory (ORNL) Global Population Project for estimating ambient population risk.

  18. LandScan 2009 High Resolution Global Population Data Set

    SciTech Connect

    2009-07-01

    The LandScan data set is a worldwide population database compiled on a 30" x 30" latitude/longitude grid. Census counts (at sub-national level) were apportioned to each grid cell based on likelihood coefficients, which are based on proximity to roads, slope, land cover, nighttime lights, and other data sets. LandScan 2001 has been developed as part of Oak Ridge National Laboratory (ORNL) Global Population Project for estimating ambient population risk.

  19. LandScan 2008 High Resolution Global Population Data Set

    SciTech Connect

    2009-01-01

    The LandScan data set is a worldwide population database compiled on a 30" x 30" latitude/longitude grid. Census counts (at sub-national level) were apportioned to each grid cell based on likelihood coefficients, which are based on proximity to roads, slope, land cover, nighttime lights, and other data sets. LandScan 2001 has been developed as part of Oak Ridge National Laboratory (ORNL) Global Population Project for estimating ambient population risk.

  20. Direct microCT imaging of non-mineralized connective tissues at high resolution.

    PubMed

    Naveh, Gili R S; Brumfeld, Vlad; Dean, Mason; Shahar, Ron; Weiner, Steve

    2014-01-01

    The 3D imaging of soft tissues in their native state is challenging, especially when high resolution is required. An X-ray-based microCT is, to date, the best choice for high resolution 3D imaging of soft tissues. However, since X-ray attenuation of soft tissues is very low, contrasting enhancement using different staining materials is needed. The staining procedure, which also usually involves tissue fixation, causes unwanted and to some extent unknown tissue alterations. Here, we demonstrate that a method that enables 3D imaging of soft tissues without fixing and staining using an X-ray-based bench-top microCT can be applied to a variety of different tissues. With the sample mounted in a custom-made loading device inside a humidity chamber, we obtained soft tissue contrast and generated 3D images of fresh, soft tissues with a resolution of 1 micron voxel size. We identified three critical conditions which make it possible to image soft tissues: humidified environment, mechanical stabilization of the sample and phase enhancement. We demonstrate the capability of the technique using different specimens: an intervertebral disc, the non-mineralized growth plate, stingray tessellated radials (calcified cartilage) and the collagenous network of the periodontal ligament. Since the scanned specimen is fresh an interesting advantage of this technique is the ability to scan a specimen under load and track the changes of the different structures. This method offers a unique opportunity for obtaining valuable insights into 3D structure-function relationships of soft tissues.

  1. High-resolution three-dimensional visualization of the rat spinal cord microvasculature by synchrotron radiation micro-CT

    SciTech Connect

    Hu, Jianzhong; Cao, Yong; Wu, Tianding; Li, Dongzhe; Lu, Hongbin

    2014-10-15

    Purpose: Understanding the three-dimensional (3D) morphology of the spinal cord microvasculature has been limited by the lack of an effective high-resolution imaging technique. In this study, synchrotron radiation microcomputed tomography (SRµCT), a novel imaging technique based on absorption imaging, was evaluated with regard to the detection of the 3D morphology of the rat spinal cord microvasculature. Methods: Ten Sprague-Dawley rats were used in this ex vivo study. After contrast agent perfusion, their spinal cords were isolated and scanned using conventional x-rays, conventional micro-CT (CµCT), and SRµCT. Results: Based on contrast agent perfusion, the microvasculature of the rat spinal cord was clearly visualized for the first time ex vivo in 3D by means of SRµCT scanning. Compared to conventional imaging techniques, SRµCT achieved higher resolution 3D vascular imaging, with the smallest vessel that could be distinguished approximately 7.4 μm in diameter. Additionally, a 3D pseudocolored image of the spinal cord microvasculature was generated in a single session of SRµCT imaging, which was conducive to detailed observation of the vessel morphology. Conclusions: The results of this study indicated that SRµCT scanning could provide higher resolution images of the vascular network of the spinal cord. This modality also has the potential to serve as a powerful imaging tool for the investigation of morphology changes in the 3D angioarchitecture of the neurovasculature in preclinical research.

  2. High resolution, high bandwidth global shutter CMOS area scan sensors

    NASA Astrophysics Data System (ADS)

    Faramarzpour, Naser; Sonder, Matthias; Li, Binqiao

    2013-10-01

    Global shuttering, sometimes also known as electronic shuttering, enables the use of CMOS sensors in a vast range of applications. Teledyne DALSA Global shutter sensors are able to integrate light synchronously across millions of pixels with microsecond accuracy. Teledyne DALSA offers 5 transistor global shutter pixels in variety of resolutions, pitches and noise and full-well combinations. One of the recent generations of these pixels is implemented in 12 mega pixel area scan device at 6 um pitch and that images up to 70 frames per second with 58 dB dynamic range. These square pixels include microlens and optional color filters. These sensors also offer exposure control, anti-blooming and high dynamic range operation by introduction of a drain and a PPD reset gate to the pixel. The state of the art sense node design of Teledyne DALSA's 5T pixel offers exceptional shutter rejection ratio. The architecture is consistent with the requirements to use stitching to achieve very large area scan devices. Parallel or serial digital output is provided on these sensors using on-chip, column-wise analog to digital converters. Flexible ADC bit depth combined with windowing (adjustable region of interest, ROI) allows these sensors to run with variety of resolution/bandwidth combinations. The low power, state of the art LVDS I/O technology allows for overall power consumptions of less than 2W at full performance conditions.

  3. Body CT (CAT Scan)

    MedlinePlus

    ... may increase the risk of an unusual adverse effect. Women should always inform their physician and the CT ... of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor. CT ...

  4. User Friendly Processing of Sediment CT Data: Software and Application in High Resolution Non-Destructive Sediment Core Data Sets

    NASA Astrophysics Data System (ADS)

    Reilly, B. T.; Stoner, J. S.; Wiest, J.; Abbott, M. B.; Francus, P.; Lapointe, F.

    2015-12-01

    Computed Tomography (CT) of sediment cores allow for high resolution images, three dimensional volumes, and down core profiles, generated through the attenuation of X-rays as a function of density and atomic number. When using a medical CT-Scanner, these quantitative data are stored in pixels using the Hounsfield scale, which are relative to the attenuation of X-rays in water and air at standard temperature and pressure. Here we present MATLAB based software specifically designed for sedimentary applications with a user friendly graphical interface to process DICOM files and stitch overlapping CT scans. For visualization, the software allows easy generation of core slice images with grayscale and false color relative to a user defined Hounsfield number range. For comparison to other high resolution non-destructive methods, down core Hounsfield number profiles are extracted using a method robust to coring imperfections, like deformation, bowing, gaps, and gas expansion. We demonstrate the usefulness of this technique with lacustrine sediment cores from the Western United States and Canadian High Arctic, including Fish Lake, Oregon, and Sawtooth Lake, Ellesmere Island. These sites represent two different depositional environments and provide examples for a variety of common coring defects and lithologies. The Hounsfield profiles and images can be used in combination with other high resolution data sets, including sediment magnetic parameters, XRF core scans and many other types of data, to provide unique insights into how lithology influences paleoenvironmental and paleomagnetic records and their interpretations.

  5. High-resolution in-vivo micro-CT scanner for small animals

    NASA Astrophysics Data System (ADS)

    Sasov, Alexander

    2001-06-01

    Small laboratory animals (mice and rats) are widely used in development of drags and treatments. To recognize the internal changes in the very early stage inside the animal body, Skyscan starts development on high-resolution micro-CT scanner for in-vivo 3D-imaging. Initial changes in the bone structure can be found as features in the size range of 10 microns. By this reason a voxel size for reconstructed cross sections has been chosen as < 10 microns. Because of full animal may be up to 8 cm in diameter the reconstructed cross section format selected as 8000 X 8000-pixels (float- point). A 2D detection system with new multi-beam geometry produce dataset for reconstruction of hundreds cross- sections after one scan. Object illuminated by microfocus sealed X-ray source with 5 microns spot size. Continuously variable energy in the range of 20 - 100 kV and energy filters allows estimate material composition like in DEXA systems. Direct streaming of the projection data to the disk reduce irradiation dose to the animal under scanning. Software package can create realistic 3D-images from the set of reconstructed cross sections and calculate internal morphological parameters.

  6. High-resolution in-vivo micro-CT scanner for small animals

    NASA Astrophysics Data System (ADS)

    Sasov, Alexander; Dewaele, Daniel

    2002-01-01

    Small laboratory animals (mice and rats) are widely used in development of drugs and treatments. To recognize the internal changes in the very early stage inside the body of alive animal, high-resolution micro-CT scanner has been developed. Initial changes in the bone structure can be found as features in the size range of 10 microns. By this reason a voxel size for reconstructed cross sections has been chosen as small as 10 microns. Full animal body may be up to 80 mm in diameter and up to 200 mm in length. By this reason the reconstructed cross section format selected as 8000 x 8000 pixels (float-point). A new 2D detection system with multibeam geometry produces dataset for reconstruction of hundreds of cross sections after one scan. Object illuminated by microfocus sealed x-ray source with 5 microns spot size. Continuously variable energy in the range of 20- 100 kV and energy filters allows estimate material composition like in DEXA systems. Direct streaming of the projection data to the disk reduce irradiation dose to the animal under scanning. Software package can create realistic 3D images from the set of reconstructed cross sections and calculate internal morphological parameters.

  7. Knee CT scan

    MedlinePlus

    CAT scan - knee; Computed axial tomography scan - knee; Computed tomography scan - knee ... scanners can perform the exam without stopping.) A computer makes several images of the body area. These ...

  8. High resolution 3D dosimetry for microbeam radiation therapy using optical CT

    NASA Astrophysics Data System (ADS)

    McErlean, C.; Bräuer-Krisch, E.; Adamovics, J.; Leach, M. O.; Doran, S. J.

    2015-01-01

    Optical Computed Tomography (CT) is a promising technique for dosimetry of Microbeam Radiation Therapy (MRT), providing high resolution 3D dose maps. Here different MRT irradiation geometries are visualised showing the potential of Optical CT as a tool for future MRT trials. The Peak-to-Valley dose ratio (PVDR) is calculated to be 7 at a depth of 3mm in the radiochromic dosimeter PRESAGE®. This is significantly lower than predicted values and possible reasons for this are discussed.

  9. Imaging of pore networks and related interfaces in soil systems by using high resolution X-ray micro-CT

    NASA Astrophysics Data System (ADS)

    Zacher, Gerhard; Eickhorst, Thilo; Schmidt, Hannes; Halisch, Matthias

    2016-04-01

    Today's high-resolution X-ray CT with its powerful tubes and great detail detectability lends itself naturally to geological and pedological applications. Those include the non-destructive interior examination and textural analysis of rock and soil samples and their permeability and porosity - to name only a few. Especially spatial distribution and geometry of pores, mineral phases and fractures are important for the evaluation of hydrologic and aeration properties in soils as well as for root development in the soil matrix. The possibility to visualize a whole soil aggregate or root tissue in a non-destructive way is undoubtedly the most valuable feature of this type of analysis and is a new area for routine application of high resolution X-ray micro-CT. The paper outlines recent developments in hard- and software requirements for high resolution CT. It highlights several pedological applications which were performed with the phoenix nanotom m, the first 180 kV nanofocus CT system tailored specifically for extremely high-resolution scans of variable sized samples with voxel-resolutions down to < 300 nm. In addition very good contrast resolution can be obtained as well which is necessary to distinguish biogenic material in soil aggregates amongst others. We will address visualization and quantification of porous networks in 3D in different environmental samples ranging from clastic sedimentary rock to soil cores and individual soil aggregates. As several processes and habitat functions are related to various pore sizes imaging of the intact soil matrix will be presented on different scales of interest - from the mm-scale representing the connectivity of macro-pores down to the micro-scale representing the space of microbial habitats. Therefore, soils were impregnated with resin and scanned via X-ray CT. Scans at higher resolution were obtained from sub-volumes cut from the entire resin impregnated block and from crop roots surrounded by rhizosphere soil. Within the

  10. Body CT (CAT Scan)

    MedlinePlus

    ... lives. CT has been shown to be a cost-effective imaging tool for a wide range of ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  11. Liver echinococcus - CT scan (image)

    MedlinePlus

    This upper abdominal CT scan shows multiple cysts in the liver, caused by dog tapeworm (echinococcus). Note the large circular cyst (seen on the left side of the screen) and multiple smaller cysts throughout ...

  12. A complete CAD system for pulmonary nodule detection in high resolution CT images

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangwei; McLennan, Geoffrey; Hoffman, Eric A.; Sonka, Milan

    2005-04-01

    The purpose of this study is to develop a computer-aided diagnosis (CAD) system to detect small-sized (from 2mm to 10mm) pulmonary nodules in high resolution helical CT scans. A new CAD system is proposed to locate both juxtapleural nodules and non-pleural nodules. Isotropic resampling and lung segmentation are performed as preprocessing steps. Morphological closing was utilized to smooth the lung contours to include the indented possible juxtapleural locations, thresholding and 3D component analysis were used to obtain 3D volumetric nodule candidates; furthermore, gray level and geometric features were extracted, and analyzed using linear discriminant analysis (LDA) classifier. Leave one case out method was used to evaluate the LDA. To deal with non-pleural nodules, a discrete-time cellular neural network (DTCNN) based on local shape features was developed. This scheme employed the local shape property to perform voxel classification. The shape index feature successfully captured the local shape difference between nodules and non-nodules, especially vessels. To tailor it for lung nodule detection, this DTCNN was trained using genetic algorithms (GAs) to derive the shape index variation pattern of nodules. Nonoverlapping training and testing sets were utilized in the non-pleural nodule detection. 19 clinical thoracic CT cases involving a total of 4838 sectional images were used in this work. The juxtapleural nodule detection method was able to obtain sensitivity 81.25% with an average of 8.29 FPs per case. The non-pleural nodule finding scheme attained sensitivity of 83.9% with an average 3.47 FPs/case. Combining the two subsystems together, an overall performance of 82.98% sensitivity with 11.76 FPs/case can be obtained.

  13. Near-real-time mosaics from high-resolution side-scan sonar

    USGS Publications Warehouse

    Danforth, William W.; O'Brien, Thomas F.; Schwab, W.C.

    1991-01-01

    High-resolution side-scan sonar has proven to be a very effective tool for stuyding and understanding the surficial geology of the seafloor. Since the mid-1970s, the US Geological Survey has used high-resolution side-scan sonar systems for mapping various areas of the continental shelf. However, two problems typically encountered included the short range and the high sampling rate of high-resolution side-scan sonar systems and the acquisition and real-time processing of the enormous volume of sonar data generated by high-resolution suystems. These problems were addressed and overcome in August 1989 when the USGS conducted a side-scan sonar and bottom sampling survey of a 1000-sq-km section of the continental shelf in the Gulf of Farallones located offshore of San Francisco. The primary goal of this survey was to map an area of critical interest for studying continental shelf sediment dynamics. This survey provided an opportunity to test an image processing scheme that enabled production of a side-scan sonar hard-copy mosaic during the cruise in near real-time.

  14. High resolution multidetector CT aided tissue analysis and quantification of lung fibrosis

    NASA Astrophysics Data System (ADS)

    Zavaletta, Vanessa A.; Karwoski, Ronald A.; Bartholmai, Brian; Robb, Richard A.

    2006-03-01

    Idiopathic pulmonary fibrosis (IPF, also known as Idiopathic Usual Interstitial Pneumontis, pathologically) is a progressive diffuse lung disease which has a median survival rate of less than four years with a prevalence of 15-20/100,000 in the United States. Global function changes are measured by pulmonary function tests and the diagnosis and extent of pulmonary structural changes are typically assessed by acquiring two-dimensional high resolution CT (HRCT) images. The acquisition and analysis of volumetric high resolution Multi-Detector CT (MDCT) images with nearly isotropic pixels offers the potential to measure both lung function and structure. This paper presents a new approach to three dimensional lung image analysis and classification of normal and abnormal structures in lungs with IPF.

  15. Gas scintillation glass GEM detector for high-resolution X-ray imaging and CT

    NASA Astrophysics Data System (ADS)

    Fujiwara, T.; Mitsuya, Y.; Fushie, T.; Murata, K.; Kawamura, A.; Koishikawa, A.; Toyokawa, H.; Takahashi, H.

    2017-04-01

    A high-spatial-resolution X-ray-imaging gaseous detector has been developed with a single high-gas-gain glass gas electron multiplier (G-GEM), scintillation gas, and optical camera. High-resolution X-ray imaging of soft elements is performed with a spatial resolution of 281 μm rms and an effective area of 100×100 mm. In addition, high-resolution X-ray 3D computed tomography (CT) is successfully demonstrated with the gaseous detector. It shows high sensitivity to low-energy X-rays, which results in high-contrast radiographs of objects containing elements with low atomic numbers. In addition, the high yield of scintillation light enables fast X-ray imaging, which is an advantage for constructing CT images with low-energy X-rays.

  16. LandScan 2012 High Resolution Global Population DataSet

    SciTech Connect

    2013-09-17

    The LandScan data set is a worldwide population database compiled on a 30"x20" latitude/longitude grid. Census counts at sub-national level were apportioned to each grid cell based on likelihood coefficients, which are based on land cover, slope, road proximity, high-resolution imagery, and other data sets.

  17. Inhalational pulmonary talcosis: high-resolution CT findings in 3 patients.

    PubMed

    Marchiori, Edson; Souza Júnior, Arthur Soares; Müller, Nestor L

    2004-01-01

    We describe the high-resolution CT findings in 3 patients with pulmonary talcosis acquired by the inhalation of talc. The predominant abnormalities consisted of small centrilobular and subpleural nodules and conglomerated masses containing focal areas of high attenuation consistent with talc deposition. All patients also had focal ground glass opacities. The abnormalities were diffuse but were most severe in the upper and middle lung zones with relative sparing of the lung bases.

  18. LandScan 2014 High-Resolution Global Population Data Set

    SciTech Connect

    2015-01-01

    The LandScan data set is a worldwide population database compiled on a 30" X 30" latitude/longitude grid. Census counts (at sub-national level) were apportioned to each grid cell based on likelihood coefficients, which are based on land cover, slope, road proximity, high-resolution imagery, and other data sets. The LandScan data set was developed as part of Oak Ridge National Laboratory (ORNL) Global Population Project for estimating ambient populations at risk.

  19. LandScan 2015 High-Resolution Global Population Data Set

    SciTech Connect

    Bright, Edward A.; Rose, Amy N.; Urban, Marie L.

    2016-01-01

    The LandScan data set is a worldwide population database compiled on a 30" x 30" latitude/longitube grid. Census counts (at sub-national level) were apportioned to each grid cell based on likelihood coefficients, which are based on land cover, slope, road proximity, high-resolution imagery, and other data sets. The LandScan data set was developed as part of Oak Ridge National Laboratory (ORNL) Global Population Project for estimating ambient populations at risk.

  20. High-resolution melting analysis using unlabeled probe and amplicon scanning simultaneously detects several lactase persistence variants.

    PubMed

    Janukonyté, Jurgita; Vestergaard, Else M; Ladefoged, Søren A; Nissen, Peter H

    2010-12-01

    Lactase persistence and thereby tolerance to lactose is a common trait in people of Northern European descent. It is linked to the LCT -13910C>T variant located in intron 13 of the MCM6 gene 13.9 kb upstream of the lactase (LCT) gene. In people of African and Middle Eastern descent, lactase persistence can be associated with other variants nearby the -13910C>T variant, limiting the use of the -13910C>T-based SNP analysis, e.g. TaqMan assays for the diagnosis of lactose intolerance. Using high-resolution melting analysis, we identified five samples that were heterozygous for the -13915T>G variant among 78 patients genotyped as -13910C/C by a TaqMan assay. All samples originated from patients of probable Middle Eastern descent. In order to detect the -13910 and -13915 variants simultaneously, we developed a new high-resolution melting (HRM) analysis assay based on unlabeled probe genotyping and simultaneous amplicon scanning analysis. By using this assay we were able to distinguish the -13910 and -13915 genotypes clearly. Furthermore, we identified two rare variants, the -13907C>G and -13913T>C. With this method, based on an inexpensive unlabeled probe, it is possible to simultaneously detect the -13910C>T and -13915T>G variants in addition to rarer variants surrounding the -13910 site. This new method may contribute to improve the diagnostic performance of the genetic analysis for lactose intolerance.

  1. Image-based motion compensation for high-resolution extremities cone-beam CT

    NASA Astrophysics Data System (ADS)

    Sisniega, A.; Stayman, J. W.; Cao, Q.; Yorkston, J.; Siewerdsen, J. H.; Zbijewski, W.

    2016-03-01

    Purpose: Cone-beam CT (CBCT) of the extremities provides high spatial resolution, but its quantitative accuracy may be challenged by involuntary sub-mm patient motion that cannot be eliminated with simple means of external immobilization. We investigate a two-step iterative motion compensation based on a multi-component metric of image sharpness. Methods: Motion is considered with respect to locally rigid motion within a particular region of interest, and the method supports application to multiple locally rigid regions. Motion is estimated by maximizing a cost function with three components: a gradient metric encouraging image sharpness, an entropy term that favors high contrast and penalizes streaks, and a penalty term encouraging smooth motion. Motion compensation involved initial coarse estimation of gross motion followed by estimation of fine-scale displacements using high resolution reconstructions. The method was evaluated in simulations with synthetic motion (1-4 mm) applied to a wrist volume obtained on a CMOS-based CBCT testbench. Structural similarity index (SSIM) quantified the agreement between motion-compensated and static data. The algorithm was also tested on a motion contaminated patient scan from dedicated extremities CBCT. Results: Excellent correction was achieved for the investigated range of displacements, indicated by good visual agreement with the static data. 10-15% improvement in SSIM was attained for 2-4 mm motions. The compensation was robust against increasing motion (4% decrease in SSIM across the investigated range, compared to 14% with no compensation). Consistent performance was achieved across a range of noise levels. Significant mitigation of artifacts was shown in patient data. Conclusion: The results indicate feasibility of image-based motion correction in extremities CBCT without the need for a priori motion models, external trackers, or fiducials.

  2. Image-Based Motion Compensation for High-Resolution Extremities Cone-Beam CT

    PubMed Central

    Sisniega, A.; Stayman, J. W.; Cao, Q.; Yorkston, J.; Siewerdsen, J. H.; Zbijewski, W.

    2016-01-01

    Purpose Cone-beam CT (CBCT) of the extremities provides high spatial resolution, but its quantitative accuracy may be challenged by involuntary sub-mm patient motion that cannot be eliminated with simple means of external immobilization. We investigate a two-step iterative motion compensation based on a multi-component metric of image sharpness. Methods Motion is considered with respect to locally rigid motion within a particular region of interest, and the method supports application to multiple locally rigid regions. Motion is estimated by maximizing a cost function with three components: a gradient metric encouraging image sharpness, an entropy term that favors high contrast and penalizes streaks, and a penalty term encouraging smooth motion. Motion compensation involved initial coarse estimation of gross motion followed by estimation of fine-scale displacements using high resolution reconstructions. The method was evaluated in simulations with synthetic motion (1–4 mm) applied to a wrist volume obtained on a CMOS-based CBCT testbench. Structural similarity index (SSIM) quantified the agreement between motion-compensated and static data. The algorithm was also tested on a motion contaminated patient scan from dedicated extremities CBCT. Results Excellent correction was achieved for the investigated range of displacements, indicated by good visual agreement with the static data. 10–15% improvement in SSIM was attained for 2–4 mm motions. The compensation was robust against increasing motion (4% decrease in SSIM across the investigated range, compared to 14% with no compensation). Consistent performance was achieved across a range of noise levels. Significant mitigation of artifacts was shown in patient data. Conclusion The results indicate feasibility of image-based motion correction in extremities CBCT without the need for a priori motion models, external trackers, or fiducials. PMID:27346909

  3. High-Resolution Imaging of Dendrimers Used in Drug Delivery via Scanning Probe Microscopy.

    PubMed

    Shi, Lifang; Fleming, Christopher J; Riechers, Shawn L; Yin, Nai-Ning; Luo, Juntao; Lam, Kit S; Liu, Gang-Yu

    2011-01-01

    Dendrimers and telodendrimer micelles represent two new classes of vehicles for drug delivery that have attracted much attention recently. Their structural characterization at the molecular and submolecular level remains a challenge due to the difficulties in reaching high resolution when imaging small particles in their native media. This investigation offers a new approach towards this challenge, using scanning tunneling microscopy (STM) and atomic force microscopy (AFM). By using new sample preparation protocols, this work demonstrates that (a) intramolecular features such as drug molecules and dendrimer termini can be resolved; and (b) telodendrimer micelles can be immobilized on the surface without compromising structural integrity, and as such, high resolution AFM imaging may be performed to attain 3D information. This high-resolution structural information should enhance our knowledge of the nanocarrier structure and nanocarrier-drug interaction and, therefore, facilitate design and optimization of the efficiency in drug delivery.

  4. Ultra-high-resolution dual-source CT for forensic dental visualization-discrimination of ceramic and composite fillings.

    PubMed

    Jackowski, C; Wyss, M; Persson, A; Classens, M; Thali, M J; Lussi, A

    2008-07-01

    Dental identification is the most valuable method to identify human remains in single cases with major postmortem alterations as well as in mass casualties because of its practicability and demanding reliability. Computed tomography (CT) has been investigated as a supportive tool for forensic identification and has proven to be valuable. It can also scan the dentition of a deceased within minutes. In the present study, we investigated currently used restorative materials using ultra-high-resolution dual-source CT and the extended CT scale for the purpose of a color-encoded, in scale, and artifact-free visualization in 3D volume rendering. In 122 human molars, 220 cavities with 2-, 3-, 4- and 5-mm diameter were prepared. With presently used filling materials (different composites, temporary filling materials, ceramic, and liner), these cavities were restored in six teeth for each material and cavity size (exception amalgam n = 1). The teeth were CT scanned and images reconstructed using an extended CT scale. Filling materials were analyzed in terms of resulting Hounsfield units (HU) and filling size representation within the images. Varying restorative materials showed distinctively differing radiopacities allowing for CT-data-based discrimination. Particularly, ceramic and composite fillings could be differentiated. The HU values were used to generate an updated volume-rendering preset for postmortem extended CT scale data of the dentition to easily visualize the position of restorations, the shape (in scale), and the material used which is color encoded in 3D. The results provide the scientific background for the application of 3D volume rendering to visualize the human dentition for forensic identification purposes.

  5. Fabrication of [001]-oriented tungsten tips for high resolution scanning tunneling microscopy.

    PubMed

    Chaika, A N; Orlova, N N; Semenov, V N; Postnova, E Yu; Krasnikov, S A; Lazarev, M G; Chekmazov, S V; Aristov, V Yu; Glebovsky, V G; Bozhko, S I; Shvets, I V

    2014-01-17

    The structure of the [001]-oriented single crystalline tungsten probes sharpened in ultra-high vacuum using electron beam heating and ion sputtering has been studied using scanning and transmission electron microscopy. The electron microscopy data prove reproducible fabrication of the single-apex tips with nanoscale pyramids grained by the {011} planes at the apexes. These sharp, [001]-oriented tungsten tips have been successfully utilized in high resolution scanning tunneling microscopy imaging of HOPG(0001), SiC(001) and graphene/SiC(001) surfaces. The electron microscopy characterization performed before and after the high resolution STM experiments provides direct correlation between the tip structure and picoscale spatial resolution achieved in the experiments.

  6. Development of high-resolution x-ray CT system using parallel beam geometry

    NASA Astrophysics Data System (ADS)

    Yoneyama, Akio; Baba, Rika; Hyodo, Kazuyuki; Takeda, Tohoru; Nakano, Haruhisa; Maki, Koutaro; Sumitani, Kazushi; Hirai, Yasuharu

    2016-01-01

    For fine three-dimensional observations of large biomedical and organic material samples, we developed a high-resolution X-ray CT system. The system consists of a sample positioner, a 5-μm scintillator, microscopy lenses, and a water-cooled sCMOS detector. Parallel beam geometry was adopted to attain a field of view of a few mm square. A fine three-dimensional image of birch branch was obtained using a 9-keV X-ray at BL16XU of SPring-8 in Japan. The spatial resolution estimated from the line profile of a sectional image was about 3 μm.

  7. Development of high-resolution x-ray CT system using parallel beam geometry

    SciTech Connect

    Yoneyama, Akio Baba, Rika; Hyodo, Kazuyuki; Takeda, Tohoru; Nakano, Haruhisa; Maki, Koutaro; Sumitani, Kazushi; Hirai, Yasuharu

    2016-01-28

    For fine three-dimensional observations of large biomedical and organic material samples, we developed a high-resolution X-ray CT system. The system consists of a sample positioner, a 5-μm scintillator, microscopy lenses, and a water-cooled sCMOS detector. Parallel beam geometry was adopted to attain a field of view of a few mm square. A fine three-dimensional image of birch branch was obtained using a 9-keV X-ray at BL16XU of SPring-8 in Japan. The spatial resolution estimated from the line profile of a sectional image was about 3 μm.

  8. Varied-space grazing incidence gratings in high resolution scanning spectrometers

    SciTech Connect

    Hettrick, M.C.; Underwood, J.H.

    1986-10-01

    We discuss the dominant geometrical aberrations of a grazing incidence reflection grating and new techniques which can be used to reduce or eliminate them. Convergent beam geometries and the aberration correction possible with varied groove spacings are each found to improve the spectral resolution and speed of grazing incidence gratings. In combination, these two techniques can result in a high resolution (lambda/..delta..lambda > 10/sup 4/) monochromator or scanning spectrometer with a simple rotational motion for scanning wavelength or selecting the spectral band. 21 refs., 4 figs.

  9. A high-resolution imaging technique using a whole-body, research photon counting detector CT system

    NASA Astrophysics Data System (ADS)

    Leng, S.; Yu, Z.; Halaweish, A.; Kappler, S.; Hahn, K.; Henning, A.; Li, Z.; Lane, J.; Levin, D. L.; Jorgensen, S.; Ritman, E.; McCollough, C.

    2016-03-01

    A high-resolution (HR) data collection mode has been introduced to a whole-body, research photon-counting-detector CT system installed in our laboratory. In this mode, 64 rows of 0.45 mm x 0.45 mm detector pixels were used, which corresponded to a pixel size of 0.25 mm x 0.25 mm at the iso-center. Spatial resolution of this HR mode was quantified by measuring the MTF from a scan of a 50 micron wire phantom. An anthropomorphic lung phantom, cadaveric swine lung, temporal bone and heart specimens were scanned using the HR mode, and image quality was subjectively assessed by two experienced radiologists. High spatial resolution of the HR mode was evidenced by the MTF measurement, with 15 lp/cm and 20 lp/cm at 10% and 2% modulation. Images from anthropomorphic phantom and cadaveric specimens showed clear delineation of small structures, such as lung vessels, lung nodules, temporal bone structures, and coronary arteries. Temporal bone images showed critical anatomy (i.e. stapes superstructure) that was clearly visible in the PCD system. These results demonstrated the potential application of this imaging mode in lung, temporal bone, and vascular imaging. Other clinical applications that require high spatial resolution, such as musculoskeletal imaging, may also benefit from this high resolution mode.

  10. Comparing XRF core scan data to conventional geochemical analyses for high resolution paleoenvironmental studies

    NASA Astrophysics Data System (ADS)

    Hennekam, Rick; De Lange, Gert J.

    2013-04-01

    X-ray fluorescence (XRF) core scanning is becoming an increasingly common method to rapidly obtain paleo-environmental data from untreated (marine) sediments. There is a large potential for this method, being cheap, rapid, and non-destructive. However, the sediment surface is not an ideal substrate for XRF-analysis, thus measurement artefacts may occur relating to water content, grain size, surface roughness, film formation, and sediment inhomogeneity. A high resolution analysis of an Eastern Mediterranean sediment core is used to compare such potential artefacts and signal-to-noise ratio of XRF core scan measurements to those of traditional analyses using XRF glass bead and ICP-AES on distinct samples. A suit of major elements (and elemental ratios), often used as paleo-proxies, have been examined in this way so as to compare the robustness of the more 'relative' XRF-scan method compared to these more 'absolute' measurements. XRF core scan data only reflect the chemical composition of a thin (5-500 µm) layer of the sediment surface. Any inhomogeneity in this surface can cause large deviations thus may result in large 'deduced' paleo-environmental variability. It is shown that (random) water-rich spots can form underneath the Ultralene covering foil, having a substantial effect on the lighter elements with shallow response depths. This can create non-existing peaks in the XRF core scan -produced paleo-environmental record. Such deviations especially occur for elemental ratios when various elements are measured in different runs (e.g. other tube-voltage settings). This study urges to verify high/low amplitudinal variability observed in XRF corescans by means of (destructive) conventional geochemical analyses prior to their interpretation.. Reference: Hennekam R. and G. de Lange. X-ray fluorescence core scanning of wet marine sediments: methods to improve quality and reproducibility of high-resolution paleoenvironmental records. Limnology and Oceanography: Methods

  11. Improved image quality and diagnostic potential using ultra-high-resolution computed tomography of the lung with small scan FOV: A prospective study

    PubMed Central

    Wang, Yali; Hamal, Preeti; You, Xiaofang; Mao, Haixia; Li, Fei; Sun, Xiwen

    2017-01-01

    The aim of this study was to assess whether CT imaging using an ultra-high-resolution CT (UHRCT) scan with a small scan field of view (FOV) provides higher image quality and helps to reduce the follow-up period compared with a conventional high-resolution CT (CHRCT) scan. We identified patients with at least one pulmonary nodule at our hospital from July 2015 to November 2015. CHRCT and UHRCT scans were conducted in all enrolled patients. Three experienced radiologists evaluated the image quality using a 5-point score and made diagnoses. The paired images were displayed side by side in a random manner and annotations of scan information were removed. The following parameters including image quality, diagnostic confidence of radiologists, follow-up recommendations and diagnostic accuracy were assessed. A total of 52 patients (62 nodules) were included in this study. UHRCT scan provides a better image quality regarding the margin of nodules and solid internal component compared to that of CHRCT (P < 0.05). Readers have higher diagnostic confidence based on the UHRCT images than of CHRCT images (P<0.05). The follow-up recommendations were significantly different between UHRCT and CHRCT images (P<0.05). Compared with the surgical pathological findings, UHRCT had a relative higher diagnostic accuracy than CHRCT (P > 0.05). These findings suggest that the UHRCT prototype scanner provides a better image quality of subsolid nodules compared to CHRCT and contributes significantly to reduce the patients' follow-up period. PMID:28231320

  12. Fractal analysis of high-resolution CT images as a tool for quantification of lung diseases

    SciTech Connect

    Uppaluri, R.; Mitsa, T.; Galvin, J.R.

    1995-12-31

    Fractal geometry is increasingly being used to model complex naturally occurring phenomena. There are two types of fractals in nature-geometric fractals and stochastic fractals. The pulmonary branching structure is a geometric fractal and the intensity of its grey scale image is a stochastic fractal. In this paper, the authors attempt to quantify the texture of CT lung images using properties of both types of fractals. A simple algorithm for detecting of abnormality in human lungs, based on 2-D and 3-D fractal dimensions, is presented. This method involves calculating the local fractal dimensions, based on intensities, in the 2-D slice to air edge enhancement. Following this, grey level thresholding is performed and a global fractal dimension, based on structure, for the entire data is estimated in 2-D and 3-D. High Resolution CT images of normal and abnormal lungs were analyzed. Preliminary results showed that classification of normal and abnormal images could be obtained based on the differences between their global fractal dimensions.

  13. CT Scans - Multiple Languages: MedlinePlus

    MedlinePlus

    ... الأشعة المقطعية الحاسوبية - العربية Bilingual PDF Health Information Translations Chinese - Simplified (简体中文) CT (Computerized Tomography) Scan CT ( ... 扫描 - 简体中文 (Chinese - Simplified) Bilingual PDF Health Information Translations Chinese - Traditional (繁體中文) CT (Computerized Tomography) Scan CT ( ...

  14. DMSO increases mutation-scanning detection sensitivity in clinical samples using high resolution melting

    PubMed Central

    Song, Chen; Castellanos-Rizaldos, Elena; Bejar, Rafael; Ebert, Benjamin L.; Makrigiorgos, G. Mike

    2016-01-01

    BACKGROUND Mutation scanning provides the simplest, lowest cost method for identifying DNA variations on single PCR amplicons, and it may be performed prior to sequencing to avoid screening of non-informative wild type samples. High resolution melting (HRM) is the most commonly used method for mutation scanning. However, by using PCR-HRM mutations below ≈ 3–10% that can still be clinically significant may often be missed. Therefore, enhancing HRM detection sensitivity is important for mutation scanning and its clinical application. METHODS We used serial dilution of TP53 exon 8 mutation containing cell lines to demonstrate the improvement in detection sensitivity for conventional-PCR-HRM in the presence of DMSO. We also conducted full-COLD-PCR to further enrich low-level mutations prior to HRM±DMSO and employed droplet-digital PCR to derive the optimal conditions for mutation enrichment. Both conventional-PCR-HRM and full-COLD-PCR-HRM ±DMSO were used for mutation scanning in TP53 exon 8 in cancer samples containing known mutations and in myelodysplastic syndrome samples with unknown mutations. Mutations in other genes were also examined. RESULTS The detection sensitivity of PCR-HRM-scanning increases 2–5-fold in the presence of DMSO, depending also on mutation type and sequence context, and can typically detect mutation abundance of about 1%. When mutation enrichment is applied during amplification using full-COLD-PCR and followed by HRM in the presence of DMSO, mutations with 0.2–0.3% mutation abundance in TP53 exon 8 can be detected. CONCLUSIONS DMSO improves HRM mutation scanning sensitivity. When full-COLD-PCR is employed, followed by DMSO-HRM, the overall improvement is about 20-fold as compared to conventional PCR-HRM. PMID:26432802

  15. High resolution images of single C 60 molecules on gold (111) using scanning tunneling microscopy

    NASA Astrophysics Data System (ADS)

    Howells, Sam; Chen, Ting; Gallagher, Mark; Sarid, Dror; Lichtenberger, Dennis L.; Wright, Laura L.; Ray, Charles D.; Huffman, Donald R.; Lamb, Lowell D.

    1992-07-01

    The electronic interactions of fullerene molecules with metals, with other molecules, and with themselves are important to the chemical and conductive properties of these materials. We demonstrate high resolution scanning tunneling microscopy images of C 60 molecules condensed on epitaxial gold (111) films on mica, in which the C 60 molecules are isolated from each other. The C 60 molecules were locked in position to the gold substrate by an ordered layer of methyl isobutyl ketone. The images of the C 60 molecules exhibit intramolecular contrast indicating a significant electronic interaction with the gold substrate. Current versus voltage measurements show that both the C 60 and the thin film of methyl isobutyl ketone have conductances comparable to that of the gold substrate.

  16. Novel method of simultaneous multiple immunogold localization on resin sections in high resolution scanning electron microscopy.

    PubMed

    Nebesarova, Jana; Wandrol, Petr; Vancova, Marie

    2016-01-01

    We present a new method of multiple immunolabeling that is suitable for a broad spectrum of biomedical applications. The general concept is to label both sides of the ultrathin section with the thickness of 70-80 nm with different antibodies conjugated to gold nanoparticles and to distinguish the labeled side by advanced imaging methods with high resolution scanning electron microscopy, such as by correlating images acquired at different energies of primary electrons using different signals. From the Clinical Editor: The use of transmission electron microscopy has become an indispensible tool in the detection of cellular proteins. In this short but interesting article, the authors described their new method of labeling and the identification of four different proteins simultaneously, which represents another advance in imaging technique.

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    Application of model-based iterative reconstruction (MBIR) to high resolution cone-beam CT (CBCT) is computationally challenging because of the very fine discretization (voxel size  <100 µm) of the reconstructed volume. Moreover, standard MBIR techniques require that the complete transaxial support for the acquired projections is reconstructed, thus precluding acceleration by restricting the reconstruction to a region-of-interest. To reduce the computational burden of high resolution MBIR, we propose a multiresolution penalized-weighted least squares (PWLS) algorithm, where the volume is parameterized as a union of fine and coarse voxel grids as well as selective binning of detector pixels. We introduce a penalty function designed to regularize across the boundaries between the two grids. The algorithm was evaluated in simulation studies emulating an extremity CBCT system and in a physical study on a test-bench. Artifacts arising from the mismatched discretization of the fine and coarse sub-volumes were investigated. The fine grid region was parameterized using 0.15 mm voxels and the voxel size in the coarse grid region was varied by changing a downsampling factor. No significant artifacts were found in either of the regions for downsampling factors of up to 4×. For a typical extremities CBCT volume size, this downsampling corresponds to an acceleration of the reconstruction that is more than five times faster than a brute force solution that applies fine voxel parameterization to the entire volume. For certain configurations of the coarse and fine grid regions, in particular when the boundary between the regions does not cross high attenuation gradients, downsampling factors as high as 10×  can be used without introducing artifacts, yielding a ~50×  speedup in PWLS. The proposed multiresolution algorithm significantly reduces the computational burden of high resolution iterative CBCT reconstruction and can be extended to other applications of

  18. High-resolution atmospheric water vapor measurements with a scanning differential absorption lidar

    NASA Astrophysics Data System (ADS)

    Späth, F.; Behrendt, A.; Muppa, S. K.; Metzendorf, S.; Riede, A.; Wulfmeyer, V.

    2014-11-01

    The scanning differential absorption lidar (DIAL) of the University of Hohenheim (UHOH) is presented. The UHOH DIAL is equipped with an injection-seeded frequency-stabilized high-power Ti:sapphire laser operated at 818 nm with a repetition rate of 250 Hz. A scanning transceiver unit with a 80 cm primary mirror receives the atmospheric backscatter signals. The system is capable of water vapor measurements with temporal resolutions of a few seconds and a range resolution between 30 and 300 m at daytime. It allows to investigate surface-vegetation-atmosphere exchange processes with high resolution. In this paper, we present the design of the instrument and illustrate its performance with recent water vapor measurements taken in Stuttgart-Hohenheim and in the frame of the HD(CP)2 Observational Prototype Experiment (HOPE). HOPE was located near research center Jülich, in western Germany, in spring 2013 as part of the project "High Definition of Clouds and Precipitation for advancing Climate Prediction" (HD(CP)2). Scanning measurements reveal the 3-dimensional structures of the water vapor field. The influence of uncertainties within the calculation of the absorption cross-section at wavelengths around 818 nm for the WV retrieval is discussed. Radiosonde intercomparisons show a very small bias between the instruments of only (-0.04 ± 0.11) g m-3 or (-1.0 ± 2.3) % in the height range of 0.5 to 3 km.

  19. A high-resolution scanning pencil-beam scatterometer: system design challenges

    NASA Astrophysics Data System (ADS)

    Chakraborty, Prantik; Gupta, Priyanka; Misra, Tapan

    2016-05-01

    The scanning pencil-beam Scatterometer configuration is pretty effective in covering a large ground-swath by rotating a moderately sized paraboloid dish at a moderate speed. For example, Oscat (Oceansat-II Scatterometer) did cover a ground-swath of 1550km using a 1m diameter reflector that was rotated at 20.5 rpm. The decade-long service (1999-2009) provided by the Seawinds instrument onboard the Quikscat mission followed by an almost half-a-decade (2009-2014) service of Oscat has made this configuration tremendously popular with the global user community. A major drawback of conventional pencil-beam systems like Seawinds and Oscat is the relatively poor spatial resolution. The ground-resolution is beamwidth-limited azimuthally while, in elevation, the resolution is improved by engaging pulse-compression and range-binning. Oscat's Instantaneous Field of View (IFOV) was 25km wide in azimuth (az) and 50km in elevation (el) at 49° incidence angle. The range-compressed resolution bins had dimensions of 6km (el) x 25km (az). Therefore, qualified wind products could be generated upon square grids no finer than 25km x 25km resolution. According to recommendations of International Ocean Vector Wind Science Team (IOVWST) and Oscat user community, high-resolution scatterometry is the requirement of the day with wind-vector cell-size dimension of 5km or better. One way to improve the resolution is to adopt the SAR principle of Range-Doppler discrimination in the scanning pencil-beam configuration. The footprint can be resolved simultaneously in range as well as in azimuth, thus significantly improving the size of the combined Range-Doppler resolution bin ( 1km). However, the addition of Doppler filtering to conically scanning radar brings with it its own disadvantages e.g. the limitations of dwell time and the constant change in orientation of isodop lines. This paper presents the constraints in system design of high-resolution scanning systems, the design trade-offs, the

  20. Target delineation for radiosurgery of a small brain arteriovenous malformation using high-resolution contrast-enhanced cone beam CT.

    PubMed

    van der Bom, Imramsjah M J; Gounis, Matthew J; Ding, Linda; Kühn, Anna Luisa; Goff, David; Puri, Ajit S; Wakhloo, Ajay K

    2014-06-01

    Three years following endovascular embolization of a 3 mm ruptured arteriovenous malformation (AVM) of the left superior colliculus in a 42-year-old man, digital subtraction angiography showed continuous regrowth of the lesion. Thin-slice MRI acquired for treatment planning did not show the AVM nidus. The patient was brought back to the angiography suite for high-resolution contrast-enhanced cone beam CT (VasoCT) acquired using an angiographic c-arm system. The lesion and nidus were visualized with VasoCT. MRI, CT and VasoCT data were transferred to radiation planning software and mutually co-registered. The nidus was annotated for radiation on VasoCT data by an experienced neurointerventional radiologist and a dose/treatment plan was completed. Due to image registration, the treatment area could be directly adopted into the MRI and CT data. The AVM was completely obliterated 10 months following completion of the radiosurgery treatment.

  1. Target delineation for radiosurgery of a small brain arteriovenous malformation using high-resolution contrast-enhanced cone beam CT.

    PubMed

    van der Bom, Imramsjah M J; Gounis, Matthew J; Ding, Linda; Kühn, Anna Luisa; Goff, David; Puri, Ajit S; Wakhloo, Ajay K

    2013-08-14

    Three years following endovascular embolization of a 3 mm ruptured arteriovenous malformation (AVM) of the left superior colliculus in a 42-year-old man, digital subtraction angiography showed continuous regrowth of the lesion. Thin-slice MRI acquired for treatment planning did not show the AVM nidus. The patient was brought back to the angiography suite for high-resolution contrast-enhanced cone beam CT (VasoCT) acquired using an angiographic c-arm system. The lesion and nidus were visualized with VasoCT. MRI, CT and VasoCT data were transferred to radiation planning software and mutually co-registered. The nidus was annotated for radiation on VasoCT data by an experienced neurointerventional radiologist and a dose/treatment plan was completed. Due to image registration, the treatment area could be directly adopted into the MRI and CT data. The AVM was completely obliterated 10 months following completion of the radiosurgery treatment.

  2. A CT-analogous method for high-resolution fluorescence molecular tomography

    NASA Astrophysics Data System (ADS)

    Li, Jiao; Gao, Feng; Zhu, Qingzhen; Li, Fenghui; Wang, Xin; Zhang, Limin; Zhao, Huijuan

    2012-03-01

    In vivo biomedical imaging using near-infrared light must overcome the effects of highly light scattering, which limit the spatial resolution and affect image quality. The high-resolution, sensitive and quantitative fluorescence imaging tool is an urgent need for the applications in small-animal imaging and clinical cancer research. A CT-analogous method for fluorescence molecular tomography (FMT) on small-animal-sized models is presented to improve the spatial resolution of FMT to a limit of several millimeters, depending on the size of the tissue region to be imaged. The method combines FMT physics with the filtered back-projection scheme for image reconstruction of the fan-beam computed tomography, based on the early-photon detection of time-resolved optical signals, and is suitable for two-dimensional (2D) imaging of small size biological models. By use of a normalized Born formulation for the inversion, the algorithm is validated using full time-resolved simulated data for 2D phantom that are generated from a hybrid finite-element and finite-time-difference photon diffusion modeling, and its superiority in the improvement of the spatial resolution is demonstrated by imaging different target-to-background contrast ratios.

  3. Automated volumetric segmentation method for growth consistency of nonsolid pulmonary nodules in high-resolution CT

    NASA Astrophysics Data System (ADS)

    Browder, William A.; Reeves, Anthony P.; Apananosovich, Tatiyana V.; Cham, Matthew D.; Yankelevitz, David F.; Henschke, Claudia I.

    2007-03-01

    There is widespread clinical interest in the study of pulmonary nodules for early diagnosis of lung cancer. These nodules can be broadly classified into one of three types, solid, nonsolid and part-solid. Solid nodules have been extensively studied, while little research has focused on the characterization of nonsolid and part-solid nodules. Nonsolid nodules have an appearance in high-resolution CT consisting of voxels only slightly more dense than that of the surrounding lung parenchyma. For the solid nodule, robust techniques are available to estimate growth rate and this is commonly used to distinguish benign from malignant. For the nonsolid types, these techniques are less well developed. In this research, we propose an automated volumetric segmentation method for nonsolid nodules that accurately determines a nonsolid nodule's growth rate. Our method starts with an initial noise-filtering stage in the parenchyma region. Each voxel is then classified into one of three tissue types; lung parenchyma, nonsolid and solid. Removal of vessel attachments to the lesion is achieved with the use of a filter that focuses on vessel characteristics. Our results indicate that the automated method is more consistent than the radiologist with a median growth consistency of 1.87 compared to 3.12 for the radiologist on a database of 25 cases.

  4. Phase-contrast tomography of neuronal tissues: from laboratory- to high resolution synchrotron CT

    NASA Astrophysics Data System (ADS)

    Töpperwien, Mareike; Krenkel, Martin; Müller, Kristin; Salditt, Tim

    2016-10-01

    Assessing the three-dimensional architecture of neuronal tissues with sub-cellular resolution presents a significant analytical challenge. Overcoming the limitations associated with serial slicing, phase-contrast x-ray tomography has the potential to contribute to this goal. Even compact laboratory CT at an optimized liquid-metal jet micro- focus source combined with suitable phase-retrieval algorithms and preparation protocols can yield renderings with single cell sensitivity in millimeter sized brain areas of mouse. Here, we show the capabilities of the setup by imaging a Golgi-Cox impregnated mouse brain. Towards higher resolution we extend these studies at our recently upgraded waveguide-based cone-beam holo-tomography instrument GINIX at DESY. This setup allows high resolution recordings with adjustable field of view and resolution, down to the voxel sizes in the range of a few ten nanometers. The recent results make us confident that important issues of neuronal connectivity can be addressed by these methods, and that 3D (virtual) histology with nanoscale resolution will become an attractive modality for neuroscience research.

  5. High Resolution Airborne Laser Scanning and Hyperspectral Imaging with a Small Uav Platform

    NASA Astrophysics Data System (ADS)

    Gallay, Michal; Eck, Christoph; Zgraggen, Carlo; Kaňuk, Ján; Dvorný, Eduard

    2016-06-01

    The capabilities of unmanned airborne systems (UAS) have become diverse with the recent development of lightweight remote sensing instruments. In this paper, we demonstrate our custom integration of the state-of-the-art technologies within an unmanned aerial platform capable of high-resolution and high-accuracy laser scanning, hyperspectral imaging, and photographic imaging. The technological solution comprises the latest development of a completely autonomous, unmanned helicopter by Aeroscout, the Scout B1-100 UAV helicopter. The helicopter is powered by a gasoline two-stroke engine and it allows for integrating 18 kg of a customized payload unit. The whole system is modular providing flexibility of payload options, which comprises the main advantage of the UAS. The UAS integrates two kinds of payloads which can be altered. Both payloads integrate a GPS/IMU with a dual GPS antenna configuration provided by OXTS for accurate navigation and position measurements during the data acquisition. The first payload comprises a VUX-1 laser scanner by RIEGL and a Sony A6000 E-Mount photo camera. The second payload for hyperspectral scanning integrates a push-broom imager AISA KESTREL 10 by SPECIM. The UAS was designed for research of various aspects of landscape dynamics (landslides, erosion, flooding, or phenology) in high spectral and spatial resolution.

  6. High-resolution raster scan optoacoustic mesoscopy of genetically modified drosophila pupae

    NASA Astrophysics Data System (ADS)

    Omar, Murad; Gateau, Jérôme; Ntziachristos, Vasilis

    2014-03-01

    Optoacoutic mesoscopy aims to bridge the gap between optoacoustic microscopy and optoacoustic tomography. We have developed a setup for optoacoustic mesoscopy where we use a high frequency, high numerical aperture spherically focused ultrasound transducer, with a wide bandwidth of 25-125 MHz. The excitation is performed using a diode laser capable of >500 μJ/pulse, 1.8ns pulse width, 1.4 kHz pulse repetition rate, at 515 nm. The system is capable to penetrate more than 5 mm with a resolution of 7 μm axially and 30 μm transversally. Using high-speed stages and scanning the transducer in a quasi-continuous mode, a field of view of 2×2 mm2 is scanned in less than 2 minutes. The system is suitable for imaging biological samples that have a diameter of 1-5 mm; zebrafish, drosophila melanogaster, and thin biological samples such as the mouse ear and mouse extremities. We have used our mesoscopic setup to generate 3- dimensional images of genetically modified drosophila fly, and drosophila pupae expressing GFP from the wings, high resolution images were generated in both cases, in the fly we can see the wings, the legs, the eyes, and the shape of the body. In the pupae the outline of the pupae, the spiracles at both ends and a strong signal corresponding to the location of the future wings are observed.

  7. CT imaging of the internal human ear: Test of a high resolution scanner

    NASA Astrophysics Data System (ADS)

    Bettuzzi, M.; Brancaccio, R.; Morigi, M. P.; Gallo, A.; Strolin, S.; Casali, F.; Lamanna, Ernesto; Ariù, Marilù

    2011-08-01

    During the course of 2009, in the framework of a project supported by the National Institute of Nuclear Physics, a number of tests were carried out at the Department of Physics of the University of Bologna in order to achieve a good quality CT scan of the internal human ear. The work was carried out in collaboration with the local “S. Orsola” Hospital in Bologna and a company (CEFLA) already involved in the production and commercialization of a CT scanner dedicated to dentistry. A laboratory scanner with a simple concept detector (CCD camera-lens-mirror-scintillator) was used to see to what extent it was possible to enhance the quality of a conventional CT scanner when examining the internal human ear. To test the system, some conventional measurements were made, such as the spatial resolution calculation with the MTF and dynamic range evaluation. Different scintillators were compared to select the most suitable for the purpose. With 0.5 mm thick structured cesium iodide and a field of view of 120×120 mm2, a spatial resolution of 6.5l p/mm at 5% MTF was obtained. The CT of a pair of human head phantoms was performed at an energy of 120 kVp. The first phantom was a rough representation of the human head shape, with soft tissue made of coarse slabs of Lucite. Some inserts, like small aluminum cylinders and cubes, with 1 mm diameter drilled holes, were used to simulate the channels that one finds inside the human inner ear. The second phantom is a plastic PVC fused head with a real human cranium inside. The bones in the cranium are well conserved and the inner ear features, such as the cochlea and semicircular channels, are clearly detectable. After a number of CT tests we obtained good results as far as structural representation and channel detection are concerned. Some images of the 3D rendering of the CT volume are shown below. The doctors of the local hospital who followed our experimentation expressed their satisfaction. The CT was compared to a virtual

  8. Simultaneous high-resolution scanning Bragg contrast and ptychographic imaging of a single solar cell nanowire

    PubMed Central

    Wallentin, Jesper; Wilke, Robin N.; Osterhoff, Markus; Salditt, Tim

    2015-01-01

    Simultaneous scanning Bragg contrast and small-angle ptychographic imaging of a single solar cell nanowire are demonstrated, using a nanofocused hard X-ray beam and two detectors. The 2.5 µm-long nanowire consists of a single-crystal InP core of 190 nm diameter, coated with amorphous SiO2 and polycrystalline indium tin oxide. The nanowire was selected and aligned in real space using the small-angle scattering of the 140 × 210 nm X-ray beam. The orientation of the nanowire, as observed in small-angle scattering, was used to find the correct rotation for the Bragg condition. After alignment in real space and rotation, high-resolution (50 nm step) raster scans were performed to simultaneously measure the distribution of small-angle scattering and Bragg diffraction in the nanowire. Ptychographic reconstruction of the coherent small-angle scattering was used to achieve sub-beam spatial resolution. The small-angle scattering images, which are sensitive to the shape and the electron density of all parts of the nanowire, showed a homogeneous profile along the nanowire axis except at the thicker head region. In contrast, the scanning Bragg diffraction microscopy, which probes only the single-crystal InP core, revealed bending and crystalline inhomogeneity. Both systematic and non-systematic real-space movement of the nanowire were observed as it was rotated, which would have been difficult to reveal only from the Bragg scattering. These results demonstrate the advantages of simultaneously collecting and analyzing the small-angle scattering in Bragg diffraction experiments. PMID:26664342

  9. Simultaneous high-resolution scanning Bragg contrast and ptychographic imaging of a single solar cell nanowire.

    PubMed

    Wallentin, Jesper; Wilke, Robin N; Osterhoff, Markus; Salditt, Tim

    2015-12-01

    Simultaneous scanning Bragg contrast and small-angle ptychographic imaging of a single solar cell nanowire are demonstrated, using a nanofocused hard X-ray beam and two detectors. The 2.5 µm-long nanowire consists of a single-crystal InP core of 190 nm diameter, coated with amorphous SiO2 and polycrystalline indium tin oxide. The nanowire was selected and aligned in real space using the small-angle scattering of the 140 × 210 nm X-ray beam. The orientation of the nanowire, as observed in small-angle scattering, was used to find the correct rotation for the Bragg condition. After alignment in real space and rotation, high-resolution (50 nm step) raster scans were performed to simultaneously measure the distribution of small-angle scattering and Bragg diffraction in the nanowire. Ptychographic reconstruction of the coherent small-angle scattering was used to achieve sub-beam spatial resolution. The small-angle scattering images, which are sensitive to the shape and the electron density of all parts of the nanowire, showed a homogeneous profile along the nanowire axis except at the thicker head region. In contrast, the scanning Bragg diffraction microscopy, which probes only the single-crystal InP core, revealed bending and crystalline inhomogeneity. Both systematic and non-systematic real-space movement of the nanowire were observed as it was rotated, which would have been difficult to reveal only from the Bragg scattering. These results demonstrate the advantages of simultaneously collecting and analyzing the small-angle scattering in Bragg diffraction experiments.

  10. Morphological Changes Along a Dike Landside Slope Sampled by 4d High Resolution Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Herrero-Huertaa, Mónica; Lindenbergh, Roderik; Ponsioen, Luc; van Damme, Myron

    2016-06-01

    Emergence of light detection and ranging (LiDAR) technology provides new tools for geomorphologic studies improving spatial and temporal resolution of data sampling hydrogeological instability phenomena. Specifically, terrestrial laser scanning (TLS) collects high resolution 3D point clouds allowing more accurate monitoring of erosion rates and processes, and thus, quantify the geomorphologic change on vertical landforms like dike landside slopes. Even so, TLS captures observations rapidly and automatically but unselectively. In this research, we demonstrate the potential of TLS for morphological change detection, profile creation and time series analysis in an emergency simulation for characterizing and monitoring slope movements in a dike. The experiment was performed near Schellebelle (Belgium) in November 2015, using a Leica Scan Station C10. Wave overtopping and overflow over a dike were simulated whereby the loading conditions were incrementally increased and 14 successful scans were performed. The aim of the present study is to analyse short-term morphological dynamic processes and the spatial distribution of erosion and deposition areas along a dike landside slope. As a result, we are able to quantify the eroded material coming from the impact on the terrain induced by wave overtopping which caused the dike failure in a few minutes in normal storm scenarios (Q = 25 l/s/m) as 1.24 m3. As this shows that the amount of erosion is measurable using close range techniques; the amount and rate of erosion could be monitored to predict dike collapse in emergency situation. The results confirm the feasibility of the proposed methodology, providing scalability to a comprehensive analysis over a large extension of a dike (tens of meters).

  11. Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes

    SciTech Connect

    Crewe, A.V.

    2000-04-18

    Disclosed are lens apparatus in which a beam of charged particles is brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscope as the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.

  12. High-resolution adaptive optics scanning laser ophthalmoscope with dual deformable mirrors for large aberration correction

    SciTech Connect

    Chen, D; Jones, S M; Silva, D A; Olivier, S S

    2007-01-25

    Scanning laser ophthalmoscopes with adaptive optics (AOSLO) have been shown previously to provide a noninvasive, cellular-scale view of the living human retina. However, the clinical utility of these systems has been limited by the available deformable mirror technology. In this paper, we demonstrate that the use of dual deformable mirrors can effectively compensate large aberrations in the human retina, making the AOSLO system a viable, non-invasive, high-resolution imaging tool for clinical diagnostics. We used a bimorph deformable mirror to correct low-order aberrations with relatively large amplitudes. The bimorph mirror is manufactured by Aoptix, Inc. with 37 elements and 18 {micro}m stroke in a 10 mm aperture. We used a MEMS deformable mirror to correct high-order aberrations with lower amplitudes. The MEMS mirror is manufactured by Boston Micromachine, Inc with 144 elements and 1.5 {micro}m stroke in a 3 mm aperture. We have achieved near diffraction-limited retina images using the dual deformable mirrors to correct large aberrations up to {+-} 3D of defocus and {+-} 3D of cylindrical aberrations with test subjects. This increases the range of spectacle corrections by the AO systems by a factor of 10, which is crucial for use in the clinical environment. This ability for large phase compensation can eliminate accurate refractive error fitting for the patients, which greatly improves the system ease of use and efficiency in the clinical environment.

  13. Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes

    DOEpatents

    Crewe, Albert V.

    2000-01-01

    Disclosed are lens apparatus in which a beam of charged particlesis brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscopeas the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.

  14. Visualizing taste papillae in vivo with scanning electron microscopy of a high resolution cast.

    PubMed

    Myers, W E; Hettinger, T P; D'Ambrosio, J A; Wendt, S L; Pearson, C B; Barry, M A; Frank, M E

    1995-02-01

    A method using polyvinylsiloxane (PVS), a high-resolution dental impression material, to obtain negative images of lingual surfaces is described. Epoxy-resin tongue replicas made from these impressions were examined with scanning electron microscopy (SEM). This method has been developed to visualize structural details of the tongue surface of living human beings and laboratory animals. The utility of the method is demonstrated with hamster tongues, which have well-defined fungiform papillae with single taste pores, and human tongues, which have more variable surface structures. Replicas made from PVS impressions of tongues of living hamsters were compared with the same tongues after fixation. The replicas contained much of the detail present in fixed tongues. With SEM, it was possible to identify individual fungiform papillae, which contained depressions with the size and the location of hamster taste pores. Individual papillae could also be recognized in human-tongue replicas, but taste pores could not be identified with certainty. These replicas provide permanent, three-dimensional records of tongue topography that could be used to document changes due to trauma, disease and aging.

  15. Exploring crystallization kinetics in natural rhyolitic melts using high resolution CT imagery of spherulites

    NASA Astrophysics Data System (ADS)

    Clow, T. W.; Befus, K. S.; Gardner, J. E.

    2014-12-01

    Little of our understanding of crystallization kinetics has been directly derived from studies of natural samples. We examine crystallization of rhyolitic melts by quantifying spherulite sizes and number densities in obsidian collected from Yellowstone caldera using high-resolution x-ray computed tomography (CT) imagery. Spherulites are spherical to ellipsoidal masses of intergrown alkali feldspar and quartz in a radiating, fibrous structure. They are thought to form in response to relatively rapid crystallization of melt in response to large amounts of undercooling. Recent research using compositional gradients that form outside of spherulites has suggested that they nucleate at 700 to 500 ˚C and their growth slows exponentially until it eventually ceases at ~400 ˚C. By quantifying spherulite textures, and using those temperature constraints, we derive new kinetic information regarding crystallization in natural rhyolitic systems. We find that spherulites range from 0.2 to 12.3 mm in diameter, and are 0.004 to 49.5 mm3 in volume. Such values generate number densities of 70 to 185 spherulites cm-3. Histograms of size display positively skewed distributions indicating small spherulites are far more abundant than larger ones. Those distributions imply nucleation rates change as a function of temperature. At higher temperatures where the melt is undercooled by 400-500 ˚C, nucleation is rare and growth is favored. With decreasing temperature, nucleation rates increase rapidly until cold enough temperatures are reached that diffusion limits crystallization and causes it to cease (undercoolings of ~650 ˚C). Assuming a cooling rate for the host obsidian of 10-5 ˚C s-1, then overall spherulite nucleation rates are 0.01 to 0.03 spherulites cm-3 hour-1.

  16. Automated method for relating regional pulmonary structure and function: integration of dynamic multislice CT and thin-slice high-resolution CT

    NASA Astrophysics Data System (ADS)

    Tajik, Jehangir K.; Kugelmass, Steven D.; Hoffman, Eric A.

    1993-07-01

    We have developed a method utilizing x-ray CT for relating pulmonary perfusion to global and regional anatomy, allowing for detailed study of structure to function relationships. A thick slice, high temporal resolution mode is used to follow a bolus contrast agent for blood flow evaluation and is fused with a high spatial resolution, thin slice mode to obtain structure- function detail. To aid analysis of blood flow, we have developed a software module, for our image analysis package (VIDA), to produce the combined structure-function image. Color coded images representing blood flow, mean transit time, regional tissue content, regional blood volume, regional air content, etc. are generated and imbedded in the high resolution volume image. A text file containing these values along with a voxel's 3-D coordinates is also generated. User input can be minimized to identifying the location of the pulmonary artery from which the input function to a blood flow model is derived. Any flow model utilizing one input and one output function can be easily added to a user selectable list. We present examples from our physiologic based research findings to demonstrate the strengths of combining dynamic CT and HRCT relative to other scanning modalities to uniquely characterize pulmonary normal and pathophysiology.

  17. High resolution micro-CT of low attenuating organic materials using large area photon-counting detector

    NASA Astrophysics Data System (ADS)

    Kumpová, I.; Vavřík, D.; Fíla, T.; Koudelka, P.; Jandejsek, I.; Jakůbek, J.; Kytýř, D.; Zlámal, P.; Vopálenský, M.; Gantar, A.

    2016-02-01

    To overcome certain limitations of contemporary materials used for bone tissue engineering, such as inflammatory response after implantation, a whole new class of materials based on polysaccharide compounds is being developed. Here, nanoparticulate bioactive glass reinforced gelan-gum (GG-BAG) has recently been proposed for the production of bone scaffolds. This material offers promising biocompatibility properties, including bioactivity and biodegradability, with the possibility of producing scaffolds with directly controlled microgeometry. However, to utilize such a scaffold with application-optimized properties, large sets of complex numerical simulations using the real microgeometry of the material have to be carried out during the development process. Because the GG-BAG is a material with intrinsically very low attenuation to X-rays, its radiographical imaging, including tomographical scanning and reconstructions, with resolution required by numerical simulations might be a very challenging task. In this paper, we present a study on X-ray imaging of GG-BAG samples. High-resolution volumetric images of investigated specimens were generated on the basis of micro-CT measurements using a large area flat-panel detector and a large area photon-counting detector. The photon-counting detector was composed of a 010× 1 matrix of Timepix edgeless silicon pixelated detectors with tiling based on overlaying rows (i.e. assembled so that no gap is present between individual rows of detectors). We compare the results from both detectors with the scanning electron microscopy on selected slices in transversal plane. It has been shown that the photon counting detector can provide approx. 3× better resolution of the details in low-attenuating materials than the integrating flat panel detectors. We demonstrate that employment of a large area photon counting detector is a good choice for imaging of low attenuating materials with the resolution sufficient for numerical simulations.

  18. High-Resolution Scanning Tunneling Microscopy of Fully Hydrated Ripple-Phase Bilayers

    PubMed Central

    Woodward IV, J. T.; Zasadzinski, J. A.

    1997-01-01

    A modified freeze-fracture replication technique for use with the scanning tunneling microscope (STM) has provided a quantitative, high-resolution description of the waveform and amplitude of rippled bilayers in the Pβ, phase of dimyristoylphosphatidylcholine (DMPC) in excess water. The ripples are uniaxial and asymmetrical, with a temperature-dependent amplitude of 2.4 nm near the chain melting temperature that decreases to zero at the chain crystallization temperature. The wavelength of 11 nm does not change with temperature. The observed ripple shape and the temperature-induced structural changes are not predicted by any current theory. Calibration and reproducibility of the STM/replica technique were tested with replicas of well-characterized bilayers of cadmium arachidate on mica that provide regular 5.5-nm steps. STM images were analyzed using a cross-correlation averaging program to eliminate the effects of noise and the finite size and shapes of the metal grains that make up the replica. The correlation averaging allowed us to develop a composite ripple profile averaged over hundreds of individual ripples measured on different samples with different STM tips. The STM/replica technique avoids many of the previous artifacts of biological STM imaging and can be used to examine a variety of periodic hydrated lipid and protein samples at a lateral resolution of about 1 nm and a vertical resolution of about 0.3 nm. This resolution is superior to conventional and tapping mode AFM of soft biological materials; the technique is substrate-free, and the conductive and chemically uniform replicas make image interpretation simple and direct. ImagesFIGURE 1FIGURE 2FIGURE 3FIGURE 5 PMID:9017222

  19. Microstructure development in latex coatings: High-resolution cryo-scanning electron microscopy

    NASA Astrophysics Data System (ADS)

    Ge, Haiyan

    2005-07-01

    High-resolution cryogenic scanning electron microscopy (Cryo-SEM) was used to investigate microstructure development in drying latex coatings: from a colloidal stable suspension into a coherent strong film by drying. Useful sample preparation artifacts during the freeze-fracture, i.e., pullouts were documented and analyzed. Pullouts indicate both physical properties of latex particles and the drying stages in latex coatings. The mechanism of pullout formation was studied both theoretically and experimentally. Latex coatings must possess satisfactory freeze-thaw stability to avoid problems during transportation and storage in cold winter. The behavior of latex particles during freeze-thaw cycles was visualized by Cryo-SEM. The images indicated that high concentration of polymerizable surfactant in a latex suspension improved its freeze-thaw stability. In film formation, skinning was captured from edge in and top down in coatings of 80nm diameter styrene-butadiene latex particles with exceptional low Tg (-65°C). Effects on skinning of drying conditions and the way the latex was initially stabilized against flocculation were investigated. A skinned pocket was unexpectedly found in the coating. The cause of such a skin around the air bubble was explained by both simple models calculating the dissolution time and force analysis on the particles. The film formation processes in conventional and low volatile organic compound (VOC) latex coatings were compared by time-sectioning Cryo-SEM. Some low-VOC latex coatings were found to dry as fast as conventional ones without deteriorating final good film properties.

  20. Detection of Aspens Using High Resolution Aerial Laser Scanning Data and Digital Aerial Images

    PubMed Central

    Säynäjoki, Raita; Packalén, Petteri; Maltamo, Matti; Vehmas, Mikko; Eerikäinen, Kalle

    2008-01-01

    The aim was to use high resolution Aerial Laser Scanning (ALS) data and aerial images to detect European aspen (Populus tremula L.) from among other deciduous trees. The field data consisted of 14 sample plots of 30 m × 30 m size located in the Koli National Park in the North Karelia, Eastern Finland. A Canopy Height Model (CHM) was interpolated from the ALS data with a pulse density of 3.86/m2, low-pass filtered using Height-Based Filtering (HBF) and binarized to create the mask needed to separate the ground pixels from the canopy pixels within individual areas. Watershed segmentation was applied to the low-pass filtered CHM in order to create preliminary canopy segments, from which the non-canopy elements were extracted to obtain the final canopy segmentation, i.e. the ground mask was analysed against the canopy mask. A manual classification of aerial images was employed to separate the canopy segments of deciduous trees from those of coniferous trees. Finally, linear discriminant analysis was applied to the correctly classified canopy segments of deciduous trees to classify them into segments belonging to aspen and those belonging to other deciduous trees. The independent variables used in the classification were obtained from the first pulse ALS point data. The accuracy of discrimination between aspen and other deciduous trees was 78.6%. The independent variables in the classification function were the proportion of vegetation hits, the standard deviation of in pulse heights, accumulated intensity at the 90th percentile and the proportion of laser points reflected at the 60th height percentile. The accuracy of classification corresponded to the validation results of earlier ALS-based studies on the classification of individual deciduous trees to tree species. PMID:27873799

  1. High resolution pulmonary computed tomography scans quantified by analysis of density distribution: application to asbestosis.

    PubMed Central

    Eterović, D; Dujić, Z; Tocilj, J; Capkun, V

    1993-01-01

    A new method for quantitative evaluation for high resolution computed tomography (HRCT) of the lungs was developed by assessment of the distribution of radiological densities within the lung slices. To enable effective reduction of data and improve the sensitivity of detection of abnormalities, the density distributions were analysed by curve fitting through the gamma variate model. The output of two variables proved most representative: the most frequent density (Hoansfield units; HU) and width of distribution (HU). The method was applied to seven patients with early asbestosis (positive histological finding and International Labour Office (ILO) profusion score up to 0/1), 15 patients with advanced stage of asbestosis (positive histological finding and ILO score above 1/2), and 13 normal controls. All patients with early asbestosis had isolated reduction of diffusing lung capacity to carbon monoxide (DLCO), whereas all patients with advanced asbestosis had reduced DLCO and restrictive disease; two of them also had an obstruction pattern. The most frequent densities were significantly greater in the advanced asbestosis group (-567 HU) when compared with both the early asbestosis group (-719 HU; p = 2 x 10(-6)), and controls (-799 HU; p = 0), and they also discriminated significantly between the early asbestosis group and controls (p = 0.0002). Significantly stronger linear correlations were established between DLCO and the most frequent densities (r = 0.86) than between DLCO and HRCT score (r = 0.57) or ILO score (r = 0.34). It is concluded that fitting the curve of the density distribution enables a more objective assessment of HRCT pulmonary scans, especially in the early stage of asbestosis. PMID:8329317

  2. 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.

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

    PubMed Central

    Sakhalkar, H. S.; Oldham, M.

    2008-01-01

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

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

    SciTech Connect

    Sakhalkar, H. S.; Oldham, M.

    2008-01-15

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

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

    PubMed

    Sakhalkar, H S; Oldham, M

    2008-01-01

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

  6. Negative appendectomy rate: influence of CT scans.

    PubMed

    McGory, Marcia L; Zingmond, David S; Nanayakkara, Darshani; Maggard, Melinda A; Ko, Clifford Y

    2005-10-01

    Negative appendectomy rate varies significantly depending on patient age and sex. However, the impact of computed tomography (CT) scans on the diagnosis of appendicitis is unknown. The goal of this study was to examine the negative appendectomy rate using a statewide database and analyze the association of receipt of CT scan. Using the California Inpatient File, all patients undergoing appendectomy in 1999-2000 were identified (n = 75,452). Demographic and clinical data were analyzed, including procedure approach (open vs laparoscopic) and appendicitis type (negative, simple, abscess, peritonitis). Patients with CT scans performed were identified to compare the negative appendectomy rate. For the entire cohort, appendicitis type was 59 per cent simple, 10 per cent with abscess, 18.7 per cent with peritonitis, and 9.3 per cent negative. Males had a lower rate of negative appendicitis than females (6.0% vs 13.4%, P < 0.0001). The use of CT scans was associated with an overall lower negative appendectomy rate for females, especially in the < 5 years and > 45 years age categories. Use of CT scans in males does not appear to be efficacious, as the negative appendectomy rates were similar across all age categories. In conclusion, use of CT was associated with lower rate of negative appendectomy, depending on patient age and sex.

  7. Simultaneous Confocal Scanning Laser Ophthalmoscopy Combined with High-Resolution Spectral-Domain Optical Coherence Tomography: A Review

    PubMed Central

    Castro Lima, Verônica; Rodrigues, Eduardo B.; Nunes, Renata P.; Sallum, Juliana F.; Farah, Michel E.; Meyer, Carsten H.

    2011-01-01

    We aimed to evaluate technical aspects and the clinical relevance of a simultaneous confocal scanning laser ophthalmoscope and a high-speed, high-resolution, spectral-domain optical coherence tomography (SDOCT) device for retinal imaging. The principle of confocal scanning laser imaging provides a high resolution of retinal and choroidal vasculature with low light exposure. Enhanced contrast, details, and image sharpness are generated using confocality. The real-time SDOCT provides a new level of accuracy for assessment of the angiographic and morphological correlation. The combined system allows for simultaneous recordings of topographic and tomographic images with accurate correlation between them. Also it can provide simultaneous multimodal imaging of retinal pathologies, such as fluorescein and indocyanine green angiographies, infrared and blue reflectance (red-free) images, fundus autofluorescence images, and OCT scans (Spectralis HRA + OCT; Heidelberg Engineering, Heidelberg, Germany). The combination of various macular diagnostic tools can lead to a better understanding and improved knowledge of macular diseases. PMID:22132313

  8. Mapping the electrostatic force field of single molecules from high-resolution scanning probe images

    PubMed Central

    Hapala, Prokop; Švec, Martin; Stetsovych, Oleksandr; van der Heijden, Nadine J.; Ondráček, Martin; van der Lit, Joost; Mutombo, Pingo; Swart, Ingmar; Jelínek, Pavel

    2016-01-01

    How electronic charge is distributed over a molecule determines to a large extent its chemical properties. Here, we demonstrate how the electrostatic force field, originating from the inhomogeneous charge distribution in a molecule, can be measured with submolecular resolution. We exploit the fact that distortions typically observed in high-resolution atomic force microscopy images are for a significant part caused by the electrostatic force acting between charges of the tip and the molecule of interest. By finding a geometrical transformation between two high-resolution AFM images acquired with two different tips, the electrostatic force field or potential over individual molecules and self-assemblies thereof can be reconstructed with submolecular resolution. PMID:27230940

  9. Combination of CT scanning and fluoroscopy imaging on a flat-panel CT scanner

    NASA Astrophysics Data System (ADS)

    Grasruck, M.; Gupta, R.; Reichardt, B.; Suess, Ch.; Schmidt, B.; Stierstorfer, K.; Popescu, S.; Brady, T.; Flohr, T.

    2006-03-01

    We developed and evaluated a prototype flat-panel detector based Volume CT (fpVCT) scanner. The fpVCT scanner consists of a Varian 4030CB a-Si flat-panel detector mounted in a multi slice CT-gantry (Siemens Medical Solutions). It provides a 25 cm field of view with 18 cm z-coverage at the isocenter. In addition to the standard tomographic scanning, fpVCT allows two new scan modes: (1) fluoroscopic imaging from any arbitrary rotation angle, and (2) continuous, time-resolved tomographic scanning of a dynamically changing viewing volume. Fluoroscopic imaging is feasible by modifying the standard CT gantry so that the imaging chain can be oriented along any user-selected rotation angle. Scanning with a stationary gantry, after it has been oriented, is equivalent to a conventional fluoroscopic examination. This scan mode enables combined use of high-resolution tomography and real-time fluoroscopy with a clinically usable field of view in the z direction. The second scan mode allows continuous observation of a timeevolving process such as perfusion. The gantry can be continuously rotated for up to 80 sec, with the rotation time ranging from 3 to 20 sec, to gather projection images of a dynamic process. The projection data, that provides a temporal log of the viewing volume, is then converted into multiple image stacks that capture the temporal evolution of a dynamic process. Studies using phantoms, ex vivo specimens, and live animals have confirmed that these new scanning modes are clinically usable and offer a unique view of the anatomy and physiology that heretofore has not been feasible using static CT scanning. At the current level of image quality and temporal resolution, several clinical applications such a dynamic angiography, tumor enhancement pattern and vascularity studies, organ perfusion, and interventional applications are in reach.

  10. Chondrocalcinosis of Femoro-Tibial and Proximal Tibio-Fibular Joints in Cadaveric Specimens: A High-Resolution CT Imaging Study of the Calcification Distribution

    PubMed Central

    Touraine, Sébastien; Ea, Hang Korng; Bousson, Valérie; Cohen-Solal, Martine; Laouisset, Liess; Chappard, Christine; Lioté, Frédéric; Laredo, Jean-Denis

    2013-01-01

    Objectives To analyze calcium deposits by computed tomography (CT) in femoro-tibial compartments and proximal tibio-fibular joints; to assess the relationship with CT-assessed osteoarthritis (OA). Methods 68 (34 pairs) cadaveric knees (mean age of 84) were scanned at high resolution CT. Menisci and hyaline cartilage calcifications in the femoro-tibial and proximal tibio-fibular joints were analyzed. OA was CT-assessed by the Kellgren and Lawrence score. Gross appearance of OA was evaluated on 29 left knees after dissection and India ink staining of tibial plateaus. Results In femoro-tibial joints, meniscal calcifications (MC) and hyaline cartilage calcifications (HCC) were detected in 23(34%) and 14(21%) knees respectively. Calcifications mainly involved the three meniscal segments and were mainly observed in all thirds of the femoro-tibial compartments. In proximal tibio-fibular joints, HCC were detected in 19(28%) knees. The association HCC-MC in femoro-tibial joints and between calcifications in femoro-tibial and proximal tibio-fibular joints was strong (p<0.0001). Femoro-tibial and proximal tibio-fibular CT-assessed OA were respectively found in 23(34%) and 19(28%) knees. HCC were significantly associated with femoro-tibial OA (p = 0.04) while MC were not (p = 0.34). OA macroscopic evaluation showed a mean surface of cartilage lesions of 35% (range 0.13–0.55). No significant difference was demonstrated regarding the CT-detection of MC, HCC or CT-assessed OA. Conclusions This is the first study to report a strong association of chondrocalcinosis between femoro-tibial and tibio-fibular joints in addition to a strong association between MC and HCC in femoro-tibial compartments. No significant relationship between chondrocalcinosis and OA was demonstrated. PMID:23372802

  11. Pulmonary nodule, solitary - CT scan (image)

    MedlinePlus

    ... a single lesion (pulmonary nodule) in the right lung. This nodule is seen as the light circle in the upper portion of the dark area on the left side of the picture. A normal lung would look completely black in a CT scan.

  12. Integration of Point Clouds from Terrestrial Laser Scanning and Image-Based Matching for Generating High-Resolution Orthoimages

    NASA Astrophysics Data System (ADS)

    Salach, A.; Markiewicza, J. S.; Zawieska, D.

    2016-06-01

    An orthoimage is one of the basic photogrammetric products used for architectural documentation of historical objects; recently, it has become a standard in such work. Considering the increasing popularity of photogrammetric techniques applied in the cultural heritage domain, this research examines the two most popular measuring technologies: terrestrial laser scanning, and automatic processing of digital photographs. The basic objective of the performed works presented in this paper was to optimize the quality of generated high-resolution orthoimages using integration of data acquired by a Z+F 5006 terrestrial laser scanner and a Canon EOS 5D Mark II digital camera. The subject was one of the walls of the "Blue Chamber" of the Museum of King Jan III's Palace at Wilanów (Warsaw, Poland). The high-resolution images resulting from integration of the point clouds acquired by the different methods were analysed in detail with respect to geometric and radiometric correctness.

  13. Automatic identification of colonic polyp in high-resolution CT images

    NASA Astrophysics Data System (ADS)

    Dehmeshki, Jamshid; Amin, Hamdan; Wong, Wing; Ebadian Dehkordi, Mandana; Kamangari, Nahid; Roddie, Mary; Costello, John

    2004-05-01

    Automatic polyp detection is a challenging task as polyps come in different sizes and shape. The detection generally consists of colon segmentation, identification of suspected polyps and classification. Classification involves discriminating polyps from among many suspected regions based on a number of features extracted from the detected regions. This paper presents the work on the first two stages of the detection. For the colon segmentation, the fuzzy connectivity region growing technique is used while for the identification of suspected polyps concave region searching is applied. A rule-based filtering based on 3D volumetric features is used to reduce a large number of non-polyp structures (false positives). The method is fast, robust and validated with a number of high-resolution colon datasets.

  14. High-resolution CT analysis of facial struts in trauma: 2. Osseous and soft-tissue complications.

    PubMed

    Gentry, L R; Manor, W F; Turski, P A; Strother, C M

    1983-03-01

    In six cadavers, high-resolution thin-section computed tomography (CT) was used to evaluate the sequelae of experimentally produced facial trauma. As confirmed by pluridirectional tomography, CT was an effective imaging method for the detection and classification of facial fractures. The ability of CT to simultaneously depict both osseous and soft-tissue structures expands the role that diagnostic radiology can play in the evaluation of the traumatized face. A method of evaluation is presented in which the face is geometrically conceptualized as a series of triplanar (horizontal, sagittal, and coronal) osseous struts. Sequential, systematic assessment of each strut for fracture and its adjacent soft tissue for injury can facilitate evaluation of the traumatized face. Using this approach the osseous and soft-tissue complications arising from experimentally produced trauma are reviewed and illustrated with CT. Examples of potential soft-tissue complications that may occur with fractures of the horizontal group of struts include disruption of the dura matter at the cribiform plate, involvement of the structures of the anterior cranial fossa, injury to the optic nerve, and involvement of the superior and inferior groups of extraocular muscles. Injury to the nasolacrimal duct, maxillary sinus ostium, medial and lateral rectus muscles, or the soft-tissue structures in the superior and inferior orbital fissures may arise from disruption of the sagittal struts. Fractures of the coronal struts may involve the frontal sinus, anterior cranial fossa, lacrimal gland, nasofrontal duct, lacrimal sac, or the soft tissues of the pterygopalatine fossa.

  15. Optical scanning holography as a technique for high-resolution three-dimensional biological microscopy

    NASA Astrophysics Data System (ADS)

    Swoger, Jim; Martinez-Corral, Manuel; Huisken, Jan; Stelzer, Ernst H. K.

    2002-09-01

    The applicability of optical scanning holography (OSH) to the field of microscopic imaging for biological applications is assessed. A generalized mathematical description of OSH that takes into account polarization effects, high numerical apertures, and generalized illumination wave fronts is presented. This description is used to show that the proposed single-beam scanning technique relaxes the restrictions under which OSH functions correctly compared with the conventional double-beam scanning method. It is also shown that, although in general OSH is restricted to thin samples, this condition can be relaxed in nonrefracting fluorescence samples, which are of importance in biological microscopy.

  16. Lung Nodule Volume Quantification and Shape Differentiation with an Ultra-High Resolution Technique on a Photon Counting Detector CT System

    PubMed Central

    Zhou, W.; Montoya, J.; Gutjahr, R.; Ferrero, A.; Halaweish, A.; Kappler, S.; McCollough, C.; Leng, S.

    2017-01-01

    A new ultra high-resolution (UHR) mode has been implemented on a whole body photon counting-detector (PCD) CT system. The UHR mode has a pixel size of 0.25 mm by 0.25 mm at the iso-center, while the conventional (macro) mode is limited to 0.5 mm by 0.5 mm. A set of synthetic lung nodules (two shapes, five sizes, and two radio-densities) was scanned using both the UHR and macro modes and reconstructed with 2 reconstruction kernels (4 sets of images in total). Linear regression analysis was performed to compare measured nodule volumes from CT images to reference volumes. Surface curvature was calculated for each nodule and the full width half maximum (FWHM) of the curvature histogram was used as a shape index to differentiate sphere and star shape nodules. Receiver operating characteristic (ROC) analysis was performed and area under the ROC curve (AUC) was used as a figure of merit for the differentiation task. Results showed strong linear relationship between measured nodule volume and reference standard for both UHR and macro mode. For all nodules, volume estimation was more accurate using UHR mode with sharp kernel (S80f), with lower mean absolute percent error (MAPE) (6.5%) compared with macro mode (11.1% to 12.9%). The improvement of volume measurement from UHR mode was more evident particularly for small nodule size (3mm, 5mm), or star-shape nodules. Images from UHR mode with sharp kernel (S80f) consistently demonstrated the best performance (AUC = 0.85) when separating star from sphere shape nodules among all acquisition and reconstruction modes. Our results showed the advantages of UHR mode on a PCD CT scanner in lung nodule characterization. Various clinical applications, including quantitative imaging, can benefit substantially from this high resolution mode. PMID:28392613

  17. High-Resolution CT and Angiographic Evaluation of NexStent Wall Adaptation

    SciTech Connect

    Nemes, Balazs Lukacs, Levente; Balazs, Gyoergy; Dosa, Edit; Berczi, Viktor; Huettl, Kalman

    2009-05-15

    Carotid stenting is a minimally invasive treatment for extracranial carotid artery stenosis. Stent design may affect technical success and complications in a certain subgroup of patients. We examined the wall adaptability of a new closed-cell carotid stent (NexStent), which has a unique rolled sheet design. Forty-one patients had 42 carotid arteries treated with angioplasty and stenting for internal carotid artery stenosis. The mean patient age was 65 {+-} 10 years. All patients underwent high-resolution computed tomographic angiography after the stent implantation. Data analysis included pre- and postprocedural stenosis, procedure complications, plaque calcification, and stent apposition. We reviewed the angiographic and computed tomographic images for plaque coverage and stent expansion. All procedures were technically successful. Mean stenosis was reduced from 84 {+-} 8% before the procedure to 15.7 {+-} 7% after stenting. Two patients experienced transient ischemic attack; one patient had bradycardia and hypotension. Stent induced kinking was observed in one case. Good plaque coverage and proper overlapping of the rolled sheet was achieved in all cases. There was weak correlation between the residual stenosis and the amount of calcification. The stent provides adequate expansion and adaptation to the tapering anatomy of the bifurcation.

  18. Fuzzy membership functions for analysis of high-resolution CT images of diffuse pulmonary diseases.

    PubMed

    Almeida, Eliana; Rangayyan, Rangaraj M; Azevedo-Marques, Paulo M

    2015-08-01

    We propose the use of fuzzy membership functions to analyze images of diffuse pulmonary diseases (DPDs) based on fractal and texture features. The features were extracted from preprocessed regions of interest (ROIs) selected from high-resolution computed tomography images. The ROIs represent five different patterns of DPDs and normal lung tissue. A Gaussian mixture model (GMM) was constructed for each feature, with six Gaussians modeling the six patterns. Feature selection was performed and the GMMs of the five significant features were used. From the GMMs, fuzzy membership functions were obtained by a probability-possibility transformation and further statistical analysis was performed. An average classification accuracy of 63.5% was obtained for the six classes. For four of the six classes, the classification accuracy was superior to 65%, and the best classification accuracy was 75.5% for one class. The use of fuzzy membership functions to assist in pattern classification is an alternative to deterministic approaches to explore strategies for medical diagnosis.

  19. High-Resolution 3D Imaging and Quantification of Gold Nanoparticles in a Whole Cell Using Scanning Transmission Ion Microscopy

    PubMed Central

    Chen, Xiao; Chen, Ce-Belle; Udalagama, Chammika N.B.; Ren, Minqin; Fong, Kah Ee; Yung, Lin Yue Lanry; Giorgia, Pastorin; Bettiol, Andrew Anthony; Watt, Frank

    2013-01-01

    Increasing interest in the use of nanoparticles (NPs) to elucidate the function of nanometer-sized assemblies of macromolecules and organelles within cells, and to develop biomedical applications such as drug delivery, labeling, diagnostic sensing, and heat treatment of cancer cells has prompted investigations into novel techniques that can image NPs within whole cells and tissue at high resolution. Using fast ions focused to nanodimensions, we show that gold NPs (AuNPs) inside whole cells can be imaged at high resolution, and the precise location of the particles and the number of particles can be quantified. High-resolution density information of the cell can be generated using scanning transmission ion microscopy, enhanced contrast for AuNPs can be achieved using forward scattering transmission ion microscopy, and depth information can be generated from elastically backscattered ions (Rutherford backscattering spectrometry). These techniques and associated instrumentation are at an early stage of technical development, but we believe there are no physical constraints that will prevent whole-cell three-dimensional imaging at <10 nm resolution. PMID:23561518

  20. A scanning Hall probe microscope for high resolution, large area, variable height magnetic field imaging

    NASA Astrophysics Data System (ADS)

    Shaw, Gorky; Kramer, R. B. G.; Dempsey, N. M.; Hasselbach, K.

    2016-11-01

    We present a scanning Hall probe microscope operating in ambient conditions. One of the unique features of this microscope is the use of the same stepper motors for both sample positioning as well as scanning, which makes it possible to have a large scan range (few mm) in the x and y directions, with a scan resolution of 0.1 μm. Protocols have been implemented to enable scanning at different heights from the sample surface. The z range is 35 mm. Microstructured Hall probes of size 1-5 μm have been developed. A minimum probe-sample distance <2 μm has been obtained by the combination of new Hall probes and probe-sample distance regulation using a tuning fork based force detection technique. The system is also capable of recording local B(z) profiles. We discuss the application of the microscope for the study of micro-magnet arrays being developed for applications in micro-systems.

  1. High-resolution quantitative determination of dielectric function by using scattering scanning near-field optical microscopy

    PubMed Central

    Tranca, D. E.; Stanciu, S. G.; Hristu, R.; Stoichita, C.; Tofail, S. A. M.; Stanciu, G. A.

    2015-01-01

    A new method for high-resolution quantitative measurement of the dielectric function by using scattering scanning near-field optical microscopy (s-SNOM) is presented. The method is based on a calibration procedure that uses the s-SNOM oscillating dipole model of the probe-sample interaction and quantitative s-SNOM measurements. The nanoscale capabilities of the method have the potential to enable novel applications in various fields such as nano-electronics, nano-photonics, biology or medicine. PMID:26138665

  2. High-resolution dichroic imaging of magnetic flux distributions in superconductors with scanning x-ray microscopy

    SciTech Connect

    Ruoß, S. Stahl, C.; Weigand, M.; Schütz, G.; Albrecht, J.

    2015-01-12

    The penetration of magnetic flux into high-temperature superconductors has been observed using a high-resolution technique based on x-ray magnetic circular dichroism. Superconductors coated with thin soft-magnetic layers are observed in a scanning x-ray microscope under the influence of external magnetic fields. Resulting electric currents in the superconductor create an inhomogeneous magnetic field distribution above the superconductor and lead to a local reorientation of the ferromagnetic layer. Measuring the local magnetization of the ferromagnet by x-ray absorption microscopy with circular-polarized radiation allows the analysis of the magnetic flux distribution in the superconductor with a spatial resolution on the nanoscale.

  3. High-resolution sagittal and coronal reformatted CT images of the larynx

    SciTech Connect

    Silverman, P.M.; Johnson, G.A.; Korobkin, M.

    1983-04-01

    Computed tomography has become the major technique for evaluation of patients with laryngeal corcinoma and trauma to the larynx. The routine examination usually consists of 5 mm contiguous selection through the larynx in quiet respiration. Reformatted images obtained from these sections have not been of clinical value, in part because of the poor resolution of these images. In the past, thin-section scanning (1.5 mm collimation) has been impractical because of the significant time required to scan the entire larynx. By using the technique of rapid sequential scanning with automated table incrementation this logistic difficulty can be overcome, and the total thin-section examination may be performed in less than 9 min. Sophisticated computer software allows rapid reformatting of transaxial images in sagittal and coronal planes. This report illustates the normal and abnormal appearance of the larynx on coronal and sagittal reformatted images and compares reformatted images using the routine technique to those using the thin-section technique.

  4. High-Resolution Imaging of Proteins in Human Teeth by Scanning Probe Microscopy

    SciTech Connect

    Gruverman, A.; Wu, D.; Rodriguez, Brian J; Kalinin, Sergei V; Habelitz, S.

    2007-01-01

    High-resolution studies of dental tissues are of considerable interest for biomedical engineering and clinical applications. In this paper, we demonstrate the application of piezoresponse force microscopy (PFM) to nanoscale imaging of internal structure of human teeth by monitoring the local mechanical response to an electrical bias applied via a conductive tip. It is shown that PFM is capable of detecting dissimilar components of dental tissues, namely, proteins and calcified matrix, which have resembling morphology but different piezoelectric properties. It is demonstrated that collagen fibrils revealed in chemically treated intertubular dentin exhibit high piezoelectric activity and can be visualized in PFM with spatial resolution of 10 nm. Evidence of the presence of protein inclusions of 100-200 nm wide and several micrometers long in tooth enamel has been obtained. Furthermore, it is found that the peritubular dentin and intertubular dentin exhibit different piezoelectric behavior suggesting different concentration of collagen fibrils. The obtained results demonstrate a high potential of PFM in providing an additional insight into the structure of dental tissues. It is suggested that the PFM approach can be used to study the structure of a wide range of biological materials by monitoring their electromechanical behavior at the nanoscale.

  5. Ultra-high resolution optical CT dosimetry for the visualisation of synchrotron microbeam therapy doses

    NASA Astrophysics Data System (ADS)

    Doran, S. J.; Rahman, A. T. Abdul; Bräuer-Krisch, E.; Brochard, T.; Adamovics, J.

    2013-06-01

    Optical CT is a method that can potentially provide both accurate dosimetry at high spatial resolution and 3-D visualisation over a large field-of-view in a single dataset. The major factors limiting spatial resolution in previous studies are analysed here and it is shown that improvements in equipment specification can overcome many of these. The need for ultra-high spatial resolution in the verification of microbeam radiation therapy verification is demonstrated and example images of a PRESAGE® sample are presented.

  6. Method and apparatus for a high-resolution three dimensional confocal scanning transmission electron microscope

    DOEpatents

    de Jonge, Niels [Oak Ridge, TN

    2010-08-17

    A confocal scanning transmission electron microscope which includes an electron illumination device providing an incident electron beam propagating in a direction defining a propagation axis, and a precision specimen scanning stage positioned along the propagation axis and movable in at least one direction transverse to the propagation axis. The precision specimen scanning stage is configured for positioning a specimen relative to the incident electron beam. A projector lens receives a transmitted electron beam transmitted through at least part of the specimen and focuses this transmitted beam onto an image plane, where the transmitted beam results from the specimen being illuminated by the incident electron beam. A detection system is placed approximately in the image plane.

  7. High resolution DAS via sinusoidal frequency scan OFDR (SFS-OFDR).

    PubMed

    Leviatan, Eyal; Eyal, Avishay

    2015-12-28

    There are many advantages to using direct frequency modulation for OFDR based DAS. However, achieving sufficiently linear scan via direct frequency modulation is challenging and poses limits on the scan parameters. A novel method for analyzing sinusoidal frequency modulated light is presented and demonstrated for both static and dynamic sensing. SFS-OFDR projects the measured signal onto appropriate sinusoidal phase terms to obtain spatial information. Thus, by using SFS-OFDR on sinusoidal modulated light it is possible to make use of the many advantages offered by direct frequency modulation without the limitations posed by the linearity requirement.

  8. High-resolution, high-throughput imaging with a multibeam scanning electron microscope.

    PubMed

    Eberle, A L; Mikula, S; Schalek, R; Lichtman, J; Knothe Tate, M L; Zeidler, D

    2015-08-01

    Electron-electron interactions and detector bandwidth limit the maximal imaging speed of single-beam scanning electron microscopes. We use multiple electron beams in a single column and detect secondary electrons in parallel to increase the imaging speed by close to two orders of magnitude and demonstrate imaging for a variety of samples ranging from biological brain tissue to semiconductor wafers.

  9. Comparison of quantitative myocardial perfusion imaging CT to fluorescent microsphere-based flow from high-resolution cryo-images

    NASA Astrophysics Data System (ADS)

    Eck, Brendan L.; Fahmi, Rachid; Levi, Jacob; Fares, Anas; Wu, Hao; Li, Yuemeng; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    Myocardial perfusion imaging using CT (MPI-CT) has the potential to provide quantitative measures of myocardial blood flow (MBF) which can aid the diagnosis of coronary artery disease. We evaluated the quantitative accuracy of MPI-CT in a porcine model of balloon-induced LAD coronary artery ischemia guided by fractional flow reserve (FFR). We quantified MBF at baseline (FFR=1.0) and under moderate ischemia (FFR=0.7) using MPI-CT and compared to fluorescent microsphere-based MBF from high-resolution cryo-images. Dynamic, contrast-enhanced CT images were obtained using a spectral detector CT (Philips Healthcare). Projection-based mono-energetic images were reconstructed and processed to obtain MBF. Three MBF quantification approaches were evaluated: singular value decomposition (SVD) with fixed Tikhonov regularization (ThSVD), SVD with regularization determined by the L-Curve criterion (LSVD), and Johnson-Wilson parameter estimation (JW). The three approaches over-estimated MBF compared to cryo-images. JW produced the most accurate MBF, with average error 33.3+/-19.2mL/min/100g, whereas LSVD and ThSVD had greater over-estimation, 59.5+/-28.3mL/min/100g and 78.3+/-25.6 mL/min/100g, respectively. Relative blood flow as assessed by a flow ratio of LAD-to-remote myocardium was strongly correlated between JW and cryo-imaging, with R2=0.97, compared to R2=0.88 and 0.78 for LSVD and ThSVD, respectively. We assessed tissue impulse response functions (IRFs) from each approach for sources of error. While JW was constrained to physiologic solutions, both LSVD and ThSVD produced IRFs with non-physiologic properties due to noise. The L-curve provided noise-adaptive regularization but did not eliminate non-physiologic IRF properties or optimize for MBF accuracy. These findings suggest that model-based MPI-CT approaches may be more appropriate for quantitative MBF estimation and that cryo-imaging can support the development of MPI-CT by providing spatial distributions of MBF.

  10. High-resolution, high-throughput imaging with a multibeam scanning electron microscope

    PubMed Central

    EBERLE, AL; MIKULA, S; SCHALEK, R; LICHTMAN, J; TATE, ML KNOTHE; ZEIDLER, D

    2015-01-01

    Electron–electron interactions and detector bandwidth limit the maximal imaging speed of single-beam scanning electron microscopes. We use multiple electron beams in a single column and detect secondary electrons in parallel to increase the imaging speed by close to two orders of magnitude and demonstrate imaging for a variety of samples ranging from biological brain tissue to semiconductor wafers. Lay Description The composition of our world and our bodies on the very small scale has always fascinated people, making them search for ways to make this visible to the human eye. Where light microscopes reach their resolution limit at a certain magnification, electron microscopes can go beyond. But their capability of visualizing extremely small features comes at the cost of a very small field of view. Some of the questions researchers seek to answer today deal with the ultrafine structure of brains, bones or computer chips. Capturing these objects with electron microscopes takes a lot of time – maybe even exceeding the time span of a human being – or new tools that do the job much faster. A new type of scanning electron microscope scans with 61 electron beams in parallel, acquiring 61 adjacent images of the sample at the same time a conventional scanning electron microscope captures one of these images. In principle, the multibeam scanning electron microscope’s field of view is 61 times larger and therefore coverage of the sample surface can be accomplished in less time. This enables researchers to think about large-scale projects, for example in the rather new field of connectomics. A very good introduction to imaging a brain at nanometre resolution can be found within course material from Harvard University on http://www.mcb80x.org/# as featured media entitled ‘connectomics’. PMID:25627873

  11. SU-E-T-296: Dosimetric Analysis of Small Animal Image-Guided Irradiator Using High Resolution Optical CT Imaging of 3D Dosimeters

    SciTech Connect

    Na, Y; Qian, X; Wuu, C; Adamovics, J

    2015-06-15

    Purpose: To verify the dosimetric characteristics of a small animal image-guided irradiator using a high-resolution of optical CT imaging of 3D dosimeters. Methods: PRESAEGE 3D dosimeters were used to determine dosimetric characteristics of a small animal image-guided irradiator and compared with EBT2 films. Cylindrical PRESAGE dosimeters with 7cm height and 6cm diameter were placed along the central axis of the beam. The films were positioned between 6×6cm{sup 2} cubed plastic water phantoms perpendicular to the beam direction with multiple depths. PRESAGE dosimeters and EBT2 films were then irradiated with the irradiator beams at 220kVp and 13mA. Each of irradiated PRESAGE dosimeters named PA1, PA2, PB1, and PB2, was independently scanned using a high-resolution single laser beam optical CT scanner. The transverse images were reconstructed with a 0.1mm high-resolution pixel. A commercial Epson Expression 10000XL flatbed scanner was used for readout of irradiated EBT2 films at a 0.4mm pixel resolution. PDD curves and beam profiles were measured for the irradiated PRESAGE dosimeters and EBT2 films. Results: The PDD agreements between the irradiated PRESAGE dosimeter PA1, PA2, PB1, PB2 and the EB2 films were 1.7, 2.3, 1.9, and 1.9% for the multiple depths at 1, 5, 10, 15, 20, 30, 40 and 50mm, respectively. The FWHM measurements for each PRESAEGE dosimeter and film agreed with 0.5, 1.1, 0.4, and 1.7%, respectively, at 30mm depth. Both PDD and FWHM measurements for the PRESAGE dosimeters and the films agreed overall within 2%. The 20%–80% penumbral widths of each PRESAGE dosimeter and the film at a given depth were respectively found to be 0.97, 0.91, 0.79, 0.88, and 0.37mm. Conclusion: Dosimetric characteristics of a small animal image-guided irradiator have been demonstrated with the measurements of PRESAGE dosimeter and EB2 film. With the high resolution and accuracy obtained from this 3D dosimetry system, precise targeting small animal irradiation can be

  12. Characterization of rock thermal conductivity by high-resolution optical scanning

    USGS Publications Warehouse

    Popov, Y.A.; Pribnow, D.F.C.; Sass, J.H.; Williams, C.F.; Burkhardt, H.

    1999-01-01

    We compared thress laboratory methods for thermal conductivity measurements: divided-bar, line-source and optical scanning. These methods are widely used in geothermal and petrophysical studies, particularly as applied to research on cores from deep scientific boreholes. The relatively new optical scanning method has recently been perfected and applied to geophysical problems. A comparison among these methods for determining the thermal conductivity tensor for anisotropic rocks is based on a representative collection of 80 crystalline rock samples from the KTB continental deep borehole (Germany). Despite substantial thermal inhomogeneity of rock thermal conductivity (up to 40-50% variation) and high anisotropy (with ratios of principal values attaining 2 and more), the results of measurements agree very well among the different methods. The discrepancy for measurements along the foliation is negligible (<1%). The component of thermal conductivity normal to the foliation reveals somewhat larger differences (3-4%). Optical scanning allowed us to characterize the thermal inhomogeneity of rocks and to identify a three-dimensional anisotropy in thermal conductivity of some gneiss samples. The merits of optical scanning include minor random errors (1.6%), the ability to record the variation of thermal conductivity along the sample, the ability to sample deeply using a slow scanning rate, freedom from constraints for sample size and shape, and quality of mechanical treatment of the sample surface, a contactless mode of measurement, high speed of operation, and the ability to measure on a cylindrical sample surface. More traditional methods remain superior for characterizing bulk conductivity at elevated temperature.Three laboratory methods including divided-bar, line-source and optical scanning are widely applied in geothermal and petrophysical studies. In this study, these three methods were compared for determining the thermal conductivity tensor for anisotropic rocks

  13. Automated Classification of Usual Interstitial Pneumonia using Regional Volumetric Texture Analysis in High-Resolution CT

    PubMed Central

    Depeursinge, Adrien; Chin, Anne S.; Leung, Ann N.; Terrone, Donato; Bristow, Michael; Rosen, Glenn; Rubin, Daniel L.

    2014-01-01

    Objectives We propose a novel computational approach for the automated classification of classic versus atypical usual interstitial pneumonia (UIP). Materials and Methods 33 patients with UIP were enrolled in this study. They were classified as classic versus atypical UIP by a consensus of two thoracic radiologists with more than 15 years of experience using the American Thoracic Society evidence–based guidelines for CT diagnosis of UIP. Two cardiothoracic fellows with one year of subspecialty training provided independent readings. The system is based on regional characterization of the morphological tissue properties of lung using volumetric texture analysis of multiple detector CT images. A simple digital atlas with 36 lung subregions is used to locate texture properties, from which the responses of multi-directional Riesz wavelets are obtained. Machine learning is used to aggregate and to map the regional texture attributes to a simple score that can be used to stratify patients with UIP into classic and atypical subtypes. Results We compared the predictions based on regional volumetric texture analysis with the ground truth established by expert consensus. The area under the receiver operating characteristic curve of the proposed score was estimated to be 0.81 using a leave-one-patient-out cross-validation, with high specificity for classic UIP. The performance of our automated method was found to be similar to that of the two fellows and to the agreement between experienced chest radiologists reported in the literature. However, the errors of our method and the fellows occurred on different cases, which suggests that combining human and computerized evaluations may be synergistic. Conclusions Our results are encouraging and suggest that an automated system may be useful in routine clinical practice as a diagnostic aid for identifying patients with complex lung disease such as classic UIP, obviating the need for invasive surgical lung biopsy and its

  14. Galileo PPR at Io: High Resolution Scans Taken in Conjunction with SSA and NIMS Data

    NASA Technical Reports Server (NTRS)

    Rathbun, J. A.; Spencer, J. R.; Tamppari, L. K.; Martin, T. Z.; Barnard, L.; Travis, L. D.

    2003-01-01

    The Galileo Photopolarimeter-Radiometer (PPR), when used in the radiometry mode which is most often used at Io, is a long-wavelength infrared single-aperture photometer. It is sensitive to temperatures from about 60 to several hundred K, and is thus useful for studying the volcanoes and background temperatures on Io. PPR can take raster scan images when it is the primary instrument being used (these data were discussed last year, see Rathbun et al., 2002). It can also take data in ride-along mode in conjunction with another remote sensing instrument (either SSI or NIMS) producing one-dimensional temperature scans. The best data of this type were taken during the close approach flybys during orbits I24, I25, I27, I31, I32, and I33 and include measurements of the volcanoes Pele, Prometheus, Pillan, Zamama, Tvashtar, Daedalus, Amarani, Gish Bar, Isum, Emakong, Tupan, and Tohil.

  15. Characterization of High Resolution Resists and Metal Shims by Scanning Probe Microscopy

    NASA Astrophysics Data System (ADS)

    Sexton, B. A.; Marnock, R. J.

    2000-03-01

    Technologies such as compact disc (CD) manufacturing, hologram embossing, and security printing rely on the reproduction of micro-patterns generated on surfaces by optical or electron-beam lithographic writing onto electron-beam or photoresists. The periodicity of such patterns varies from sub-micron to several microns, with depths up to 0.5 [mu]m. The scanning probe microscope (SPM) is becoming a routine tool for analysis of these micro-patterns, to check on depths and lateral dimensions of features. Direct scanning of resist-covered plates is now possible, without damage, using resonant low-contact force SPM with etched silicon cantilevers. Metal shims produced from the master resist plates can also be scanned and checked for defects prior to production of embossed foils. The present article discusses examples of the use of a Digital Instruments 3100 microscope in analysis of production electron-beam lithography plates with a 0.5 [mu]m resist thickness. We also examine features of nickel replicas (father and mother shims) produced by electroforming from the original plate. With SPM measurements of the development profile of a particular plate, corrections can be made to exposures and development times during production to correct errors. An example is given of such a feedback process.

  16. Imaging interactions of metal oxide nanoparticles with macrophage cells by ultra-high resolution scanning electron microscopy techniques.

    PubMed

    Plascencia-Villa, Germán; Starr, Clarise R; Armstrong, Linda S; Ponce, Arturo; José-Yacamán, Miguel

    2012-11-01

    Use of engineered metal oxide nanoparticles in a plethora of biological applications and custom products has warned about some possible dose-dependent cytotoxic effects. Macrophages are key components of the innate immune system used to study possible toxic effects and internalization of different nanoparticulate materials. In this work, ultra-high resolution field emission scanning electron microscopy (FE-SEM) was used to offer new insights into the dynamical processes of interaction of nanomaterials with macrophage cells dosed with different concentrations of metal oxide nanoparticles (CeO(2), TiO(2) and ZnO). The versatility of FE-SEM has allowed obtaining a detailed characterization of processes of adsorption and endocytosis of nanoparticles, by using advanced analytical and imaging techniques on complete unstained uncoated cells, including secondary electron imaging, high-sensitive backscattered electron imaging, X-ray microanalysis and stereoimaging. Low voltage BF/DF-STEM confirmed nanoparticle adsorption and internalization into endosomes of CeO(2) and TiO(2), whereas ZnO develop apoptosis after 24 h of interaction caused by dissolution and invasion of cell nucleus. Ultra-high resolution scanning electron microscopy techniques provided new insights into interactions of inorganic nanoparticles with macrophage cells with high spatial resolution.

  17. High-resolution adaptive optics scanning laser ophthalmoscope with multiple deformable mirrors

    DOEpatents

    Chen, Diana C.; Olivier, Scot S.; Jones; Steven M.

    2010-02-23

    An adaptive optics scanning laser ophthalmoscopes is introduced to produce non-invasive views of the human retina. The use of dual deformable mirrors improved the dynamic range for correction of the wavefront aberrations compared with the use of the MEMS mirror alone, and improved the quality of the wavefront correction compared with the use of the bimorph mirror alone. The large-stroke bimorph deformable mirror improved the capability for axial sectioning with the confocal imaging system by providing an easier way to move the focus axially through different layers of the retina.

  18. Laser Scanning for the definition of high resolution topography in the Apuan Alps (IT) marble district

    NASA Astrophysics Data System (ADS)

    Riccucci, Silvia; Salvini, Riccardo; Francioni, Mirko

    2010-05-01

    The present paper describes the results of five laser scanning surveys performed by a Leica™ ScanStation2 with the aim of producing an high definition topography of a quarry, at the scale of 1:1,000. The project comes from a joint research carried out by the Authors in collaboration with the Local Sanitary Unit Agency (ASL n.1) of Massa and Carrara (IT). The main objective of this work has been the survey of both the exploited quarry walls and the upper residual and natural slopes. The area of interest is characterized by several quarry fronts which develop to variable and alternate directions to create very evident rock spurs, from NW-SE to NE-SW trending for a total wideness of about 2 hectares. Moreover, the quarry walls are sub-vertical and sometimes overhang by a total height of 100 m in respect to the quarry floor. Differential GPS and orthometric correction have been applied in order to co-register and to georeference the five point clouds; for these purposes a series of optical targets have been measured using a Laser Total Station. The subsequent phase has been the mesh construction and editing, from which a topographic map, 25 cm equidistance contours lines, has been created. The planimetric map shows the position and the geometry of crests, banks, escarpments, walls and all others exploitation features and the characteristics of the upper natural slopes. Morphological profiles along the maximum slope have been realized in order to better plan the future extractive activities according to the regional law. In order to make easier the prospective observation of detailed and overall areas, 3D views of multi-directional orientation have been realized. The produced data has been published by using the free LeicaTM TruView plug-in for Internet Explorer in a way to easily view the photographs and to measure the laser scan point clouds. Processing results have highlighted the higher spatial resolution of data coming from laser scanning in respect to the

  19. Microstructure development in particulate coatings examined with high-resolution cryogenic scanning electron microscopy

    SciTech Connect

    Sheehan, J.G.; Davis, H.T.; Scriven, L.E.; Takamura, Koichi

    1993-12-01

    The authors used cryogenic scanning electron microscopy to examine the early stages of latex film formation. They visualized the influence of ionic strength and extent of carboxylation in latex-calcium carbonate formulations and in latex-only formulations. Results demonstrated that latex particles deposited on calcium carbonate surfaces creating a suspension of carboxylic acid-stabilized calcium carbonate particles. Images of consolidation fronts showed that variation of ionic strength and extent of carboxylation dramatically changes the way latex particles consolidate and form films.

  20. Scanning Photovoltage Technique for High Resolution Non-Destructive Characterization of Semiconductor Wafers.

    DTIC Science & Technology

    1985-10-01

    41 Fmenti I 13-255-5309 AA~ L lvfP FORM 1473,84 MlAR 83 APR edition may 3e use jintii emnausved. SECURITY CLASSIFICATION OF THIS All orier edicions ...radiation hard- ness. In particular, the GaAs industry that fabricates both digital and micro- wave integrated circuits requires defect mapping...scanning is provided by a piezoelectric x-y stage with a resolution of 0.5 microns. A digital controller is used to coordinate the motion of these two x-y

  1. High resolution scanning optical imaging of a frozen polymer p-n junction

    NASA Astrophysics Data System (ADS)

    AlTal, Faleh; Gao, Jun

    2016-09-01

    Semiconductor homojunctions such as p-n or p-i-n junctions are the building blocks of many semiconductor devices such as diodes, photodetectors, transistors, or solar cells. The determination of junction depletion width is crucial for the design and realization of high-performance devices. The polymer analogue of a conventional p-n or p-i-n junction can be created by in situ electrochemical doping in a polymer light-emitting electrochemical cell (LEC). As a result of doping and junction formation, the LECs possess some highly desirable device characteristics. The LEC junction, however, is still poorly understood due to the difficulties of characterizing a dynamic-junction device. Here, we report concerted optical-beam-induced-current (OBIC) and scanning photoluminescence (PL) imaging studies of planar LECs that have been frozen to preserve the doping profile. By optimizing the cell composition, the electrode work function, and the turn-on conditions, we realize a long, straight, and highly emissive p-n junction with an interelectrode spacing of 700 μm. The extremely broad planar cell allows for time-lapse fluorescence imaging of the in situ electrochemical doping process and detailed scanning of the entire cell. A total of eighteen scans at seven locations along the junction have been performed using a versatile, custom cryogenic laser scanning apparatus. The Gaussian OBIC profiles yield an average 1/e2 junction width of only 1.5 μm, which is the smallest ever reported in a planar LEC. The controlled dedoping of the frozen device via warming cycles leads to an unexpectedly narrower OBIC profile, suggesting the presence and disappearance of fine structures at the edges of the frozen p-n junction. The results reported in this work provide new insight into the nature and structure of the LEC p-n junction. Since only about 0.2% of the entire device area is photoactive in response to an incident optical beam, the effective junction width (or volume) must be

  2. Line-scanning confocal microscopy for high-resolution imaging of upconverting rare-earth-based contrast agents

    NASA Astrophysics Data System (ADS)

    Higgins, Laura M.; Zevon, Margot; Ganapathy, Vidya; Sheng, Yang; Tan, Mei Chee; Riman, Richard E.; Roth, Charles M.; Moghe, Prabhas V.; Pierce, Mark C.

    2015-11-01

    Rare-earth (RE) doped nanocomposites emit visible luminescence when illuminated with continuous wave near-infrared light, making them appealing candidates for use as contrast agents in biomedical imaging. However, the emission lifetime of these materials is much longer than the pixel dwell times used in scanning intravital microscopy. To overcome this limitation, we have developed a line-scanning confocal microscope for high-resolution, optically sectioned imaging of samples labeled with RE-based nanomaterials. Instrument performance is quantified using calibrated test objects. NaYF4:Er,Yb nanocomposites are imaged in vitro, and in ex vivo tissue specimens, with direct comparison to point-scanning confocal microscopy. We demonstrate that the extended pixel dwell time of line-scanning confocal microscopy enables subcellular-level imaging of these nanomaterials while maintaining optical sectioning. The line-scanning approach thus enables microscopic imaging of this emerging class of contrast agents for preclinical studies, with the potential to be adapted for real-time in vivo imaging in the clinic.

  3. Line-scanning confocal microscopy for high-resolution imaging of upconverting rare-earth-based contrast agents

    PubMed Central

    Higgins, Laura M.; Zevon, Margot; Ganapathy, Vidya; Sheng, Yang; Tan, Mei Chee; Riman, Richard E.; Roth, Charles M.; Moghe, Prabhas V.; Pierce, Mark C.

    2015-01-01

    Abstract. Rare-earth (RE) doped nanocomposites emit visible luminescence when illuminated with continuous wave near-infrared light, making them appealing candidates for use as contrast agents in biomedical imaging. However, the emission lifetime of these materials is much longer than the pixel dwell times used in scanning intravital microscopy. To overcome this limitation, we have developed a line-scanning confocal microscope for high-resolution, optically sectioned imaging of samples labeled with RE-based nanomaterials. Instrument performance is quantified using calibrated test objects. NaYF4:Er,Yb nanocomposites are imaged in vitro, and in ex vivo tissue specimens, with direct comparison to point-scanning confocal microscopy. We demonstrate that the extended pixel dwell time of line-scanning confocal microscopy enables subcellular-level imaging of these nanomaterials while maintaining optical sectioning. The line-scanning approach thus enables microscopic imaging of this emerging class of contrast agents for preclinical studies, with the potential to be adapted for real-time in vivo imaging in the clinic. PMID:26603495

  4. High-resolution differential scanning calorimetric analysis of the subunits of Escherichia coli aspartate transcarbamoylase.

    PubMed

    Edge, V; Allewell, N M; Sturtevant, J M

    1985-10-08

    The thermal denaturation of the catalytic (c3) and regulatory (r2) subunits of Escherichia coli aspartate transcarbamoylase (c6r6) in the absence and presence of various ligands has been studied by means of highly sensitive differential scanning calorimetry. The denaturation of both types of subunit is irreversible as judged by the facts that the proteins coagulate when heated and that no endotherm is observed when previously scanned protein is rescanned. Despite this apparent irreversibility, there is empirical justification for analyzing the calorimetric data in terms of equilibrium thermodynamics as embodied in the van't Hoff equation. The observed curves of excess apparent specific heat vs. temperature are asymmetric and can be expressed within experimental uncertainty as the sums of sequential two-state steps, a minimum of two steps being required for r2 and three for c3. As previously reported [Vickers, K. P., Donovan, J. W., & Schachman, H. K. (1978) J. Biol. Chem. 253, 8493-8498], the addition of the effectors ATP and CTP raises the denaturation temperature of r2 and lowers that of c3 while the addition of the bisubstrate analogue N-(phosphonoacetyl)-L-aspartate raises the denaturation temperature of c3 and lowers that of r2. These effects vary with ligand concentration in the manner expected from the van't Hoff equation, indicating that they are simply manifestations of Le Chatelier's principle rather than being due to "stabilization" or "destabilization" of the proteins. The denaturational enthalpy is increased in those cases of ligand binding in which the denaturation temperature is increased, because of the contribution from the enthalpy of dissociation of the ligand.

  5. A maximum likelihood method for high resolution proton radiography/proton CT

    NASA Astrophysics Data System (ADS)

    Collins-Fekete, Charles-Antoine; Brousmiche, Sébastien; Portillo, Stephen K. N.; Beaulieu, Luc; Seco, Joao

    2016-12-01

    Multiple Coulomb scattering (MCS) is the largest contributor to blurring in proton imaging. In this work, we developed a maximum likelihood least squares estimator that improves proton radiography’s spatial resolution. The water equivalent thickness (WET) through projections defined from the source to the detector pixels were estimated such that they maximizes the likelihood of the energy loss of every proton crossing the volume. The length spent in each projection was calculated through the optimized cubic spline path estimate. The proton radiographies were produced using Geant4 simulations. Three phantoms were studied here: a slanted cube in a tank of water to measure 2D spatial resolution, a voxelized head phantom for clinical performance evaluation as well as a parametric Catphan phantom (CTP528) for 3D spatial resolution. Two proton beam configurations were used: a parallel and a conical beam. Proton beams of 200 and 330 MeV were simulated to acquire the radiography. Spatial resolution is increased from 2.44 lp cm-1 to 4.53 lp cm-1 in the 200 MeV beam and from 3.49 lp cm-1 to 5.76 lp cm-1 in the 330 MeV beam. Beam configurations do not affect the reconstructed spatial resolution as investigated between a radiography acquired with the parallel (3.49 lp cm-1 to 5.76 lp cm-1) or conical beam (from 3.49 lp cm-1 to 5.56 lp cm-1). The improved images were then used as input in a photon tomography algorithm. The proton CT reconstruction of the Catphan phantom shows high spatial resolution (from 2.79 to 5.55 lp cm-1 for the parallel beam and from 3.03 to 5.15 lp cm-1 for the conical beam) and the reconstruction of the head phantom, although qualitative, shows high contrast in the gradient region. The proposed formulation of the optimization demonstrates serious potential to increase the spatial resolution (up by 65 % ) in proton radiography and greatly accelerate proton computed tomography reconstruction.

  6. A maximum likelihood method for high resolution proton radiography/proton CT.

    PubMed

    Collins-Fekete, Charles-Antoine; Brousmiche, Sébastien; Portillo, Stephen K N; Beaulieu, Luc; Seco, Joao

    2016-12-07

    Multiple Coulomb scattering (MCS) is the largest contributor to blurring in proton imaging. In this work, we developed a maximum likelihood least squares estimator that improves proton radiography's spatial resolution. The water equivalent thickness (WET) through projections defined from the source to the detector pixels were estimated such that they maximizes the likelihood of the energy loss of every proton crossing the volume. The length spent in each projection was calculated through the optimized cubic spline path estimate. The proton radiographies were produced using Geant4 simulations. Three phantoms were studied here: a slanted cube in a tank of water to measure 2D spatial resolution, a voxelized head phantom for clinical performance evaluation as well as a parametric Catphan phantom (CTP528) for 3D spatial resolution. Two proton beam configurations were used: a parallel and a conical beam. Proton beams of 200 and 330 MeV were simulated to acquire the radiography. Spatial resolution is increased from 2.44 lp cm(-1) to 4.53 lp cm(-1) in the 200 MeV beam and from 3.49 lp cm(-1) to 5.76 lp cm(-1) in the 330 MeV beam. Beam configurations do not affect the reconstructed spatial resolution as investigated between a radiography acquired with the parallel (3.49 lp cm(-1) to 5.76 lp cm(-1)) or conical beam (from 3.49 lp cm(-1) to 5.56 lp cm(-1)). The improved images were then used as input in a photon tomography algorithm. The proton CT reconstruction of the Catphan phantom shows high spatial resolution (from 2.79 to 5.55 lp cm(-1) for the parallel beam and from 3.03 to 5.15 lp cm(-1) for the conical beam) and the reconstruction of the head phantom, although qualitative, shows high contrast in the gradient region. The proposed formulation of the optimization demonstrates serious potential to increase the spatial resolution (up by 65[Formula: see text]) in proton radiography and greatly accelerate proton computed tomography reconstruction.

  7. Acquisition of a High Resolution Field Emission Scanning Electron Microscope for the Analysis of Returned Samples

    NASA Technical Reports Server (NTRS)

    Nittler, Larry R.

    2003-01-01

    This grant furnished funds to purchase a state-of-the-art scanning electron microscope (SEM) to support our analytical facilities for extraterrestrial samples. After evaluating several instruments, we purchased a JEOL 6500F thermal field emission SEM with the following analytical accessories: EDAX energy-dispersive x-ray analysis system with fully automated control of instrument and sample stage; EDAX LEXS wavelength-dispersive x-ray spectrometer for high sensitivity light-element analysis; EDAX/TSL electron backscatter diffraction (EBSD) system with software for phase identification and crystal orientation mapping; Robinson backscatter electron detector; and an in situ micro-manipulator (Kleindiek). The total price was $550,000 (with $150,000 of the purchase supported by Carnegie institution matching funds). The microscope was delivered in October 2002, and most of the analytical accessories were installed by January 2003. With the exception of the wavelength spectrometer (which has been undergoing design changes) everything is working well and the SEM is in routine use in our laboratory.

  8. Efficient green lasers for high-resolution scanning micro-projector displays

    NASA Astrophysics Data System (ADS)

    Bhatia, Vikram; Bauco, Anthony S.; Oubei, Hassan M.; Loeber, David A. S.

    2010-02-01

    Laser-based projectors are gaining increased acceptance in mobile device market due to their low power consumption, superior image quality and small size. The basic configuration of such micro-projectors is a miniature mirror that creates an image by raster scanning the collinear red, blue and green laser beams that are individually modulated on a pixel-bypixel basis. The image resolution of these displays can be limited by the modulation bandwidth of the laser sources, and the modulation speed of the green laser has been one of the key limitations in the development of these displays. We will discuss how this limitation is fundamental to the architecture of many laser designs and then present a green laser configuration which overcomes these difficulties. In this green laser architecture infra-red light from a distributed Bragg-reflector (DBR) laser diode undergoes conversion to green light in a waveguided second harmonic generator (SHG) crystal. The direct doubling in a single pass through the SHG crystal allows the device to operate at the large modulation bandwidth of the DBR laser. We demonstrate that the resultant product has a small footprint (<0.7 cc envelope volume), high efficiency (>9% electrical-to-optical conversion) and large modulation bandwidth (>100 MHz).

  9. I-IMAS: A 1.5D sensor for high-resolution scanning

    NASA Astrophysics Data System (ADS)

    Fant, A.; Gasiorek, P.; Turchetta, R.; Avset, B.; Bergamaschi, A.; Cavouras, D.; Evangelou, I.; French, M. J.; Galbiati, A.; Georgiou, H.; Hall, G.; Iles, G.; Jones, J.; Longo, R.; Manthos, N.; Metaxas, M. G.; Noy, M.; Ostby, J. M.; Psomadellis, F.; Royle, G. J.; Schulerud, H.; Speller, R. D.; van der Stelt, P. F.; Theodoridis, S.; Triantis, F.; Venanzi, C.

    2007-04-01

    We have developed a 1.5 D CMOS active pixel sensor to be used in conjunction with a scintillator for X-ray imaging. Within the Intelligent Imaging Sensors (I-ImaS) project, multiple sensors will be aligned to form a line-scanning system and its performance evaluated with respect to existing sensors in other digital radiography systems. Each sensor contains a 512×32 array of pixels and the electronics to convert the collected amount of charge to a digital output value. These include programmable gain amplifiers (PGAs) and analogue-to-digital converters (ADCs). The gain of the PGA can be switched between one or two, to increase the sensitivity for smaller collected charge; the ADC is a 14-bit successive approximation with a sampling rate of 1.25 MHz. The ASIC includes a programmable column fixed pattern noise mitigation circuit and a digitally controllable pixel reset mode block. Here we will describe the sensor design and the expected performance.

  10. High-Resolution Adaptive Optics Scanning Laser Ophthalmoscope with Dual Deformable Mirrors

    SciTech Connect

    Chen, D C; Jones, S M; Silva, D A; Olivier, S S

    2006-08-11

    Adaptive optics scanning laser ophthalmoscope (AO SLO) has demonstrated superior optical quality of non-invasive view of the living retina, but with limited capability of aberration compensation. In this paper, we demonstrate that the use of dual deformable mirrors can effectively compensate large aberrations in the human retina. We used a bimorph mirror to correct large-stroke, low-order aberrations and a MEMS mirror to correct low-stroke, high-order aberration. The measured ocular RMS wavefront error of a test subject was 240 nm without AO compensation. We were able to reduce the RMS wavefront error to 90 nm in clinical settings using one deformable mirror for the phase compensation and further reduced the wavefront error to 48 nm using two deformable mirrors. Compared with that of a single-deformable-mirror SLO system, dual AO SLO offers much improved dynamic range and better correction of the wavefront aberrations. The use of large-stroke deformable mirrors provided the system with the capability of axial sectioning different layers of the retina. We have achieved diffraction-limited in-vivo retinal images of targeted retinal layers such as photoreceptor layer, blood vessel layer and nerve fiber layers with the combined phase compensation of the two deformable mirrors in the AO SLO.

  11. High-resolution imaging by scanning electron microscopy of semithin sections in correlation with light microscopy.

    PubMed

    Koga, Daisuke; Kusumi, Satoshi; Shodo, Ryusuke; Dan, Yukari; Ushiki, Tatsuo

    2015-12-01

    In this study, we introduce scanning electron microscopy (SEM) of semithin resin sections. In this technique, semithin sections were adhered on glass slides, stained with both uranyl acetate and lead citrate, and observed with a backscattered electron detector at a low accelerating voltage. As the specimens are stained in the same manner as conventional transmission electron microscopy (TEM), the contrast of SEM images of semithin sections was similar to TEM images of ultrathin sections. Using this technique, wide areas of semithin sections were also observed by SEM, without the obstruction of grids, which was inevitable for traditional TEM. This study also applied semithin section SEM to correlative light and electron microscopy. Correlative immunofluorescence microscopy and immune-SEM were performed in semithin sections of LR white resin-embedded specimens using a FluoroNanogold-labeled secondary antibody. Because LR white resin is hydrophilic and electron stable, this resin is suitable for immunostaining and SEM observation. Using correlative microscopy, the precise localization of the primary antibody was demonstrated by fluorescence microscopy and SEM. This method has great potential for studies examining the precise localization of molecules, including Golgi- and ER-associated proteins, in correlation with LM and SEM.

  12. Scan-o-matic: High-Resolution Microbial Phenomics at a Massive Scale

    PubMed Central

    Zackrisson, Martin; Hallin, Johan; Ottosson, Lars-Göran; Dahl, Peter; Fernandez-Parada, Esteban; Ländström, Erik; Fernandez-Ricaud, Luciano; Kaferle, Petra; Skyman, Andreas; Stenberg, Simon; Omholt, Stig; Petrovič, Uroš; Warringer, Jonas; Blomberg, Anders

    2016-01-01

    The capacity to map traits over large cohorts of individuals—phenomics—lags far behind the explosive development in genomics. For microbes, the estimation of growth is the key phenotype because of its link to fitness. We introduce an automated microbial phenomics framework that delivers accurate, precise, and highly resolved growth phenotypes at an unprecedented scale. Advancements were achieved through the introduction of transmissive scanning hardware and software technology, frequent acquisition of exact colony population size measurements, extraction of population growth rates from growth curves, and removal of spatial bias by reference-surface normalization. Our prototype arrangement automatically records and analyzes close to 100,000 growth curves in parallel. We demonstrate the power of the approach by extending and nuancing the known salt-defense biology in baker’s yeast. The introduced framework represents a major advance in microbial phenomics by providing high-quality data for extensive cohorts of individuals and generating well-populated and standardized phenomics databases PMID:27371952

  13. Extended Depth of Field for High-Resolution Scanning Transmission Electron Microscopy

    SciTech Connect

    Hovden, Robert; Xin, Huolin L.; Muller, David A.

    2010-12-02

    Aberration-corrected scanning transmission electron microscopes (STEMs) provide sub-Angstrom lateral resolution; however, the large convergence angle greatly reduces the depth of field. For microscopes with a small depth of field, information outside of the focal plane quickly becomes blurred and less defined. It may not be possible to image some samples entirely in focus. Extended depth-of-field techniques, however, allow a single image, with all areas in focus, to be extracted from a series of images focused at a range of depths. In recent years, a variety of algorithmic approaches have been employed for bright-field optical microscopy. Here, we demonstrate that some established optical microscopy methods can also be applied to extend the ~6 nm depth of focus of a 100 kV 5th-order aberration-corrected STEM (α{sub max} = 33 mrad) to image Pt-Co nanoparticles on a thick vulcanized carbon support. These techniques allow us to automatically obtain a single image with all the particles in focus as well as a complimentary topography map.

  14. Extended depth of field for high-resolution scanning transmission electron microscopy.

    PubMed

    Hovden, Robert; Xin, Huolin L; Muller, David A

    2011-02-01

    Aberration-corrected scanning transmission electron microscopes (STEMs) provide sub-Angstrom lateral resolution; however, the large convergence angle greatly reduces the depth of field. For microscopes with a small depth of field, information outside of the focal plane quickly becomes blurred and less defined. It may not be possible to image some samples entirely in focus. Extended depth-of-field techniques, however, allow a single image, with all areas in focus, to be extracted from a series of images focused at a range of depths. In recent years, a variety of algorithmic approaches have been employed for bright-field optical microscopy. Here, we demonstrate that some established optical microscopy methods can also be applied to extend the ∼ 6 nm depth of focus of a 100 kV 5th-order aberration-corrected STEM (α max = 33 mrad) to image Pt-Co nanoparticles on a thick vulcanized carbon support. These techniques allow us to automatically obtain a single image with all the particles in focus as well as a complimentary topography map.

  15. High resolution fundus imaging by confocal scanning laser ophthalmoscopy in the mouse.

    PubMed

    Paques, Michel; Simonutti, Manuel; Roux, Michel J; Picaud, Serge; Levavasseur, Etienne; Bellman, Caren; Sahel, José-Alain

    2006-04-01

    We evaluated fundus imaging using a modified confocal scanning laser ophthalmoscope (cSLO) in mice. Examinations were performed in conscious, untrained mice. The largest field of view measured 1,520 x 1,520 mu, with a significant interindividual variability, itself correlated to biometric variability. The composite field of view extended up to the ora serrata. The reflectance imaging associated light reflection from nerve fiber bundles and vessel walls, and absorption by hemoglobin and melanin. Light absorption by the pigment epithelium indeed increased the contrast of the nerve fiber layer, but impaired viewing of the choroid. Due to the confocal mode, fluorescence angiograms with clear separation of retinal and choroidal fluorescence could be obtained even in albino mice. Micrometric-scale transverse resolution and several planes of optical sectioning within the retina were obtained. This permitted for instance tridimensional, subcellular viewing of gfp-expressing retinal microglial cells in CX(3)CR1 mice. We concluded that cSLO is a promising tool for noninvasive, multimodal intravital microscopy of the fundus in the mouse.

  16. Radiological findings of the cochlear aqueduct in patients with Meniere's disease using high-resolution CT and high-resolution MRI.

    PubMed

    Park, Jonas J-H; Shen, Anmin; Keil, Sebastian; Kraemer, Nils; Westhofen, Martin

    2014-12-01

    The objective of the present study was to evaluate the cochlear aqueduct (CA) in Meniere's disease (MD) and to disclose radiological differences of CA between MD and non-MD patients by means of high-resolution computed tomography (HRCT) and high-resolution magnetic resonance imaging (HRMRI). Radiological data of 86 ears of MD patients which were separated into 52 ears of diseased side group (MD-D group) and 34 ears of contralateral non-affected side group of unilateral MD (MD-ND group), 27 ears of patients with sensorineural hearing loss (SNHL group) and 56 ears of patients with somatoform dizziness and normal hearing (control group) were analyzed retrospectively. The bony type of CA, the bony length of CA, and the bony width of CA medial orifice was measured in HRCT. The visibility of CA in HRMRI was scored. Fluid length in CA and fluid width in medial orifice were measured in HRMRI. Data were compared between MD-D, MD-ND, SNHL, and control group. There were no significant differences in the bony type of CA, bony length of CA, bony width of CA medial orifice, and fluid width of CA medial orifice between MD-D, MD-ND, SNHL and control group (p > 0.05). However, CA fluid length of MD-D (5.13 ± 1.88 mm) and of MD-ND group (5.44 ± 1.81 mm) was significantly shorter than fluid length of SNHL (6.90 ± 1.55 mm) (p < 0.001, p = 0.001) and of control group (7.43 ± 1.24 mm) (p < 0.001, p < 0.001). The ratio between CA fluid length and CA bony length was the smallest in MD-D group (0.403; p = 0.009). CA bony dimensions of affected ears of MD are normal, but CA fluid length is decreased.

  17. Review: two-photon scanning systems for clinical high resolution in vivo tissue imaging

    NASA Astrophysics Data System (ADS)

    König, K.; Müller, J.; Höfer, M.; Müller, C.; Weinigel, M.; Bückle, R.; Elsner, P.; Kaatz, M.; Messerschmidt, B.

    2008-02-01

    The femtosecond laser multiphoton tomograph DermaInspect as well as high NA two-photon GRIN microendoscopes for in vivo tomography of human skin have been used to detect malignant melanoma as well as to study the diffusion and intradermal accumulation of topically applied cosmetical and pharmaceutical components. So far, more than 500 patients and volunteers in Europe, Australia, and Asia have been investigated with this unique tomograph. Near infrared 80 MHz picojoule femtosecond laser pulses were employed to excite endogenous fluorophores such as NAD(P)H, flavoproteins, melanin, and elastin as well as fluorescent components of a variety of ointments via a twophoton excitation process. In addition, collagen has been imaged by second harmonic generation. Using a two-PMT detection system, the ratio of elastin to collagen was determined during optical sectioning. A high submicron spatial resolution and 50 picosecond temporal resolution was achieved using galvoscan mirrors and piezodriven focusing optics as well as a time-correlated single photon counting module with a fast microchannel plate detector and fast photomultipliers. Individual intratissue cells, mitochondria, melanosomes, and the morphology of the nuclei as well as extracellular matrix elements could be clearly visualized due to molecular imaging and the calculation of fluorescence lifetime images. Nanoparticles and intratissue drugs have been detected non-invasively, in situ and over a period of up to 3 months. In addition, hydration effects and UV effects were studied by monitoring modifications of cellular morphology and autofluorescence. The system was used to observe the diffusion through the stratum corneum and the accumulation and release of functionalized nanoparticles along hair shafts and epidermal ridges. The DermaInspect been also employed to gain information on skin age and wound healing in patients with ulcers. Novel developments include a galvo/piezo-scan driven flexible articulated arm as

  18. Understanding the structure of nanocatalysts with high resolution scanning/transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Francis, L. D.; Rivas, J.; José-Yacamán, M.

    2014-03-01

    Nanomaterials including nanoparticles, nanowires and nanotubes play an important role in heterogeneous catalysis. Thanks to the rapid improvement of the electron microscopic techniques and with the advent of aberration corrected electron microscopy as well as theoretical methodologies, the potential effects induced by nanocatalysts are better understood than before by unravelling their atomic structure. A brief introduction to advanced electron microscopic techniques namely aberration corrected scanning transmission electron microscopy (Cs-STEM) is presented and subsequently two examples of nanocatalysts are considered in the present review. The first example will focus on the study of bimetallic/core-shell nanoalloys. In heterogeneous catalysis, catalysts containing two or more metals might show significantly different catalytic properties compared to the parent metals and thus are widely utilized in several catalytic reactions. Atom-by-atom insights of the nanoalloy based catalysts ex: Au-Pd will be described in the present review using a combination of advanced electron microscopic and spectroscopic techniques. A related example on the understanding of bimetallic clusters by HAADF-STEM will also be presented in addition to nanoparticles. In the second case understanding the structure of transition metal chalcogenide based nanocatalysts by HRTEM and aberration corrected STEM, for the case of MoS2 will be discussed. MoS2-based catalysts serve as model catalysts and are employed in the hydrodesulphurisations (HDS) reactions in the removal of sulphur from gasoline and related petrochemical products. They have been studied in various forms including nanowires, nanotubes and nanoplates. Their structure, atomic insights and as a consequence elucidation of their corresponding catalytic activity are thus important.

  19. Modeling river bed morphology, roughness, and surface sedimentology using high resolution terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Brasington, J.; Vericat, D.; Rychkov, I.

    2012-11-01

    Recent advances in technology have revolutionized the acquisition of topographic data, offering new perspectives on the structure and morphology of the Earth's surface. These developments have had a profound impact on the practice of river science, creating a step change in the dimensionality, resolution, and precision of fluvial terrain models. The emergence of "hyperscale" survey methods, including structure from motion photogrammetry and terrestrial laser scanning (TLS), now presents the opportunity to acquire 3-D point cloud data that capture grain-scale detail over reach-scale extents. Translating these data into geomorphologically relevant products is, however, not straightforward. Unlike traditional survey methods, TLS acquires observations rapidly and automatically, but unselectively. This results in considerable "noise" associated with backscatter from vegetation and other artifacts. Moreover, the large data volumes are difficult to visualize; require very high capacity storage; and are not incorporated readily into GIS and simulation models. In this paper we analyze the geomorphological integrity of multiscale terrain models rendered from a TLS survey of the braided River Feshie, Scotland. These raster terrain models are generated using a new, computationally efficient geospatial toolkit: the topographic point cloud analysis toolkit (ToPCAT). This performs an intelligent decimation of point cloud data into a set of 2.5-D terrain models that retain information on the high-frequency subgrid topography, as the moments of the locally detrended elevation distribution. The results quantify the degree of terrain generalization inherent in conventional fluvial DEMs and illustrate how subgrid topographic statistics can be used to map the spatial pattern of particle size, grain roughness, and sedimentary facies at the reach scale.

  20. Pulmonary fibrosis: tissue characterization using late-enhanced MRI compared with unenhanced anatomic high-resolution CT

    PubMed Central

    Lavelle, Lisa P.; Brady, Darragh; McEvoy, Sinead; Murphy, David; Gibney, Brian; Gallagher, Annika; Butler, Marcus; Shortt, Fionnula; McMullen, Marie; Fabre, Aurelie; Lynch, David A.; Keane, Michael P.; Dodd, Jonathan D.

    2017-01-01

    PURPOSE We aimed to prospectively evaluate anatomic chest computed tomography (CT) with tissue characterization late gadolinium-enhanced magnetic resonance imaging (MRI) in the evaluation of pulmonary fibrosis (PF). METHODS Twenty patients with idiopathic pulmonary fibrosis (IPF) and twelve control patients underwent late-enhanced MRI and high-resolution CT. Tissue characterization of PF was depicted using a segmented inversion-recovery turbo low-angle shot MRI sequence. Pulmonary arterial blood pool nulling was achieved by nulling main pulmonary artery signal. Images were read in random order by a blinded reader for presence and extent of overall PF (reticulation and honeycombing) at five anatomic levels. Overall extent of IPF was estimated to the nearest 5% as well as an evaluation of the ratios of IPF made up of reticulation and honeycombing. Overall grade of severity was dependent on the extent of reticulation and honeycombing. RESULTS No control patient exhibited contrast enhancement on lung late-enhanced MRI. All IPF patients were identified with late-enhanced MRI. Mean signal intensity of the late-enhanced fibrotic lung was 31.8±10.6 vs. 10.5±1.6 for normal lung regions, P < 0.001, resulting in a percent elevation in signal intensity from PF of 204.8%±90.6 compared with the signal intensity of normal lung. The mean contrast-to-noise ratio was 22.8±10.7. Late-enhanced MRI correlated significantly with chest CT for the extent of PF (R=0.78, P = 0.001) but not for reticulation, honeycombing, or coarseness of reticulation or honeycombing. CONCLUSION Tissue characterization of IPF is possible using inversion recovery sequence thoracic MRI. PMID:28067202

  1. Terrestrial laser scanning for high resolution cyclostratigraphy of chert in pelagic limestone series

    NASA Astrophysics Data System (ADS)

    Penasa, L.; Franceschi, M.; Preto, N.

    2012-04-01

    We here propose the use of terrestrial laser scanning (TLS) for the mapping of chert on natural outcrops and for rapid extraction of its distribution along stratigraphic sections. The technique permits rapid production of high-definition time series for cyclostratigraphic analysis. Chert, sometimes referred to as flint, is a widespread component of sedimentary successions. It is often found in deep water and pelagic sediments and is constituted by cryptocrystalline varieties of quartz. It is generally accepted that the origin of chert is principally biogenic; it derives from the slow alteration, through a process called maturation, of opaline organic components as tests and spicules under the influence of pore waters. Most often, chert forms nodules of various size, or more or less continuous layers. Its color shows strong variability (white, red, gray, black). Although it could record paleoceanographic and climatic changes because of its biogenic nature, the cyclostratigraphic study of chert is largely neglected. This is mainly due to the difficulty of logging it. Hand logging is time consuming, but also, because of nodules' highly variable shape, lateral variability of chert abundance is large. Photographic image-processing techniques could help in principle, but they become difficult to use when chert has a color similar to that of the host rock. Chert is easily detectable in TLS generated images because of its very low reflectivity at infrared (IR) wavelengths, also where the color of chert in visible light is close to that of the host rock. Thus, TLS data can be used to map the distribution of chert on an outcrop, and to compute its abundance along a stratigraphic section. The ultimate result of such data processing, for which a suite of original procedures was implemented, is a stratigraphic log that is suitable for time series analysis. A section in the early Cretaceous Maiolica Formation of Central Italy (Gubbio) was considered as preliminary case study for

  2. High-Resolution Imaging of Polyethylene Glycol Coated Dendrimers via Combined Atomic Force and Scanning Tunneling Microscopy.

    PubMed

    Riechers, Shawn; Zhong, Qian; Yin, Nai-Ning; Karsai, Arpad; da Rocha, Sandro R P; Liu, Gang-Yu

    2015-01-01

    Dendrimers have shown great promise as drug delivery vehicles in recent years because they can be synthesized with designed size and functionalities for optimal transportation, targeting, and biocompatibility. One of the most well-known termini used for biocompatibility is polyethylene glycol (PEG), whose performance is affected by its actual conformation. However, the conformation of individual PEG bound to soft materials such as dendrimers has not been directly observed. Using atomic force microscopy (AFM) and scanning tunneling microscopy (STM), this work characterizes the structure adopted by PEGylated dendrimers with the highest resolution reported to date. AFM imaging enables visualization of the individual dendrimers, as well as the differentiation and characterization of the dendrimer core and PEG shell. STM provides direct imaging of the PEG extensions with high-resolution. Collectively, this investigation provides important insight into the structure of coated dendrimers, which is crucial for the design and development of better drug delivery vehicles.

  3. The role of high-resolution chest CT in the diagnosis of neuroendocrine cell hyperplasia of infancy - A rare form of pediatric interstitial lung disease.

    PubMed

    Lee, Julia; Sanchez, Thomas Ray; Zhang, Yanhong; Jhawar, Sanjay

    2015-01-01

    Interstitial lung disease (ILD) is rare in infancy or early childhood. Differentiating between the different types of ILD is important for reasons of treatment, monitoring of clinical course and prognosis. We present a case of a 5-month old female with tachypnea and hypoxemia. The clinical suspicion of neuroendocrine cell hyperplasia of infancy (NEHI) was confirmed by high-resolution chest CT and subsequent lung biopsy. We conclude that high-resolution chest CT has characteristics findings that can be used as a non-invasive test to support the clinical diagnosis of neuroendocrine cell hyperplasia of infancy.

  4. CT scan correlates of gesture recognition.

    PubMed

    Ferro, J M; Martins, I P; Mariano, G; Caldas, A C

    1983-10-01

    The ability to recognise gestures was studied in 65 left-hemispheric stroke patients whose lesions were located by CT scan. In the acute stage (first month) frontal lobe and basal ganglia were frequently involved in patients showing inability to recognise gestures. In the later (third to fourth month) and chronic stages (greater than 6 months) parietal lobe involvement was important; lesions causing gesture recognition impairment were larger, had more extensive and frequent parietal involvement and produced less temporal lobe damage than those causing aural comprehension defects. These findings are discussed in the light of recent models of cerebral localisation of complex functions.

  5. SU-E-CAMPUS-T-05: Validation of High-Resolution 3D Patient QA for Proton Pencil Beam Scanning and IMPT by Polymer Gel Dosimetry

    SciTech Connect

    Cardin, A; Avery, S; Ding, X; Kassaee, A; Lin, L; Maryanski, M

    2014-06-15

    Purpose: Validation of high-resolution 3D patient QA for proton pencil beam scanning and IMPT by polymer gel dosimetry. Methods: Four BANG3Pro polymer gel dosimeters (manufactured by MGS Research Inc, Madison, CT) were used for patient QA at the Robert's Proton Therapy Center (RPTC, Philadelphia, PA). All dosimeters were sealed in identical thin-wall Pyrex glass spheres. Each dosimeter contained a set of markers for 3D registration purposes. The dosimeters were mounted in a consistent and reproducible manner using a custom build holder. Two proton pencil beam scanning plans were designed using Varian Eclipse™ treatment planning system: 1) A two-field intensity modulated proton therapy (IMPT) plan and 2) one single field uniform dose (SFUD) plan. The IMPT fields were evaluated as a composite plan and individual fields, the SFUD plan was delivered as a single field plan.Laser CT scanning was performed using the manufacturer's OCTOPUS-IQ axial transmission laser CT scanner using a 1 mm slice thickness. 3D registration, analysis, and OD/cm to absorbed dose calibrations were perfomed using DICOM RT-Dose and CT files, and software developed by the manufacturer. 3D delta index, a metric equivalent to the gamma tool, was used for dose comparison. Results: Very good agreement with single IMPT fields and with SFUD was obtained. Composite IMPT fields had a less satisfactory agreement. The single fields had 3D delta index passing rates (3% dose difference, 3 mm DTA) of 98.98% and 94.91%. The composite 3D delta index passing rate was 80.80%. The SFUD passing rate was 93.77%. Required shifts of the dose distributions were less than 4 mm. Conclusion: A formulation of the BANG3Pro polymer gel dosimeter, suitable for 3D QA of proton patient plans is established and validated. Likewise, the mailed QA analysis service provided by the manufacturer is a practical option when required resources are unavailable. We fully disclose that the subject of this research regards a production

  6. Modeling Shift-Variant X-Ray Focal Spot Blur for High-Resolution Flat-Panel Cone-Beam CT

    PubMed Central

    Tilley, Steven; Zbijewski, Wojciech; Siewerdsen, Jeffrey H.; Stayman, J. Webster

    2016-01-01

    Flat-panel cone-beam CT (CBCT) has been applied clinically in a number of high-resolution applications. Increasing geometric magnification can potentially improve resolution, but also increases blur due to an extended x-ray focal-spot. We present a shift-variant focal-spot blur model and incorporate it into a model-based iterative-reconstruction algorithm. We apply this algorithm to simulation and CBCT test-bench data. In a trabecular bone simulation study, we find traditional reconstruction approaches without a blur model exhibit shift-variant resolution properties that depend greatly on the acquisition protocol (e.g. short vs. full scans) and the anode angles of the rays used to reconstruct a particular region. For physical CBCT experiments focal spot blur was characterized and a spatial resolution phantom was scanned and reconstructed. In both experiments image quality using the shift-variant model was significantly improved over approaches that modeled no blur or only a shift-invariant blur, suggesting a potential means to overcome traditional CBCT spatial resolution and system design limitations. PMID:28361129

  7. Technical Note: Skin thickness measurements using high-resolution flat-panel cone-beam dedicated breast CT

    SciTech Connect

    Shi Linxi; Vedantham, Srinivasan; Karellas, Andrew; O'Connell, Avice M.

    2013-03-15

    Purpose: To determine the mean and range of location-averaged breast skin thickness using high-resolution dedicated breast CT for use in Monte Carlo-based estimation of normalized glandular dose coefficients. Methods: This study retrospectively analyzed image data from a clinical study investigating dedicated breast CT. An algorithm similar to that described by Huang et al.['The effect of skin thickness determined using breast CT on mammographic dosimetry,' Med. Phys. 35(4), 1199-1206 (2008)] was used to determine the skin thickness in 137 dedicated breast CT volumes from 136 women. The location-averaged mean breast skin thickness for each breast was estimated and the study population mean and range were determined. Pathology results were available for 132 women, and were used to investigate if the distribution of location-averaged mean breast skin thickness varied with pathology. The effect of surface fitting to account for breast curvature was also studied. Results: The study mean ({+-} interbreast SD) for breast skin thickness was 1.44 {+-} 0.25 mm (range: 0.87-2.34 mm), which was in excellent agreement with Huang et al. Based on pathology, pair-wise statistical analysis (Mann-Whitney test) indicated that at the 0.05 significance level, there were no significant difference in the location-averaged mean breast skin thickness distributions between the groups: benign vs malignant (p= 0.223), benign vs hyperplasia (p= 0.651), hyperplasia vs malignant (p= 0.229), and malignant vs nonmalignant (p= 0.172). Conclusions: Considering this study used a different clinical prototype system, and the study participants were from a different geographical location, the observed agreement between the two studies suggests that the choice of 1.45 mm thick skin layer comprising the epidermis and the dermis for breast dosimetry is appropriate. While some benign and malignant conditions could cause skin thickening, in this study cohort the location-averaged mean breast skin thickness

  8. Exploring miniature insect brains using micro-CT scanning techniques

    PubMed Central

    Smith, Dylan B.; Bernhardt, Galina; Raine, Nigel E.; Abel, Richard L.; Sykes, Dan; Ahmed, Farah; Pedroso, Inti; Gill, Richard J.

    2016-01-01

    The capacity to explore soft tissue structures in detail is important in understanding animal physiology and how this determines features such as movement, behaviour and the impact of trauma on regular function. Here we use advances in micro-computed tomography (micro-CT) technology to explore the brain of an important insect pollinator and model organism, the bumblebee (Bombus terrestris). Here we present a method for accurate imaging and exploration of insect brains that keeps brain tissue free from trauma and in its natural stereo-geometry, and showcase our 3D reconstructions and analyses of 19 individual brains at high resolution. Development of this protocol allows relatively rapid and cost effective brain reconstructions, making it an accessible methodology to the wider scientific community. The protocol describes the necessary steps for sample preparation, tissue staining, micro-CT scanning and 3D reconstruction, followed by a method for image analysis using the freeware SPIERS. These image analysis methods describe how to virtually extract key composite structures from the insect brain, and we demonstrate the application and precision of this method by calculating structural volumes and investigating the allometric relationships between bumblebee brain structures. PMID:26908205

  9. Exploring miniature insect brains using micro-CT scanning techniques.

    PubMed

    Smith, Dylan B; Bernhardt, Galina; Raine, Nigel E; Abel, Richard L; Sykes, Dan; Ahmed, Farah; Pedroso, Inti; Gill, Richard J

    2016-02-24

    The capacity to explore soft tissue structures in detail is important in understanding animal physiology and how this determines features such as movement, behaviour and the impact of trauma on regular function. Here we use advances in micro-computed tomography (micro-CT) technology to explore the brain of an important insect pollinator and model organism, the bumblebee (Bombus terrestris). Here we present a method for accurate imaging and exploration of insect brains that keeps brain tissue free from trauma and in its natural stereo-geometry, and showcase our 3D reconstructions and analyses of 19 individual brains at high resolution. Development of this protocol allows relatively rapid and cost effective brain reconstructions, making it an accessible methodology to the wider scientific community. The protocol describes the necessary steps for sample preparation, tissue staining, micro-CT scanning and 3D reconstruction, followed by a method for image analysis using the freeware SPIERS. These image analysis methods describe how to virtually extract key composite structures from the insect brain, and we demonstrate the application and precision of this method by calculating structural volumes and investigating the allometric relationships between bumblebee brain structures.

  10. Evaluation of gas chromatography - electron ionization - full scan high resolution Orbitrap mass spectrometry for pesticide residue analysis.

    PubMed

    Mol, Hans G J; Tienstra, Marc; Zomer, Paul

    2016-09-07

    Gas chromatography with electron ionization and full scan high resolution mass spectrometry with an Orbitrap mass analyzer (GC-EI-full scan Orbitrap HRMS) was evaluated for residue analysis. Pesticides in fruit and vegetables were taken as an example application. The relevant aspects for GC-MS based residue analysis, including the resolving power (15,000 to 120,000 FWHM at m/z 200), scan rate, dynamic range, selectivity, sensitivity, analyte identification, and utility of existing EI-libraries, are assessed and discussed in detail. The optimum acquisition conditions in full scan mode (m/z 50-500) were a resolving power of 60,000 and an automatic-gain-control target value of 3E6. These conditions provided (i) an optimum mass accuracy: within 2 ppm over a wide concentration range, with/without matrix, enabling the use of ±5 ppm mass extraction windows (ii) adequate scan speed: minimum 12 scans/peak, (iii) an intra-scan dynamic range sufficient to achieve LOD/LOQs ≤0.5 pg in fruit/vegetable matrices (corresponding to ≤0.5 μg kg(-1)) for most pesticides. EI-Orbitrap spectra were consistent over a very wide concentration range (5 orders) with good match values against NIST (EI-quadrupole) spectra. The applicability for quantitative residue analysis was verified by validation of 54 pesticides in three matrices (tomato, leek, orange) at 10 and 50 μg/kg. The method involved a QuEChERS-based extraction with a solvent switch into iso-octane, and 1 μL hot splitless injection into the GC-HRMS system. A recovery between 70 and 120% and a repeatability RSD <10% was obtained in most cases. Linearity was demonstrated for the range ≤5-250 μg kg(-1). The pesticides could be identified according to the applicable EU criteria for GC-HRMS (SANTE/11945/2015). GC-EI-full scan Orbitrap HRMS was found to be highly suited for quantitative pesticide residue analysis. The potential of qualitative screening to extend the scope makes it an attractive alternative to GC

  11. High-resolution secondary reconstructions with the use of flat panel CT in the clinical assessment of patients with cochlear implants.

    PubMed

    Pearl, M S; Roy, A; Limb, C J

    2014-06-01

    Radiologic assessment of cochlear implants can be limited because of metallic streak artifacts and the high attenuation of the temporal bones. We report on 14 patients with 18 cochlear implants (17 Med-El standard 31.5-mm arrays, 1 Med-El medium 24-mm array) who underwent flat panel CT with the use of high-resolution secondary reconstruction techniques. Flat panel CT depicted the insertion site, cochlear implant course, and all 216 individual electrode contacts. The calculated mean angular insertion depth for standard arrays was 591.9° (SD = 70.9; range, 280°). High-resolution secondary reconstructions of the initial flat panel CT dataset, by use of a manually generated field of view, Hounsfield unit kernel type, and sharp image characteristics, provided high-quality images with improved spatial resolution. Flat panel CT is a promising imaging tool for the postoperative evaluation of cochlear implant placement.

  12. An implementation of dual energy CT scanning.

    PubMed

    Marshall, W; Hall, E; Doost-Hoseini, A; Alvarez, R; Macovski, A; Cassel, D

    1984-08-01

    We have described a prereconstruction method for dual energy (PREDECT) analysis of CT scans. In theory, this method can (a) eliminate beam hardening and produce an accuracy comparable with monoenergetic scans and (b) provide the effective atomic number and electron density of any voxel scanned. Our implementation proves these statements and eliminates some of the objectionable noise. We constructed a phantom with a cylindrical sleeve-like compartment containing known amounts of high atomic number material simulating a removable skull. Conventional scans, with and without this beam hardener, were done of a water bath containing tubes of high electron and high atomic number material. Dual energy scans were then done for PREDECT. To increase the effective separation of the low and high energy beams by using more appropriate tube filtration, we fabricated a beam filter changer containing erbium, tungsten, aluminum, and steel. We used erbium, tungsten, and steel at high energy and aluminum, steel, and erbium at low energy for data acquisition. The reconstructions were compared visually and numerically for noise levels with the original steel only filtration. We found a decrease in noise down to approximately one-half the prior level when erbium/aluminum or tungsten/aluminum replaced the steel/steel filter. Erbium and tungsten were equally effective. Steel/erbium and steel/aluminum also significantly reduced image noise. The noise in the photoelectric (P) and Compton (C) images is negatively correlated. At any pixel, if the noise is positive in the P image, it is most probably negative in the C. Using this fact, the noise was reduced by postreconstruction processing.

  13. Multimodal imaging of the human temporal bone: A comparison of CT and optical scanning techniques

    NASA Astrophysics Data System (ADS)

    Voie, Arne H.; Whiting, Bruce; Skinner, Margaret; Neely, J. Gail; Lee, Kenneth; Holden, Tim; Brunsden, Barry

    2003-10-01

    A collaborative effort between Washington University in St. Louis and Spencer Technologies in Seattle, WA has been undertaken to create a multimodal 3D reconstruction of the human cochlea and vestibular system. The goal of this project is to improve the accuracy of in vivo CT reconstructions of implanted cochleae, and to expand the knowledge of high-resolution anatomical detail provided by orthogonal-plane optical sectioning (OPFOS). At WUSL, computed tomography (CT) images of the cochlea are used to determine the position of cochlear implant electrodes relative to target auditory neurons. The cochlear implant position is determined using pre- and post-operative CT scans. The CT volumes are cross-registered to align the semicircular canals and internal auditory canal, which have a unique configuration in 3-D space. The head of a human body donor was scanned with a clinical CT device, after which the temporal bones were removed, fixed in formalin and trimmed prior to scanning with a laboratory Micro CT scanner. Following CT, the temporal bones were sent to the OPFOS Imaging Lab at Spencer Technologies for a further analysis. 3-D reconstructions of CT and OPFOS imaging modalities were compared, and results are presented. [Work supported by NIDCD Grants R44-03623-5 and R01-00581-13.

  14. HIGH RESOLUTION AND FAST SCANNING SQUID BASED NON-DESTRUCTIVE INSPECTION SYSTEM OF NIOBIUM SHEETS FOR SRF CAVITIES

    SciTech Connect

    SHU, QUAN-SHENG

    2008-06-08

    Applications in high energy physics accelerators and other fields require the use of thousands of superconducting RF (SRF) cavities that are made of high purity Nb material and the purity of niobium is critical for these cavities to reach the highest accelerating fields. Tantalum is the most prolific of metal inclusions, which can cause thermal breakdown and prevent the cavities from reaching their theoretical performance limits of 45-50 MV/m, and DOE Labs are searching for a technology that could detect small impurities in superconducting Nb sheets reaching the highest possible accelerating fields. The proposed innovative SQUID-based Nondestructive system can scan Niobium sheets used in the manufacturing of SRF cavities with both high speed and high resolution. A highly sensitive SQUID system with a gradiometer probe, non-magnetic dewar, data acquisition system, and a scanning system will be developed for fast detection of impurities in planar Nb sheets. In phase I, we will modify our existing SQUID-based eddy current system to detect 100 micron size Ta defects and a great effort will focus on achieving fast scanning of a large number of niobium sheets in a shorter time and with reasonable resolution. An older system operated by moving the sample 1 mm, stopping and waiting for 1-2 seconds, then activating a measurement by the SQUID after the short settle time is modified. A preliminary designed and implemented a SQUID scanning system that is fast and is capable of scanning a 30 cm x 30 cm Nb sheet in 15 minutes by continuously moving the table at speeds up to 10 mm/s while activating the SQUID at 1mm interval is modified and reached the Phase I goal of 100mm resolution. We have successfully demonstrated the feasibility that a fast speed SQUID scanner without sacrificing the resolution of detection can be done, and a data acquisition and analysis system is also preliminary developed. The SQUID based scanner will help reach the highest accelerating field in SRF

  15. Creation of High Resolution Terrain Models of Barringer Meteorite Crater (Meteor Crater) Using Photogrammetry and Terrestrial Laser Scanning Methods

    NASA Technical Reports Server (NTRS)

    Brown, Richard B.; Navard, Andrew R.; Holland, Donald E.; McKellip, Rodney D.; Brannon, David P.

    2010-01-01

    Barringer Meteorite Crater or Meteor Crater, AZ, has been a site of high interest for lunar and Mars analog crater and terrain studies since the early days of the Apollo-Saturn program. It continues to be a site of exceptional interest to lunar, Mars, and other planetary crater and impact analog studies because of its relatively young age (est. 50 thousand years) and well-preserved structure. High resolution (2 meter to 1 decimeter) digital terrain models of Meteor Crater in whole or in part were created at NASA Stennis Space Center to support several lunar surface analog modeling activities using photogrammetric and ground based laser scanning techniques. The dataset created by this activity provides new and highly accurate 3D models of the inside slope of the crater as well as the downslope rock distribution of the western ejecta field. The data are presented to the science community for possible use in furthering studies of Meteor Crater and impact craters in general as well as its current near term lunar exploration use in providing a beneficial test model for lunar surface analog modeling and surface operation studies.

  16. Using a geographic information system and scanning technology to create high-resolution land-use data sets

    USGS Publications Warehouse

    Harvey, Craig A.; Kolpin, Dana W.; Battaglin, William A.

    1996-01-01

    A geographic information system (GIS) procedure was developed to compile low-altitude aerial photography, digitized data, and land-use data from U.S. Department of Agriculture Consolidated Farm Service Agency (CFSA) offices into a high-resolution (approximately 5 meters) land-use GIS data set. The aerial photography consisted of 35-mm slides which were scanned into tagged information file format (TIFF) images. These TIFF images were then imported into the GIS where they were registered into a geographically referenced coordinate system. Boundaries between land use were delineated from these GIS data sets using on-screen digitizing techniques. Crop types were determined using information obtained from the U.S. Department of Agriculture CFSA offices. Crop information not supplied by the CFSA was attributed by manual classification procedures. Automated methods to provide delineation of the field boundaries and land-use classification were investigated. It was determined that using these data sources, automated methods were less efficient and accurate than manual methods of delineating field boundaries and classifying land use.

  17. High-Resolution Imaging by Adaptive Optics Scanning Laser Ophthalmoscopy Reveals Two Morphologically Distinct Types of Retinal Hard Exudates

    PubMed Central

    Yamaguchi, Muneo; Nakao, Shintaro; Kaizu, Yoshihiro; Kobayashi, Yoshiyuki; Nakama, Takahito; Arima, Mitsuru; Yoshida, Shigeo; Oshima, Yuji; Takeda, Atsunobu; Ikeda, Yasuhiro; Mukai, Shizuo; Ishibashi, Tatsuro; Sonoda, Koh-hei

    2016-01-01

    Histological studies from autopsy specimens have characterized hard exudates as a composition of lipid-laden macrophages or noncellular materials including lipid and proteinaceous substances (hyaline substances). However, the characteristics of hard exudates in living patients have not been examined due to insufficient resolution of existing equipment. In this study, we used adaptive optics scanning laser ophthalmoscopy (AO-SLO) to examine the characteristics of hard exudates in patients with retinal vascular diseases. High resolution imaging using AO-SLO enables morphological classification of retinal hard exudates into two types, which could not be distinguished either on fundus examination or by spectral domain optical coherence tomography (SD-OCT). One, termed a round type, consisted of an accumulation of spherical particles (average diameter of particles: 26.9 ± 4.4 μm). The other, termed an irregular type, comprised an irregularly shaped hyper-reflective deposition. The retinal thickness in regions with round hard exudates was significantly greater than the thickness in regions with irregular hard exudates (P = 0.01 →0.02). This differentiation of retinal hard exudates in patients by AO-SLO may help in understanding the pathogenesis and clinical prognosis of retinal vascular diseases. PMID:27641223

  18. High-resolution Terrestrial Laser Scanning (TLS) on cushion peatlands - a case study from the Peruvian Andes

    NASA Astrophysics Data System (ADS)

    Forbriger, M.; Höfle, B.; Siart, C.; Schittek, K.; Bubenzer, O.

    2012-04-01

    So-called cushion peatlands located in the high mountain areas of the Peruvian Andes are unique ecotopes, which are of major importance for both palaeoenvironmental reconstructions and permanent water supply of the valley oases in the presently hyperarid Peruvian desert. In this context, a case study was performed on the Cerro Llamoca peatland (southern Peru, province Lucanas, 14° S) in the uppermost reaches of the Rió Grande catchment area (4000-4450 m a.s.l.) within the framework of the BMBF-funded project 'Andean Transect - Climate Sensitivity of pre-Columbian Man-Environment-Systems' and serves as a basis for a long-term, multitemporal observation study. As small-scale geomorphologic investigations require high-resolution elevation data, which is still not available for this remote study site, and local microrelief is characterised by features not visible from aerial view (e.g. channel cuttings within the peatland), terrestrial laser scanning (TLS) was applied. Data acquisition was carried out with one of the latest 'time-of-flight'-scanners (Riegl VZ-400). A total of 46 positions was recorded to capture the whole area of interest leading to more 370 million single laser points within an area of approximately 1,8 km2. Registration of scan positions was performed by means of GPS measurements, coarse registration and the iterative closest point (ICP) algorithm provided by the plugin Multi-Station Adjustment within the RiSCAN PRO software (Riegl). The large amount of output data required the use of special LiDAR software for further processing and digital elevation raster generation (OPALS software). The defined target raster resolution was set to values between 0.1 and 2 m depending on the average point density. It is important to have access to the original point cloud including additional laser point attributes (e.g. signal amplitude and echo width) for digital terrain model generation (i.e. terrain point filtering) and geomorphologic mapping by means of

  19. Gallbladder opacification on gadoxetate disodium-enhanced CT scan.

    PubMed

    Karam, Adib R; Scortegagna, Eduardo; Chen, Byron Y; Dupuis, Carolyn S; Coughlin, Dennis D

    2017-04-01

    This study aimed to evaluate the radiologist's ability to identify excreted gadoxetate disodium within the gallbladder on CT scan. Thirty three healthy adults underwent imaging of the liver during work-up for potential liver donation. Three patients had undergone prior cholecystectomy and therefore were excluded. Imaging consisted of gadoxetate disodium-enhanced magnetic resonance cholangiography (MRC) and multiphase contrast-enhanced CT scan of the abdomen and pelvis. Two fellowship-trained abdominal imaging radiologists, who were blinded to the MRC images and the contrast agent used during MRC, independently reviewed the CT scans of the 30 patients that were included. The scans were evaluated for the presence or absence of abnormal hyperdensity within the gallbladder. Three patients did not receive intravenous gadoxetate disodium, 4 patients had their MRC after the CT scan, and 1 patient had the CT scans 5 days following the MRC. Twenty two patients had the CT scan within 24 h following the gadoxetate disodium-enhanced MRC. Of the 22 patients expected to have gadolinium in the gallbladder, both reviewers identified hyperdensity in the same 20 patients (90%). Both reviewers reported no abnormal hyperdensity within the gallbladder in the remaining 10 patients. CT scan can reveal excreted gadoxetate disodium within the gallbladder lumen and therefore gadoxetate disodium-enhanced CT scan can potentially play a role in the evaluation of cystic duct patency and work-up of acute cholecystitis.

  20. High Resolution Computed Tomography

    DTIC Science & Technology

    1992-07-31

    samples. 14. SUBJECTTERMS 15. NUMBER OF PAGES 38 High Resolution, Microfocus , Characterization, X - Ray , Micrography, Computed Tomography (CT), Failure...high resolutions (50 g.tm feature sensitivity) when a small field of view (50 mm) is used [11]. Specially designed detectors and a microfocus X - ray ...Wright Laboratories. Feldkamp [14] at Ford used a microfocus X - ray source and an X - ray image intensifier to develop a system capable of 20 g.m

  1. UT-CT: A National Resource for Applications of High-Resolution X-ray Computed Tomography in the Geological Sciences

    NASA Astrophysics Data System (ADS)

    Carlson, W. D.; Ketcham, R. A.; Rowe, T. B.

    2002-12-01

    An NSF-sponsored (EAR-IF) shared multi-user facility dedicated to research applications of high-resolution X-ray computed tomography (CT) in the geological sciences has been in operation since 1997 at the University of Texas at Austin. The centerpiece of the facility is an industrial CT scanner custom-designed for geological applications. Because the instrument can optimize trade-offs among penetrating ability, spatial resolution, density discrimination, imaging modes, and scan times, it can image a very broad range of geological specimens and materials, and thus offers significant advantages over medical scanners and desktop microtomographs. Two tungsten-target X-ray sources (200-kV microfocal and 420-kV) and three X-ray detectors (image-intensifier, high-sensitivity cadmium tungstate linear array, and high-resolution gadolinium-oxysulfide radiographic line scanner) can be used in various combinations to meet specific imaging goals. Further flexibility is provided by multiple imaging modes: second-generation (translate-rotate), third-generation (rotate-only; centered and variably offset), and cone-beam (volume CT). The instrument can accommodate specimens as small as about 1 mm on a side, and as large as 0.5 m in diameter and 1.5 m tall. Applications in petrology and structural geology include measuring crystal sizes and locations to identify mechanisms governing the kinetics of metamorphic reactions; visualizing relationships between alteration zones and abundant macrodiamonds in Siberian eclogites to elucidate metasomatic processes in the mantle; characterizing morphologies of spiral inclusion trails in garnet to test hypotheses of porphyroblast rotation during growth; measuring vesicle size distributions in basaltic flows for determination of elevation at the time of eruption to constrain timing and rates of continental uplift; analysis of the geometry, connectivity, and tortuosity of migmatite leucosomes to define the topology of melt flow paths, for numerical

  2. Direct Observation of the Outermost Surfaces of Mesoporous Silica Thin Films by High Resolution Ultralow Voltage Scanning Electron Microscopy.

    PubMed

    Kobayashi, Maho; Susuki, Kyoka; Otsuji, Haruo; Sakuda, Yusuke; Asahina, Shunsuke; Kikuchi, Naoki; Kanazawa, Toshiyuki; Kuroda, Yoshiyuki; Wada, Hiroaki; Shimojima, Atsushi; Kuroda, Kazuyuki

    2017-03-07

    The properties of the outermost surfaces of mesoporous silica thin films are critical in determining their functions. Obtaining information on the presence or absence of silica layers on the film surfaces and on the degree of mesopore opening is essential for applications of surface mesopores. In this study, the outermost surfaces of mesoporous silica thin films with 3-dimensional orthorhombic and 2-dimensional hexagonal structures were observed using ultralow voltage high resolution scanning electron microscopy (HR-SEM) with decelerating optics. SEM images of the surfaces before and after etching with NH4F were taken at various landing voltages. Comparing the images taken under different conditions indicated that the outermost surfaces of the nonetched mesoporous silica thin films are coated with a thin layer of silica. The images taken at an ultralow landing voltage (i.e., 80 V) showed that the presence or absence of surface silica layers depends on whether the film was etched with an aqueous solution of NH4F. The mesostructures of both the etched and nonetched films were visible in images taken at a conventional landing voltage (2 kV); hence, the ultralow landing voltage was more suitable for analyzing the outermost surfaces. The SEM observations provided detailed information about the surfaces of mesoporous silica thin films, such as the degree of pore opening and their homogeneities. AFM images of nonetched 2-dimensional hexagonal mesoporous silica thin films show that the shape of the silica layer on the surface of the films reflects the curvature of the top surface of the cylindrical mesochannels. SEM images taken at various landing voltages are discussed, with respect to the electron penetration range at each voltage. This study increases our understanding of the surfaces of mesoporous silica thin films, which may lead to potential applications utilizing the periodically arranged mesopores on these surfaces.

  3. Real-time Data Processing and Visualization for the Airborne Scanning High-resolution Interferometer Sounder (S-HIS)

    NASA Astrophysics Data System (ADS)

    Taylor, J. K.; Revercomb, H. E.; Hoese, D.; Garcia, R. K.; Smith, W. L.; Weisz, E.; Tobin, D. C.; Best, F. A.; Knuteson, R. O.; Sullivan, D. V.; Barnes, C. M.; Van Gilst, D. P.

    2015-12-01

    The Hurricane and Severe Storm Sentinel (HS3) is a five-year NASA mission targeted to enhance the understanding of the formation and evolution of hurricanes in the Atlantic basin. Measurements were made from two NASA Global Hawk Unmanned Aircraft Systems (UAS) during the 2012 through 2014 hurricane seasons, with flights conducted from the NASA Wallops Flight Facility. The Global Hawk aircraft are capable of high altitude flights with durations of up to 30 hours, which allow extensive observations over distant storms, not typically possible with manned aircraft. The two NASA Global Hawks were equipped with instrument suites to study the storm environment, and inner core structure and processes, respectively. The Scanning High-resolution Interferometer Sounder (S-HIS), designed and built by the University of Wisconsin (UW) Space Science and Engineering Center (SSEC), measures emitted thermal radiation at high spectral resolution between 3.3 and 18 microns. The radiance measurements are used to obtain temperature and water vapor profiles of the Earth's atmosphere. The S-HIS spatial resolution is 2 km at nadir, across a 40 km ground swath from a nominal altitude of 20 kilometers. Since 1998, the S-HIS has participated in 33 field campaigns and has proven to be extremely dependable, effective, and highly accurate. It has flown on the NASA ER-2, DC-8, Proteus, WB-57, and Global Hawk airborne platforms. The UW S-HIS infrared sounder instrument is equipped with a real-time ground data processing system capable of delivering atmospheric profiles, radiance data, and engineering status to mission support scientists - all within less than one minute from the time of observation. This ground data processing system was assembled by a small team using existing software and proven practical techniques similar to a satellite ground system architecture. This summary outlines the design overview for the system and illustrates the data path, content, and outcomes.

  4. Multifrequency Ultra-High Resolution Miniature Scanning Microscope Using Microchannel And Solid-State Sensor Technologies And Method For Scanning Samples

    NASA Technical Reports Server (NTRS)

    Wang, Yu (Inventor)

    2006-01-01

    A miniature, ultra-high resolution, and color scanning microscope using microchannel and solid-state technology that does not require focus adjustment. One embodiment includes a source of collimated radiant energy for illuminating a sample, a plurality of narrow angle filters comprising a microchannel structure to permit the passage of only unscattered radiant energy through the microchannels with some portion of the radiant energy entering the microchannels from the sample, a solid-state sensor array attached to the microchannel structure, the microchannels being aligned with an element of the solid-state sensor array, that portion of the radiant energy entering the microchannels parallel to the microchannel walls travels to the sensor element generating an electrical signal from which an image is reconstructed by an external device, and a moving element for movement of the microchannel structure relative to the sample. Discloses a method for scanning samples whereby the sensor array elements trace parallel paths that are arbitrarily close to the parallel paths traced by other elements of the array.

  5. CT scanning of the breast using a conventional CT scanner.

    PubMed

    Doust, B D; Milbrath, J R; Doust, V L

    1981-09-01

    Using a conventional body CT scanner, computed tomography of the breast was performed on 32 patients known to have or suspected of having breast masses. Xeromammograms were available for comparison in all cases. All mass lesions were histologically proved. Seven patients were examined prone, 25 supine. The prone position yielded pictures that resembled craniocaudal mammograms. Breast asymmetry, skin thickening, stranding from a mass to the chest wall, calcification, and axillary lymphadenopathy could be demonstrated by means of CT. The portion of the breast adjacent to the chest wall was more readily examined by means of CT than by conventional mammography. Internal mammary nodes could not be demonstrated.

  6. Flat-Panel Computed Tomography (DYNA-CT) in Neuroradiology. From High-Resolution Imaging of Implants to One-Stop-Shopping for Acute Stroke.

    PubMed

    Doerfler, A; Gölitz, P; Engelhorn, T; Kloska, S; Struffert, T

    2015-10-01

    Originally aimed at improving standard radiography by providing higher absorption efficiency and a wider dynamic range, flat-panel detector technology has meanwhile got widely accepted in the neuroradiological community. Especially flat-panel detector computed tomography (FD-CT) using rotational C-arm mounted flat-panel detector technology is capable of volumetric imaging with a high spatial resolution. By providing CT-like images of the brain within the angio suite, FD-CT is able to rapidly visualize hemorrhage and may thus improve complication management without the need of patient transfer. As "Angiographic CT" FD-CT may be helpful during many diagnostic and neurointerventional procedures and for noninvasive monitoring and follow-up. In addition, spinal interventions and high-resolution imaging of the temporal bone might also benefit from FD-CT. Finally, using novel dynamic perfusion and angiographic protocols, FD-CT may provide functional information on brain perfusion and vasculature with the potential to replace standard imaging in selected acute stroke patients.

  7. Three-dimensional analysis of vesicle and crystal fragment textures in pumice using high-resolution X-ray CT: Textural evidence of eruptive processes

    NASA Astrophysics Data System (ADS)

    Ketcham, R. A.; Gardner, J. E.; Abbott, S.

    2011-12-01

    Three-dimensional analysis of high-resolution X-ray computed tomographic (CT) imagery of pumice from Popocatépetl Volcano in central Mexico yields fresh insights into processes of vesicle formation and coalescence and crystal fragmentation that occur during explosive volcanism. Six ~2 cm pumice fragments of varying bulk vesicularity were imaged at ~20 μm resolution. Three-dimensional blob and fabric analysis quantitatively document textural features, and visualization facilitated contextualization of measurements and overall interpretation. Vesicles range in size from mm-scale to below the resolution of the scan data. By comparing the whole-sample 3D vesicle size distributions derived from CT with more detailed distributions from sub-volumes obtained by standard petrographic analysis, we can discern two distinct, roughly log-normal populations in each sample. Vesicles in all samples have preferred orientations, and fabric analysis based on the star volume distribution and displayed as 3D rose diagrams documents a range of preferred shapes from elongate to flattened. Aspect ratios range from 1 to 6, and converge to values of ~2-3 with increasing size. Surface to volume ratios show increasing departure from sphericity with increasing size, which is probably attributable in large part to irregular shapes caused by coalescence. The vesicle fabric was strongest in the highest-vesicularity sample. Some pumices showed evidence of welding or poor mixing between two or more differently devolatilized portions of melt. Interfaces are in some cases apparently welded, with low-vesicularity glass contact zones, and in others are simply sub-planar intersections between distinct glasses. In one instance of the latter, correlated vesicle and phenocryst orientations across both melt portions and not parallel to their interface suggests that their juxtaposition took place before final eruption, while there was still time for fabric development. The pumices show abundant evidence of

  8. Automated segmentation of the lungs from high resolution CT images for quantitative study of chronic obstructive pulmonary diseases

    NASA Astrophysics Data System (ADS)

    Garg, Ishita; Karwoski, Ronald A.; Camp, Jon J.; Bartholmai, Brian J.; Robb, Richard A.

    2005-04-01

    Chronic obstructive pulmonary diseases (COPD) are debilitating conditions of the lung and are the fourth leading cause of death in the United States. Early diagnosis is critical for timely intervention and effective treatment. The ability to quantify particular imaging features of specific pathology and accurately assess progression or response to treatment with current imaging tools is relatively poor. The goal of this project was to develop automated segmentation techniques that would be clinically useful as computer assisted diagnostic tools for COPD. The lungs were segmented using an optimized segmentation threshold and the trachea was segmented using a fixed threshold characteristic of air. The segmented images were smoothed by a morphological close operation using spherical elements of different sizes. The results were compared to other segmentation approaches using an optimized threshold to segment the trachea. Comparison of the segmentation results from 10 datasets showed that the method of trachea segmentation using a fixed air threshold followed by morphological closing with spherical element of size 23x23x5 yielded the best results. Inclusion of greater number of pulmonary vessels in the lung volume is important for the development of computer assisted diagnostic tools because the physiological changes of COPD can result in quantifiable anatomic changes in pulmonary vessels. Using a fixed threshold to segment the trachea removed airways from the lungs to a better extent as compared to using an optimized threshold. Preliminary measurements gathered from patient"s CT scans suggest that segmented images can be used for accurate analysis of total lung volume and volumes of regional lung parenchyma. Additionally, reproducible segmentation allows for quantification of specific pathologic features, such as lower intensity pixels, which are characteristic of abnormal air spaces in diseases like emphysema.

  9. Innovative advanced occlusion planning with superimposed CT and optical scans.

    PubMed

    Tremblay, Gilbert

    2011-04-01

    In order to increase the likelihood of a successful treatment plan outcome, it is critical to be able to effectively view the patient's underlying bony skeletal relationship of his or her TMJ. An innovative approach suggested to achieve this is to use the CT scan, optical scan, and Kois deprogrammer. Once the vertical dimension has been increased, the novelty of this approach is the ability to superimpose both scans along with the Kois deprogrammer and, using computer software, evaluate the TMJ position in three dimensions. This case presentation describes how TMJ CT scan evaluation is used in planning a complex rehabilitation case, given that the occlusion structures can be visualized independently and interactively.

  10. Purulent lupus panniculitis unmasked by FDG-PET/CT scan

    PubMed Central

    van der Geest, Kornelis S.M.; Moerman, Rada V.; Koopmans, Klaas P.; Holman, Nicole D.; Janssen, Wilbert M.T.

    2016-01-01

    Abstract Rationale: Lupus panniculitis (LP) is a unique variant of cutaneous lupus erythematosus. Clinical manifestations are typically mild and include erythema, nodules, and small ulcers. In certain cases, diagnosing LP may be challenging. Skin overlying the typical subcutaneous inflammation may appear normal, and bacterial superinfections of the skin sometimes mask the underlying LP. It has been suggested that a computed tomography (CT) scan may help to identify obscure LP lesions. Here, we report a case of a 54-year-old woman with an unusually severe form of LP, in which the full disease extent was only revealed by a fluorodeoxyglucose positron emission tomography (FDG-PET)/CT scan. Patient concerns/Diagnoses/Interventions/Outcomes: Our patient initially presented with a bacterial infection of the skin. After initial improvement with antibiotic treatment, new erythematous lesions and sterile subcutaneous pus collections developed. An FDG-PET/CT scan revealed extensive subcutaneous inflammation at sites that had appeared normal during physical examination and on CT scan. As the subcutaneous lesions showed a remarkably linear pattern on FDG-PET/CT scan, the patient was suspected of having LP. After confirmation of this diagnosis by a deep-skin biopsy, our patient was treated with systemic glucocorticoids. Eventually, our patient succumbed to complications of LP and its treatment. Lessons: Our case demonstrates that clinical manifestations of LP are not always mild and that timely diagnosis is needed. Furthermore, we show that obscure LP lesions are more readily identified on an FDG-PET/CT scan than CT scan. PMID:27902603

  11. Hybrid detection of lung nodules on CT scan images

    SciTech Connect

    Lu, Lin; Tan, Yongqiang; Schwartz, Lawrence H.; Zhao, Binsheng

    2015-09-15

    Purpose: The diversity of lung nodules poses difficulty for the current computer-aided diagnostic (CAD) schemes for lung nodule detection on computed tomography (CT) scan images, especially in large-scale CT screening studies. We proposed a novel CAD scheme based on a hybrid method to address the challenges of detection in diverse lung nodules. Methods: The hybrid method proposed in this paper integrates several existing and widely used algorithms in the field of nodule detection, including morphological operation, dot-enhancement based on Hessian matrix, fuzzy connectedness segmentation, local density maximum algorithm, geodesic distance map, and regression tree classification. All of the adopted algorithms were organized into tree structures with multi-nodes. Each node in the tree structure aimed to deal with one type of lung nodule. Results: The method has been evaluated on 294 CT scans from the Lung Image Database Consortium (LIDC) dataset. The CT scans were randomly divided into two independent subsets: a training set (196 scans) and a test set (98 scans). In total, the 294 CT scans contained 631 lung nodules, which were annotated by at least two radiologists participating in the LIDC project. The sensitivity and false positive per scan for the training set were 87% and 2.61%. The sensitivity and false positive per scan for the testing set were 85.2% and 3.13%. Conclusions: The proposed hybrid method yielded high performance on the evaluation dataset and exhibits advantages over existing CAD schemes. We believe that the present method would be useful for a wide variety of CT imaging protocols used in both routine diagnosis and screening studies.

  12. State-of-the-art in CT hardware and scan modes for cardiovascular CT

    PubMed Central

    Halliburton, Sandra; Arbab-Zadeh, Armin; Dey, Damini; Einstein, Andrew J.; Gentry, Ralph; George, Richard T.; Gerber, Thomas; Mahesh, Mahadevappa; Weigold, Wm. Guy

    2013-01-01

    Multidetector row computed tomography (CT) allows noninvasive anatomic and functional imaging of the heart, great vessels, and the coronary arteries. In recent years, there have been several advances in CT hardware, which have expanded the clinical utility of CT for cardiovascular imaging; such advances are ongoing. This review article from the Society of Cardiovascular Computed Tomography (SCCT) Basic and Emerging Sciences and Technology (BEST) Working Group summarizes the technical aspects of current state-of-the-art CT hardware and describes the scan modes this hardware supports for cardiovascular CT imaging. PMID:22551595

  13. State-of-the-art in CT hardware and scan modes for cardiovascular CT.

    PubMed

    Halliburton, Sandra; Arbab-Zadeh, Armin; Dey, Damini; Einstein, Andrew J; Gentry, Ralph; George, Richard T; Gerber, Thomas; Mahesh, Mahadevappa; Weigold, Wm Guy

    2012-01-01

    Multidetector row computed tomography (CT) allows noninvasive anatomic and functional imaging of the heart, great vessels, and coronary arteries. In recent years, there have been several advances in CT hardware, which have expanded the clinical utility of CT for cardiovascular imaging; such advances are ongoing. This review article from the Society of Cardiovascular Computed Tomography Basic and Emerging Sciences and Technology Working Group summarizes the technical aspects of current state-of-the-art CT hardware and describes the scan modes this hardware supports for cardiovascular CT imaging.

  14. CT Scan of NASA Booster Nozzle

    SciTech Connect

    Schneberk, D; Perry, R; Thompson, R

    2004-07-27

    We scanned a Booster Nozzle for NASA with our 9 meV LINAC, AmSi panel scanner. Three scans were performed using different filtering schemes and different positions of the nozzle. The results of the scan presented here are taken from the scan which provided the best contrast and lowest noise of the three. Our inspection data shows a number of indications of voids in the outer coating of rubber/carbon. The voids are mostly on the side of the nozzle, but a few small voids are present at the ends of the nozzle. We saw no large voids in the adhesive layer between the Aluminum and the inner layer of carbon. This 3D inspection data did show some variation in the size of the adhesive layer, but none of the indications were larger than 3 pixels in extent (21 mils). We have developed a variety of contour estimation and extraction techniques for inspecting small spaces between layers. These tools might work directly on un-sectioned nozzles since the circular contours will fit with our tools a little better. Consequently, it would be useful to scan a full nozzle to ensure there are no untoward degradations in data quality, and to see if our tools would work to extract the adhesive layer.

  15. Comparison of CT scanning and radionuclide imaging in liver disease

    SciTech Connect

    Friedman, M.L.; Esposito, F.S.

    1980-01-01

    Early experience with body CT suggested its usefulness in many diagnostic problems; jaundice, renal and pancreatic masses, and in the evaluation of relatively inaccessible parts of the body, such as the retroperitineum, mediastinum, and pelvis. Investigation of hepatic disease by CT was not unexpectedly compared to radionuclide liver scanning, the major preexisting modality for imaging the liver. In the evaluation of the jaundiced patient, CT rapidly assumed a major role, providing more specific information about the liver than the RN liver scan, as well as demonstrating adjacent organs. CT differentiate obstructive from non-obstructive jaundice. With respect to mass lesions of the liver, the RN liver scan is more sensitive than CT but less specific. The abnormalities on an isotope image of the liver consist of normal variants in configuration, extrinsic compression by adjacent structures, cysts, hemangiomata, abscesses, and neoplasms. These suspected lesions may then be better delineated by the CT image, and a more precise diagnosis made. The physiologic information provided by the RN liver scan is an added facet which is helpful in the patient with diffuse hepatic disease. The CT image will be normal in many of these patients, however, hemochromatosis and fatty infiltration lend themselves especially to density evaluation by CT. The evaluation of lymphoma is more thorough with CT. Structures other than the liver, such as lymph nodes, are visualized. Gallium, however, provides additional isotopic information in patients with lymphoma, and in addition, is known to be useful in the investigation of a febrile patient with an abscess. Newer isotopic agents expand hepatic imaging in other directions, visualizing the biliary tree and evaluating the jaundiced patient.

  16. Large-volume reconstruction of brain tissue from high-resolution serial section images acquired by SEM-based scanning transmission electron microscopy.

    PubMed

    Kuwajima, Masaaki; Mendenhall, John M; Harris, Kristen M

    2013-01-01

    With recent improvements in instrumentation and computational tools, serial section electron microscopy has become increasingly straightforward. A new method for imaging ultrathin serial sections is developed based on a field emission scanning electron microscope fitted with a transmitted electron detector. This method is capable of automatically acquiring high-resolution serial images with a large field size and very little optical and physical distortions. In this chapter, we describe the procedures leading to the generation and analyses of a large-volume stack of high-resolution images (64 μm × 64 μm × 10 μm, or larger, at 2 nm pixel size), including how to obtain large-area serial sections of uniform thickness from well-preserved brain tissue that is rapidly perfusion-fixed with mixed aldehydes, processed with a microwave-enhanced method, and embedded into epoxy resin.

  17. Dynamic CT scanning of spinal column trauma

    SciTech Connect

    Brown, B.M.; Brant-Zawadzki, M.; Cann, C.E.

    1982-12-01

    Dynamic sequential computed tomographic scanning with automatic table incrementation uses low milliampere-second technique to eliminate tube cooling delays between scanning slices and, thus, markedly shortens examination times. A total of 25 patients with spinal column trauma involving 28 levels were studied with dynamic scans and retrospectively reviewed. Dynamic studies were considerably faster than conventional spine examinations and yielded reliable diagnosis. Bone disruption and subluxation was accurately evaluated, and the use of intrathecal metrizamide in low doses allowed direct visualization of spinal cord or radicular compromise. Multiplanar image reformation was aided by the dynamic incrementation technique, since motion between slices (and the resulting misregistration artifact on image reformation) was minimized. A phantom was devised to test spatial resolution of computed tomography for objects 1-3 mm in size and disclosed minimal differences for dynamic and conventional computed tomographic techniques in resolving medium-to-high-contrast objects.

  18. Helium ion microscopy and ultra-high-resolution scanning electron microscopy analysis of membrane-extracted cells reveals novel characteristics of the cytoskeleton of Giardia intestinalis.

    PubMed

    Gadelha, Ana Paula Rocha; Benchimol, Marlene; de Souza, Wanderley

    2015-06-01

    Giardia intestinalis presents a complex microtubular cytoskeleton formed by specialized structures, such as the adhesive disk, four pairs of flagella, the funis and the median body. The ultrastructural organization of the Giardia cytoskeleton has been analyzed using different microscopic techniques, including high-resolution scanning electron microscopy. Recent advances in scanning microscopy technology have opened a new venue for the characterization of cellular structures and include scanning probe microscopy techniques such as ultra-high-resolution scanning electron microscopy (UHRSEM) and helium ion microscopy (HIM). Here, we studied the organization of the cytoskeleton of G. intestinalis trophozoites using UHRSEM and HIM in membrane-extracted cells. The results revealed a number of new cytoskeletal elements associated with the lateral crest and the dorsal surface of the parasite. The fine structure of the banded collar was also observed. The marginal plates were seen linked to a network of filaments, which were continuous with filaments parallel to the main cell axis. Cytoplasmic filaments that supported the internal structures were seen by the first time. Using anti-actin antibody, we observed a labeling in these filamentous structures. Taken together, these data revealed new surface characteristics of the cytoskeleton of G. intestinalis and may contribute to an improved understanding of the structural organization of trophozoites.

  19. High-Resolution 4D Imaging of Technetium Transport in Porous Media using Preclinical SPECT-CT

    NASA Astrophysics Data System (ADS)

    Dogan, M.; DeVol, T. A.; Groen, H.; Moysey, S. M.; Ramakers, R.; Powell, B. A.

    2015-12-01

    Preclinical SPECT-CT (single-photon emission computed tomography with integrated X-ray computed tomography) offers the potential to quantitatively image the dynamic three-dimensional distribution of radioisotopes with sub-millimeter resolution, overlaid with structural CT images (20-200 micron resolution), making this an attractive method for studying transport in porous media. A preclinical SPECT-CT system (U-SPECT4CT, MILabs BV. Utrecht, The Netherlands) was evaluated for imaging flow and transport of 99mTc (t1/2=6hrs) using a 46,5mm by 156,4mm column packed with individual layers consisting of <0.2mm diameter silica gel, 0.2-0.25, 0.5, 1.0, 2.0, 3.0, and 4.0mm diameter glass beads, and a natural soil sample obtained from the Savannah River Site. The column was saturated with water prior to injecting the 99mTc solution. During the injection the flow was interrupted intermittently for 10 minute periods to allow for the acquisition of a SPECT image of the transport front. Non-uniformity of the front was clearly observed in the images as well as the retarded movement of 99mTc in the soil layer. The latter is suggesting good potential for monitoring transport processes occurring on the timescale of hours. After breakthrough of 99mTc was achieved, the flow was stopped and SPECT data were collected in one hour increments to evaluate the sensitivity of the instrument as the isotope decayed. Fused SPECT- CT images allowed for improved interpretation of 99mTc distributions within individual pore spaces. With ~3 MBq remaining in the column, the lowest activity imaged, it was not possible to clearly discriminate any of the pore spaces.

  20. A scanning, all-fiber Sagnac interferometer for high resolution magneto-optic measurements at 820 nm

    SciTech Connect

    Fried, Alexander; Fejer, Martin; Kapitulnik, Aharon

    2014-10-15

    The Sagnac Interferometer has historically been used for detecting non-reciprocal phenomena, such as rotation. We demonstrate an apparatus in which this technique is employed for high resolution measurements of the Magneto-Optical Polar Kerr effect—a direct indicator of magnetism. Previous designs have incorporated free-space components which are bulky and difficult to align. We improve upon this technique by using all fiber-optic coupled components and demonstrate operation at a new wavelength, 820 nm, with which we can achieve better than 1 μrad resolution. Mounting the system on a piezo-electric scanner allows us to acquire diffraction limited images with 1.5 μm spatial resolution. We also provide extensive discussion on the details and of the Sagnac Interferometer's construction.

  1. CT scan of the brain (image)

    MedlinePlus

    ... CAT scan (computed tomography) is a much more sensitive imaging technique than x-ray, allowing high definition not only of the bony structures, but of the soft tissues. Clear images of organs such as the brain, muscles, joint structures, veins ...

  2. X-ray microtomography (micro-CT): a reference technology for high-resolution quantification of xylem embolism in trees.

    PubMed

    Cochard, H; Delzon, S; Badel, E

    2015-01-01

    As current methods for measuring xylem embolism in trees are indirect and prone to artefacts, there is an ongoing controversy over the capacity of trees to resist or recover from embolism. The debate will not end until we get direct visualization of the vessel content. Here, we propose desktop X-ray microtomography (micro-CT) as a reference direct technique to quantify xylem embolism and thus validate more widespread measurements based upon either hydraulic or acoustic methods. We used desktop micro-CT to measure embolism levels in dehydrated or centrifuged shoots of laurel - a long-vesseled species thought to display daily cycles of embolism formation and refilling. Our direct observations demonstrate that this Mediterranean species is highly resistant to embolism and is not vulnerable to drought-induced embolism in a normal range of xylem tensions. We therefore recommend that embolism studies in long-vesseled species should be validated by direct methods such as micro-CT to clear up any misunderstandings on their physiology.

  3. (Un)targeted Scanning of Locks of Hair for Drugs of Abuse by Direct Analysis in Real Time-High-Resolution Mass Spectrometry.

    PubMed

    Duvivier, Wilco F; van Putten, Marc R; van Beek, Teris A; Nielen, Michel W F

    2016-02-16

    Forensic hair evidence can be used to obtain retrospective timelines of drug use by analysis of hair segments. However, this is a laborious and time-consuming process, and mass spectrometric (MS) imaging techniques, which show great potential for single-hair targeted analysis, are less useful due to differences in hair growth rate between individual hairs. As an alternative, a fast untargeted analysis method was developed that uses direct analysis in real time-high-resolution mass spectrometry (DART-HRMS) to longitudinally scan intact locks of hair without extensive sample preparation or segmentation. The hair scan method was validated for cocaine against an accredited liquid chromatography/tandem mass spectrometry (LC/MS/MS) method. The detection limit for cocaine in hair was found to comply with the cutoff value of 0.5 ng/mg recommended by the Society of Hair Testing; that is, the DART hair scan method is amenable to forensic cases. Under DART conditions, no significant thermal degradation of cocaine occurred. The standard DART spot size of 5.1 ± 1.1 mm could be improved to 3.3 ± 1.0 mm, corresponding to approximately 10 days of hair growth, by using a high spatial resolution exit cone. By use of data-dependent product ion scans, multiple drugs of abuse could be detected in a single drug user hair scan with confirmation of identity by both exact mass and MS/HRMS fragmentation patterns. Furthermore, full-scan high-resolution data were retrospectively interrogated versus a list of more than 100 compounds and revealed additional hits and temporal profiles in good correlation with reported drug use.

  4. High-resolution computed tomography of the paranasal sinuses, pharynx and related regions: Impact of CT identification on diagnosis and patient management

    SciTech Connect

    Maatman, G.

    1986-01-01

    The purpose of this textbook is two-fold: to define the normal anatomic structure and pathologic conditions of the nose, paranasal sinuses, pharynx and soft tissues, and to discuss the diagnostic impact and ultimate-effect of computed tomography (CT) in the treatment of patients with head and neck disorders. The two chapters on normal gross and CT anatomic configuration are meticulously constructed. The subsequent sections on pathologic conditions are illustrated with examples of neoplastic disease. The CT scans are very good; a few of these were obtained in the direct sagittal plane. There is considerable discussion of the reasons that CT is equal to better than, or worse than other imaging modalities with respect to patient treatment in terms of both diagnosis and therapy.

  5. CT scan diagnosis of bleeding peptic ulcer after gastric bypass.

    PubMed

    Husain, Syed; Ahmed, Ahmed R; Johnson, Joseph; Boss, Thad; O'Malley, William

    2007-11-01

    Investigation of the bypassed stomach in patients with suspected peptic ulcer disease presents a major challenge to bariatric surgeons. Various methods have been suggested for visualization of the duodenum and bypassed stomach. These include endoscopy via percutaneous gastrostomy access, retrograde endoscopy and virtual gastroscopy using CT scan. We present a case of peptic ulcer bleeding diagnosed with the help of conventional CT scan. To the best of our knowledge, this is the second such case reported in the literature and the first in the bariatric population.

  6. In-Lens Cryo-High Resolution Scanning Electron Microscopy: Methodologies for Molecular Imaging of Self-Assembled Organic Hydrogels

    NASA Astrophysics Data System (ADS)

    Apkarian, Robert P.; Wright, Elizabeth R.; Seredyuk, Victor A.; Eustis, Susan; Lyon, L. Andrew; Conticello, Vincent P.; Menger, Fredric M.

    2003-08-01

    The micro- and nanoarchitectures of water-swollen hydrogels were routinely analyzed in three dimensions at very high resolution by two cryopreparation methods that provide stable low-temperature specimens for in-lens high magnification recordings. Gemini surfactants (gS), poly-N-isopropylacrylamides (p-NIP Am), and elastin-mimetic di- (db-E) and triblock (tb-E) copolymer proteins that form hydrogels have been routinely analyzed to the sub-10-nm level in a single day. After they were quench or high pressure frozen, samples in bulk planchets were subsequently chromium coated and observed at low temperature in an in-lens field emission SEM. Pre-equilibrated planchets (4 40°C) that hold 5 10 [mu]l of hydrogel facilitate dynamic morphological studies above and below their transition temperatures. Rapidly frozen samples were fractured under liquid nitrogen, low-temperature metal coated, and observed in-lens to assess the dispersion characteristics of micelles and fragile colloidal assemblies within bulk frozen water. Utilizing the same planchet freezing system, the cryoetch-HRSEM technique removed bulk frozen water from the hydrogel matrix by low-temperature, high-vacuum sublimation. The remaining frozen solid-state sample faithfully represented the hydrogel matrix. Cryo- and cryoetch-HRSEM provided vast vistas of hydrogels at low and intermediate magnifications whereas high magnification recordings and anaglyphs (stereo images) provided a three-dimensional prospective and measurements on a molecular level.

  7. Treatment of Alzheimer Disease With CT Scans

    PubMed Central

    Moore, Eugene R.; Hosfeld, Victor D.; Nadolski, David L.

    2016-01-01

    Alzheimer disease (AD) primarily affects older adults. This neurodegenerative disorder is the most common cause of dementia and is a leading source of their morbidity and mortality. Patient care costs in the United States are about 200 billion dollars and will more than double by 2040. This case report describes the remarkable improvement in a patient with advanced AD in hospice who received 5 computed tomography scans of the brain, about 40 mGy each, over a period of 3 months. The mechanism appears to be radiation-induced upregulation of the patient’s adaptive protection systems against AD, which partially restored cognition, memory, speech, movement, and appetite. PMID:27103883

  8. Design of a high-resolution small-animal SPECT-CT system sharing a CdTe semiconductor detector

    NASA Astrophysics Data System (ADS)

    Ryu, Hyun-Ju; Lee, Young-Jin; Lee, Seung-Wan; Cho, Hyo-Min; Choi, Yu-Na; Kim, Hee-Joung

    2012-07-01

    A single photon emission computed tomography (SPECT) system with a co-registered X-y computed tomography (CT) system allows the convergence of functional information and morphologic information. The localization of radiopharmaceuticals on a SPECT can be enhanced by combining the SPECT with an anatomical modality, such as X-ray CT. Gamma-ray imaging for nuclear medicine devices and X-ray imaging systems for diagnostics has recently been developed based on semiconductor detectors, and semiconductor detector materials such as cadmium telluride (CdTe) or cadmium zinc telluride (CZT) are available for both X-ray and gamma-ray systems for small-animal imaging. CdTe or CZT detectors provide strong absorption and high detection efficiency of high energy X-ray and gamma-ray photons because of their large atomic numbers. In this study, a pinhole collimator SPECT system sharing a cadmium telluride (CdTe) detector with a CT was designed. The GEANT4 application for tomographic emission (GATE) v.6.1 was used for the simulation. The pinhole collimator was designed to obtain a high spatial resolution of the SPECT system. The acquisition time for each projection was 40 seconds, and 60 projections were obtained for tomographic image acquisition. The reconstruction was performed using ordered subset expectation maximization (OS-EM) algorithms. The sensitivity and the spatial resolution were measured on the GATE simulation to evaluate the system characteristics. The spatial resolution of the system calculated from the FWHM of Gaussian fitted PSF curve was 0.69 mm, and the sensitivity of the system was measured to be 0.354 cps/kBq by using a Tc-99m point source of 1 MBq for 800 seconds. A phantom study was performed to verify the design of the dual imaging modality system. The system will be built as designed, and it can be applied as a pre-clinical imaging system.

  9. Digital radiographic localization for CT scanning of the larynx

    SciTech Connect

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

    1983-12-01

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

  10. Comparison of full-scan and half-scan for cone beam breast CT imaging

    NASA Astrophysics Data System (ADS)

    Chen, Lingyun; Shaw, Chris C.; Lai, Chao-jen; Altunbas, Mustafa C.; Wang, Tianpeng; Tu, Shu-ju; Liu, Xinming

    2006-03-01

    The half-scan cone beam technique, requiring a scan for 180° plus detector width only, can help achieve both shorter scan time as well as higher exposure in each individual projection image. This purpose of this paper is to investigate whether half-scan cone beam CT technique can provide acceptable images for clinical application. The half-scan cone beam reconstruction algorithm uses modified Parker's weighting function and reconstructs from slightly more than half of the projection views for full-scan, giving out promising results. A rotation phantom, stationary gantry bench top system was built to conduct experiments to evaluate half-scan cone beam breast CT technique. A post-mastectomy breast specimen, a stack of lunch meat slices embedded with various sizes of calcifications and a polycarbonate phantom inserted with glandular and adipose tissue equivalents are imaged and reconstructed for comparison study. A subset of full-scan projection images of a mastectomy specimen were extracted and used as the half-scan projection data for reconstruction. The results show half-scan reconstruction algorithm for cone beam breast CT images does not significantly degrade image quality when compared with the images of same or even half the radiation dose level. Our results are encouraging, emphasizing the potential advantages in the use of half-scan technique for cone beam breast imaging.

  11. Self-sensing cantilevers with integrated conductive coaxial tips for high-resolution electrical scanning probe metrology

    NASA Astrophysics Data System (ADS)

    Haemmerli, Alexandre J.; Harjee, Nahid; Koenig, Markus; Garcia, Andrei G. F.; Goldhaber-Gordon, David; Pruitt, Beth L.

    2015-07-01

    The lateral resolution of many electrical scanning probe techniques is limited by the spatial extent of the electrostatic potential profiles produced by their probes. Conventional unshielded conductive atomic force microscopy probes produce broad potential profiles. Shielded probes could offer higher resolution and easier data interpretation in the study of nanostructures. Electrical scanning probe techniques require a method of locating structures of interest, often by mapping surface topography. As the samples studied with these techniques are often photosensitive, the typical laser measurement of cantilever deflection can excite the sample, causing undesirable changes electrical properties. In this work, we present the design, fabrication, and characterization of probes that integrate coaxial tips for spatially sharp potential profiles with piezoresistors for self-contained, electrical displacement sensing. With the apex 100 nm above the sample surface, the electrostatic potential profile produced by our coaxial tips is more than 2 times narrower than that of unshielded tips with no long tails. In a scan bandwidth of 1 Hz-10 kHz, our probes have a displacement resolution of 2.9 Å at 293 K and 79 Å at 2 K, where the low-temperature performance is limited by amplifier noise. We show scanning gate microscopy images of a quantum point contact obtained with our probes, highlighting the improvement to lateral resolution resulting from the coaxial tip.

  12. Self-sensing cantilevers with integrated conductive coaxial tips for high-resolution electrical scanning probe metrology

    SciTech Connect

    Haemmerli, Alexandre J.; Pruitt, Beth L.; Harjee, Nahid; Koenig, Markus; Garcia, Andrei G. F.; Goldhaber-Gordon, David

    2015-07-21

    The lateral resolution of many electrical scanning probe techniques is limited by the spatial extent of the electrostatic potential profiles produced by their probes. Conventional unshielded conductive atomic force microscopy probes produce broad potential profiles. Shielded probes could offer higher resolution and easier data interpretation in the study of nanostructures. Electrical scanning probe techniques require a method of locating structures of interest, often by mapping surface topography. As the samples studied with these techniques are often photosensitive, the typical laser measurement of cantilever deflection can excite the sample, causing undesirable changes electrical properties. In this work, we present the design, fabrication, and characterization of probes that integrate coaxial tips for spatially sharp potential profiles with piezoresistors for self-contained, electrical displacement sensing. With the apex 100 nm above the sample surface, the electrostatic potential profile produced by our coaxial tips is more than 2 times narrower than that of unshielded tips with no long tails. In a scan bandwidth of 1 Hz–10 kHz, our probes have a displacement resolution of 2.9 Å at 293 K and 79 Å at 2 K, where the low-temperature performance is limited by amplifier noise. We show scanning gate microscopy images of a quantum point contact obtained with our probes, highlighting the improvement to lateral resolution resulting from the coaxial tip.

  13. Development of 36M-pixel x-ray detector for large field of view and high-resolution micro-CT

    NASA Astrophysics Data System (ADS)

    Umetani, Keiji; Kawata, Yoshiki; Niki, Noboru

    2016-10-01

    A high-resolution and large field-of-view micro-CT system is indispensable for the visualization of fine threedimensional (3-D) structures of a large specimen. Such a system drastically increases the overall number of effective sensor pixels. At SPring-8 over a decade ago, a micro-CT system based on a 10M-pixel CCD camera was developed for 3-D specimen imaging of centimeter-sized objects with approximately 7 μm spatial resolution. Subsequently, more recent studies have required systems with higher spatial resolution and a wider field-of-view. Detectors with spatial resolution of around 5 μm can visualize capillaries. However, such detectors make it extremely expensive to develop a new x-ray detector with several tens of megapixels in a conventional manner. Fortunately, dizzying advances in image sensor technology for consumer appliances have enabled the development of x-ray detectors with spatial resolution of around 5 μm using a commercial digital single-lens reflex camera fitted with a 36M-pixel CMOS image sensor for the visualization of fine 3-D structures of large human lung specimens. This paper describes a comparison of the performance offered by the new 36M-pixel micro-CT system and the 10M-pixel system.

  14. Liquid chromatography with high resolution mass spectrometry for identification of organic contaminants in fish fillet: screening and quantification assessment using two scan modes for data acquisition.

    PubMed

    Munaretto, Juliana S; May, Marília M; Saibt, Nathália; Zanella, Renato

    2016-07-22

    This study proposed a strategy to identify and quantify 182 organic contaminants from different chemical classes, as for instance pesticides, veterinary drug and personal care products, in fish fillet using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QToF/MS). For this purpose, two different scan methods (full scan and all ions MS/MS) were evaluated to assess the best option for screening analysis in spiked fish fillet samples. In general, full scan acquisition was found to be more reliable (84%) in the automatic identification and quantification when compared to all ions MS/MS with 72% of the compounds detected. Additionally, a qualitative automatic search showed a mass accuracy error below 5ppm for 77% of the compounds in full scan mode compared to only 52% in all ions MS/MS scan. However, all ions MS/MS provides fragmentation information of the target compounds. Undoubtedly, structural information of a wide number of compounds can be obtained using high resolution mass spectrometry (HRMS), but it is necessary thoroughly assess it, in order to choose the best scan mode.

  15. Systematic analyses of vibration noise of a vibration isolation system for high-resolution scanning tunneling microscopes.

    PubMed

    Iwaya, Katsuya; Shimizu, Ryota; Hashizume, Tomihiro; Hitosugi, Taro

    2011-08-01

    We designed and constructed an effective vibration isolation system for stable scanning tunneling microscopy measurements using a separate foundation and two vibration isolation stages (i.e., a combination of passive and active vibration isolation dampers). Systematic analyses of vibration data along the horizontal and vertical directions are present, including the vibration transfer functions of each stage and the overall vibration isolation system. To demonstrate the performance of the system, tunneling current noise measurements are conducted with and without the vibration isolation. Combining passive and active vibration isolation dampers successfully removes most of the vibration noise in the tunneling current up to 100 Hz. These comprehensive vibration noise data, along with details of the entire system, can be used to establish a clear guideline for building an effective vibration isolation system for various scanning probe microscopes and electron microscopes.

  16. Automated lung segmentation of low resolution CT scans of rats

    NASA Astrophysics Data System (ADS)

    Rizzo, Benjamin M.; Haworth, Steven T.; Clough, Anne V.

    2014-03-01

    Dual modality micro-CT and SPECT imaging can play an important role in preclinical studies designed to investigate mechanisms, progression, and therapies for acute lung injury in rats. SPECT imaging involves examining the uptake of radiopharmaceuticals within the lung, with the hypothesis that uptake is sensitive to the health or disease status of the lung tissue. Methods of quantifying lung uptake and comparison of right and left lung uptake generally begin with identifying and segmenting the lung region within the 3D reconstructed SPECT volume. However, identification of the lung boundaries and the fissure between the left and right lung is not always possible from the SPECT images directly since the radiopharmaceutical may be taken up by other surrounding tissues. Thus, our SPECT protocol begins with a fast CT scan, the lung boundaries are identified from the CT volume, and the CT region is coregistered with the SPECT volume to obtain the SPECT lung region. Segmenting rat lungs within the CT volume is particularly challenging due to the relatively low resolution of the images and the rat's unique anatomy. Thus, we have developed an automated segmentation algorithm for low resolution micro-CT scans that utilizes depth maps to detect fissures on the surface of the lung volume. The fissure's surface location is in turn used to interpolate the fissure throughout the lung volume. Results indicate that the segmentation method results in left and right lung regions consistent with rat lung anatomy.

  17. Applying very high resolution microfocus X-ray CT and 3-D reconstruction to the human auditory apparatus.

    PubMed

    Shibata, T; Nagano, T

    1996-08-01

    Conventional high-resolution X-ray computed tomography (XCT) is an important medical technique because it provides sectional images (tomograms) of internal structures without destroying the specimen. However, it is difficult to observe and to analyze fine structures less than a few cubic millimeters in size because of its low spatial resolution of 0.4 mm. Overcoming this problem would not only enable visualization of human anatomical structures in living subjects by means of computer images but would make it possible to obtain the equivalent of microscopic images by XCT without making microscopic sections of biopsy material, which would allow the examination of the entire body and detection of focal lesions at an early stage. Bonse et al. and Kinney et al. studied absorption contrast microtomography by using synchrotron radiation and achieved 8-microns spatial resolution in human cancellous bone. Recently, Momose et al. reported examining the soft tissue of cancerous rabbit liver by a modification of the phase-contrast technique using synchrotron radiation with a spatial resolution of 30 microns (ref. 4). However, the equipment for synchrotron radiation requires a great deal of space and is very expensive. Aoki et al., on a different tack, reported microtomography of frog embryos by using a conventional laboratory microfocus X-ray source with a spot size of about 2 microns (ref. 5). As no human tomographic studies by superresolution microfocus XCT (MFXCT) using a normal open-type X-ray source have been reported, we tried using MFXCT with a maximum experimental spatial resolution of 2.5 microns, especially designed for industrial use, on the auditory ossicles of a human fetus, the smallest and lightest bones in the skeletal system. No XCT studies of fetal auditory ossicles have been reported to date. The fine tomograms with three-dimensional reconstructions obtained showed the existence of an apparently previously undescribed joint between the tympanic ring and the

  18. High resolution scanning electron microscopy of rabbit corneal endothelium to show effects of UV-visible irradiation in the presence of chlorpromazine

    SciTech Connect

    Lea, P.J.; Hollenberg, M.J.; Menon, I.A.; Temkin, R.J.; Persad, S.D.; Basu, P.K. )

    1989-01-01

    The ultrastructure of rabbit cornea endothelial cells was examined by scanning electron microscopy (SEM) in freeze-cleaved corneas using a Hitachi S-570 scanning electron microscope in the high resolution mode (HRSEM). In order to study phototoxic effects in vitro, rabbit corneas (experimental) were cultured as organ culture in the presence of 5 micrograms/ml chlorpromazine (CPZ) and irradiated. For comparison, control 1 corneas were not irradiated but incubated in the dark without CPZ in the medium; control 2 corneas were also kept in the dark but in the presence of CPZ; control 3 corneas were irradiated with no CPZ in the medium. Cellular damage was not seen in the three types of control corneas, but in the experimental corneas the endothelial cells showed extensive disruption of the cell membrane and some deterioration of the intracellular components. Our study confirmed that HRSEM is a satisfactory new technique for visualizing damage of the intracellular organelles of corneal endothelium.

  19. High resolution digital holographic microscopy with a wide field of view based on a synthetic aperture technique and use of linear CCD scanning.

    PubMed

    Di, Jianglei; Zhao, Jianlin; Jiang, Hongzhen; Zhang, Peng; Fan, Qi; Sun, Weiwei

    2008-10-20

    Theoretical analysis shows that, to improve the resolution and the range of the field of view of the reconstructed image in digital lensless Fourier transform holography, an effective solution is to increase the area and the pixel number of the recorded digital hologram. A new approach based on the synthetic aperture technique and use of linear CCD scanning is presented to obtain digital holographic images with high resolution and a wide field of view. By using a synthetic aperture technique and linear CCD scanning, we obtained digital lensless Fourier transform holograms with a large area of 3.5 cm x 3.5 cm (5000 x 5000 pixels). The numerical reconstruction of a 4 mm object at a distance of 14 cm by use of a Rayleigh-Sommerfeld integral shows that a theoretically minimum resolvable distance of 2.57 microm can be achieved at a wavelength of 632.8 nm. The experimental results are consistent with the theoretical analysis.

  20. Harms of CT scanning prior to surgery for suspected appendicitis.

    PubMed

    Rogers, William; Hoffman, Jerome; Noori, Naudereh

    2015-02-01

    In this brief analysis we compare the risks and benefits of performing a CT scan to confirm appendicitis prior to surgery instead of operating based on the surgeon's clinical diagnosis. We conclude that the benefit of universal imaging is to avoid 12 unnecessary appendectomies but the cost of those 12 avoided surgeries is one cancer death due to the imaging.

  1. Do CT scans aid assessment of distal tibial physeal fractures?

    PubMed

    Cutler, L; Molloy, A; Dhukuram, V; Bass, A

    2004-03-01

    Distal tibial physeal fractures are the second most common growth plate injury and the most common cause of growth arrest and deformity. This study assesses the accuracy of pre-operative planning for placement of the screws in these fractures using either standard radiographs or CT scans. We studied 62 consecutive physeal fractures over a period of four years. An outline of a single cut of the CT scan was used for each patient. An ideal position for the screw was determined as being perpendicular to and at the midpoint of the fracture. The difference in entry point and direction of the screw between the ideal and the observers' assessments were compared using the paired Student's t-test. There was a statistically significant improvement (p < 0.0001) in the accuracy of the point of insertion and the direction of the screw on the pre-operative plan when CT scans were used rather than plain radiographs. We would, therefore, recommend that CT scans are routinely used in the pre-operative assessment and treatment of distal tibial physeal fractures.

  2. Thromboembolic Complications Following Spine Surgery Assessed with Spiral CT Scans

    PubMed Central

    Kim, Han Jo; Walcott-Sapp, Sarah; Adler, Ronald S.; Pavlov, Helene; Boachie-Adjei, Oheneba

    2010-01-01

    Spine surgery is associated with a significant risk of postoperative pulmonary embolism (PE) and/or deep vein thrombosis (DVT). The goal of this study was to determine which symptoms and risk factors were associated with spiral CT scans positive for PE and/or DVT in the postoperative spine surgery patient. We conducted a retrospective review of all spine patients who underwent a postoperative CT to rule out PE during the period of March 2004–February 2006. The type of surgical procedure, risk factors, symptoms prompting scan ordering, anticoagulation, and treatment were recorded. Logistic regression models were used to determine significant predictors of a positive CT in this patient population. Of the 3,331 patients that had spine surgery during the study period, 130 (3.9%) had a spiral CT scan to rule out PE and/or proximal DVT. Thirty-three of the 130 (25.4%) CT scans were positive for PE only, five (3.8%) for PE and DVT, and three (2.3%) for DVT only. Only 24.5% (32) patients had risk factors for thromboembolic disease, and of these, a history of PE and/or DVT was the only significant risk factor for a positive scan (p = 0.03). No presenting symptoms or demographic variables were noted to have a significant association with PE and/or DVT. The type of surgical procedure (i.e., anterior, posterior, and percutaneous) was not associated with an increased risk for PE and/or DVT. Patients who are undergoing spine surgery with a history of thromboembolic disease should be carefully monitored postoperatively and may benefit from more aggressive prophylaxis. PMID:22294955

  3. First application of liquid-metal-jet sources for small-animal imaging: High-resolution CT and phase-contrast tumor demarcation

    SciTech Connect

    Larsson, Daniel H.; Lundstroem, Ulf; Burvall, Anna; Hertz, Hans M.

    2013-02-15

    Purpose: Small-animal studies require images with high spatial resolution and high contrast due to the small scale of the structures. X-ray imaging systems for small animals are often limited by the microfocus source. Here, the authors investigate the applicability of liquid-metal-jet x-ray sources for such high-resolution small-animal imaging, both in tomography based on absorption and in soft-tissue tumor imaging based on in-line phase contrast. Methods: The experimental arrangement consists of a liquid-metal-jet x-ray source, the small-animal object on a rotating stage, and an imaging detector. The source-to-object and object-to-detector distances are adjusted for the preferred contrast mechanism. Two different liquid-metal-jet sources are used, one circulating a Ga/In/Sn alloy and the other an In/Ga alloy for higher penetration through thick tissue. Both sources are operated at 40-50 W electron-beam power with {approx}7 {mu}m x-ray spots, providing high spatial resolution in absorption imaging and high spatial coherence for the phase-contrast imaging. Results: High-resolution absorption imaging is demonstrated on mice with CT, showing 50 {mu}m bone details in the reconstructed slices. High-resolution phase-contrast soft-tissue imaging shows clear demarcation of mm-sized tumors at much lower dose than is required in absorption. Conclusions: This is the first application of liquid-metal-jet x-ray sources for whole-body small-animal x-ray imaging. In absorption, the method allows high-resolution tomographic skeletal imaging with potential for significantly shorter exposure times due to the power scalability of liquid-metal-jet sources. In phase contrast, the authors use a simple in-line arrangement to show distinct tumor demarcation of few-mm-sized tumors. This is, to their knowledge, the first small-animal tumor visualization with a laboratory phase-contrast system.

  4. Fast high-resolution 3D total internal reflection fluorescence microscopy by incidence angle scanning and azimuthal averaging

    PubMed Central

    Boulanger, Jérôme; Gueudry, Charles; Münch, Daniel; Cinquin, Bertrand; Paul-Gilloteaux, Perrine; Bardin, Sabine; Guérin, Christophe; Senger, Fabrice; Blanchoin, Laurent; Salamero, Jean

    2014-01-01

    Total internal reflection fluorescence microscopy (TIRFM) is the method of choice to visualize a variety of cellular processes in particular events localized near the plasma membrane of live adherent cells. This imaging technique not relying on particular fluorescent probes provides a high sectioning capability. It is, however, restricted to a single plane. We present here a method based on a versatile design enabling fast multiwavelength azimuthal averaging and incidence angles scanning to computationally reconstruct 3D images sequences. We achieve unprecedented 50-nm axial resolution over a range of 800 nm above the coverslip. We apply this imaging modality to obtain structural and dynamical information about 3D actin architectures. We also temporally decipher distinct Rab11a-dependent exocytosis events in 3D at a rate of seven stacks per second. PMID:25404337

  5. Fast high-resolution 3D total internal reflection fluorescence microscopy by incidence angle scanning and azimuthal averaging.

    PubMed

    Boulanger, Jérôme; Gueudry, Charles; Münch, Daniel; Cinquin, Bertrand; Paul-Gilloteaux, Perrine; Bardin, Sabine; Guérin, Christophe; Senger, Fabrice; Blanchoin, Laurent; Salamero, Jean

    2014-12-02

    Total internal reflection fluorescence microscopy (TIRFM) is the method of choice to visualize a variety of cellular processes in particular events localized near the plasma membrane of live adherent cells. This imaging technique not relying on particular fluorescent probes provides a high sectioning capability. It is, however, restricted to a single plane. We present here a method based on a versatile design enabling fast multiwavelength azimuthal averaging and incidence angles scanning to computationally reconstruct 3D images sequences. We achieve unprecedented 50-nm axial resolution over a range of 800 nm above the coverslip. We apply this imaging modality to obtain structural and dynamical information about 3D actin architectures. We also temporally decipher distinct Rab11a-dependent exocytosis events in 3D at a rate of seven stacks per second.

  6. High-resolution Crop Surface Models (CSM) and Crop Volume Models (CVM) on field level by terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Hoffmeister, Dirk; Bolten, Andreas; Curdt, Constanze; Waldhoff, Guido; Bareth, Georg

    2010-11-01

    The interdisciplinary Transregional Collaborative Research Center 32 (CRC/TR 32) works on exchange processes between soil, vegetation, and the adjacent atmospheric boundary layer (SVA). Within this research project a terrestrial laser scanning sensor is used in a multitemporal approach for determining agricultural plant parameters. In contrast to other studies with phase-change or optical probe sensors, time-of-flight measurements are used. On three dates in the year 2008 a sugar beet field (4.3 ha) in Western Germany was surveyed by a terrestrial laser scanner (Riegl LMS-Z420i). Point clouds are georeferenced, trimmed, and compared with official elevation data. The estimated plant parameters are (i) surface model comparison between different crop surfaces and (ii) crop volumes as well as (iii) soil roughness parameters for SVA-Modelling. The results show, that the estimation of these parameters is possible and the method should be validated and extended.

  7. Optimal experimental design for the detection of light atoms from high-resolution scanning transmission electron microscopy images

    SciTech Connect

    Gonnissen, J.; De Backer, A.; Martinez, G. T.; Van Aert, S.; Dekker, A. J. den; Rosenauer, A.; Sijbers, J.

    2014-08-11

    We report an innovative method to explore the optimal experimental settings to detect light atoms from scanning transmission electron microscopy (STEM) images. Since light elements play a key role in many technologically important materials, such as lithium-battery devices or hydrogen storage applications, much effort has been made to optimize the STEM technique in order to detect light elements. Therefore, classical performance criteria, such as contrast or signal-to-noise ratio, are often discussed hereby aiming at improvements of the direct visual interpretability. However, when images are interpreted quantitatively, one needs an alternative criterion, which we derive based on statistical detection theory. Using realistic simulations of technologically important materials, we demonstrate the benefits of the proposed method and compare the results with existing approaches.

  8. Changes in intracortical microporosities induced by pharmaceutical treatment of osteoporosis as detected by high resolution micro-CT

    SciTech Connect

    Tommasini S. M.; Miller L.; Trinward, A.; Acerbo, A.S.; De Carlo F. and Judex, S.

    2011-12-28

    Bone's microporosities play important biologic and mechanical roles. Here, we quantified 3D changes in cortical osteocyte-lacunae and other small porosities induced by estrogen withdrawal and two different osteoporosistreatments. Unlike 2D measurements, these data collected via synchrotron radiation-based {mu}CT describe the size and 3D spatial distribution of a large number of porous structures. Six-month old female Sprague-Dawley rats were separated into four groups of age-matched controls, untreated OVX, OVX treated with PTH, and OVX treated with Alendronate (ALN). Intracortical microporosity of the medial quadrant of the femoral diaphysis was quantified at endosteal, intracortical, and periosteal regions of the samples, allowing the quantification of osteocyte lacunae that were formed primarily before versus after the start of treatment. Across the overall thickness of the medial cortex, lacunar volume fraction (Lc.V/TV) was significantly lower in ALN treated rats compared to PTH. In the endosteal region, average osteocyte lacunar volume (< Lc.V >) of untreated OVX rats was significantly lower than in age-matched controls, indicating a decrease in osteocyte lacunar size in bone formed on the endosteal surface after estrogen withdrawal. The effect of treatment (OVX, ALN, PTH) on the number of lacunae per tissue volume (Lc.N/TV) was dependent on the specific location within the cortex (endosteal, intracortical, periosteal). In both the endosteal and intracortical regions, Lc.N/TV was significantly lower in ALN than in untreated OVX, suggesting a site-specific effect in osteocyte lacuna density with ALN treatment. There also were a significantly greater number of small pores (5-100 {micro}m{sup 3} in volume) in the endosteal region for PTH compared to ALN. The mechanical impact of this altered microporosity structure is unknown, but might serve to enhance, rather than deteriorate bone strength with PTH treatment, as smaller osteocyte lacunae may be better able to

  9. Sedimentary features of the south Texas continental slope as revealed by side-scan sonar and high-resolution seismic data

    SciTech Connect

    Rothwell, R.G.; Kenyon, N.H. ); McGregor, B.A. )

    1991-02-01

    Sedimentary provinces on the south Texas slope have been identified by their acoustic character on long-range side-scan sonar records and high-resolution seismic profiles. Probable lithofacies within these provinces have been identified by core data and by analogy with previously cored acoustic facies. In the northern part of the study area, the East Breaks Slide is a prominent mass-transport feature. Revised bathymetry shows that the slide originated on the upper slope (200-1,000 m), in front of a sandy late Wisconsinan shelf-margin delta, where the gradient is up to 3{degree}. Side-scan sonar data indicates that the slide is a strongly backscattering feature extending more than 110 km downslope from the shelf edge. it consists of two lobes that are separated by a diapiric high. Diapiric highs on the middle slope have blocked most of the flow. borehole data shows that the slide deposit contains intercalated sands and contorted bedding. The slide is therefore attributed to failure of sandy deltaic material deposited close to the shelf edge during the last period of low sea level (late Wisconsinan, circa 11-29 Ka). Core data suggests that the weakly backscattering acoustic facies adjacent to the slide are fine-grained sediments (mudturbidites and hemipelagites) of a slope mud drape. The middle slope in front of the sandy late Wisconsinan shelf-margin delta of the Rio Grande has an intermediate level of backscattering with numerous channels leading to the Sigsbee Deep. Acoustic facies mapping using long-range side-scan sonar matches well with acoustic facies mapping using 3.5-kHz high-resolution seismic profiles.

  10. Recording Approach of Heritage Sites Based on Merging Point Clouds from High Resolution Photogrammetry and Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Grussenmeyer, P.; Alby, E.; Landes, T.; Koehl, M.; Guillemin, S.; Hullo, J. F.; Assali, P.; Smigiel, E.

    2012-07-01

    Different approaches and tools are required in Cultural Heritage Documentation to deal with the complexity of monuments and sites. The documentation process has strongly changed in the last few years, always driven by technology. Accurate documentation is closely relied to advances of technology (imaging sensors, high speed scanning, automation in recording and processing data) for the purposes of conservation works, management, appraisal, assessment of the structural condition, archiving, publication and research (Patias et al., 2008). We want to focus in this paper on the recording aspects of cultural heritage documentation, especially the generation of geometric and photorealistic 3D models for accurate reconstruction and visualization purposes. The selected approaches are based on the combination of photogrammetric dense matching and Terrestrial Laser Scanning (TLS) techniques. Both techniques have pros and cons and recent advances have changed the way of the recording approach. The choice of the best workflow relies on the site configuration, the performances of the sensors, and criteria as geometry, accuracy, resolution, georeferencing, texture, and of course processing time. TLS techniques (time of flight or phase shift systems) are widely used for recording large and complex objects and sites. Point cloud generation from images by dense stereo or multi-view matching can be used as an alternative or as a complementary method to TLS. Compared to TLS, the photogrammetric solution is a low cost one, as the acquisition system is limited to a high-performance digital camera and a few accessories only. Indeed, the stereo or multi-view matching process offers a cheap, flexible and accurate solution to get 3D point clouds. Moreover, the captured images might also be used for models texturing. Several software packages are available, whether web-based, open source or commercial. The main advantage of this photogrammetric or computer vision based technology is to

  11. High-resolution and site-specific scanning spreading resistance microscopy and its applications to silicon devices

    SciTech Connect

    Zhang, L.; Koike, M.; Takeno, S.; Hara, K.

    2012-11-06

    Due to the continuous reduction of the critical dimensions of semiconductor devices, it becomes very important to know the two dimensional (2D) doping profile for improving device performance. Scanning spreading resistance microscopy (SSRM) performed in high vacuum is a powerful technique for quantitative 2D-doping profiling, with high spatial resolution and wide dynamic range of carrier concentration, as well as capability of site-specific analysis for accurate position. In this paper, we review SSRM applications to source/drain engineering in Si devices and their correlation with device characteristics by demonstrating several case studies. Direct observation of (110)/(100) CMOSFETs clarified significant differences between both pFETs and nFETs on (110) and (100) silicon substrates, revealing 2D channeling effect of boron ion implantation in pFETs; as well as silicidation impact on junction leakage-current characteristics in nFETs. Furthermore, our sample-preparation breakthrough enables site-specific SSRM characterization within 60 nm ultra thin samples and therefore failure analysis of real SRAM devices, demonstrating the high potential of SSRM technology for further device scaling and for failure analysis.

  12. High-resolution characterization of the diffusion of light chemical elements in metallic components by scanning microwave microscopy

    NASA Astrophysics Data System (ADS)

    Optasanu, Virgil; Bourillot, Eric; Vitry, Pauline; Plassard, Cédric; Beaurenaut, Laure; Jacquinot, Pierre; Herbst, Frédéric; Berger, Pascal; Lesniewska, Eric; Montessin, Tony

    2014-11-01

    An original sub-surface, high spatial resolution tomographic technique based on scanning microwave microscopy (SMM) is used to visualize in-depth materials with different chemical compositions. A significant phase difference in SMM between aluminum and chromium buried patterns has been observed. Moreover this technique was used to characterize a solid solution of a light chemical element (oxygen) in a metal lattice (zirconium). The large solubility of the oxygen in zirconium leads to modifications of the properties of the solid solution that can be measured by the phase shift signal in the SMM technique. The signal obtained in cross-section of an oxidized Zr sample shows the excellent agreement between phase shift profiles measured at different depths. Such a profile can reveal the length of diffusion of the oxygen in zirconium under the surface. The comparison with the oxygen concentration measured by nuclear reaction analysis shows excellent agreement in terms of length of diffusion and spatial distribution of the oxygen. A rapid calibration shows a linear dependence between the phase shift and the oxygen concentration. The SMM method opens up new possibilities for indirect measurements of the oxygen concentration dissolved in the metal lattice.

  13. Retinal damage in chloroquine maculopathy, revealed by high resolution imaging: a case report utilizing adaptive optics scanning laser ophthalmoscopy.

    PubMed

    Bae, Eun Jin; Kim, Kyoung Rae; Tsang, Stephen H; Park, Sung Pyo; Chang, Stanley

    2014-02-01

    A 53-year-old Asian woman was treated with hydroxychloroquine and chloroquine for lupus erythematosus. Within a few years, she noticed circle-shaped shadows in her central vision. Upon examination, the patient's visual acuity was 20 / 25 in both eyes. Humphrey visual field (HVF) testing revealed a central visual defect, and fundoscopy showed a ring-shaped area of parafoveal retinal pigment epithelium depigmentation. Fundus autofluorescence imaging showed a hypofluorescent lesion consistent with bull's eye retinopathy. Adaptive optics scanning laser ophthalmoscope (AO-SLO) revealed patch cone mosaic lesions, in which cones were missing or lost. In addition, the remaining cones consisted of asymmetrical shapes and sizes that varied in brightness. Unlike previous studies employing deformable mirrors for wavefront aberration correction, our AO-SLO approach utilized dual liquid crystal on silicon spatial light modulators. Thus, by using AO-SLO, we were able to create a photographic montage consisting of high quality images. Disrupted cone AO-SLO images were matched with visual field test results and functional deficits were associated with a precise location on the montage, which allowed correlation of histological findings with functional changes determined by HVF. We also investigated whether adaptive optics imaging was more sensitive to anatomical changes compared with spectral-domain optical coherence tomography.

  14. Interactive annotation of textures in thoracic CT scans

    NASA Astrophysics Data System (ADS)

    Kockelkorn, Thessa T. J. P.; de Jong, Pim A.; Gietema, Hester A.; Grutters, Jan C.; Prokop, Mathias; van Ginneken, Bram

    2010-03-01

    This study describes a system for interactive annotation of thoracic CT scans. Lung volumes in these scans are segmented and subdivided into roughly spherical volumes of interest (VOIs) with homogeneous texture using a clustering procedure. For each 3D VOI, 72 features are calculated. The observer inspects the scan to determine which textures are present and annotates, with mouse clicks, several VOIs of each texture. Based on these annotations, a k-nearest-neighbor classifier is trained, which classifies all remaining VOIs in the scan. The algorithm then presents a slice with suggested annotations to the user, in which the user can correct mistakes. The classifier is retrained, taking into account these new annotations, and the user is presented another slice for correction. This process continues until at least 50% of all lung voxels in the scan have been classified. The remaining VOIs are classified automatically. In this way, the entire lung volume is annotated. The system has been applied to scans of patients with usual and non-specific interstitial pneumonia. The results of interactive annotation are compared to a setup in which the user annotates all predefined VOIs manually. The interactive system is 3.7 times as fast as complete manual annotation of VOIs and differences between the methods are similar to interobserver variability. This is a first step towards precise volumetric quantitation of texture patterns in thoracic CT in clinical research and in clinical practice.

  15. High-resolution scanning tunneling microscopy imaging of Si(1 1 1)-7 × 7 structure and intrinsic molecular states.

    PubMed

    Guo, Haiming; Wang, Yeliang; Du, Shixuan; Gao, Hong-jun

    2014-10-01

    We review our achievements in exploring the high resolution imaging of scanning tunneling microscopy (STM) on the surface and adsorbates in a ultra-high vacuum system, by modifying the STM tip or introducing a decoupled layer onto the substrate. With an ultra-sharp tip, the highest resolution of Si(1 1 1)-7 × 7 reconstruction can be achieved, in which all the rest atoms and adatoms are observed simultaneously with high contrast. Further functionalization of STM tips can realize selective imaging of inherent molecular states. The electronic states of perylene and metal-phthalocyanine molecules are resolved with special decorated tips on metal substrates at low temperature. Moreover, we present two kinds of buffer layer: an organic molecular layer and epitaxially grown graphene to decouple the molecular electronic structure from the influence of the underlying metallic substrate and allow the direct imaging of the intrinsic orbitals of the adsorbed molecules. Theoretical calculations and STM simulations, based on first-principle density function theory, are performed in order to understand and verify the mechanism of high-resolution images. We propose that our results provide impactful routes to pursue the goal of higher resolution, more detailed information and extensive properties for future STM applications.

  16. Measurement of the retinal arteriolar response to a hyperoxic provocation in nonsmokers and smokers, using a high-resolution confocal scanning laser ophthalmoscope

    NASA Astrophysics Data System (ADS)

    O' Halloran, Margaret; O'Donoghue, Eamonn; Dainty, Chris

    2014-07-01

    We used a high-resolution confocal scanning laser ophthalmoscope to measure the magnitude of change in retinal arteriolar diameters in response to oxygen breathing in young, healthy nonsmokers and smokers. Image sequences were obtained before and during oxygen breathing. Image sequences were desinusoided, registered, and averaged, before vessel diameters were measured using a sliding linear regression filter. Arteriole diameters were observed to constrict during the first 5 min. of oxygen breathing, plateau, and remain stable while hyperoxia was maintained, returning to baseline at the end of the hyperoxic period. Blood flow to the temporal retina was found to be higher than to the nasal retina (p=0.008). The percentage constriction of vessels did not vary across retinal quadrants (p=0.372, analysis of variance) and did not depend on vessel size (p=0.538). Baseline diameters were unaffected by acute cigarette smoking. The magnitude of vasoconstriction was diminished in smokers compared to nonsmokers (p=0.017), while acute smoking did not influence the percentage constriction attained by the vessels (p=0.621). Using a high-resolution imaging technique allowed us to measure reactivity to a high degree of accuracy and to assess it in vessels of smaller caliber than were previously studied.

  17. A high-resolution photon-counting breast CT system with tensor-framelet based iterative image reconstruction for radiation dose reduction

    PubMed Central

    Ding, Huanjun; Gao, Hao; Zhao, Bo; Cho, Hyo-Min; Molloi, Sabee

    2016-01-01

    Both computer simulations and experimental phantom studies were carried out to investigate the radiation dose reduction with tensor framelet based iterative image reconstruction (TFIR) for a dedicated high-resolution spectral breast computed tomography (CT) based on a silicon strip photon-counting detector. The simulation was performed with a 10 cm-diameter water phantom including three contrast materials (polyethylene, 8 mg/ml iodine and B-100 bone-equivalent plastic). In the experimental study, the data were acquired with a 1.3 cm-diameter polymethylmethacrylate (PMMA) phantom containing iodine in three concentrations (8, 16 and 32 mg/ml) at various radiation doses (1.2, 2.4 and 3.6 mGy) and then CT images were reconstructed using filtered-back-projection (FBP) technique and TFIR technique, respectively. The image quality between these two techniques was evaluated by the quantitative analysis on contrast-to-noise ratio (CNR) and spatial resolution that was evaluated using the tasked-based modulation transfer function (MTF). Both simulation and experimental results indicated that the task-based MTF obtained from TFIR reconstruction with one-third of the radiation dose was comparable to that from FBP reconstruction for low contrast target. For high contrast target, TFIR was substantially superior to FBP reconstruction in term of spatial resolution. In addition, TFIR was able to achieve a factor of 1.6 to 1.8 increase in CNR depending on the target contrast level. This study demonstrates that TFIR can reduce the required radiation dose by a factor of two-third for a CT image reconstruction compared to FBP technique. It achieves much better CNR and spatial resolution for high contrast target in addition to retaining similar spatial resolution for low contrast target. This TFIR technique has been implemented with a graphic processing unit (GPU) system and it takes approximately 10 seconds to reconstruct a single-slice CT image, which can be potentially used in a

  18. Atomic arrangement at ZnTe/CdSe interfaces determined by high resolution scanning transmission electron microscopy and atom probe tomography

    SciTech Connect

    Bonef, Bastien; Rouvière, Jean-Luc; Jouneau, Pierre-Henri; Bellet-Amalric, Edith; Gérard, Lionel; Mariette, Henri; André, Régis; Bougerol, Catherine; Grenier, Adeline

    2015-02-02

    High resolution scanning transmission electron microscopy and atom probe tomography experiments reveal the presence of an intermediate layer at the interface between two binary compounds with no common atom, namely, ZnTe and CdSe for samples grown by Molecular Beam Epitaxy under standard conditions. This thin transition layer, of the order of 1 to 3 atomic planes, contains typically one monolayer of ZnSe. Even if it occurs at each interface, the direct interface, i.e., ZnTe on CdSe, is sharper than the reverse one, where the ZnSe layer is likely surrounded by alloyed layers. On the other hand, a CdTe-like interface was never observed. This interface knowledge is crucial to properly design superlattices for optoelectronic applications and to master band-gap engineering.

  19. Development of a High-Resolution Melting Approach for Scanning Beta Globin Gene Point Mutations in the Greek and Other Mediterranean Populations.

    PubMed

    Chassanidis, Christos; Boutou, Effrossyni; Voskaridou, Ersi; Balassopoulou, Angeliki

    2016-01-01

    Beta-thalassaemia is one of the most common autosomal recessive disorders worldwide. The disease's high incidence, which is observed in the broader Mediterranean area has led to the establishment of molecular diagnostics' assays to prevent affected births. Therefore, the development of a reliable, cost-effective and rapid scanning method for β globin gene point mutations, easily adapted to a routine laboratory, is absolutely essential. Here, we describe, for the first time, the development of a High-Resolution Melting Analysis (HRMA) approach, suitable for scanning the particularly heterogeneous beta globin gene mutations present in the Greek population, and thus adaptable to the Mediterranean and other areas where these mutations have been identified. Within this context, β globin gene regions containing mutations frequently identified in the Greek population were divided in ten overlapping amplicons. Our reactions' setup allowed for the simultaneous amplification of multiple primer sets and partial multiplexing, thereby resulting in significant reduction of the experimental time. DNA samples from β-thalassaemia patients/carriers with defined genotypes were tested. Distinct genotypes displayed distinguishable melting curves, enabling accurate detection of mutations. The described HRMA can be adapted to a high-throughput level. It represents a rapid, simple, cost-effective, reliable, highly feasible and sensitive method for β-thalassaemia gene scanning.

  20. Semi-automatic classification of textures in thoracic CT scans

    NASA Astrophysics Data System (ADS)

    Kockelkorn, Thessa T. J. P.; de Jong, Pim A.; Schaefer-Prokop, Cornelia M.; Wittenberg, Rianne; Tiehuis, Audrey M.; Gietema, Hester A.; Grutters, Jan C.; Viergever, Max A.; van Ginneken, Bram

    2016-08-01

    The textural patterns in the lung parenchyma, as visible on computed tomography (CT) scans, are essential to make a correct diagnosis in interstitial lung disease. We developed one automatic and two interactive protocols for classification of normal and seven types of abnormal lung textures. Lungs were segmented and subdivided into volumes of interest (VOIs) with homogeneous texture using a clustering approach. In the automatic protocol, VOIs were classified automatically by an extra-trees classifier that was trained using annotations of VOIs from other CT scans. In the interactive protocols, an observer iteratively trained an extra-trees classifier to distinguish the different textures, by correcting mistakes the classifier makes in a slice-by-slice manner. The difference between the two interactive methods was whether or not training data from previously annotated scans was used in classification of the first slice. The protocols were compared in terms of the percentages of VOIs that observers needed to relabel. Validation experiments were carried out using software that simulated observer behavior. In the automatic classification protocol, observers needed to relabel on average 58% of the VOIs. During interactive annotation without the use of previous training data, the average percentage of relabeled VOIs decreased from 64% for the first slice to 13% for the second half of the scan. Overall, 21% of the VOIs were relabeled. When previous training data was available, the average overall percentage of VOIs requiring relabeling was 20%, decreasing from 56% in the first slice to 13% in the second half of the scan.

  1. Quaternary sedimentary processes on the northwestern African continental margin - An integrated study using side-scan sonar, high-resolution profiling, and core data

    SciTech Connect

    Masson, D.G.; Huggett, Q.J.; Weaver, P.P.E. ); Kidd, R.B. ); Gardner, J.V. )

    1991-08-01

    Side-scan sonar data, cores, and high-resolution profiles have been used to produce an integrated model of sedimentation for the continental margin west of the Canary Islands. Long-range side-scan sonar (GLORIA) data and a grid of 3.5-kHz profiles, covering some 200,000 km{sup 2} allow a regional appraisal of sedimentation. More detailed studies of selected areas have been undertaken using a new 30 kHz deep-towed side-scan sonar (TOBI) developed by the U.K. Institute of Oceanographic Sciences. Sediment cores have been used both to calibrate acoustic facies identified on sonographs and for detailed stratigraphic studies. The most recent significant sedimentation event in the area is to Saharan Sediment Slide, which carried material from the upper continental slope off West Africa to the edge of the Madeira Abyssal Plain, a distance of some 1000 km. The authors data shows the downslope evolution of the debris flow. Near the Canaries, it is a 20-m-thick deposit rafting coherent blocks of more than 1 km diameter; side-scan records show a strong flow-parallel fabric on a scale of tens of meters. On the lower slope, the debris flow thins to a few meters, the flow fabric disappears, and the rafted blocks decrease to meters in diameter. Side-scan data from the lower slope show that the Saharan Slide buries an older landscape of turbidity current channels, typically 1 km wide and 50 m deep. Evidence from the Madeiran Abyssal Plain indicates a history of large but infrequent turbidity currents, the emplacement of which is related to the effects of sea level changes on the northwest African margin.

  2. Colitis detection on abdominal CT scans by rich feature hierarchies

    NASA Astrophysics Data System (ADS)

    Liu, Jiamin; Lay, Nathan; Wei, Zhuoshi; Lu, Le; Kim, Lauren; Turkbey, Evrim; Summers, Ronald M.

    2016-03-01

    Colitis is inflammation of the colon due to neutropenia, inflammatory bowel disease (such as Crohn disease), infection and immune compromise. Colitis is often associated with thickening of the colon wall. The wall of a colon afflicted with colitis is much thicker than normal. For example, the mean wall thickness in Crohn disease is 11-13 mm compared to the wall of the normal colon that should measure less than 3 mm. Colitis can be debilitating or life threatening, and early detection is essential to initiate proper treatment. In this work, we apply high-capacity convolutional neural networks (CNNs) to bottom-up region proposals to detect potential colitis on CT scans. Our method first generates around 3000 category-independent region proposals for each slice of the input CT scan using selective search. Then, a fixed-length feature vector is extracted from each region proposal using a CNN. Finally, each region proposal is classified and assigned a confidence score with linear SVMs. We applied the detection method to 260 images from 26 CT scans of patients with colitis for evaluation. The detection system can achieve 0.85 sensitivity at 1 false positive per image.

  3. Variation of quantitative emphysema measurements from CT scans

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Henschke, Claudia I.; Barr, R. Graham; Yankelevitz, David F.

    2008-03-01

    Emphysema is a lung disease characterized by destruction of the alveolar air sacs and is associated with long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema, and several measures have been introduced for the quantification of the extent of disease. In this paper we compare these measures for repeatability over time. The measures of interest in this study are emphysema index, mean lung density, histogram percentile, and the fractal dimension. To allow for direct comparisons, the measures were normalized to a 0-100 scale. These measures have been computed for a set of 2,027 scan pairs in which the mean interval between scans was 1.15 years (σ: 93 days). These independent pairs were considered with respect to three different scanning conditions (a) 223 pairs where both were scanned with a 5 mm slice thickness protocol, (b) 695 with the first scanned with the 5 mm protocol and the second with a 1.25 mm protocol, and (c) 1109 pairs scanned both times using a 1.25 mm protocol. We found that average normalized emphysema index and histogram percentiles scores increased by 5.9 and 11 points respectively, while the fractal dimension showed stability with a mean difference of 1.2. We also found, a 7 point bias introduced for emphysema index under condition (b), and that the fractal dimension measure is least affected by scanner parameter changes.

  4. Complications in CT-guided Procedures: Do We Really Need Postinterventional CT Control Scans?

    SciTech Connect

    Nattenmüller, Johanna Filsinger, Matthias Bryant, Mark Stiller, Wolfram Radeleff, Boris Grenacher, Lars Kauczor, Hans-Ullrich Hosch, Waldemar

    2013-06-19

    PurposeThe aim of this study is twofold: to determine the complication rate in computed tomography (CT)-guided biopsies and drainages, and to evaluate the value of postinterventional CT control scans.MethodsRetrospective analysis of 1,067 CT-guided diagnostic biopsies (n = 476) and therapeutic drainages (n = 591) in thoracic (n = 37), abdominal (n = 866), and musculoskeletal (ms) (n = 164) locations. Severity of any complication was categorized as minor or major. To assess the need for postinterventional CT control scans, it was determined whether complications were detected clinically, on peri-procedural scans or on postinterventional scans only.ResultsThe complication rate was 2.5 % in all procedures (n = 27), 4.4 % in diagnostic punctures, and 1.0 % in drainages; 13.5 % in thoracic, 2.0 % in abdominal, and 3.0 % in musculoskeletal procedures. There was only 1 major complication (0.1 %). Pneumothorax (n = 14) was most frequent, followed by bleeding (n = 9), paresthesia (n = 2), material damage (n = 1), and bone fissure (n = 1). Postinterventional control acquisitions were performed in 65.7 % (701 of 1,067). Six complications were solely detectable in postinterventional control acquisitions (3 retroperitoneal bleeds, 3 pneumothoraces); all other complications were clinically detectable (n = 4) and/or visible in peri-interventional controls (n = 21).ConclusionComplications in CT-guided interventions are rare. Of these, thoracic interventions had the highest rate, while pneumothoraces and bleeding were most frequent. Most complications can be detected clinically or peri-interventionally. To reduce the radiation dose, postinterventional CT controls should not be performed routinely and should be restricted to complicated or retroperitoneal interventions only.

  5. Diffusible iodine-based contrast-enhanced computed tomography (diceCT): an emerging tool for rapid, high-resolution, 3-D imaging of metazoan soft tissues.

    PubMed

    Gignac, Paul M; Kley, Nathan J; Clarke, Julia A; Colbert, Matthew W; Morhardt, Ashley C; Cerio, Donald; Cost, Ian N; Cox, Philip G; Daza, Juan D; Early, Catherine M; Echols, M Scott; Henkelman, R Mark; Herdina, A Nele; Holliday, Casey M; Li, Zhiheng; Mahlow, Kristin; Merchant, Samer; Müller, Johannes; Orsbon, Courtney P; Paluh, Daniel J; Thies, Monte L; Tsai, Henry P; Witmer, Lawrence M

    2016-06-01

    Morphologists have historically had to rely on destructive procedures to visualize the three-dimensional (3-D) anatomy of animals. More recently, however, non-destructive techniques have come to the forefront. These include X-ray computed tomography (CT), which has been used most commonly to examine the mineralized, hard-tissue anatomy of living and fossil metazoans. One relatively new and potentially transformative aspect of current CT-based research is the use of chemical agents to render visible, and differentiate between, soft-tissue structures in X-ray images. Specifically, iodine has emerged as one of the most widely used of these contrast agents among animal morphologists due to its ease of handling, cost effectiveness, and differential affinities for major types of soft tissues. The rapid adoption of iodine-based contrast agents has resulted in a proliferation of distinct specimen preparations and scanning parameter choices, as well as an increasing variety of imaging hardware and software preferences. Here we provide a critical review of the recent contributions to iodine-based, contrast-enhanced CT research to enable researchers just beginning to employ contrast enhancement to make sense of this complex new landscape of methodologies. We provide a detailed summary of recent case studies, assess factors that govern success at each step of the specimen storage, preparation, and imaging processes, and make recommendations for standardizing both techniques and reporting practices. Finally, we discuss potential cutting-edge applications of diffusible iodine-based contrast-enhanced computed tomography (diceCT) and the issues that must still be overcome to facilitate the broader adoption of diceCT going forward.

  6. Application of sensitive, high-resolution imaging at a commercial lab-based X-ray micro-CT system using propagation-based phase retrieval.

    PubMed

    Bidola, P; Morgan, K; Willner, M; Fehringer, A; Allner, S; Prade, F; Pfeiffer, F; Achterhold, K

    2017-02-09

    Several dedicated commercial lab-based micro-computed tomography (μCT) systems exist, which provide high-resolution images of samples, with the capability to also deliver in-line phase contrast. X-ray phase contrast is particularly beneficial when visualizing very small features and weakly absorbing samples. The raw measured projections will include both phase and absorption effects. Extending our previous work that addressed the optimization of experimental conditions at the commercial ZEISS Xradia 500 Versa system, single-distance phase-contrast imaging is demonstrated on complex biological and material samples. From data captured at this system, we demonstrate extraction of the phase signal or the correction of the mixed image for the phase shift, and show how this procedure increases the contrast and removes artefacts. These high-quality images, measured without the use of a synchrotron X-ray source, demonstrate that highly sensitive, micrometre-resolution imaging of 3D volumes is widely accessible using commercially advanced laboratory devices.

  7. Background correction in separation techniques hyphenated to high-resolution mass spectrometry - Thorough correction with MS scans recorded as profile spectra.

    PubMed

    Erny, Guillaume L; Acunha, Tanize; Simó, Carolina; Cifuentes, Alejandro; Alves, Arminda

    2017-03-01

    Separation techniques hyphenated with high-resolution mass spectrometry have been a true revolution in analytical separation techniques. Such instruments not only provide unmatched resolution, but they also allow measuring the peaks accurate masses that permit identifying monoisotopic formulae. However, data files can be large, with a major contribution from background noise and background ions. Such unnecessary contribution to the overall signal can hide important features as well as decrease the accuracy of the centroid determination, especially with minor features. Thus, noise and baseline correction can be a valuable pre-processing step. The methodology that is described here, unlike any other approach, is used to correct the original dataset with the MS scans recorded as profiles spectrum. Using urine metabolic studies as examples, we demonstrate that this thorough correction reduces the data complexity by more than 90%. Such correction not only permits an improved visualisation of secondary peaks in the chromatographic domain, but it also facilitates the complete assignment of each MS scan which is invaluable to detect possible comigration/coeluting species.

  8. High Resolution Trichromatic Road Surface Scanning with a Line Scan Camera and Light Emitting Diode Lighting for Road-Kill Detection.

    PubMed

    Lopes, Gil; Ribeiro, A Fernando; Sillero, Neftalí; Gonçalves-Seco, Luís; Silva, Cristiano; Franch, Marc; Trigueiros, Paulo

    2016-04-19

    This paper presents a road surface scanning system that operates with a trichromatic line scan camera with light emitting diode (LED) lighting achieving road surface resolution under a millimeter. It was part of a project named Roadkills-Intelligent systems for surveying mortality of amphibians in Portuguese roads, sponsored by the Portuguese Science and Technology Foundation. A trailer was developed in order to accommodate the complete system with standalone power generation, computer image capture and recording, controlled lighting to operate day or night without disturbance, incremental encoder with 5000 pulses per revolution attached to one of the trailer wheels, under a meter Global Positioning System (GPS) localization, easy to utilize with any vehicle with a trailer towing system and focused on a complete low cost solution. The paper describes the system architecture of the developed prototype, its calibration procedure, the performed experimentation and some obtained results, along with a discussion and comparison with existing systems. Sustained operating trailer speeds of up to 30 km/h are achievable without loss of quality at 4096 pixels' image width (1 m width of road surface) with 250 µm/pixel resolution. Higher scanning speeds can be achieved by lowering the image resolution (120 km/h with 1 mm/pixel). Computer vision algorithms are under development to operate on the captured images in order to automatically detect road-kills of amphibians.

  9. High Resolution Trichromatic Road Surface Scanning with a Line Scan Camera and Light Emitting Diode Lighting for Road-Kill Detection

    PubMed Central

    Lopes, Gil; Ribeiro, A. Fernando; Sillero, Neftalí; Gonçalves-Seco, Luís; Silva, Cristiano; Franch, Marc; Trigueiros, Paulo

    2016-01-01

    This paper presents a road surface scanning system that operates with a trichromatic line scan camera with light emitting diode (LED) lighting achieving road surface resolution under a millimeter. It was part of a project named Roadkills—Intelligent systems for surveying mortality of amphibians in Portuguese roads, sponsored by the Portuguese Science and Technology Foundation. A trailer was developed in order to accommodate the complete system with standalone power generation, computer image capture and recording, controlled lighting to operate day or night without disturbance, incremental encoder with 5000 pulses per revolution attached to one of the trailer wheels, under a meter Global Positioning System (GPS) localization, easy to utilize with any vehicle with a trailer towing system and focused on a complete low cost solution. The paper describes the system architecture of the developed prototype, its calibration procedure, the performed experimentation and some obtained results, along with a discussion and comparison with existing systems. Sustained operating trailer speeds of up to 30 km/h are achievable without loss of quality at 4096 pixels’ image width (1 m width of road surface) with 250 µm/pixel resolution. Higher scanning speeds can be achieved by lowering the image resolution (120 km/h with 1 mm/pixel). Computer vision algorithms are under development to operate on the captured images in order to automatically detect road-kills of amphibians. PMID:27104535

  10. Single-view volumetric PIV via high-resolution scanning, isotropic voxel restructuring and 3D least-squares matching (3D-LSM)

    NASA Astrophysics Data System (ADS)

    Brücker, C.; Hess, D.; Kitzhofer, J.

    2013-02-01

    Scanning PIV as introduced by Brücker (1995 Exp. Fluids 19 255-63, 1996a Appl. Sci. Res. 56 157-79) has been successfully applied in the last 20 years to different flow problems where the frame rate was sufficient to ensure a ‘frozen’ field condition. The limited number of parallel planes however leads typically to an under-sampling in the scan direction in depth; therefore, the spatial resolution in depth is typically considerably lower than the spatial resolution in the plane of the laser sheet (depth resolution = scan shift Δz ≫ pixel unit in object space). In addition, a partial volume averaging effect due to the thickness of the light sheet must be taken into account. Herein, the method is further developed using a high-resolution scanning in combination with a Gaussian regression technique to achieve an isotropic representation of the tracer particles in a voxel-based volume reconstruction with cuboidal voxels. This eliminates the partial volume averaging effect due to light sheet thickness and leads to comparable spatial resolution of the particle field reconstructions in x-, y- and z-axes. In addition, advantage of voxel-based processing with estimations of translation, rotation and shear/strain is taken by using a 3D least-squares matching method, well suited for reconstruction of grey-level pattern fields. The method is discussed in this paper and used to investigate the ring vortex instability at Re = 2500 within a measurement volume of roughly 75 × 75 × 50 mm3 with a spatial resolution of 100 µm/voxel (750 × 750 × 500 voxel elements). The volume has been scanned with a number of 100 light sheets and scan rates of 10 kHz. The results show the growth of the Tsai-Widnall azimuthal instabilities accompanied with a precession of the axis of the vortex ring. Prior to breakdown, secondary instabilities evolve along the core with streamwise oriented striations. The front stagnation point's streamwise distance to the core starts to decrease while

  11. Suomi NPP/JPSS Cross-track Infrared Sounder (CrIS): Calibration Validation With The Aircraft Based Scanning High-resolution Interferometer Sounder (S-HIS)

    NASA Astrophysics Data System (ADS)

    Taylor, J. K.; Revercomb, H. E.; Tobin, D.; Knuteson, R. O.; Best, F. A.; Adler, D. A.; Pettersen, C.; Garcia, R. K.; Gero, P.

    2013-12-01

    To better accommodate climate change monitoring and improved weather forecasting, there is an established need for higher accuracy and more refined error characterization of radiance measurements from space and the corresponding geophysical products. This need has led to emphasizing direct tests of on-orbit performance, referred to as validation. Currently, validation typically involves (1) collecting high quality reference data from airborne and/or ground-based instruments during the satellite overpass, and (2) a detailed comparison between the satellite-based radiance measurements and the corresponding high quality reference data. Additionally, for future missions technology advancements at the University of Wisconsin Space Science and Engineering Center (UW-SSEC) have led to the development of an on-orbit absolute radiance reference utilizing miniature phase change cells to provide direct on-orbit traceability to International Standards (SI). The detailed comparison between the satellite-based radiance measurements and the corresponding measurements made from a high-altitude aircraft must account for instrument noise and scene variations, as well as differences in instrument observation altitudes, view angles, spatial footprints, and spectral response. Most importantly, for the calibration validation process to be both accurate and repeatable the reference data instrument must be extremely well characterized and understood, carefully maintained, and accurately calibrated, with traceability to absolute standards. The Scanning High-resolution Interferometer Sounder (S-HIS) meets and exceeds these requirements and has proven to do so on multiple airborne platforms, each with significantly different instrument operating environments. The Cross-track Infrared Sounder (CrIS) on Suomi NPP, launched 28 October 2011, is designed to give scientists more refined information about Earth's atmosphere and improve weather forecasts and our understanding of climate. CrIS is an

  12. The neural elements in the lining of the ventricular-subventricular zone: making an old story new by high-resolution scanning electron microscopy.

    PubMed

    Haemmerle, Carlos Alexandre Dos Santos; Nogueira, Maria Inês; Watanabe, Ii-Sei

    2015-01-01

    The classical description of the neural elements that compose the lining of brain ventricles introduces us to the single layer of ependymal cells. However, new findings, especially in the lateral ventricle (LV)-the major niche for the generation of new neurons in the adult brain-have provided information about additional cell elements that influence the organization of this part of the ventricular system and produce important contributions to neurogenesis. To complement the cell neurochemistry findings, we present a three-dimensional in situ description that demonstrates the anatomical details of the different types of ciliated cells and the innervation of these elements. After processing adult rat brains for ultrastructural analysis by high-resolution scanning electron microscopy (HRSEM) and transmission electron microscopy, we observed a heterogeneous pattern of cilia distribution at the different poles of the LV surface. Furthermore, we describe the particular three-dimensional aspects of the ciliated cells of the LV, in addition the fiber bundles and varicose axons surrounding these cells. Therefore, we provide a unique ultrastructural description of the three-dimensional in situ organization of the LV surface, highlighting its innervation, to corroborate the available neurochemical and functional findings regarding the factors that regulate this neurogenic niche.

  13. In situ investigation of ion-induced dewetting of a thin iron-oxide film on silicon by high resolution scanning electron microscopy

    SciTech Connect

    Amirthapandian, S.; Schuchart, F.; Garmatter, D.; Bolse, W.

    2012-11-15

    Using our new in situ high resolution scanning electron microscope, which is integrated into the UNILAC ion beamline at the Helmholtzzentrum fuer Schwerionenforschung (GSI) in Darmstadt, Germany, we investigated the swift heavy ion induced dewetting of a thin iron oxide layer on Si. Besides heterogeneous hole nucleation at defects and spontaneous (homogeneous) hole nucleation, we could clearly identify a dewetting mechanism, which is similar to the spinodal dewetting observed for liquid films. Instead of being due to capillary waves, it is based on a stress induced surface instability. The latter results in the formation of a wavy surface with constant dominant wave-length and increasing amplitude during ion irradiation. Dewetting sets in as soon as the wave-troughs reach the film-substrate interface. Inspection of the hole radii and rim shapes indicates that removal of the material from the hole area occurs mainly by plastic deformation at the inner boundary and ion induced viscous flow in the peripheral zone due to surface tension.

  14. Hydration effects on skin microstructure as probed by high-resolution cryo-scanning electron microscopy and mechanistic implications to enhanced transcutaneous delivery of biomacromolecules.

    PubMed

    Tan, Grace; Xu, Peng; Lawson, Louise B; He, Jibao; Freytag, Lucia C; Clements, John D; John, Vijay T

    2010-02-01

    Although hydration is long known to improve the permeability of skin, penetration of macromolecules such as proteins is limited and the understanding of enhanced transport is based on empirical observations. This study uses high-resolution cryo-scanning electron microscopy to visualize microstructural changes in the stratum corneum (SC) and enable a mechanistic interpretation of biomacromolecule penetration through highly hydrated porcine skin. Swollen corneocytes, separation of lipid bilayers in the SC intercellular space to form cisternae, and networks of spherical particulates are observed in porcine skin tissue hydrated for a period of 4-10 h. This is explained through compaction of skin lipids when hydrated, a reversal in the conformational transition from unilamellar liposomes in lamellar granules to lamellae between keratinocytes when the SC skin barrier is initially established. Confocal microscopy studies show distinct enhancement in penetration of fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) through skin hydrated for 4-10 h, and limited penetration of FITC-BSA once skin is restored to its natively hydrated structure when exposed to the environment for 2-3 h. These results demonstrate the effectiveness of a 4-10 h hydration period to enhance transcutaneous penetration of large biomacromolecules without permanently damaging the skin.

  15. An Examination of the Surface and Sub-Surface of Modern and Historical Platinum Photographic Prints Using Low Vacuum High-Resolution Scanning Electron Microscopy.

    PubMed

    Ravines, Patrick; Erdman, Natasha; McElroy, Rob

    2016-08-01

    Photographic prints of platinum metal on paper supports are some of the most exquisite and expressive in the world of fine art photography. Platinum prints were produced from about 1890 to 1920 in the USA and Europe. The chemical and material nature of these valuable prints is of great interest to many who are interested in their long-term preservation, in the intersection of science and art, and in the scientific and technical study of cultural heritage. This paper presents the results of a characterization study using newer electron microscopy techniques. In this study, a low vacuum high-resolution scanning electron microscope was used to study the surface and sub-surface of historic and modern platinum and/or palladium print samples. Using environmental SEM pressures allowed us to investigate the actual top surface and sub-surface with cross-sections without any preparation; no coatings of carbon or other material. Cross-sections were prepared using an argon plasma cross-polishing system. This study shows that the photographic image of platinum prints is composed of platinum nanoparticles embedded in the upper layers of the paper's cellulosic fibers.

  16. Lava morphology mapping by expert system classification of high-resolution side-scan sonar imagery from the East Pacific Rise, 9° 10°N

    NASA Astrophysics Data System (ADS)

    Meyer, Jason D.; White, Scott M.

    2007-06-01

    Fine-scale lava morphology has been classified on the ridge crest of the East Pacific Rise between 9°15'N and 10°02'N using an expert system classification method. This method establishes the means to classify complicated seafloor environments by integrating textural and geometric feature attributes from a high-resolution side-scan sonar dataset where ground-reference data are available from near-bottom visual observations. The classification in this study focuses upon mapping the lava morphology distribution of sheet, lobate, and pillow flows along the East Pacific Rise. The reliability of the classification has been evaluated using an accuracy assessment. The study region yields a coverage area of 37,814 m2 (44%) for lobate flows; 10,421 m2 (12%) for pillow flows; 15,096 m2 (18%) for sheet flows; 19,679 m2 (23%) for fissured areas; and 2,967 m2 (3%) for shadows or no data. The systematic distribution of lava morphology along the ridge found in this study supports the idea of using the regional distribution of surface morphology as an indicator of emplacement dynamics and supports an organization of the volcanic plumbing system at a third order segmentation scale beneath mid-ocean ridges.

  17. Structural Evidence for Actin-like Filaments in Toxoplasma gondii Using High-Resolution Low-Voltage Field Emission Scanning Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Schatten, Heide; Sibley, L. David; Ris, Hans

    2003-08-01

    The protozoan parasite Toxoplasma gondii is representative of a large group of parasites within the phylum Apicomplexa, which share a highly unusual motility system that is crucial for locomotion and active host cell invasion. Despite the importance of motility in the pathology of these unicellular organisms, the motor mechanisms for locomotion remain uncertain, largely because only limited data exist about composition and organization of the cytoskeleton. By using cytoskeleton stabilizing protocols on membrane-extracted parasites and novel imaging with high-resolution low-voltage field emission scanning electron microscopy (LVFESEM), we were able to visualize for the first time a network of actin-sized filaments just below the cell membrane. A complex cytoskeletal network remained after removing the actin-sized fibers with cytochalasin D, revealing longitudinally arranged, subpellicular microtubules and intermediate-sized fibers of 10 nm, which, in stereo images, are seen both above and below the microtubules. These approaches open new possibilities to characterize more fully the largely unexplored and unconventional cytoskeletal motility complex in apicomplexan parasites.

  18. Single grain analysis on a nanoscale in ZrO2:Al2O3 nano-composites by means of high-resolution scanning transmission electron Microscopy

    NASA Astrophysics Data System (ADS)

    Brossmann, Ulrich; Albu, Mihaela; Hofer, Ferdinand; Würschum, Roland

    2016-12-01

    Nano-particulate powders of Al2O3:ZrO2 composites and the pure constituents were prepared by microwave plasma process synthesis and studied by high resolution scanning transmission electron microscopy. The ZrO2:Al2O3 nanocomposite samples showed a structure of randomly arranged, crystalline grains of both ZrO2 and Al2O3 with a size in the range of 3-5 nm. For each constituent, both cubic and monoclinic grains were observed. Similarly prepared, single phase Al2O3 nanoparticles were found to be completely amorphous. In the case of ZrO2, the crystallite size and the fraction of the monoclinic ZrO2 phase is noticeably reduced in the ZrO2:Al2O3 nanocomposite in comparison to single phase samples. The observation of ultra-small crystalline Al2O3 in the composite samples, is tentatively ascribed to a modification of the interface energy by the contact of Al2O3 and ZrO2 as well as a possible uptake of ZrO2 into the Al2O3 grains from the gas phase during synthesis.

  19. Comprehensive Non-Destructive Conservation Documentation of Lunar Samples Using High-Resolution Image-Based 3D Reconstructions and X-Ray CT Data

    NASA Technical Reports Server (NTRS)

    Blumenfeld, E. H.; Evans, C. A.; Oshel, E. R.; Liddle, D. A.; Beaulieu, K.; Zeigler, R. A.; Hanna, R. D.; Ketcham, R. A.

    2015-01-01

    Established contemporary conservation methods within the fields of Natural and Cultural Heritage encourage an interdisciplinary approach to preservation of heritage material (both tangible and intangible) that holds "Outstanding Universal Value" for our global community. NASA's lunar samples were acquired from the moon for the primary purpose of intensive scientific investigation. These samples, however, also invoke cultural significance, as evidenced by the millions of people per year that visit lunar displays in museums and heritage centers around the world. Being both scientifically and culturally significant, the lunar samples require a unique conservation approach. Government mandate dictates that NASA's Astromaterials Acquisition and Curation Office develop and maintain protocols for "documentation, preservation, preparation and distribution of samples for research, education and public outreach" for both current and future collections of astromaterials. Documentation, considered the first stage within the conservation methodology, has evolved many new techniques since curation protocols for the lunar samples were first implemented, and the development of new documentation strategies for current and future astromaterials is beneficial to keeping curation protocols up to date. We have developed and tested a comprehensive non-destructive documentation technique using high-resolution image-based 3D reconstruction and X-ray CT (XCT) data in order to create interactive 3D models of lunar samples that would ultimately be served to both researchers and the public. These data enhance preliminary scientific investigations including targeted sample requests, and also provide a new visual platform for the public to experience and interact with the lunar samples. We intend to serve these data as they are acquired on NASA's Astromaterials Acquisistion and Curation website at http://curator.jsc.nasa.gov/. Providing 3D interior and exterior documentation of astromaterial

  20. The high resolution topographic evolution of an active retrogressive thaw slump compiled from a decade of photography, ground surveys, laser scans and satellite imagery

    NASA Astrophysics Data System (ADS)

    Crosby, B. T.; Barnhart, T. B.; Rowland, J. C.

    2015-12-01

    Remote sensing imagery has enables the temporal reconstruction of thermal erosion features including lakes, shorelines and hillslope failures in remote Arctic locations, yet these planar data limit analysis to lines and areas. This study explores the application of varying techniques to reconstruct the three dimensional evolution of a single thermal erosion feature using a mixture of opportunistic oblique photos, ground surveys and satellite imagery. At the Selawik River retrogressive thaw slump in northwest Alaska, a bush plane collected oblique aerial photos when the feature was first discovered in 2004 and in subsequent years. These images were recently processed via Structure from Motion to generate georeferenced point clouds for the years prior to the initiation of our research. High resolution ground surveys in 2007, 2009 and 2010 were completed using robotic total station. Terrestrial laser scans (TLS) were collected in the summers of 2011 and 2012. Analysis of stereo satellite imagery from 2012 and 2015 enable continued monitoring of the feature after ground campaigns ended. As accurate coregistraion between point clouds is vital to topographic change detection, all prior and subsequent datasets were georeferenced to stable features observed in the 2012 TLS scan. Though this coregistration introduces uncertainty into each image, the magnitudes of uncertainty are significantly smaller than the topographic changes detected. Upslope retreat of the slump headwall generally decreases over time as the slump floor progresses from a highly dissected gully topography to a low relief, earthflow dominated depositional plane. The decreasing slope of the slump floor diminishes transport capacity, resulting in the progressive burial of the slump headwall, thus decreasing headwall retreat rates. This self-regulation of slump size based on feature relief and transport capacity suggests a capacity to predict the maximum size a given feature can expand to before

  1. Bombesin receptors and transplanted stem cells in rat brain: High-resolution scan with 99mTc BN1.1

    NASA Astrophysics Data System (ADS)

    Scopinaro, F.; Paschali, E.; Di Santo, G.; Antonellis, T.; Massari, R.; Trotta, C.; Gourni, H.; Bouziotis, P.; David, V.; Soluri, A.; Varvarigou, A. D.

    2006-12-01

    The aim of this work is to detect the presence of transplanted stem cells (TSC) in rat brain with high-resolution (HR) scintigraphy and labelled bombesin (BN). BN is a morphogen for Central Nervous System (CNS) as well as for other organs: CNS-oriented TSC over-express BN Receptors (BNR). BN is also a neurotransmitter and modulates several functions of CNS. 99mTc labelled BN-like peptide scan of CNS is the ideal method to detect growing TSC once knowing normal distribution of BNRs in CNS. HR Planar and single photon emission computerized tomography (SPECT) images of rat brain were performed with new HR detectors (Li-tech, Italy). Pertechnetate, 99mTc HMPAO and the new 99mTc BN1.1 (patented) were i.v. administered in five rats. HR SPECT of 99mTc BN1.1 detected olfactory tract, fronto-lateral cortex, cerebellum, basal ganglia and amygdale. Results of SPECT were confirmed by bio-distribution study performed after autopsy of three of the five rats. The remaining two rats underwent cerebral lesions followed by transplant of TSC. Three months later, HR scintigraphy was repeated and showed images completely different from previous basal study, with hot spot of 99mTc BN1.1 corresponding to the site of TSC transplant. Immuno-histochemistry confirmed the presence of viable TSC. Not only 99mTc BN1.1 HR scan showed viability of transplanted TSC but also the "background brain" was the still now unknown map of BNR in mammalian brain.

  2. Light scattering in optical CT scanning of Presage dosimeters

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Adamovics, J.; Cheeseborough, J. C.; Chao, K. S.; Wuu, C. S.

    2010-11-01

    The intensity of the scattered light from the Presage dosimeters was measured using a Thorlabs PM100D optical power meter (Thorlabs Inc, Newton, NJ) with an optical sensor of 1 mm diameter sensitive area. Five Presage dosimeters were made as cylinders of 15.2 cm, 10 cm, 4 cm diameters and irradiated with 6 MV photons using a Varian Clinac 2100EX. Each dosimeter was put into the scanning tank of an OCTOPUS" optical CT scanner (MGS Research Inc, Madison, CT) filled with a refractive index matching liquid. A laser diode was positioned at one side of the water tank to generate a stationary laser beam of 0.8 mm width. On the other side of the tank, an in-house manufactured positioning system was used to move the optical sensor in the direction perpendicular to the outgoing laser beam from the dosimeters at an increment of 1 mm. The amount of scattered photons was found to be more than 1% of the primary light signal within 2 mm from the laser beam but decreases sharply with increasing off-axis distance. The intensity of the scattered light increases with increasing light attenuations and/or absorptions in the dosimeters. The scattered light at the same off-axis distance was weaker for dosimeters of larger diameters and for larger detector-to-dosimeter distances. Methods for minimizing the effect of the light scattering in different types of optical CT scanners are discussed.

  3. High resolution computed tomography of advanced composite and ceramic materials

    NASA Technical Reports Server (NTRS)

    Yancey, R. N.; Klima, S. J.

    1991-01-01

    Advanced composite and ceramic materials are being developed for use in many new defense and commercial applications. In order to achieve the desired mechanical properties of these materials, the structural elements must be carefully analyzed and engineered. A study was conducted to evaluate the use of high resolution computed tomography (CT) as a macrostructural analysis tool for advanced composite and ceramic materials. Several samples were scanned using a laboratory high resolution CT scanner. Samples were also destructively analyzed at the locations of the scans and the nondestructive and destructive results were compared. The study provides useful information outlining the strengths and limitations of this technique and the prospects for further research in this area.

  4. CT Scan Method Accurately Assesses Humeral Head Retroversion

    PubMed Central

    Boileau, P.; Mazzoleni, N.; Walch, G.; Urien, J. P.

    2008-01-01

    Humeral head retroversion is not well described with the literature controversial regarding accuracy of measurement methods and ranges of normal values. We therefore determined normal humeral head retroversion and assessed the measurement methods. We measured retroversion in 65 cadaveric humeri, including 52 paired specimens, using four methods: radiographic, computed tomography (CT) scan, computer-assisted, and direct methods. We also assessed the distance between the humeral head central axis and the bicipital groove. CT scan methods accurately measure humeral head retroversion, while radiographic methods do not. The retroversion with respect to the transepicondylar axis was 17.9° and 21.5° with respect to the trochlear tangent axis. The difference between the right and left humeri was 8.9°. The distance between the central axis of the humeral head and the bicipital groove was 7.0 mm and was consistent between right and left humeri. Humeral head retroversion may be most accurately obtained using the patient’s own anatomic landmarks or, if not, identifiable retroversion as measured by those landmarks on contralateral side or the bicipital groove. PMID:18264854

  5. Lipiodol enhanced CT scanning of malignant hepatic tumors.

    PubMed

    Eurvilaichit, C

    2000-04-01

    From August 1984 to March 1991, 41 patients with malignant liver tumors, 30 males and 11 females, aged 30-75 years were treated at Ramathibodi Hospital with injection of mitomycin-C lipiodol emulsion into the tumor via the feeding artery followed by embolization of the feeding artery with gelfoam particles. The patients comprised 30 cases of hepatocellular carcinoma, 4 cases of cholangiocarcinoma and 7 cases of metastatic tumors of which one was from CA stomach, three were from CA breast, and three from CA colon. The vascularity of the tumor was assessed in angiogram obtained prior to treatment and retention pattern of lipiodol in the tumor was evaluated in lipiodol-enhanced CT scan images taken 2-4 weeks following therapy. The results showed that lipiodol CT scan images exhibited four patterns of lipiodol retention in the tumor appearing as opacity as follows (1) homogenous (2) heterogeneous (3) ring-like and (4) none. Lipiodol retention pattern appeared to be somewhat related to vascularity of the tumor. Most of the hypervascular tumors such as hepatocellular carcinoma had homogeneous lipiodol accumulation pattern if the tumor size was less than 5 cm. Metastatic tumors and cholangiocarcinoma showed heterogeneous or ring-like pattern of lipiodol accumulation because they were relatively hypovascular. Hypervascular hepatocellular carcinoma may exhibit heterogeneous or ring-like pattern if they are larger than 5 cms, and have multiple feeding arteries, necrosis or AV shunting. Hepatocellular carcinoma with AV shunting may not show any lipiodol accumulation at all.

  6. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the specimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view is made from three orthogonal slices. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: Los Alamos National Laboratory and the University of Colorado at Boulder).

  7. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. These views depict vertical slices from side to middle of a flight specimen. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  8. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view is made from a series of horizontal slices. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  9. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view depict horizontal slices from top to bottom of a flight specimen. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  10. Linking playa surface dust emission potential to feedbacks between surface moisture and salt crust expansion through high resolution terrestrial laser scanning measurements

    NASA Astrophysics Data System (ADS)

    Nield, J. M.; King, J.; Wiggs, G.

    2012-12-01

    The dust emissivity of salt pans (or playas) can be significant but is controlled by interactions between wind erosivity, surface moisture, salt chemistry and crust morphology. These surface properties influence the aeolian transport threshold and can be highly variable over both short temporal and spatial scales. In the past, field studies have been hampered by practical difficulties in accurately measuring properties controlling sediment availability at the surface in high resolution. Studies typically therefore, have investigated large scale monthly or seasonal change using remote sensing and assume a homogeneous surface when predicting dust emissivity. Here we present the first high resolution measurements (sub-cm) of salt crust expansion related to changes in diurnal moisture over daily and weekly time periods using terrestrial laser scanning (TLS, ground-based LiDAR) on Sua Pan, Botswana. The TLS measures both elevation and relative surface moisture change simultaneously, without disturbing the surface. Measurement sequences enable the variability in aeolian sediment availability to be quantified along with temporal feedbacks associated with crust degradation. On crusts with well-developed polygon ridges (high aerodynamic and surface roughness), daily surface expansion was greater than 30mm. The greatest surface change occurred overnight on the upper, exposed sections of the ridges, particularly when surface temperatures dropping below 10°C. These areas also experienced the greatest moisture variation and became increasingly moist overnight in response to an increase in relative humidity. In contrast, during daylight hours, the ridge areas were drier than the lower lying inter-ridge areas. Positive feedbacks between surface topography and moisture reinforced the maximum diurnal moisture variation at ridge peaks, encouraging crust thrusting due to overnight salt hydration, further enhancing the surface, and therefore, aerodynamic roughness. These feedbacks

  11. Flat panel CT detectors for sub-second volumetric scanning

    NASA Astrophysics Data System (ADS)

    Colbeth, Richard E.; Mollov, Ivan P.; Roos, Pieter G.; Shapiro, Edward G.

    2005-04-01

    This paper explores the potential of flat panel detectors in sub-second CT scanning applications. Using a PaxScan 4030CB with 600um thick CsI(Tl), a central section of the panel (16 to 32 rows), was scanned at frame rates up to 1000fps. Using this platform, fundamental issues related to high speed scanning were characterized. The offset drift of the imager over 60 seconds was found to be less than 0.014 ppm/sec relative to full scale. The gain stability over a 10 hour period is better than +/- .45%, which is at the resolution limit of the measurement. Two different types of lag measurements were performed in order to separate the photodiode array lag from the CsI afterglow. The panel lag was found to be 0.41% 1st frame and 0.054% 25th frame at 1000fps. The CsI(Tl) afterglow, however, is roughly an order of magnitude higher, dominating the lag for sub-second scans. At 1000fps the 1st frame lag due to afterglow was 3.3% and the 25th frame lag was 0.34%. Both the lag and afterglow are independent of signal level and each follows a simple power law evolution versus time. Reconstructions of anatomical phantoms and the CATPHAN 500 phantom are presented. With a 2 second, 1200 projection scan of the CATPHAN phantom at 600fps in 32 slice mode, using 120kVp and CTDI100 of 43.2mGy, 0.3% contrast resolution for a 6mm diameter target, can be visualized. In addition, 15lp/cm spatial resolution was achieved with a 2mm slice and a central CTDI100 of 10.8mGy.

  12. Multi-detector row CT scanning in Paleoanthropology at various tube current settings and scanning mode.

    PubMed

    Badawi-Fayad, J; Yazbeck, C; Balzeau, A; Nguyen, T H; Istoc, A; Grimaud-Hervé, D; Cabanis, E- A

    2005-12-01

    The purpose of this study was to determine the optimal tube current setting and scanning mode for hominid fossil skull scanning, using multi-detector row computed tomography (CT). Four fossil skulls (La Ferrassie 1, Abri Pataud 1, CroMagnon 2 and Cro-Magnon 3) were examined by using the CT scanner LightSpeed 16 (General Electric Medical Systems) with varying dose per section (160, 250, and 300 mAs) and scanning mode (helical and conventional). Image quality of two-dimensional (2D) multiplanar reconstructions, three-dimensional (3D) reconstructions and native images was assessed by four reviewers using a four-point grading scale. An ANOVA (analysis of variance) model was used to compare the mean score for each sequence and the overall mean score according to the levels of the scanning parameters. Compared with helical CT (mean score=12.03), the conventional technique showed sustained poor image quality (mean score=4.17). With the helical mode, we observed a better image quality at 300 mAs than at 160 in the 3D sequences (P=0.03). Whereas in native images, a reduction in the effective tube current induced no degradation in image quality (P=0.05). Our study suggests a standardized protocol for fossil scanning with a 16 x 0.625 detector configuration, a 10 mm beam collimation, a 0.562:1 acquisition mode, a 0.625/0.4 mm slice thickness/reconstruction interval, a pitch of 5.62, 120 kV and 300 mAs especially when a 3D study is required.

  13. Automated CT Scan Scores of Bronchiectasis and Air Trapping in Cystic Fibrosis

    PubMed Central

    Swiercz, Waldemar; Heltshe, Sonya L.; Anthony, Margaret M.; Szefler, Paul; Klein, Rebecca; Strain, John; Brody, Alan S.; Sagel, Scott D.

    2014-01-01

    Background: Computer analysis of high-resolution CT (HRCT) scans may improve the assessment of structural lung injury in children with cystic fibrosis (CF). The goal of this cross-sectional pilot study was to validate automated, observer-independent image analysis software to establish objective, simple criteria for bronchiectasis and air trapping. Methods: HRCT scans of the chest were performed in 35 children with CF and compared with scans from 12 disease control subjects. Automated image analysis software was developed to count visible airways on inspiratory images and to measure a low attenuation density (LAD) index on expiratory images. Among the children with CF, relationships among automated measures, Brody HRCT scanning scores, lung function, and sputum markers of inflammation were assessed. Results: The number of total, central, and peripheral airways on inspiratory images and LAD (%) on expiratory images were significantly higher in children with CF compared with control subjects. Among subjects with CF, peripheral airway counts correlated strongly with Brody bronchiectasis scores by two raters (r = 0.86, P < .0001; r = 0.91, P < .0001), correlated negatively with lung function, and were positively associated with sputum free neutrophil elastase activity. LAD (%) correlated with Brody air trapping scores (r = 0.83, P < .0001; r = 0.69, P < .0001) but did not correlate with lung function or sputum inflammatory markers. Conclusions: Quantitative airway counts and LAD (%) on HRCT scans appear to be useful surrogates for bronchiectasis and air trapping in children with CF. Our automated methodology provides objective quantitative measures of bronchiectasis and air trapping that may serve as end points in CF clinical trials. PMID:24114359

  14. Qualitative aspects and validation of a screening method for pesticides in vegetables and fruits based on liquid chromatography coupled to full scan high resolution (Orbitrap) mass spectrometry.

    PubMed

    Mol, Hans G J; Zomer, Paul; de Koning, Maarten

    2012-07-01

    The analytical capabilities of liquid chromatography with single-stage high-resolution mass spectrometry have been investigated with emphasis on qualitative aspects related to selective detection during screening and to identification. The study involved 21 different vegetable and fruit commodities, a screening database of 556 pesticides for evaluation of false positives, and a test set of 130 pesticides spiked to the commodities at 0.01, 0.05, and 0.20 mg/kg for evaluation of false negatives. The final method involved a QuEChERS-based sample preparation (without dSPE clean up) and full scan acquisition using alternating scan events without/with fragmentation, at a resolving power of 50,000. Analyte detection was based on extraction of the exact mass (±5 ppm) of the major adduct ion at the database retention time ±30 s and the presence of a second diagnostic ion. Various options for the additional ion were investigated and compared (other adduct ions, M + 1 or M + 2 isotopes, fragments). The two-ion approach for selective detection of the pesticides in the full scan data was compared with two alternative approaches based on response thresholds. Using the two-ion approach, the number of false positives out of 11,676 pesticide/commodity combinations targeted was 36 (0.3 %). The percentage of false negatives, assessed for 2,730 pesticide/commodity combinations, was 13 %, 3 %, and 1 % at the 0.01-, 0.05-, and 0.20-mg/kg level, respectively (slightly higher with fully automated detection). Following the SANCO/12495/2011 protocol for validation of screening methods, the screening detection limit was determined for 130 pesticides and found to be 0.01, 0.05, and ≥0.20 mg/kg for 86, 30, and 14 pesticides, respectively. For the detected pesticides in the spiked samples, the ability for unambiguous identification according to EU criteria was evaluated. A proposal for adaption of the criteria was made.

  15. A study evaluating the dependence of the patient dose on the CT dose change in a SPECT/CT scan

    NASA Astrophysics Data System (ADS)

    Kim, Woo-Hyun; Kim, Ho-Sung; Dong, Kyung-Rae; Chung, Woon-Kwan; Cho, Jae-Hwan; Shin, Jae-Woo

    2012-07-01

    This study assessed ways of reducing the patient dose by examining the dependence of the patient dose on the CT (computed tomography) dose in a SPECT (single-photon emission computed tomography)/CT scan. To measure the patient dose, we used Precedence 16 SPECT/CT along with a phantom for the CT dose measurement (CT dose phantom kit for adult's head and body, Model 76-414-4150), a 100-mm ionization chamber (CT Ion Chamber) and an X-ray detector (Victoreen Model 4000M+). In addition, the patient dose was evaluated under conditions similar to those for an actual examination using an ImPACT (imaging performance assessment of CT scanners) dosimetry calculator in the Monte Carlo simulation method. The experimental method involved the use of a CT dose phantom to measure the patient dose under different CT conditions (kVp and mAs) to determine the CTDI (CT dose index) under each condition. An ImPACT dosimetry calculator was also used to measure CTDIw (CT dose index water ), CTDIv (CT dose index volume ), DLP (dose-length product), and effective dose. According to the patient dose measurements using the CT dose phantom, the CTDI showed an approximately 54 fold difference between when the maximum (140 kVp and 250 mAs) and the minimum dose (90 kVp and 25 mAs) was used. The CTDI showed a 4.2 fold difference between the conditions (120 kVp and 200 mAs) used mainly in a common CT scan and the conditions (120 kVp and 50 mAs) used mainly in a SPECT/CT scan. According to the measurement results using the dosimetry calculator, the effective dose showed an approximately 35 fold difference between the conditions for the maximum and the minimum doses, as in the case with the CT dose phantom. The effective dose showed a 4.1 fold difference between the conditions used mainly in a common CT scan and those used mainly in a SPECT/CT scan. This study examined the patient dose by reducing the CT dose in a SPECT/CT scan. As various examinations can be conducted due to the development of

  16. Orthogonal-rotating tetrahedral scanning for cone-beam CT

    NASA Astrophysics Data System (ADS)

    Ye, Ivan B.; Wang, Ge

    2012-10-01

    In this article, a cone-beam CT scanning mode is designed assuming four x-ray sources and a spherical sample. The x-ray sources are mounted at the vertices of a regular tetrahedron. On the circumsphere of the tetrahedron, four detection panels are mounted opposite to each vertex. To avoid x-ray interference, the largest half angle of each x-ray cone beam is 27°22', while the radius of the largest ball fully covered by all the cone beams is 0.460, when the radius of the circumsphere is 1. Several scanning schemes are proposed which consist of two rotations about orthogonal axes, such that each quarter turn provides sufficient data for theoretically exact and stable reconstruction. This design can be used in biomedical or industrial settings, such as when a sequence of reconstructions of an object is desired. Similar scanning schemes based on other regular or irregular polyhedra and various rotation speeds are also discussed.

  17. CT scanning phantom for normalization of infant brain attenuation.

    PubMed

    Thompson, J R; Triolo, P J; Moore, R J; Hinshaw, D B; Hasso, A N

    1984-01-01

    The x-ray attenuation values of brain studied with computed tomography (CT) are strikingly affected by the ages of the subjects. Premature neonates, for example, may have brain attenuation values 20-30 H below adult values. These lower attenuation values for developing compared with adult brain can be ascribed partly to machine-related effects (beam-hardening, adult algorithms, scanning geometry, etc.). A scanning phantom made from aluminum was developed that can be used to develop a nomogram for any particular scanner from which normalized brain attenuation may be derived for any small head size. Using this nomogram, predicted neonatal attenuations are still 10-15 H higher than those actually observed in scanning neonates. The model predicts that, at the most, 3-4 H of this discrepancy can be accounted for by less beam-hardening from the lower bone attenuation of the thinner developing skull. Presumably, the rest is from a lower brain density in neonates (higher water content). By normalizing to cerebrospinal fluid (water) with special care to avoid partial-volume artifacts, one can predict attenuation values for developing brain more accurately.

  18. SU-E-I-37: Eye Lens Dose Reduction From CT Scan Using Organ Based Tube Current Modulation

    SciTech Connect

    Liu, H; Liu, T; Xu, X; Wu, J; Zhuo, W

    2015-06-15

    Purpose: To investigate the eye lens dose reduction by CT scan with organ based tube current modulation (OBTCM) using GPU Monte Carlo code ARCHER-CT. Methods: 36 X-ray sources and bowtie filters were placed around the patient head with the projection angle interval of 10° for one rotation of CT scan, each projection was simulated respectively. The voxel eye models with high resolution(0.1mm*0.1mm*0.1mm) were used in the simulation and different tube voltage including 80kVp, 100kVp, 120kVp and 140kVp were taken into consideration. Results: The radiation doses to the eye lens increased with the tube voltage raised from 80kVp to 140kVp, and the dose results from 0° (AP) direction are much higher than those from 180° (PA) direction for all the 4 different tube voltage investigated. This 360° projection dose characteristic enables organ based TCM, which can reduce the eye lens dose by more than 55%. Conclusion: As the eye lens belongs to superficial tissues, its radiation dose to external exposure like CT is direction sensitive, and this characteristic feature makes organ based TCM to be an effective way to reduce the eye lens dose, so more clinical use of this technique were recommended. National Nature Science Foundation of China(No.11475047)

  19. Characterization of Soft Contact Lens Edge Fitting Using Ultra-High Resolution and Ultra-Long Scan Depth Optical Coherence Tomography

    PubMed Central

    Shen, Meixiao; Cui, Lele; Riley, Colleen; Wang, Michael R.

    2011-01-01

    Purpose. To characterize the edge fitting of soft contact lenses using ultra-high resolution optical coherence tomography (UHR-OCT) and ultra-long scan depth optical coherence tomography (UL-OCT). Methods. A total of 20 participants (11 men, 9 women; mean age, 32.3 years) were recruited. Four different types of soft contact lenses were randomly fitted to both eyes of each subject on two separate visits. After 30 minutes, the horizontal meridians of the corneal center, midperiphery, and limbus were imaged by UHR-OCT. UL-OCT imaged each lens in vitro and the ocular surface of a physical model eye. Results. Angle-edged lenses had significantly less conjunctival buildup than did round-edged lenses (P = 0.008). Limbal post-lens tear film gaps were present in 42% of the eyes, with the round-edged lenses having the most at 68%. Similarly, post-lens tear film gaps at the corneal mid-periphery were present in 47% of all eyes, with the round-edged lens having the most at 75%. Mismatches between the lens and the ocular surface were simulated based on UL-OCT images of the in vitro lenses and the model eye. The existence of tear film gaps and touching points were predicted in the simulation. Conclusions. The soft contact lens edge fitting was characterized by the conjunctival buildup and tear film gaps. Different types of contact lenses presented different levels of conjunctival buildup as well as different frequencies of tear film gaps. The findings by UHR-OCT were predicted in the simulation by UL-OCT. The application of these new technologies may open new ways of designing lenses and evaluating their fit. PMID:21372023

  20. Tropospheric Carbon Monoxide Measurements from the Scanning High-resolution Interferometer Sounder on 7 September 2000 in Southern Africa during SAFARI 2000

    NASA Technical Reports Server (NTRS)

    McMillan, W. W.; McCourt, M. L.; Revercomb, H. E.; Knuteson, R. O.; Christian, T. J.; Doddridge, B. G.; Hobbs, P. V.; Lukovich, P. C.; Novelli, P. C.; Piketh, S. J.

    2003-01-01

    Retrieved tropospheric carbon monoxide (CO) column densities are presented for more than 9000 spectra obtained by the University of Wisconsin-Madison (UWis) Scanning High-Resolution Interferometer Sounder (SHIS) during a flight on the NASA ER-2 on 7 September 2000 as part of the Southern African Regional Science Initiative (SAFARI 2000) dry season field campaign. Enhancements in tropospheric column CO were detected in the vicinity of a controlled biomass burn in the Timbavati Game Reserve in northeastern South Africa and over the edge of the river of smoke in south central Mozambique. Relatively clean air was observed over the far southern coast of Mozambique. Quantitative comparisons are presented with in situ measurements from five different instruments flying on two other aircraft: the University of Washington Convair-580 (CV) and the South African Aerocommander JRB in the vicinity of the Timbavati fire. Measured tropospheric CO columns (extrapolated from 337 to 100 mb) of 2.1 x 10(exp 18) per square centimeter in background air and up to 1.5 x 10(exp 19) per square centimeter in the smoke plume agree well with SHIS retrieved tropospheric CO columns of (2.3 plus or minus 0.25) x 10(exp 18) per square centimeter over background air near the fire and (1.5 plus or minus 0.35) x 10(exp 19) per square centimeter over the smoke plume. Qualitative comparisons are presented with three other in situ CO profiles obtained by the South African JRA aircraft over Mozambique and northern South Africa showing the influence of the river of smoke.

  1. Unconventional Specimen Preparation Techniques Using High Resolution Low Voltage Field Emission Scanning Electron Microscopy to Study Cell Motility, Host Cell Invasion, and Internal Cell Structures in Toxoplasma gondii

    NASA Astrophysics Data System (ADS)

    Schatten, Heide; Ris, Hans

    2002-04-01

    Apicomplexan parasites employ complex and unconventional mechanisms for cell locomotion, host cell invasion, and cell division that are only poorly understood. While immunofluorescence and conventional transmission electron microscopy have been used to answer questions about the localization of some cytoskeletal proteins and cell organelles, many questions remain unanswered, partly because new methods are needed to study the complex interactions of cytoskeletal proteins and organelles that play a role in cell locomotion, host cell invasion, and cell division. The choice of fixation and preparation methods has proven critical for the analysis of cytoskeletal proteins because of the rapid turnover of actin filaments and the dense spatial organization of the cytoskeleton and its association with the complex membrane system. Here we introduce new methods to study structural aspects of cytoskeletal motility, host cell invasion, and cell division of Toxoplasma gondii, a most suitable laboratory model that is representative of apicomplexan parasites. The novel approach in our experiments is the use of high resolution low voltage field emission scanning electron microscopy (LVFESEM) combined with two new specimen preparation techniques. The first method uses LVFESEM after membrane extraction and stabilization of the cytoskeleton. This method allows viewing of actin filaments which had not been possible with any other method available so far. The second approach of imaging the parasite's ultrastructure and interactions with host cells uses semithick sections (200 nm) that are resin de-embedded (Ris and Malecki, 1993) and imaged with LVFESEM. This method allows analysis of structural detail in the parasite before and after host cell invasion and interactions with the membrane of the parasitophorous vacuole as well as parasite cell division.

  2. Morphometric, quantitative, and three-dimensional analysis of the heart muscle fibers of old rats: transmission electron microscopy and high-resolution scanning electron microscopy methods.

    PubMed

    Cury, Diego Pulzatto; Dias, Fernando José; Sosthenes, Marcia Consentino Kronka; Dos Santos Haemmerle, Carlos Alexandre; Ogawa, Koichi; Da Silva, Marcelo Cavenaghi Pereira; Mardegan Issa, João Paulo; Iyomasa, Mamie Mizusaki; Watanabe, Ii-Sei

    2013-02-01

    This research investigated the morphological, morphometric, and ultrastructural cardiomyocyte characteristics of male Wistar rats at 18 months of age. The animals were euthanized using an overdose of anesthesia (ketamine and xylazine, 150/10 mg/kg) and perfused transcardially, after which samples were collected for light microscopy, transmission electron microscopy, and high-resolution scanning electron microscopy. The results showed that cardiomyocyte arrangement was disposed parallel between the mitochondria and the A-, I-, and H-bands and their M- and Z-lines from the sarcomere. The sarcomere junction areas had intercalated disks, a specific structure of heart muscle. The ultrastructural analysis revealed several mitochondria of various sizes and shapes intermingled between the blood capillaries and their endothelial cells; some red cells inside vessels are noted. The muscle cell sarcolemma could be observed associated with the described structures. The cardiomyocytes of old rats presented an average sarcomere length of 2.071 ± 0.09 μm, a mitochondrial volume density (Vv) of 0.3383, a mitochondrial average area of 0.537 ± 0.278 μm(2), a mitochondrial average length of 1.024 ± 0.352 μm, an average mitochondrial cristae thickness of 0.038 ± 0.09 μm and a ratio of mitochondrial greater length/lesser length of 1.929 ± 0.965. Of the observed mitochondrial shapes, 23.4% were rounded, 45.3% were elongated, and 31.1% had irregular profiles. In this study, we analyzed the morphology and morphometry of cardiomyocytes in old rats, focusing on mitochondria. These data are important for researchers who focus the changes in cardiac tissue, especially changes owing to pathologies and drug administration that may or may not be correlated with aging.

  3. Possibilities of CT Scanning as Analysis Method in Laser Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Karme, Aleksis; Kallonen, Aki; Matilainen, Ville-Pekka; Piili, Heidi; Salminen, Antti

    Laser additive manufacturing is an established and constantly developing technique. Structural assessment should be a key component to ensure directed evolution towards higher level of manufacturing. The macroscopic properties of metallic structures are determined by their internal microscopic features, which are difficult to assess using conventional surface measuring methodologies. X-ray microtomography (CT) is a promising technique for three-dimensional non-destructive probing of internal composition and build of various materials. Aim of this study is to define the possibilities of using CT scanning as quality control method in LAM fabricated parts. Since the parts fabricated with LAM are very often used in high quality and accuracy demanding applications in various industries such as medical and aerospace, it is important to be able to define the accuracy of the build parts. The tubular stainless steel test specimens were 3D modelled, manufactured with a modified research AM equipment and imaged after manufacturing with a high-power, high-resolution CT scanner. 3D properties, such as surface texture and the amount and distribution of internal pores, were also evaluated in this study. Surface roughness was higher on the interior wall of the tube, and deviation from the model was systematically directed towards the central axis. Pore distribution showed clear organization and divided into two populations; one following the polygon model seams along both rims, and the other being associated with the concentric and equidistant movement path of the laser. Assessment of samples can enhance the fabrication by guiding the improvement of both modelling and manufacturing process.

  4. Scanning electrochemical cell microscopy: theory and experiment for quantitative high resolution spatially-resolved voltammetry and simultaneous ion-conductance measurements.

    PubMed

    Snowden, Michael E; Güell, Aleix G; Lai, Stanley C S; McKelvey, Kim; Ebejer, Neil; O'Connell, Michael A; Colburn, Alexander W; Unwin, Patrick R

    2012-03-06

    Scanning electrochemical cell microscopy (SECCM) is a high resolution electrochemical scanning probe technique that employs a dual-barrel theta pipet probe containing electrolyte solution and quasi-reference counter electrodes (QRCE) in each barrel. A thin layer of electrolyte protruding from the tip of the pipet ensures that a gentle meniscus contact is made with a substrate surface, which defines the active surface area of an electrochemical cell. The substrate can be an electrical conductor, semiconductor, or insulator. The main focus here is on the general case where the substrate is a working electrode, and both ion-conductance measurements between the QRCEs in the two barrels and voltammetric/amperometric measurements at the substrate can be made simultaneously. In usual practice, a small perpendicular oscillation of the probe with respect to the substrate is employed, so that an alternating conductance current (ac) develops, due to the change in the dimensions of the electrolyte contact (and hence resistance), as well as the direct conductance current (dc). It is shown that the dc current can be predicted for a fixed probe by solving the Nernst-Planck equation and that the ac response can also be derived from this response. Both responses are shown to agree well with experiment. It is found that the pipet geometry plays an important role in controlling the dc conductance current and that this is easily measured by microscopy. A key feature of SECCM is that mass transport to the substrate surface is by diffusion and, for charged analytes, ion migration which can be controlled and varied quantifiably via the bias between the two QRCEs. For a working electrode substrate this means that charged redox-active analytes can be transported to the electrode/solution interface in a well-defined and controllable manner and that relatively fast heterogeneous electron transfer kinetics can be studied. The factors controlling the voltammetric response are determined by

  5. TU-A-12A-12: Improved Airway Measurement Accuracy for Low Dose Quantitative CT (qCT) Using Statistical (ASIR), at Reduced DFOV, and High Resolution Kernels in a Phantom and Swine Model

    SciTech Connect

    Yadava, G; Imai, Y; Hsieh, J

    2014-06-15

    Purpose: Quantitative accuracy of Iodine Hounsfield Unit (HU) in conventional single-kVp scanning is susceptible to beam-hardening effect. Dual-energy CT has unique capabilities of quantification using monochromatic CT images, but this scanning mode requires the availability of the state-of-the-art CT scanner and, therefore, is limited in routine clinical practice. Purpose of this work was to develop a beam-hardening-correction (BHC) for single-kVp CT that can linearize Iodine projections at any nominal energy, apply this approach to study Iodine response with respect to keV, and compare with dual-energy based monochromatic images obtained from material-decomposition using 80kVp and 140kVp. Methods: Tissue characterization phantoms (Gammex Inc.), containing solid-Iodine inserts of different concentrations, were scanned using GE multi-slice CT scanner at 80, 100, 120, and 140 kVp. A model-based BHC algorithm was developed where Iodine was estimated using re-projection of image volume and corrected through an iterative process. In the correction, the re-projected Iodine was linearized using a polynomial mapping between monochromatic path-lengths at various nominal energies (40 to 140 keV) and physically modeled polychromatic path-lengths. The beam-hardening-corrected 80kVp and 140kVp images (linearized approximately at effective energy of the beam) were used for dual-energy material-decomposition in Water-Iodine basis-pair followed by generation of monochromatic images. Characterization of Iodine HU and noise in the images obtained from singlekVp with BHC at various nominal keV, and corresponding dual-energy monochromatic images, was carried out. Results: Iodine HU vs. keV response from single-kVp with BHC and dual-energy monochromatic images were found to be very similar, indicating that single-kVp data may be used to create material specific monochromatic equivalent using modelbased projection linearization. Conclusion: This approach may enable quantification of

  6. Use of high resolution Airborne Laser Scanning data for landslide interpretation under mixed forest and tropical rainforest: case study in Barcelonnette, France and Cameron Highlands, Malaysia

    NASA Astrophysics Data System (ADS)

    Azahari Razak, Khamarrul; Straatsma, Menno; van Westen, Cees; Malet, Jean-Philippe; de Jong, Steven M.

    2010-05-01

    Airborne Laser Scanning (ALS) is the state of the art technology for topographic mapping over a wide variety of spatial and temporal scales. It is also a promising technique for identification and mapping of landslides in a forested mountainous landscape. This technology demonstrates the ability to pass through the gaps between forest foliage and record the terrain height under vegetation cover. To date, most of the images either derived from satellite imagery, aerial-photograph or synthetic aperture radar are not appropriate for visual interpretation of landslide features that are covered by dense vegetation. However, it is a necessity to carefully map the landslides in order to understand its processes. This is essential for landslide hazard and risk assessment. This research demonstrates the capabilities of high resolution ALS data to recognize and identify different types of landslides in mixed forest in Barcelonnette, France and tropical rainforest in Cameron Highlands, Malaysia. ALS measurements over the 100-years old forest in Bois Noir catchment were carried out in 2007 and 2009. Both ALS dataset were captured using a Riegl laser scanner. First and last pulse with density of one point per meter square was derived from 2007 ALS dataset, whereas multiple return (of up to five returns) pulse was derived from July 2009 ALS dataset, which consists of 60 points per meter square over forested terrain. Generally, this catchment is highly affected by shallow landslides which mostly occur beneath dense vegetation. It is located in the dry intra-Alpine zone and represented by the climatic of the South French Alps. In the Cameron Highlands, first and last pulse data was captured in 2004 which covers an area of up to 300 kilometres square. Here, the Optech laser scanner was used under the Malaysian national pilot study which has slightly low point density. With precipitation intensity of up to 3000 mm per year over rugged topography and elevations up to 2800 m a

  7. High-resolution and high sensitivity mesoscopic fluorescence tomography based on de-scanning EMCCD: System design and thick tissue imaging applications

    NASA Astrophysics Data System (ADS)

    Ozturk, Mehmet Saadeddin

    showcased by applying it to the longitudinal assessment of Ink-Jet Bio-Printed tumor models. This preliminary investigation focuses on monitoring four patient-derived glioblastoma multiforme (GBM) spheroids within their bioreactor for up to 70 days and following their volume change prior to and after exposure to a cytotoxic drug. Overall, our studies indicate that 2GMFMT is a powerful technique for in-vitro and in-vivo thick tissue molecular imaging applications due to its high resolution, fast tomographic imaging capability, and high sensitivity.

  8. Analysis of surface drag over Antarctic sea ice from combined analyses of High-Resolution measurements from Terrestrial Laser Scanning and Large Eddy Simulations

    NASA Astrophysics Data System (ADS)

    Trujillo, E.; Giometto, M. G.; Leonard, K. C.; Maksym, T. L.; Meneveau, C. V.; Parlange, M. B.; Lehning, M.

    2013-12-01

    Sea ice/snow surface interactions with the atmosphere are major drivers of large-scale patterns of sea ice flows and deformations in Polar Regions. Climate and weather prediction models require parameterizations of the subgrid-scale surface drag caused by the interactions between the ice/snow surfaces and surface winds. Here, we report on the results from a two part study, in which we combine the analysis of sea ice/snow surface topography at very high-resolutions (~1-10 cm), local wind measurements, and Large Eddy Simulations (LES) of fully developed wind flow to study surface drag and roughness from process scales to floe scales (~ 1 cm - 100 m). In this part, we focus on the analyses and implications of the results from the LES using the aforementioned dataset, while on the first part of the series we focus on the technical details of the LES. The snow/ice elevations were obtained using a Terrestrial Laser Scanner (TLS) during the SIPEX II (Sea Ice Physics and Ecosystem eXperiment II) research voyage to East Antarctica (September-November 2012). LES are performed over fine scans of typical surface structures, and over larger domains resampled at coarser grid resolutions (~ 1 m). A total of six ice floes are studied, with before and after-storm TLS data at one of the floes for an analysis of the changes in the surface structure and its effects on the surface-atmosphere interactions. The spatial distributions of shear velocities (U*), wind profiles, and variations of z0 values along different directions are obtained from the LES for scenarios with variations in wind forcings and predominant wind directions relative to the general alignment of surface features. Results from the LES are compared to spatial statistics of the surface at the locations to determine relationships with the general characteristics of the floes, and analyzing the variations in these relationships between the different floes studied. Implications from these results and improvements over

  9. A Critical Comparison Between Two Scanning Protocols of High-Resolution Peripheral Quantitative Computed Tomography at the Distal Radius in Adolescents.

    PubMed

    Cheuk, Ka-Yee; Tam, Elisa Man-Shan; Yu, Fiona Wai-Ping; Yip, Benjamin Hon-Kei; Hung, Vivian Wing-Yin; Wang, Xiaofang; Ghasem-Zadeh, Ali; Zhu, Tracy Y; Qin, Ling; Cheng, Jack Chun-Yiu; Lam, Tsz-Ping

    2016-01-01

    High-resolution peripheral quantitative computed tomography (HR-pQCT) is a unique technology for assessing bone mineral density and bone microarchitecture. Currently, no universally accepted protocol for selecting the region of interest (ROI) at the distal radius has been established for growing subjects. This study aimed (1) to investigate the differences in HR-pQCT measurements of 2 different ROI protocols applied to the distal radius of healthy adolescents and (2) to identify the least common area of ROI (the least common ROI) between the protocols. Twenty-six boys and 26 girls aged between 13 and 16 yr old were recruited. Nondominant distal radius was scanned by 2 HR-pQCT protocols, namely, the "5-mm protocol," where the distal end of ROI started at 5 mm proximal to a reference line, and the "4% protocol," where the ROI started at 4% of the ulnar length proximal to another reference line. The least common ROI between the 2 protocols was identified and the slice numbering within the common ROI was determined. Bland-Altman plots were used to check the agreement of the least common ROIs between the 2 protocols. Paired t-test and Wilcoxon signed-rank test were used for analysis. In boys, significant differences between protocols were found in most parameters with the maximum difference observed in the cortical area (25.0%, p < 0.001). In girls, differences were observed only for total volumetric bone mineral density (3.6%, p = 0.032). The number of slices in the least common ROI was 66 (60.0%) and 57 (51.8%) in boys and girls, respectively. Good agreements on all HR-pQCT parameters from the least common ROI between the 2 protocols were found. Significant differences in bone parameters were noted between the 2 protocols. When comparing the 2 protocols, observed gender differences could reflect the differences in skeletal growth at the peripubertal period between genders. Least common ROI could be useful for cross-center comparisons and when merging

  10. Childhood CT scans linked to leukemia and brain cancer later in life

    Cancer.gov

    Children and young adults scanned multiple times by computed tomography (CT), a commonly used diagnostic tool, have a small increased risk of leukemia and brain tumors in the decade following their first scan.

  11. 68Gallium-DOTATATE PET/CT Scanning Results in Patients with MEN1

    PubMed Central

    Sadowski, Samira M; Millo, Corina; Cottle-Delisle, Candice; Merkel, Roxanne; Yang, Lily A; Herscovitch, Peter; Pacak, Karel; Simonds, William F; Marx, Stephen J; Kebebew, Electron

    2015-01-01

    Background Screening for neuroendocrine tumors (NETs) in patients with multiple endocrine neoplasia type 1 (MEN1) is recommended to detect primary and metastatic tumors, which can result in significant morbidity and mortality. The utility of somatostatin receptor imaging 68Gallium-DOTATATE PET/CT in patients with MEN1 is not known. The aim of this study was to prospectively determine the accuracy of 68Gallium-DOTATATE PET/CT versus 111In-pentetreotide SPECT/CT and anatomic imaging in patients with MEN1. Study design Prospective study comparing 68Gallium-DOTATATE PET/CT, 111In-pentetreotide SPECT/CT, and triphasic CT scan to clinical, biochemical and pathological data in 26 patients with MEN1. Results 68Gallium-DOTATATE PET/CT detected 107 lesions; 111In- pentetreotide SPECT/CT detected 33 lesions; and CT scan detected 48 lesions. Lesions detected on 68Gallium-DOTATATE PET/CT had high SUVmax (median SUVmax = 72.8 [range 19–191]). In 7 of the 26 patients (27%), 68Gallium-DOTATATE PET/CT was positive with a negative 111In-pentetreotide SPECT/CT, and in 10 patients (38.5%), additional metastases were detected (range 0.3 cm to 1.5 cm). In 8 of the 26 patients (31%), there was a change in management recommendations as a result of the findings on 68Gallium-DOTATATE PET/CT that were not seen on 111In- pentetreotide SPECT/CT and CT scan. Conclusions 68Gallium-DOTATATE PET/CT is more sensitive for detecting NETs than 111In-pentetreotide SPECT/CT and CT scan in patients with MEN1. This imaging technique should be integrated into radiologic screening and surveillance of patients with MEN1, as it can significantly alter management recommendations. PMID:26206648

  12. Fully automatic segmentation of femurs with medullary canal definition in high and in low resolution CT scans.

    PubMed

    Almeida, Diogo F; Ruben, Rui B; Folgado, João; Fernandes, Paulo R; Audenaert, Emmanuel; Verhegghe, Benedict; De Beule, Matthieu

    2016-12-01

    Femur segmentation can be an important tool in orthopedic surgical planning. However, in order to overcome the need of an experienced user with extensive knowledge on the techniques, segmentation should be fully automatic. In this paper a new fully automatic femur segmentation method for CT images is presented. This method is also able to define automatically the medullary canal and performs well even in low resolution CT scans. Fully automatic femoral segmentation was performed adapting a template mesh of the femoral volume to medical images. In order to achieve this, an adaptation of the active shape model (ASM) technique based on the statistical shape model (SSM) and local appearance model (LAM) of the femur with a novel initialization method was used, to drive the template mesh deformation in order to fit the in-image femoral shape in a time effective approach. With the proposed method a 98% convergence rate was achieved. For high resolution CT images group the average error is less than 1mm. For the low resolution image group the results are also accurate and the average error is less than 1.5mm. The proposed segmentation pipeline is accurate, robust and completely user free. The method is robust to patient orientation, image artifacts and poorly defined edges. The results excelled even in CT images with a significant slice thickness, i.e., above 5mm. Medullary canal segmentation increases the geometric information that can be used in orthopedic surgical planning or in finite element analysis.

  13. Automatic colon segmentation with dual scan CT colonography.

    PubMed

    Li, Hong; Santago, Peter

    2005-03-01

    We present a fully automated three-dimensional (3-D) segmentation algorithm to extract the colon lumen surface in CT colonography. Focusing on significant-size polyp detection, we target at an efficient algorithm that maximizes overall colon coverage, minimizes the extracolonic components, maintains local shape accuracy, and achieves high segmentation speed. Two-dimensional (2-D) image processing techniques are employed first, resulting in automatic seed placement and better colon coverage. This is followed by near-air threshold 3-D region-growing using an improved marching-cubes algorithm, which provides fast and accurate surface generation. The algorithm constructs a well-organized vertex-triangle structure that uniquely employs a hash table method, yielding an order of magnitude speed improvement. We segment two scans, prone and supine, independently and with the goal of improved colon coverage. Both segmentations would be available for subsequent polyp detection systems. Segmenting and analyzing both scans improves surface coverage by at least 6% over supine or prone alone. According to subjective evaluation, the average coverage is about 87.5% of the entire colon. Employing near-air threshold and elongation criteria, only 6% of the data sets include extracolonic components (EC) in the segmentation. The observed surface shape accuracy of the segmentation is adequate for significant-size (6 mm) polyp detection, which is also verified by the results of the prototype detection algorithm. The segmentation takes less than 5 minutes on an AMD 1-GHz single-processor PC, which includes reading the volume data and writing the surface results. The surface-based segmentation algorithm is practical for subsequent polyp detection algorithms in that it produces high coverage, has a low EC rate, maintains local shape accuracy, and has a computational efficiency that makes real-time polyp detection possible. A fully automatic or computer-aided polyp detection system using this

  14. Knowledge Representation Of CT Scans Of The Head

    NASA Astrophysics Data System (ADS)

    Ackerman, Laurens V.; Burke, M. W.; Rada, Roy

    1984-06-01

    We have been investigating diagnostic knowledge models which assist in the automatic classification of medical images by combining information extracted from each image with knowledge specific to that class of images. In a more general sense we are trying to integrate verbal and pictorial descriptions of disease via representations of knowledge, study automatic hypothesis generation as related to clinical medicine, evolve new mathematical image measures while integrating them into the total diagnostic process, and investigate ways to augment the knowledge of the physician. Specifically, we have constructed an artificial intelligence knowledge model using the technique of a production system blending pictorial and verbal knowledge about the respective CT scan and patient history. It is an attempt to tie together different sources of knowledge representation, picture feature extraction and hypothesis generation. Our knowledge reasoning and representation system (KRRS) works with data at the conscious reasoning level of the practicing physician while at the visual perceptional level we are building another production system, the picture parameter extractor (PPE). This paper describes KRRS and its relationship to PPE.

  15. Study on Neurological Manifestations of Eclampsia & Findings of CT scan of Brain.

    PubMed

    Begum, F; Nahar, K; Ahmed, M U; Ferdousi, R A; Akter, F A; Rahman, M M

    2015-10-01

    This cross sectional study was carried out in the Department of Obstetrics & Gynaecology in Mymensingh Medical College Hospital during the period of January 2011 to December 2012 to evaluate neurological manifestations in eclampsia by CT scan of brain. A total 35 patients with eclampsia were studied, who underwent CT scan of brain in Radiology & Imaging Department of Mymensingh Medical College Hospital. The study patients were divided into two groups, those who had changes in brain on CT scan (Group A) & those who had no changes in brain on CT scan (Group B). Finally the study variables were compared between these two groups. Each selected patient fulfilling the criteria was sent to the department of Radiology & Imaging for CT scanning of brain. In antepartum cases of eclampsia CT scan of brain were done after delivery/ termination of pregnancy. In all cases, CT scan of brain was done within 72 hours of admission. Out of 35 patients total 85.72% had changes in brain on CT scan & 14.28% had no changes in brain on CT scan. Among them 45.72% patients had cerebral oedema, 37.14% had cerebral infarct & 2.86% patients had intracerebral haemorrhage. Comparison of neurological parameters were done & showed that there were statistically significant difference between the two groups regarding headache, visual disturbance, hypereflexia & depression of consciousness. There was no statistically significant difference regarding aphasia & hemiplegia between the two groups. So the CT scan of brain has been useful in demonstrating the lesion of brain in patients with eclampsia & also helpful to evaluate the neurological manifestations in eclampsia.

  16. Semi-automated fault system extraction and displacement analysis of an excavated oyster reef using high-resolution laser scanned data

    NASA Astrophysics Data System (ADS)

    Molnár, Gábor; Székely, Balázs; Harzhauser, Mathias; Djuricic, Ana; Mandic, Oleg; Dorninger, Peter; Nothegger, Clemens; Exner, Ulrike; Pfeifer, Norbert

    2015-04-01

    In this contribution we present a semi-automated method for reconstructing the brittle deformation field of an excavated Miocene oyster reef, in Stetten, Korneuburg Basin, Lower Austria. Oyster shells up to 80 cm in size were scattered in a shallow estuarine bay forming a continuous and almost isochronous layer as a consequence of a catastrophic event in the Miocene. This shell bed was preserved by burial of several hundred meters of sandy to silty sediments. Later the layers were tilted westward, uplifted and erosion almost exhumed them. An excavation revealed a 27 by 17 meters area of the oyster covered layer. During the tectonic processes the sediment volume suffered brittle deformation. Faults mostly with some centimeter normal component and NW-SE striking affected the oyster covered volume, dissecting many shells and the surrounding matrix as well. Faults and displacements due to them can be traced along the site typically at several meters long, and as fossil oysters are broken and parts are displaced due to the faulting, along some faults it is possible to follow these displacements in 3D. In order to quantify these varying displacements and to map the undulating fault traces high-resolution scanning of the excavated and cleaned surface of the oyster bed has been carried out using a terrestrial laser scanner. The resulting point clouds have been co-georeferenced at mm accuracy and a 1mm resolution 3D point cloud of the surface has been created. As the faults are well-represented in the point cloud, this enables us to measure the dislocations of the dissected shell parts along the fault lines. We used a semi-automatic method to quantify these dislocations. First we manually digitized the fault lines in 2D as an initial model. In the next step we estimated the vertical (i.e. perpendicular to the layer) component of the dislocation along these fault lines comparing the elevations on two sides of the faults with moving averaging windows. To estimate the strike

  17. High Resolution Laboratory Spectroscopy

    NASA Astrophysics Data System (ADS)

    Brünken, S.; Schlemmer, S.

    2016-05-01

    In this short review we will highlight some of the recent advancements in the field of high-resolution laboratory spectroscopy that meet the needs dictated by the advent of highly sensitive and broadband telescopes like ALMA and SOFIA. Among these is the development of broadband techniques for the study of complex organic molecules, like fast scanning conventional absorption spectroscopy based on multiplier chains, chirped pulse instrumentation, or the use of synchrotron facilities. Of similar importance is the extension of the accessible frequency range to THz frequencies, where many light hydrides have their ground state rotational transitions. Another key experimental challenge is the production of sufficiently high number densities of refractory and transient species in the laboratory, where discharges have proven to be efficient sources that can also be coupled to molecular jets. For ionic molecular species sensitive action spectroscopic schemes have recently been developed to overcome some of the limitations of conventional absorption spectroscopy. Throughout this review examples demonstrating the strong interplay between laboratory and observational studies will be given.

  18. A Simple Low-dose X-ray CT Simulation from High-dose Scan.

    PubMed

    Zeng, Dong; Huang, Jing; Bian, Zhaoying; Niu, Shanzhou; Zhang, Hua; Feng, Qianjin; Liang, Zhengrong; Ma, Jianhua

    2015-10-01

    Low-dose X-ray computed tomography (CT) simulation from high-dose scan is required in optimizing radiation dose to patients. In this study, we propose a simple low-dose CT simulation strategy in sinogram domain using the raw data from high-dose scan. Specially, a relationship between the incident fluxes of low- and high- dose scans is first determined according to the repeated projection measurements and analysis. Second, the incident flux level of the simulated low-dose scan is generated by properly scaling the incident flux level of high-dose scan via the determined relationship in the first step. Third, the low-dose CT transmission data by energy integrating detection is simulated by adding a statistically independent Poisson noise distribution plus a statistically independent Gaussian noise distribution. Finally, a filtered back-projection (FBP) algorithm is implemented to reconstruct the resultant low-dose CT images. The present low-dose simulation strategy is verified on the simulations and real scans by comparing it with the existing low-dose CT simulation tool. Experimental results demonstrated that the present low-dose CT simulation strategy can generate accurate low-dose CT sinogram data from high-dose scan in terms of qualitative and quantitative measurements.

  19. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    NASA Astrophysics Data System (ADS)

    Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

    2014-11-01

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  20. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    SciTech Connect

    Alva-Sánchez, Héctor

    2014-11-07

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  1. The Beatles, the Nobel Prize, and CT scanning of the chest.

    PubMed

    Goodman, Lawrence R

    2010-01-01

    From its first test scan on a mouse, in 1967, to current medical practice, the CT scanner has become a core imaging tool in thoracic diagnosis. Initially financed by money from Beatles' record sales, the first patient scan was performed in 1971. Only 8 years later, a Nobel Prize in Physics and Medicine was awarded to Hounsfield and Cormack for their discovery. This article traces the history of CT scanner development and how each technical advance expanded chest diagnostic frontiers. Chest imaging now accounts for 30% of all CT scanning.

  2. A high-resolution field-emission-gun, scanning electron microscope investigation of anisotropic hydrogen decrepitation in Nd-Fe-B-based sintered magnets

    NASA Astrophysics Data System (ADS)

    Soderznik, Marko; McGuiness, Paul; Zuzek-Rozman, Kristina; Škulj, Irena; Yan, Gaolin; Kobe, Spomenka

    2010-05-01

    In this investigation commercial magnets based on (Nd,Dy)14(Fe,Co)79B7 were prepared by a conventional powder-metallurgy route with a degree of alignment equal to ˜90% and then exposed to hydrogen at a pressure of 1 bar. The magnets, in the form of cylinders, were observed to decrepitate exclusively from the ends. High-resolution electron microscopy was able to identify the presence of crack formation within the Nd2Fe14B grains, with the cracks running parallel to the c axis of these grains. Based on the concentration profile for hydrogen in a rare-earth transition-metal material, it is clear that the presence of hydrogen-induced cracks running perpendicular to the ends of the magnet provides for a much more rapidly progressing hydrogen front in this direction than from the sides of the magnet. This results in the magnet exhibiting a macroscopic tendency to decrepitate from the poles of the magnet toward the center. This combination of microstructural modification via particle alignment as part of the sintering process and direct observation via high-resolution electron microscopy has led to a satisfying explanation for the anisotropic hydrogen-decrepitation effect.

  3. 18F-FDG PET of the hands with a dedicated high-resolution PEM system (arthro-PET): correlation with PET/CT, radiography and clinical parameters

    PubMed Central

    Mhlanga, Joyce C.; Carrino, John A.; Lodge, Martin; Wang, Hao

    2015-01-01

    Purpose The aim of this study was to prospectively determine the feasibility and compare the novel use of a positron emission mammography (PEM) scanner with standard PET/CT for evaluating hand osteoarthritis (OA) with 18F-FDG. Methods Institutional review board approval and written informed consent were obtained for this HIPAA-compliant prospective study in which 14 adults referred for oncological 18F-FDG PET/CT underwent dedicated hand PET/CT followed by arthro-PET using the PEM device. Hand radiographs were obtained and scored for the presence and severity of OA. Summed qualitative and quantitative joint glycolytic scores for each modality were compared with the findings on plain radiography and clinical features. Results Eight patients with clinical and/or radiographic evidence of OA comprised the OA group (mean age 73±7.7 years). Six patients served as the control group (53.7±9.3 years). Arthro-PET quantitative and qualitative joint glycolytic scores were highly correlated with PET/CT findings in the OA patients (r=0.86. p =0.007; r=0.94, p=0.001). Qualitative arthro-PET and PET/CT joint scores were significantly higher in the OA patients than in controls (38.7±6.6 vs. 32.2±0.4, p=0.02; 37.5±5.4 vs. 32.2±0.4, p=0.03, respectively). Quantitative arthro-PET and PET/CT maximum SUV-lean joint scores were higher in the OA patients, although they did not reach statistical significance (20.8±4.2 vs. 18±1.8, p= 0.13; 22.8±5.38 vs. 20.1±1.54, p=0.21). By definition, OA patients had higher radiographic joint scores than controls (30.9±31.3 vs. 0, p=0.03). Conclusion Hand imaging using a small field of view PEM system (arthro-PET) with FDG is feasible, performing comparably to PET/CT in assessing metabolic joint activity. Arthro-PET and PET/CT showed higher joint FDG uptake in OA. Further exploration of arthro-PET in arthritis management is warranted. PMID:25134669

  4. Improving In Vivo High-Resolution CT Imaging of the Tumour Vasculature in Xenograft Mouse Models through Reduction of Motion and Bone-Streak Artefacts

    PubMed Central

    Kersemans, Veerle; Kannan, Pavitra; Beech, John S.; Bates, Russell; Irving, Benjamin; Gilchrist, Stuart; Allen, Philip D.; Thompson, James; Kinchesh, Paul; Casteleyn, Christophe; Schnabel, Julia; Partridge, Mike; Muschel, Ruth J.; Smart, Sean C.

    2015-01-01

    Introduction Preclinical in vivo CT is commonly used to visualise vessels at a macroscopic scale. However, it is prone to many artefacts which can degrade the quality of CT images significantly. Although some artefacts can be partially corrected for during image processing, they are best avoided during acquisition. Here, a novel imaging cradle and tumour holder was designed to maximise CT resolution. This approach was used to improve preclinical in vivo imaging of the tumour vasculature. Procedures A custom built cradle containing a tumour holder was developed and fix-mounted to the CT system gantry to avoid artefacts arising from scanner vibrations and out-of-field sample positioning. The tumour holder separated the tumour from bones along the axis of rotation of the CT scanner to avoid bone-streaking. It also kept the tumour stationary and insensitive to respiratory motion. System performance was evaluated in terms of tumour immobilisation and reduction of motion and bone artefacts. Pre- and post-contrast CT followed by sequential DCE-MRI of the tumour vasculature in xenograft transplanted mice was performed to confirm vessel patency and demonstrate the multimodal capacity of the new cradle. Vessel characteristics such as diameter, and branching were quantified. Results Image artefacts originating from bones and out-of-field sample positioning were avoided whilst those resulting from motions were reduced significantly, thereby maximising the resolution that can be achieved with CT imaging in vivo. Tumour vessels ≥ 77 μm could be resolved and blood flow to the tumour remained functional. The diameter of each tumour vessel was determined and plotted as histograms and vessel branching maps were created. Multimodal imaging using this cradle assembly was preserved and demonstrated. Conclusions The presented imaging workflow minimised image artefacts arising from scanner induced vibrations, respiratory motion and radiopaque structures and enabled in vivo CT imaging

  5. Acquisition, preprocessing, and reconstruction of ultralow dose volumetric CT scout for organ-based CT scan planning

    SciTech Connect

    Yin, Zhye De Man, Bruno; Yao, Yangyang; Wu, Mingye; Montillo, Albert; Edic, Peter M.; Kalra, Mannudeep

    2015-05-15

    Purpose: Traditionally, 2D radiographic preparatory scan images (scout scans) are used to plan diagnostic CT scans. However, a 3D CT volume with a full 3D organ segmentation map could provide superior information for customized scan planning and other purposes. A practical challenge is to design the volumetric scout acquisition and processing steps to provide good image quality (at least good enough to enable 3D organ segmentation) while delivering a radiation dose similar to that of the conventional 2D scout. Methods: The authors explored various acquisition methods, scan parameters, postprocessing methods, and reconstruction methods through simulation and cadaver data studies to achieve an ultralow dose 3D scout while simultaneously reducing the noise and maintaining the edge strength around the target organ. Results: In a simulation study, the 3D scout with the proposed acquisition, preprocessing, and reconstruction strategy provided a similar level of organ segmentation capability as a traditional 240 mAs diagnostic scan, based on noise and normalized edge strength metrics. At the same time, the proposed approach delivers only 1.25% of the dose of a traditional scan. In a cadaver study, the authors’ pictorial-structures based organ localization algorithm successfully located the major abdominal-thoracic organs from the ultralow dose 3D scout obtained with the proposed strategy. Conclusions: The authors demonstrated that images with a similar degree of segmentation capability (interpretability) as conventional dose CT scans can be achieved with an ultralow dose 3D scout acquisition and suitable postprocessing. Furthermore, the authors applied these techniques to real cadaver CT scans with a CTDI dose level of less than 0.1 mGy and successfully generated a 3D organ localization map.

  6. Few CT Scan Abnormalities Found Even in Neurologically Impaired Learning Disabled Children.

    ERIC Educational Resources Information Center

    Denckla, Martha Bridge; And Others

    1985-01-01

    Most of 32 learning disabled children (seven to 14 years old) with neurological lateralization characteristics marked by right and left hemispheres had a normal CT (computerized tomography) scan. (CL)

  7. Micro computed tomography (CT) scanned anatomical gateway to insect pest bioinformatics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An international collaboration to establish an interactive Digital Video Library for a Systems Biology Approach to study the Asian citrus Psyllid and psyllid genomics/proteomics interactions is demonstrated. Advances in micro-CT, digital computed tomography (CT) scan uses X-rays to make detailed pic...

  8. Dual energy micro CT SkyScan 1173 for the characterization of urinary stone

    NASA Astrophysics Data System (ADS)

    Fitri, L. A.; Asyana, V.; Ridwan, T.; Anwary, F.; Soekersi, H.; Latief, F. D. E.; Haryanto, F.

    2016-03-01

    Knowledge of the composition of urinary stones is an essential part to determine suitable treatments for patients. The aim of this research is to characterize the urinary stones by using dual energy micro CT SkyScan 11173. This technique combines high-energy and low- energy scanning during a single acquisition. Six human urinary stones were scanned in vitro using 80 kV and 120 kV micro CT SkyScan 1173. Projected images were produced by micro CT SkyScan 1173 and then reconstructed using NRecon (in-house software from SkyScan) to obtain a complete 3D image. The urinary stone images were analysed using CT analyser to obtain information of internal structure and Hounsfield Unit (HU) values to determine the information regarding the composition of the urinary stones, respectively. HU values obtained from some regions of interest in the same slice are compared to a reference HU. The analysis shows information of the composition of the six scanned stones obtained. The six stones consist of stone number 1 (calcium+cystine), number 2 (calcium+struvite), number 3 (calcium+cystine+struvite), number 4 (calcium), number 5 (calcium+cystine+struvite), and number 6 (calcium+uric acid). This shows that dual energy micro CT SkyScan 1173 was able to characterize the composition of the urinary stone.

  9. Non Destructive Characterization, Inspection, Failure Analysis of Advanced Components and Sensors With a High Resolution & High Contrast Microtomography (microCT) System

    DTIC Science & Technology

    2006-11-01

    1999: Tomography reconstruction of an integrated circuit interconnect, Applied Physics Letters, 74(1), 150-152 \\ ...flip chip, showing the internal structure slice by slice without the need for physical or chemical deprocessing MicroCT has the advantage over...preparation, vacuum requirement or physical deprocessing . While conventional microCTs are currently being used for bio-medical1-2, material, industrial

  10. Increase in dicentric chromosome formation after a single CT scan in adults.

    PubMed

    Abe, Yu; Miura, Tomisato; Yoshida, Mitsuaki A; Ujiie, Risa; Kurosu, Yumiko; Kato, Nagisa; Katafuchi, Atsushi; Tsuyama, Naohiro; Ohba, Takashi; Inamasu, Tomoko; Shishido, Fumio; Noji, Hideyoshi; Ogawa, Kazuei; Yokouchi, Hiroshi; Kanazawa, Kenya; Ishida, Takashi; Muto, Satoshi; Ohsugi, Jun; Suzuki, Hiroyuki; Ishikawa, Tetsuo; Kamiya, Kenji; Sakai, Akira

    2015-09-09

    Excess risk of leukemia and brain tumors after CT scans in children has been reported. We performed dicentric chromosome assay (DCAs) before and after CT scan to assess effects of low-dose ionizing radiation on chromosomes. Peripheral blood (PB) lymphocytes were collected from 10 patients before and after a CT scan. DCA was performed by analyzing either 1,000 or 2,000 metaphases using both Giemsa staining and centromere-fluorescence in situ hybridization (Centromere-FISH). The increment of DIC formation was compared with effective radiation dose calculated using the computational dosimetry system, WAZA-ARI and dose length product (DLP) in a CT scan. Dicentric chromosome (DIC) formation increased significantly after a single CT scan, and increased DIC formation was found in all patients. A good correlation between the increment of DIC formation determined by analysis of 2,000 metaphases using Giemsa staining and those by 2,000 metaphases using Centromere-FISH was observed. However, no correlation was observed between the increment of DIC formation and the effective radiation dose. Therefore, these results suggest that chromosome cleavage may be induced by one CT scan, and we recommend 2,000 or more metaphases be analyzed in Giemsa staining or Centromere-FISH for DCAs in cases of low-dose radiation exposure.

  11. Dual energy CT with one full scan and a second sparse-view scan using structure preserving iterative reconstruction (SPIR).

    PubMed

    Wang, Tonghe; Zhu, Lei

    2016-09-21

    Conventional dual-energy CT (DECT) reconstruction requires two full-size projection datasets with two different energy spectra. In this study, we propose an iterative algorithm to enable a new data acquisition scheme which requires one full scan and a second sparse-view scan for potential reduction in imaging dose and engineering cost of DECT. A bilateral filter is calculated as a similarity matrix from the first full-scan CT image to quantify the similarity between any two pixels, which is assumed unchanged on a second CT image since DECT scans are performed on the same object. The second CT image from reduced projections is reconstructed by an iterative algorithm which updates the image by minimizing the total variation of the difference between the image and its filtered image by the similarity matrix under data fidelity constraint. As the redundant structural information of the two CT images is contained in the similarity matrix for CT reconstruction, we refer to the algorithm as structure preserving iterative reconstruction (SPIR). The proposed method is evaluated on both digital and physical phantoms, and is compared with the filtered-backprojection (FBP) method, the conventional total-variation-regularization-based algorithm (TVR) and prior-image-constrained-compressed-sensing (PICCS). SPIR with a second 10-view scan reduces the image noise STD by a factor of one order of magnitude with same spatial resolution as full-view FBP image. SPIR substantially improves over TVR on the reconstruction accuracy of a 10-view scan by decreasing the reconstruction error from 6.18% to 1.33%, and outperforms TVR at 50 and 20-view scans on spatial resolution with a higher frequency at the modulation transfer function value of 10% by an average factor of 4. Compared with the 20-view scan PICCS result, the SPIR image has 7 times lower noise STD with similar spatial resolution. The electron density map obtained from the SPIR-based DECT images with a second 10-view scan has an

  12. Dual energy CT with one full scan and a second sparse-view scan using structure preserving iterative reconstruction (SPIR)

    NASA Astrophysics Data System (ADS)

    Wang, Tonghe; Zhu, Lei

    2016-09-01

    Conventional dual-energy CT (DECT) reconstruction requires two full-size projection datasets with two different energy spectra. In this study, we propose an iterative algorithm to enable a new data acquisition scheme which requires one full scan and a second sparse-view scan for potential reduction in imaging dose and engineering cost of DECT. A bilateral filter is calculated as a similarity matrix from the first full-scan CT image to quantify the similarity between any two pixels, which is assumed unchanged on a second CT image since DECT scans are performed on the same object. The second CT image from reduced projections is reconstructed by an iterative algorithm which updates the image by minimizing the total variation of the difference between the image and its filtered image by the similarity matrix under data fidelity constraint. As the redundant structural information of the two CT images is contained in the similarity matrix for CT reconstruction, we refer to the algorithm as structure preserving iterative reconstruction (SPIR). The proposed method is evaluated on both digital and physical phantoms, and is compared with the filtered-backprojection (FBP) method, the conventional total-variation-regularization-based algorithm (TVR) and prior-image-constrained-compressed-sensing (PICCS). SPIR with a second 10-view scan reduces the image noise STD by a factor of one order of magnitude with same spatial resolution as full-view FBP image. SPIR substantially improves over TVR on the reconstruction accuracy of a 10-view scan by decreasing the reconstruction error from 6.18% to 1.33%, and outperforms TVR at 50 and 20-view scans on spatial resolution with a higher frequency at the modulation transfer function value of 10% by an average factor of 4. Compared with the 20-view scan PICCS result, the SPIR image has 7 times lower noise STD with similar spatial resolution. The electron density map obtained from the SPIR-based DECT images with a second 10-view scan has an

  13. Utility of the CT Scan in Diagnosing Midgut Volvulus in Patients with Chronic Abdominal Pain

    PubMed Central

    Morshedi, Mehdi; Baradaran Jamili, Mohammad; Shafizadeh Barmi, Fatemeh

    2017-01-01

    Symptomatic intestinal malrotation first presenting in the adults is rare. Midgut volvulus is the most common complication of malrotation in the adults. Because of more differential diagnosis, Computed Tomography (CT) scan can play an important role in the evaluation of patients with this abnormality. The whirl pattern around the superior mesenteric artery found on CT scan in patients with midgut volvulus is pathognomonic and diagnostic. We describe a case of intestinal malrotation complicated by midgut volvulus in an adult patient. The preoperative CT findings were pathognomonic. PMID:28182093

  14. Drug-induced pneumonitis detected earlier by 18F-FDG-PET than by high-resolution CT: a case report with non-Hodgkin's lymphoma.

    PubMed

    Yamane, Tomohiko; Daimaru, Osami; Ito, Satoshi; Nagata, Takeshi; Yoshiya, Kazuhiko; Fukaya, Nobuyuki; Ito, Shinichi; Imai, Teruhiko; Uchida, Hideo

    2008-10-01

    Drug-induced pneumonitis is a serious and an unpredictable side effect of chemotherapy in patients with malignant lymphoma. We present the case of a 51-year-old man who developed drug-induced pneumonitis during chemotherapy for non-Hodgkin's lymphoma in which pneumonitis was detected earlier by 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) than by high-resolution computed tomography (HRCT). After five courses of chemotherapy, 18F-FDG-PET was performed for assessing residual lesions, and diffuse lung uptake was incidentally observed. No symptoms were present, and HRCT performed immediately following PET revealed no abnormalities. Mild dyspnea appeared 3 days after PET, and additional HRCT revealed patchy ground-glass opacities disseminated with the appearance of interlobular septum thickening. Drug-induced pneumonitis was finally diagnosed, and treatment was initiated. 18F-FDG-PET can be an imaging modality for detecting drug-induced pneumonitis at an extremely early stage in which HRCT is incapable of revealing any abnormal changes.

  15. A redescription of Carrolla craddocki (Lepospondyli: Brachystelechidae) based on high-resolution CT, and the impacts of miniaturization and fossoriality on morphology.

    PubMed

    Maddin, Hillary C; Olori, Jennifer C; Anderson, Jason S

    2011-06-01

    Some recent morphological analyses have brought into question the monophyly of Lissamphibia (frogs, salamanders, and caecilians). In these analyses, brachystelechid "microsaurs" are found to be sister group to caecilians. To test this hypothesis, the holotype specimen of the brachystelechid Carrolla craddocki was submitted to high-resolution X-ray computed tomography to gain insight into the nature of the morphology supporting the potential relationship between brachystelechids and caecilians. This analysis enabled us to conduct a detailed description of the internal anatomy such as the braincase and otic capsule endocast (the first of its kind for a lepospondyl), and new information regarding the architecture of the skull. Our results suggest brachystelechid cranial morphology is strongly influenced by miniaturization (enlarged sensory organs, anterior placement of the jaw articulation, and combination of both reduced- and hyper-ossifications) and burrowing habits (co-ossified braincase with broad, sloping occipital surface, overlapping joints between skull roof bones, and well-ossified anterior braincase). Characteristics of brachystelechids that appear unrelated to size-reduction and burrowing are the diamond-shaped skull and possible pedicellate dentition. We provide a revised diagnosis for Carrolla and identify possible new characters within the anatomy of the braincase and inner ear. Several characters currently uniting caecilians and "microsaurs" are among those associated with either miniaturization or burrowing, demonstrating that future efforts should continue to focus on fine details of anatomy minimally affected by these influences to contribute to the resolution of the question of the origin of caecilians.

  16. Mutation Scanning in a Single and a Stacked Genetically Modified (GM) Event by Real-Time PCR and High Resolution Melting (HRM) Analysis

    PubMed Central

    Ben Ali, Sina-Elisabeth; Madi, Zita Erika; Hochegger, Rupert; Quist, David; Prewein, Bernhard; Haslberger, Alexander G.; Brandes, Christian

    2014-01-01

    Genetic mutations must be avoided during the production and use of seeds. In the European Union (EU), Directive 2001/18/EC requires any DNA construct introduced via transformation to be stable. Establishing genetic stability is critical for the approval of genetically modified organisms (GMOs). In this study, genetic stability of two GMOs was examined using high resolution melting (HRM) analysis and real-time polymerase chain reaction (PCR) employing Scorpion primers for amplification. The genetic variability of the transgenic insert and that of the flanking regions in a single oilseed rape variety (GT73) and a stacked maize (MON88017 × MON810) was studied. The GT73 and the 5' region of MON810 showed no instabilities in the examined regions. However; two out of 100 analyzed samples carried a heterozygous point mutation in the 3' region of MON810 in the stacked variety. These results were verified by direct sequencing of the amplified PCR products as well as by sequencing of cloned PCR fragments. The occurrence of the mutation suggests that the 5' region is more suitable than the 3' region for the quantification of MON810. The identification of the single nucleotide polymorphism (SNP) in a stacked event is in contrast to the results of earlier studies of the same MON810 region in a single event where no DNA polymorphism was found. PMID:25365178

  17. Implementation of a parallel-beam optical-CT apparatus for three-dimensional radiation dosimetry using a high-resolution CCD camera

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Tzeng; Chen, Chin-Hsing; Hung, Chao-Nan; Tuan, Chiu-Ching; Chang, Yuan-Jen

    2015-06-01

    In this study, a charge-coupled device (CCD) camera with 2-megapixel (1920×1080-pixel) and 12-bit resolution was developed for optical computed tomography(optical CT). The signal-to-noise ratio (SNR) of our system was 30.12 dB, better than that of commercially available CCD cameras (25.31 dB). The 50% modulation transfer function (MTF50) of our 1920×1080-pixel camera gave a line width per picture height (LW/PH) of 745, which is 73% of the diffraction-limited resolution. Compared with a commercially available 1-megapixel CCD camera (1296×966-pixel) with a LW/PH=358 and 46.6% of the diffraction-limited resolution, our camera system provided higher spatial resolution and better image quality. The NIPAM gel dosimeter was used to evaluate the optical CT with a 2-megapixel CCD. A clinical five-field irradiation treatment plan was generated using the Eclipse planning system (Varian Corp., Palo Alto, CA, USA). The gel phantom was irradiated using a 6-MV Varian Clinac IX linear accelerator (Varian). The measured NIPAM gel dose distributions and the calculated dose distributions, generated by the treatment planning software (TPS), were compared using the 3% dose-difference and 3 mm distance-to-agreement criteria. The gamma pass rate was as high as 98.2% when 2-megapixel CCD camera was used in optical CT. However, the gamma pass rate was only 96.0% when a commercially available 1-megapixel CCD camera was used.

  18. Relationship between Hounsfield unit in CT scan and gray scale in CBCT

    NASA Astrophysics Data System (ADS)

    Kamaruddin, Noorshaida; Rajion, Zainul Ahmad; Yusof, Asilah; Aziz, Mohd Ezane

    2016-12-01

    Cone-beam computed tomography (CBCT) is an imaging system which has advantages over computed tomography (CT). Recently, CBCT has become widely used for oral and maxillofacial imaging. In CT scan, Hounsfield Unit (HU) is proportional to the degree of x-ray attenuation by the tissue. In CBCT, the degree of x-ray attenuation is shown by gray scale (voxel value). The aim of the present (in vitro) study was to investigate the relationship between gray scale in CBCT and HU in CT scan. In this descriptive study, the anthropomorphic head phantom was scanned with CBCT and CT scanner. Gray scales and HUs were detected on images at the crown of the teeth, trabecular and cortical bone of mandible. The images were analyzed to obtain the gray scale value and HU value. The obtained value then used to investigate the relationship between CBCT gray scales and HUs. For the statistical analysis, t-test, Pearson's correlation and regression analysis were used. The differences between the gray scale of CBCT and HU of CT were statistically not significant, whereas the Pearson's correlation coefficients demonstrated a statistically significant correlation between gray scale of CBCT and HU of CT values. Considering the fact that gray scale in CBCT is important in pre assessment evaluation of bone density before implant treatments, it is recommended because of the lower dose and cost compared to CT scan.

  19. Co-registration of isotope bone scan with CT scan and MRI in the investigation of spinal pathology.

    PubMed

    Brazenor, Graeme A; Malham, Gregory M; Ballok, Zita E

    2014-09-01

    Image fusion software enables technetium(99m)-methylene diphosphonate (Tc(99m)-MDP) bone scan images to be co-registered with CT scan or MRI, allowing greater anatomical discrimination. We examined the role of bone scan images co-registered with CT scan or MRI in the investigation of patients presenting with axial spinal pain and/or limb pain. One hundred and thirty-nine consecutive patients were examined, and thereafter investigated with CT scan, MRI, and/or dynamic plain films. At this point diagnosis (pathology type and anatomical site) and treatment intention were declared. The co-registered Tc(99m)-MDP bone scan images were then studied, after which diagnosis (pathology type and anatomical site) and treatment intention were re-declared. This data were then analysed to determine whether the addition of co-registered bone scan images resulted in any change in diagnosis or treatment intention. The most significant change in diagnosis was pathology type (10%). Anatomical site changed markedly without overlap of the pre and post-isotope fields in 5%, and with overlap in 10%. Treatment intention had a major change in 3.6% and minor change in 8.6%. In the two groups where there was (i) no obvious pathology after full pre-isotope investigation, or (ii) a spinal fusion under suspicion, addition of the bone scan information led to a major change in the pathology and/or anatomical localisation in 18% and 19%, respectively. The addition of co-registered Tc(99m)-MDP bone scan images offers significant diagnostic assistance, particularly in the difficult diagnostic groups where a failed spinal fusion may be the suspected pain generator, or when no pain generator can otherwise be found.

  20. Relationship between Hounsfield Unit in CT Scan and Gray Scale in CBCT.

    PubMed

    Razi, Tahmineh; Niknami, Mahdi; Alavi Ghazani, Fakhri

    2014-01-01

    Background and aims. Cone-beam computed tomography (CBCT) is an imaging system which has many advantages over computed tomography (CT). In CT scan, Hounsfield Unit (HU) is proportional to the degree of x-ray attenuation by the tissue. In CBCT, the degree of x-ray attenuation is shown by gray scale (voxel value). The aim of the present study was to investigate the relationship between gray scale in CBCT) and Hounsfield Unit (HU) in CT scan. Materials and methods. In this descriptive study, the head of a sheep was scanned with 3 CBCT and one medical CT scanner. Gray scales and HUs were detected on images. Reconstructed data were analyzed to investigate relationship between CBCT gray scales and HUs. Results. A strong correlation between gray scales of CBCT and HUs of CT scan was determined. Conclusion. Considering the fact that gray scale in CBCT is the criteria in measurement of bone density before implant treatments, it is recommended because of the lower dose and cost compared to CT scan.

  1. High-resolution CT in simple coal workers' pneumoconiosis. Lack of correlation with pulmonary function tests and arterial blood gas values

    SciTech Connect

    Collins, L.C.; Willing, S.; Bretz, R.; Harty, M.; Lane, E.; Anderson, W.H. )

    1993-10-01

    We examined 21 miners by means of standard chest radiography, high-resolution computerized tomography (HRCT), pulmonary function tests, and resting arterial blood gas levels. Using the ILO/UC classification of pneumoconiosis, 7 miners had category 1/0 or 2/1 simple coal workers' pneumoconiosis (CWP). By HRCT, nodules were identified in 12 miners; 4 of 9 were classified as category 0/0 CWP; 2 of 5, 0/1 CWP; 5 of 6, 1/0 CWP; and 1 of 1, 2/1 CWP by chest radiograph. Focal emphysema was identified by HRCT in 7 miners; 4 of 9 were classified as 0/0 CWP; 2 of 5, 0/1 CWP; and 1 of 6, 1/0 CWP by standard chest radiography. Four miners with definite nodules confirmed by HRCT had focal emphysema, while three without nodules had focal emphysema. Pulmonary function testing was not different between miners with or without CWP by standard chest radiography, nor was it different between miners with or without definite nodules evidenced by HRCT. No difference in resting oxygenation was found between any group of miners. The presence of focal emphysema confirmed by HRCT did not significantly affect pulmonary function tests on resting arterial blood gas values. There was, however, a significantly lower FEV1 and mean forced expiratory flow during the middle half of forced vital capacity with lifetime nonsmoking miners. The presence of CWP on chest radiography was significantly correlated with smoking cigarettes but not the years of mining. The presence of nodules on HRCT approached a significant correlation with cigarette smoking, but focal emphysema did not. For detecting evidence of coal dust accumulation in lung parenchyma and identifying focal emphysema, HRCT was more sensitive than standard chest radiography. However, despite earlier detection of parenchymal abnormalities, abnormal pulmonary function attributable to coal dust could not be identified.

  2. Iofetamine HCI I-123 brain scanning in stroke: a comparison with transmission CT

    SciTech Connect

    Park, C.H.; Madsen, M.T.; McLellan, T.; Schwartzman, R.J.

    1988-03-01

    Although IMP scans fail to show fine anatomical details of the brain, because of poor resolution of a single head rotational system, adequate information is offered by the scans to localize most perfusion defects caused by stroke. The following conclusions can be drawn from our study: 1. The planar IMP brain scans processed through the computer are sensitive in the early diagnosis of acute stroke except for small and deeply localized lesions. 2. The SPECT IMP imaging is more sensitive than the planar or transmission CT scans in the early diagnosis of stroke. Semiquantitative evaluations are feasible with IMP SPECT. 3. Neither transmission CT nor IMP SPECT are sensitive in the detection of acute lacunar infarcts. 4. In acute infarction, the transmission CT is usually negative or minimally positive in the early stages, while impaired uptake of IMP occurs immediately after the onset of the stroke. In acute stroke, the extent of the perfusion defect on IMP is usually greater than the abnormality seen on the transmission CT. 5. On followup studies, IMP scans show improved perfusion reflecting physiologic changes, while transmission CT scans show further dense anatomical changes when compared to the initial studies. 6. Hyperemic changes are likely due to collateral circulation or luxury perfusion. This finding suggests that the IMP reflects local cerebral blood flow in strokes.

  3. Scan-rescan reproducibility of CT densitometric measures of emphysema

    NASA Astrophysics Data System (ADS)

    Chong, D.; van Rikxoort, E. M.; Kim, H. J.; Goldin, J. G.; Brown, M. S.

    2011-03-01

    This study investigated the reproducibility of HRCT densitometric measures of emphysema in patients scanned twice one week apart. 24 emphysema patients from a multicenter study were scanned at full inspiration (TLC) and expiration (RV), then again a week later for four scans total. Scans for each patient used the same scanner and protocol, except for tube current in three patients. Lung segmentation with gross airway removal was performed on the scans. Volume, weight, mean lung density (MLD), relative area under -950HU (RA-950), and 15th percentile (PD-15) were calculated for TLC, and volume and an airtrapping mask (RA-air) between -950 and -850HU for RV. For each measure, absolute differences were computed for each scan pair, and linear regression was performed against volume difference in a subgroup with volume difference <500mL. Two TLC scan pairs were excluded due to segmentation failure. The mean lung volumes were 5802 +/- 1420mL for TLC, 3878 +/- 1077mL for RV. The mean absolute differences were 169mL for TLC volume, 316mL for RV volume, 14.5g for weight, 5.0HU for MLD, 0.66p.p. for RA-950, 2.4HU for PD-15, and 3.1p.p. for RA-air. The <500mL subgroup had 20 scan pairs for TLC and RV. The R2 values were 0.8 for weight, 0.60 for MLD, 0.29 for RA-950, 0.31 for PD-15, and 0.64 for RA-air. Our results indicate that considerable variability exists in densitometric measures over one week that cannot be attributed to breathhold or physiology. This has implications for clinical trials relying on these measures to assess emphysema treatment efficacy.

  4. MTF characterization in 2D and 3D for a high resolution, large field of view flat panel imager for cone beam CT

    NASA Astrophysics Data System (ADS)

    Shah, Jainil; Mann, Steve D.; Tornai, Martin P.; Richmond, Michelle; Zentai, George

    2014-03-01

    The 2D and 3D modulation transfer functions (MTFs) of a custom made, large 40x30cm2 area, 600- micron CsI-TFT based flat panel imager having 127-micron pixellation, along with the micro-fiber scintillator structure, were characterized in detail using various techniques. The larger area detector yields a reconstructed FOV of 25cm diameter with an 80cm SID in CT mode. The MTFs were determined with 1x1 (intrinsic) binning. The 2D MTFs were determined using a 50.8 micron tungsten wire and a solid lead edge, and the 3D MTF was measured using a custom made phantom consisting of three nearly orthogonal 50.8 micron tungsten wires suspended in an acrylic cubic frame. The 2D projection data was reconstructed using an iterative OSC algorithm using 16 subsets and 5 iterations. As additional verification of the resolution, along with scatter, the Catphan® phantom was also imaged and reconstructed with identical parameters. The measured 2D MTF was ~4% using the wire technique and ~1% using the edge technique at the 3.94 lp/mm Nyquist cut-off frequency. The average 3D MTF measured along the wires was ~8% at the Nyquist. At 50% MTF, the resolutions were 1.2 and 2.1 lp/mm in 2D and 3D, respectively. In the Catphan® phantom, the 1.7 lp/mm bars were easily observed. Lastly, the 3D MTF measured on the three wires has an observed 5.9% RMSD, indicating that the resolution of the imaging system is uniform and spatially independent. This high performance detector is integrated into a dedicated breast SPECT-CT imaging system.

  5. High-resolution 3-D mapping using terrestrial laser scanning as a tool for geomorphological and speleogenetical studies in caves: An example from the Lessini mountains (North Italy)

    NASA Astrophysics Data System (ADS)

    Fabbri, Stefano; Sauro, Francesco; Santagata, Tommaso; Rossi, Guido; De Waele, Jo

    2017-03-01

    Terrestrial laser scanning (TLS) is increasingly used in geomorphology for the study of medium- to small scale landforms. A light weight, compact and portable TLS device has been used in the Grotta A Cave (Mt. Lessini, N Italy) to make a detailed 3D model of the underground environment. A total of 16 scans were used to survey the about 150 m long cave in < 6 h. The 3D model of the cave walls makes it possible to carry out morphometric measurements on the different cave environments. The TLS data allowed us to calculate cave volumes and distinguish cupola, phreatic conduit and basalt dike volumes. Wall roughness analysis also allowed recognising smaller-scale morphologies such as megascallops, differential corrosion forms and mineral crusts. These observations have enabled us to discern between different karstification processes and speleogenetic phases, highlighting the importance of condensation-corrosion on the cave passage enlargement in a quantitative way.

  6. Three-Dimensions Segmentation of Pulmonary Vascular Trees for Low Dose CT Scans

    NASA Astrophysics Data System (ADS)

    Lai, Jun; Huang, Ying; Wang, Ying; Wang, Jun

    2016-12-01

    Due to the low contrast and the partial volume effects, providing an accurate and in vivo analysis for pulmonary vascular trees from low dose CT scans is a challenging task. This paper proposes an automatic integration segmentation approach for the vascular trees in low dose CT scans. It consists of the following steps: firstly, lung volumes are acquired by the knowledge based method from the CT scans, and then the data are smoothed by the 3D Gaussian filter; secondly, two or three seeds are gotten by the adaptive 2D segmentation and the maximum area selecting from different position scans; thirdly, each seed as the start voxel is inputted for a quick multi-seeds 3D region growing to get vascular trees; finally, the trees are refined by the smooth filter. Through skeleton analyzing for the vascular trees, the results show that the proposed method can provide much better and lower level vascular branches.

  7. Evaluation of geometrical effects of microneedles on skin penetration by CT scan and finite element analysis.

    PubMed

    Loizidou, Eriketi Z; Inoue, Nicholas T; Ashton-Barnett, Johnny; Barrow, David A; Allender, Chris J

    2016-10-01

    Computerized tomography scan (CT scan) imaging and finite element analysis were employed to investigate how the geometric composition of microneedles affects their mechanical strength and penetration characteristics. Simulations of microneedle arrays, comprising triangular, square and hexagonal microneedle base, revealed a linear dependence of the mechanical strength to the number of vertices in the polygon base. A laser-enabled, micromoulding technique was then used to fabricate 3×3 microneedle arrays, each individual microneedle having triangular, square or hexagonal base geometries. Their penetration characteristics into ex-vivo porcine skin, were investigated for the first time by CT scan imaging. This revealed greater penetration depths for the triangular and square-based microneedles, demonstrating CT scan as a powerful and reliable technique for studying microneedle skin penetration.

  8. CT of multiple sclerosis: reassessment of delayed scanning with high doses of contrast material

    SciTech Connect

    Spiegel, S.M.; Vinuela, F.; Fox, A.J.; Pelz, D.M.

    1985-09-01

    A prospective study involving 87 patients was carried out to evaluate the necessity for a high dose of contrast material in addition to delayed computed tomographic (CT) scanning for optimal detection of the lesions of multiple sclerosis in the brain. In patients with either clinically definite multiple sclerosis or laboratory-supported definite multiple sclerosis, CT scans were obtained with a uniform protocol. Lesions consistent with multiple sclerosis were demonstrated on the second scan in 54 patients. In 36 of these 54 patients, the high-dose delayed scan added information. These results are quite similar to those of a previous study from this institution using different patients, in whom the second scan was obtained immediately after the bolus injection of contrast material containing 40 g of organically bound iodine. The lack of real difference in the results of the two studies indicate that the increased dose, not just the delay in scanning, is necessary for a proper study.

  9. Application of offset-CT scanning to the inspection of high power feeder lines and connections

    NASA Astrophysics Data System (ADS)

    Schneberk, Daniel; Maziuk, Robert; Soyfer, Boris; Shashishekhar, N.; Alreja, Rahul

    2016-02-01

    VJT is developing techniques and scanning methods for the in-situ Radiographic and Computed Tomographic inspection of underground high-power feeder cables. The goals for the inspection are to measure the 3D state of the cables and the cable-connections. Recent in-situ Digital Radiographic inspections performed by VJT have demonstrated the value of NDE inspection information for buried power lines. These NDE data have raised further questions as to the exact state of the cables and connections and pointed to the need for more 3D information of the type provided by volumetric CT scanning. VJT is pursuing a three phased approach to address the many issues involved in this type of inspection: 1) develop a high-power feeder-cable test-bed CT scanner, 2) acquire scans on underground feeder pipes that have been removed from service, and 3) from the work in 1) and 2) develop limited-angle CT scanning methods for extending in-situ Digital Radiography to volumetric CT measurements. To this end, VJT has developed and fielded a high-energy test-bed Gantry-type CT scanner (the source and detector move around the object) with a number of important properties. First, the geometry of the gantry-scans can be configured to match the techniques used in the in-situ radiographic inspection. The same X-ray source is employed as in portable Radiographic inspections, a 7.5 MeV Betatron coupled to a Perkin-Elmer Amorphous Silicon detector. Offset-CT scanning is employed as the high-power feeder line assembly is larger than the detector. A description of this scanner and the scan geometry will be presented showing the connection to in-situ radiography. Results from the CT scans of high-power feeder-cable specimens removed from service will be presented with a focus on the inspection potential of volumetric CT data on these assemblies. An evaluation of the scan performance properties of these data compared to the spectrum of life-cycle inspection issues will be presented. Continuing and

  10. High-resolution headlamp

    NASA Astrophysics Data System (ADS)

    Gut, Carsten; Cristea, Iulia; Neumann, Cornelius

    2016-04-01

    The following article shall describe how human vision by night can be influenced. At first, front lighting systems that are already available on the market will be described, followed by their analysis with respect to the positive effects on traffic safety. Furthermore, how traffic safety by night can be increased since the introduction of high resolution headlamps shall be discussed.

  11. Investigation of ultra low-dose scans in the context of quantum-counting clinical CT

    NASA Astrophysics Data System (ADS)

    Weidinger, T.; Buzug, T. M.; Flohr, T.; Fung, G. S. K.; Kappler, S.; Stierstorfer, K.; Tsui, B. M. W.

    2012-03-01

    In clinical computed tomography (CT), images from patient examinations taken with conventional scanners exhibit noise characteristics governed by electronics noise, when scanning strongly attenuating obese patients or with an ultra-low X-ray dose. Unlike CT systems based on energy integrating detectors, a system with a quantum counting detector does not suffer from this drawback. Instead, the noise from the electronics mainly affects the spectral resolution of these detectors. Therefore, it does not contribute to the image noise in spectrally non-resolved CT images. This promises improved image quality due to image noise reduction in scans obtained from clinical CT examinations with lowest X-ray tube currents or obese patients. To quantify the benefits of quantum counting detectors in clinical CT we have carried out an extensive simulation study of the complete scanning and reconstruction process for both kinds of detectors. The simulation chain encompasses modeling of the X-ray source, beam attenuation in the patient, and calculation of the detector response. Moreover, in each case the subsequent image preprocessing and reconstruction is modeled as well. The simulation-based, theoretical evaluation is validated by experiments with a novel prototype quantum counting system and a Siemens Definition Flash scanner with a conventional energy integrating CT detector. We demonstrate and quantify the improvement from image noise reduction achievable with quantum counting techniques in CT examinations with ultra-low X-ray dose and strong attenuation.

  12. CT Scans of Cores Metadata, Barrow, Alaska 2015

    DOE Data Explorer

    Katie McKnight; Tim Kneafsey; Craig Ulrich

    2015-03-11

    Individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, throughout 2013 and 2014. Cores were drilled along different transects to sample polygonal features (i.e. the trough, center and rim of high, transitional and low center polygons). Most cores were drilled around 1 meter in depth and a few deep cores were drilled around 3 meters in depth. Three-dimensional images of the frozen cores were constructed using a medical X-ray computed tomography (CT) scanner. TIFF files can be uploaded to ImageJ (an open-source imaging software) to examine soil structure and densities within each core.

  13. Pancreas tumor model in rabbit imaged by perfusion CT scans

    NASA Astrophysics Data System (ADS)

    Gunn, Jason; Tichauer, Kenneth; Moodie, Karen; Kane, Susan; Hoopes, Jack; Stewart, Errol E.; Hadway, Jennifer; Lee, Ting-Yim; Pereira, Stephen P.; Pogue, Brian W.

    2013-03-01

    The goal of this work was to develop and validate a pancreas tumor animal model to investigate the relationship between photodynamic therapy (PDT) effectiveness and photosensitizer drug delivery. More specifically, this work lays the foundation for investigating the utility of dynamic contrast enhanced blood perfusion imaging to be used to inform subsequent PDT. A VX2 carcinoma rabbit cell line was grown in the tail of the pancreas of three New Zealand White rabbits and approximately 3-4 weeks after implantation the rabbits were imaged on a CT scanner using a contrast enhanced perfusion protocol, providing parametric maps of blood flow, blood volume, mean transit time, and vascular permeability surface area product.

  14. Paired inspiratory-expiratory chest CT scans to assess for small airways disease in COPD

    PubMed Central

    2013-01-01

    Background Gas trapping quantified on chest CT scans has been proposed as a surrogate for small airway disease in COPD. We sought to determine if measurements using paired inspiratory and expiratory CT scans may be better able to separate gas trapping due to emphysema from gas trapping due to small airway disease. Methods Smokers with and without COPD from the COPDGene Study underwent inspiratory and expiratory chest CT scans. Emphysema was quantified by the percent of lung with attenuation < −950HU on inspiratory CT. Four gas trapping measures were defined: (1) Exp−856, the percent of lung < −856HU on expiratory imaging; (2) E/I MLA, the ratio of expiratory to inspiratory mean lung attenuation; (3) RVC856-950, the difference between expiratory and inspiratory lung volumes with attenuation between −856 and −950 HU; and (4) Residuals from the regression of Exp−856 on percent emphysema. Results In 8517 subjects with complete data, Exp−856 was highly correlated with emphysema. The measures based on paired inspiratory and expiratory CT scans were less strongly correlated with emphysema. Exp−856, E/I MLA and RVC856-950 were predictive of spirometry, exercise capacity and quality of life in all subjects and in subjects without emphysema. In subjects with severe emphysema, E/I MLA and RVC856-950 showed the highest correlations with clinical variables. Conclusions Quantitative measures based on paired inspiratory and expiratory chest CT scans can be used as markers of small airway disease in smokers with and without COPD, but this will require that future studies acquire both inspiratory and expiratory CT scans. PMID:23566024

  15. Single energy micro CT SkyScan 1173 for the characterization of urinary stone

    NASA Astrophysics Data System (ADS)

    Fitri, L. A.; Asyana, V.; Ridwan, T.; Anwary, F.; Soekersi, H.; Latief, F. D. E.; Haryanto, F.

    2016-08-01

    A urinary stone is a solid piece of material produced from crystallization of excreted substances in the urine. Knowledge of the composition of urinary stones is essential to determine the suitable treatment for the patient. The aim of this research was to characterize urinary stones using single energy micro CT SkyScan 1173. Six human urinary stones were scanned in vitro using 80 kV in micro CT SkyScan 1173. The produced projection, images, were reconstructed using NRecon (in-house software from SkyScan). The images of urinary stones were analyzed using CT Analyser (CT An) to obtain information of the internal structure and the Hounsfield Unit (HU) value to determine the information regarding the composition of the urinary stones, respectively. The average HU values from certain region of interests in the same slice were compared with spectral curves of known materials from National Institute of Standards and Technology (NIST). From the analysis, the composition of the six scanned stones were obtained. Two stones are composed of cystine, two are composed of struvite, two other stones are composed of struvite+cystine. In conclusion, the single energy micro CT with 80 kV can be used identifying cystine and struvite urinary stone.

  16. Oxidation products of the niobium tungsten oxide Nb{sub 4}W{sub 13}O{sub 47}: A high-resolution scanning transmission electron microscopy study

    SciTech Connect

    Krumeich, Frank . E-mail: krumeich@inorg.chem.ethz.ch; Nesper, Reinhard

    2006-06-15

    Nb{sub 4}W{sub 13}O{sub 47}, a member of the solid solution series Nb{sub 8-n}W{sub 9+n}O{sub 47} (0=scanning transmission electron microscopy applying a high-angle annular dark field detector. At the selected imaging conditions (Z contrast), not only the metal positions are revealed by this technique but valuable additional information about the elemental distribution can be obtained simultaneously.

  17. High-resolution three-dimensional scanning transmission electron microscopy characterization of oxide-nitride-oxide layer interfaces in Si-based semiconductors using computed tomography.

    PubMed

    Sadayama, Shoji; Sekiguchi, Hiromi; Bright, Alexander; Suzuki, Naohisa; Yamada, Kazuhiro; Kaneko, Kenji

    2011-01-01

    Oxide-nitride-oxide (ONO) layer structures are widely used for charge storage in flash memory devices. The ONO layer interfaces should be as flat as possible, so measurement of the nanoscale roughness of those interfaces is needed. In this study, quantification of an ONO film from a commercially available flash memory device was carried out with a pillar-shaped specimen using scanning transmission electron microscopy (STEM) and computed tomography. The ONO area contained only low Z- and low STEM-contrast materials, which makes high-quality reconstruction difficult. The optimum three-dimensional reconstruction was achieved with an STEM annular dark-field detector inner collection angle of 32 mrad, a sample tilt range from -78° to +78° and 25 iterations for the simultaneous iterative reconstruction technique.

  18. High resolution data acquisition

    DOEpatents

    Thornton, G.W.; Fuller, K.R.

    1993-04-06

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock, pulse train, and analog circuitry for generating a triangular wave synchronously with the pulse train (as seen in diagram on patent). The triangular wave has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter counts the clock pulse train during the interval to form a gross event interval time. A computer then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  19. High resolution data acquisition

    DOEpatents

    Thornton, Glenn W.; Fuller, Kenneth R.

    1993-01-01

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock (38) pulse train (37) and analog circuitry (44) for generating a triangular wave (46) synchronously with the pulse train (37). The triangular wave (46) has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter (18, 32) forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter (26) counts the clock pulse train (37) during the interval to form a gross event interval time. A computer (52) then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  20. High-Resolution Autoradiography

    NASA Technical Reports Server (NTRS)

    Towe, George C; Gomberg, Henry J; Freemen, J W

    1955-01-01

    This investigation was made to adapt wet-process autoradiography to metallurgical samples to obtain high resolution of segregated radioactive elements in microstructures. Results are confined to development of the technique, which was perfected to a resolution of less than 10 microns. The radioactive samples included carbon-14 carburized iron and steel, nickel-63 electroplated samples, a powder product containing nickel-63, and tungsten-185 in N-155 alloy.

  1. Ultra high resolution tomography

    SciTech Connect

    Haddad, W.S.

    1994-11-15

    Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

  2. Compact high-resolution gamma-ray computed tomography system for multiphase flow studies

    SciTech Connect

    Bieberle, A.; Nehring, H.; Berger, R.; Arlit, M.; Haerting, H.-U.; Schubert, M.; Hampel, U.

    2013-03-15

    In this paper, a compact high-resolution gamma-ray Computed Tomography (CompaCT) measurement system for multiphase flow studies and tomographic imaging of technical objects is presented. Its compact and robust design makes it particularly suitable for studies on industrial facilities and outdoor applications. Special care has been given to thermal ruggedness, shock resistance, and radiation protection. Main components of the system are a collimated {sup 137}Cs isotopic source, a thermally stabilised modular high-resolution gamma-ray detector arc with 112 scintillation detector elements, and a transportable rotary unit. The CompaCT allows full CT scans of objects with a diameter of up to 130 mm and can be operated with any tilting angle from 0 Degree-Sign (horizontal) to 90 Degree-Sign (vertical).

  3. Analyzing the human liver vascular architecture by combining vascular corrosion casting and micro-CT scanning: a feasibility study

    PubMed Central

    Debbaut, Charlotte; Segers, Patrick; Cornillie, Pieter; Casteleyn, Christophe; Dierick, Manuel; Laleman, Wim; Monbaliu, Diethard

    2014-01-01

    Although a full understanding of the hepatic circulation is one of the keys to successfully perform liver surgery and to elucidate liver pathology, relatively little is known about the functional organization of the liver vasculature. Therefore, we materialized and visualized the human hepatic vasculature at different scales, and performed a morphological analysis by combining vascular corrosion casting with novel micro-computer tomography (CT) and image analysis techniques. A human liver vascular corrosion cast was obtained by simultaneous resin injection in the hepatic artery (HA) and portal vein (PV). A high resolution (110 μm) micro-CT scan of the total cast allowed gathering detailed macrovascular data. Subsequently, a mesocirculation sample (starting at generation 5; 88 × 68 × 80 mm³) and a microcirculation sample (terminal vessels including sinusoids; 2.0 × 1.5 × 1.7 mm³) were dissected and imaged at a 71-μm and 2.6-μm resolution, respectively. Segmentations and 3D reconstructions allowed quantifying the macro-and mesoscale branching topology, and geometrical features of HA, PV and hepatic venous trees up to 13 generations (radii ranging from 13.2 mm to 80 μm; lengths from 74.4 mm to 0.74 mm), as well as microvascular characteristics (mean sinusoidal radius of 6.63 μm). Combining corrosion casting and micro-CT imaging allows quantifying the branching topology and geometrical features of hepatic trees using a multiscale approach from the macro-down to the microcirculation. This may lead to novel insights into liver circulation, such as internal blood flow distributions and anatomical consequences of pathologies (e.g. cirrhosis). PMID:24433401

  4. Construction of mouse phantoms from segmented CT scan data for radiation dosimetry studies

    NASA Astrophysics Data System (ADS)

    Welch, D.; Harken, A. D.; Randers-Pehrson, G.; Brenner, D. J.

    2015-05-01

    We present the complete construction methodology for an anatomically accurate mouse phantom made using materials which mimic the characteristics of tissue, lung, and bone for radiation dosimetry studies. Phantoms were constructed using 2 mm thick slices of tissue equivalent material which was precision machined to clear regions for insertion of lung and bone equivalent material where appropriate. Images obtained using a 3D computed tomography (CT) scan clearly indicate regions of tissue, lung, and bone that match their position within the original mouse CT scan. Additionally, radiographic films are used with the phantom to demonstrate dose mapping capabilities. The construction methodology presented here can be quickly and easily adapted to create a phantom of any specific small animal given a segmented CT scan of the animal. These physical phantoms are a useful tool to examine individual organ dose and dosimetry within mouse systems that are complicated by density inhomogeneity due to bone and lung regions.

  5. Construction of mouse phantoms from segmented CT scan data for radiation dosimetry studies.

    PubMed

    Welch, D; Harken, A D; Randers-Pehrson, G; Brenner, D J

    2015-05-07

    We present the complete construction methodology for an anatomically accurate mouse phantom made using materials which mimic the characteristics of tissue, lung, and bone for radiation dosimetry studies. Phantoms were constructed using 2 mm thick slices of tissue equivalent material which was precision machined to clear regions for insertion of lung and bone equivalent material where appropriate. Images obtained using a 3D computed tomography (CT) scan clearly indicate regions of tissue, lung, and bone that match their position within the original mouse CT scan. Additionally, radiographic films are used with the phantom to demonstrate dose mapping capabilities. The construction methodology presented here can be quickly and easily adapted to create a phantom of any specific small animal given a segmented CT scan of the animal. These physical phantoms are a useful tool to examine individual organ dose and dosimetry within mouse systems that are complicated by density inhomogeneity due to bone and lung regions.

  6. Construction of mouse phantoms from segmented CT scan data for radiation dosimetry studies

    PubMed Central

    Welch, D; Harken, A D; Randers-Pehrson, G; Brenner, D J

    2015-01-01

    We present the complete construction methodology for an anatomically accurate mouse phantom made using materials which mimic the characteristics of tissue, lung, and bone for radiation dosimetry studies. Phantoms were constructed using 2 mm thick slices of tissue equivalent material which was precision machined to clear regions for insertion of lung and bone equivalent material where appropriate. Images obtained using a 3D computed tomography (CT) scan clearly indicate regions of tissue, lung, and bone that match their position within the original mouse CT scan. Additionally, radiographic films are used with the phantom to demonstrate dose mapping capabilities. The construction methodology presented here can be quickly and easily adapted to create a phantom of any specific small animal given a segmented CT scan of the animal. These physical phantoms are a useful tool to examine individual organ dose and dosimetry within mouse systems that are complicated by density inhomogeneity due to bone and lung regions. PMID:25860401

  7. Overbeaming and overlapping of volume-scan CT with tube current modulation in a 320-detector row CT scanner

    NASA Astrophysics Data System (ADS)

    Liao, Ying-Lan; Chen, Yan-Shi; Lai, Nan-Ku; Chuang, Keh-Shih; Tsai, Hui-Yu

    2014-11-01

    The purpose of this study was to evaluate the performance of volume scan tube current modulation (VS-ATCM) with adaptive iterative dose reduction 3D (AIDR3D) technique in abdomen CT examinations. We scanned an elliptical cone-shaped phantom utilizing AIDR3D technique combined with VS-ATCM mode in a 320-detector row CT scanner. The image noise distributions with conventional filtered back-projction (FBP) technique and those with AIDR3D technique were compared. The radiation dose profile and tube current time product (mAs) in three noise levels of VS-ATCM modes were compared. The radiation beam profiles of five preset scan lengths were measured using Gafchromic film strips to assess the effects of overbeaming and everlapping. The results indicated that the image noises with AIDR3D technique was 13-74% lower than those in FBP technique. The mAs distributions can be a prediction for various abdominal sizes when undergoing a VS-ATCM mode scan. Patients can receive the radiation dose of overbeaming and overlapping during the VS-ATCM mode scans.

  8. Estimating Radiation Dose Metrics for Patients Undergoing Tube Current Modulation CT Scans

    NASA Astrophysics Data System (ADS)

    McMillan, Kyle Lorin

    Computed tomography (CT) has long been a powerful tool in the diagnosis of disease, identification of tumors and guidance of interventional procedures. With CT examinations comes the concern of radiation exposure and the associated risks. In order to properly understand those risks on a patient-specific level, organ dose must be quantified for each CT scan. Some of the most widely used organ dose estimates are derived from fixed tube current (FTC) scans of a standard sized idealized patient model. However, in current clinical practice, patient size varies from neonates weighing just a few kg to morbidly obese patients weighing over 200 kg, and nearly all CT exams are performed with tube current modulation (TCM), a scanning technique that adjusts scanner output according to changes in patient attenuation. Methods to account for TCM in CT organ dose estimates have been previously demonstrated, but these methods are limited in scope and/or restricted to idealized TCM profiles that are not based on physical observations and not scanner specific (e.g. don't account for tube limits, scanner-specific effects, etc.). The goal of this work was to develop methods to estimate organ doses to patients undergoing CT scans that take into account both the patient size as well as the effects of TCM. This work started with the development and validation of methods to estimate scanner-specific TCM schemes for any voxelized patient model. An approach was developed to generate estimated TCM schemes that match actual TCM schemes that would have been acquired on the scanner for any patient model. Using this approach, TCM schemes were then generated for a variety of body CT protocols for a set of reference voxelized phantoms for which TCM information does not currently exist. These are whole body patient models representing a variety of sizes, ages and genders that have all radiosensitive organs identified. TCM schemes for these models facilitated Monte Carlo-based estimates of fully

  9. Radiation dose calculations for CT scans with tube current modulation using the approach to equilibrium function

    SciTech Connect

    Li, Xinhua; Zhang, Da; Liu, Bob

    2014-11-01

    Purpose: The approach to equilibrium function has been used previously to calculate the radiation dose to a shift-invariant medium undergoing CT scans with constant tube current [Li, Zhang, and Liu, Med. Phys. 39, 5347–5352 (2012)]. The authors have adapted this method to CT scans with tube current modulation (TCM). Methods: For a scan with variable tube current, the scan range was divided into multiple subscan ranges, each with a nearly constant tube current. Then the dose calculation algorithm presented previously was applied. For a clinical CT scan series that presented tube current per slice, the authors adopted an efficient approach that computed the longitudinal dose distribution for one scan length equal to the slice thickness, which center was at z = 0. The cumulative dose at a specific point was a summation of the contributions from all slices and the overscan. Results: The dose calculations performed for a total of four constant and variable tube current distributions agreed with the published results of Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)]. For an abdomen/pelvis scan of an anthropomorphic phantom (model ATOM 701-B, CIRS, Inc., VA) on a GE Lightspeed Pro 16 scanner with 120 kV, N × T = 20 mm, pitch = 1.375, z axis current modulation (auto mA), and angular current modulation (smart mA), dose measurements were performed using two lines of optically stimulated luminescence dosimeters, one of which was placed near the phantom center and the other on the surface. Dose calculations were performed on the central and peripheral axes of a cylinder containing water, whose cross-sectional mass was about equal to that of the ATOM phantom in its abdominal region, and the results agreed with the measurements within 28.4%. Conclusions: The described method provides an effective approach that takes into account subject size, scan length, and constant or variable tube current to evaluate CT dose to a shift-invariant medium. For a clinical CT scan

  10. High-resolution imaging of living mammalian cells bound by nanobeads-connected antibodies in a medium using scanning electron-assisted dielectric microscopy

    PubMed Central

    Okada, Tomoko; Ogura, Toshihiko

    2017-01-01

    Nanometre-scale-resolution imaging technologies for liquid-phase specimens are indispensable tools in various scientific fields. In biology, observing untreated living cells in a medium is essential for analysing cellular functions. However, nanoparticles that bind living cells in a medium are hard to detect directly using traditional optical or electron microscopy. Therefore, we previously developed a novel scanning electron-assisted dielectric microscope (SE-ADM) capable of nanoscale observations. This method enables observation of intact cells in aqueous conditions. Here, we use this SE-ADM system to clearly observe antibody-binding nanobeads in liquid-phase. We also report the successful direct detection of streptavidin-conjugated nanobeads binding to untreated cells in a medium via a biotin-conjugated anti-CD44 antibody. Our system is capable of obtaining clear images of cellular organelles and beads on the cells at the same time. The direct observation of living cells with nanoparticles in a medium allowed by our system may contribute the development of carriers for drug delivery systems (DDS). PMID:28230204

  11. Effect of fabrication parameters on three-dimensional nanostructures of bulk heterojunctions imaged by high-resolution scanning ToF-SIMS.

    PubMed

    Yu, Bang-Ying; Lin, Wei-Chun; Wang, Wei-Ben; Iida, Shin-Ichi; Chen, Sun-Zen; Liu, Chia-Yi; Kuo, Che-Hung; Lee, Szu-Hsian; Kao, Wei-Lun; Yen, Guo-Ji; You, Yun-Wen; Liu, Chi-Ping; Jou, Jwo-Huei; Shyue, Jing-Jong

    2010-02-23

    Solution processable fullerene and copolymer bulk heterojunctions are widely used as the active layers of solar cells. In this work, scanning time-of-flight secondary ion mass spectrometry (ToF-SIMS) is used to examine the distribution of [6,6]phenyl-C61-butyric acid methyl ester (PCBM) and regio-regular poly(3-hexylthiophene) (rrP3HT) that forms the bulk heterojunction. The planar phase separation of P3HT:PCBM is observed by ToF-SIMS imaging. The depth profile of the fragment distribution that reflects the molecular distribution is achieved by low energy Cs(+) ion sputtering. The depth profile clearly shows a vertical phase separation of P3HT:PCBM before annealing, and hence, the inverted device architecture is beneficial. After annealing, the phase segregation is suppressed, and the device efficiency is dramatically enhanced with a normal device structure. The 3D image is obtained by stacking the 2D ToF-SIMS images acquired at different sputtering times, and 50 nm features are clearly differentiated. The whole imaging process requires less than 2 h, making it both rapid and versatile.

  12. High-resolution 1050 nm spectral domain retinal optical coherence tomography at 120 kHz A-scan rate with 6.1 mm imaging depth

    PubMed Central

    An, Lin; Li, Peng; Lan, Gongpu; Malchow, Doug; Wang, Ruikang K.

    2013-01-01

    We report a newly developed high speed 1050nm spectral domain optical coherence tomography (SD-OCT) system for imaging posterior segment of human eye. The system is capable of an axial resolution at ~10 µm in air, an imaging depth of 6.1 mm in air, a system sensitivity fall-off at ~6 dB/3mm and an imaging speed of 120,000 A-scans per second. We experimentally demonstrate the system’s capability to perform phase-resolved imaging of dynamic blood flow within retina, indicating high phase stability of the SDOCT system. Finally, we show an example that uses this newly developed system to image posterior segment of human eye with a large view of view (10 × 9 mm2), providing detailed visualization of microstructural features from anterior retina to posterior choroid. The demonstrated system parameters and imaging performances are comparable to those that a typical 1 µm swept source OCT would deliver for retinal imaging. PMID:23411636

  13. Periodic cation segregation in Cs0.44[Nb2.54W2.46O14] quantified by high-resolution scanning transmission electron microscopy.

    PubMed

    Heidelmann, Markus; Barthel, Juri; Cox, Gerhard; Weirich, Thomas E

    2014-10-01

    The atomic structure of Cs0.44[Nb2.54W2.46O14] closely resembles the structure of the most active catalyst for the synthesis of acrylic acid, the M1 phase of Mo10V2(4+)Nb2TeO42-x. Consistently with observations made for the latter compound, the high-angle electron scattering signal recorded by scanning transmission electron microscopy shows a significant intensity variation, which repeats periodically with the projected crystallographic unit cell. The occupation factors for the individual mixed Nb/W atomic columns are extracted from the observed intensity variations. For this purpose, experimental images and simulated images are compared on an identical intensity scale, which enables a quantification of the cation distribution. According to our analysis specific sites possess low tungsten concentrations of 25%, whereas other sites have tungsten concentrations above 70%. These findings allow us to refine the existing structure model of the target compound, which has until now described a uniform distribution of the niobium and tungsten atoms in the unit cell, showing that the similarity between Cs0.44[Nb2.54W2.46O14] and the related catalytic compounds also extends to the level of the cation segregation.

  14. Design and performance of a combined secondary ion mass spectrometry-scanning probe microscopy instrument for high sensitivity and high-resolution elemental three-dimensional analysis

    SciTech Connect

    Wirtz, Tom; Fleming, Yves; Gerard, Mathieu; Gysin, Urs; Glatzel, Thilo; Meyer, Ernst; Wegmann, Urs; Maier, Urs; Odriozola, Aitziber Herrero; Uehli, Daniel

    2012-06-15

    State-of-the-art secondary ion mass spectrometry (SIMS) instruments allow producing 3D chemical mappings with excellent sensitivity and spatial resolution. Several important artifacts however arise from the fact that SIMS 3D mapping does not take into account the surface topography of the sample. In order to correct these artifacts, we have integrated a specially developed scanning probe microscopy (SPM) system into a commercial Cameca NanoSIMS 50 instrument. This new SPM module, which was designed as a DN200CF flange-mounted bolt-on accessory, includes a new high-precision sample stage, a scanner with a range of 100 {mu}m in x and y direction, and a dedicated SPM head which can be operated in the atomic force microscopy (AFM) and Kelvin probe force microscopy modes. Topographical information gained from AFM measurements taken before, during, and after SIMS analysis as well as the SIMS data are automatically compiled into an accurate 3D reconstruction using the software program 'SARINA,' which was developed for this first combined SIMS-SPM instrument. The achievable lateral resolutions are 6 nm in the SPM mode and 45 nm in the SIMS mode. Elemental 3D images obtained with our integrated SIMS-SPM instrument on Al/Cu and polystyrene/poly(methyl methacrylate) samples demonstrate the advantages of the combined SIMS-SPM approach.

  15. Design and performance of a combined secondary ion mass spectrometry-scanning probe microscopy instrument for high sensitivity and high-resolution elemental three-dimensional analysis.

    PubMed

    Wirtz, Tom; Fleming, Yves; Gerard, Mathieu; Gysin, Urs; Glatzel, Thilo; Meyer, Ernst; Wegmann, Urs; Maier, Urs; Odriozola, Aitziber Herrero; Uehli, Daniel

    2012-06-01

    State-of-the-art secondary ion mass spectrometry (SIMS) instruments allow producing 3D chemical mappings with excellent sensitivity and spatial resolution. Several important artifacts however arise from the fact that SIMS 3D mapping does not take into account the surface topography of the sample. In order to correct these artifacts, we have integrated a specially developed scanning probe microscopy (SPM) system into a commercial Cameca NanoSIMS 50 instrument. This new SPM module, which was designed as a DN200CF flange-mounted bolt-on accessory, includes a new high-precision sample stage, a scanner with a range of 100 μm in x and y direction, and a dedicated SPM head which can be operated in the atomic force microscopy (AFM) and Kelvin probe force microscopy modes. Topographical information gained from AFM measurements taken before, during, and after SIMS analysis as well as the SIMS data are automatically compiled into an accurate 3D reconstruction using the software program "SARINA," which was developed for this first combined SIMS-SPM instrument. The achievable lateral resolutions are 6 nm in the SPM mode and 45 nm in the SIMS mode. Elemental 3D images obtained with our integrated SIMS-SPM instrument on Al/Cu and polystyrene/poly(methyl methacrylate) samples demonstrate the advantages of the combined SIMS-SPM approach.

  16. Design and performance of a combined secondary ion mass spectrometry-scanning probe microscopy instrument for high sensitivity and high-resolution elemental three-dimensional analysis

    NASA Astrophysics Data System (ADS)

    Wirtz, Tom; Fleming, Yves; Gerard, Mathieu; Gysin, Urs; Glatzel, Thilo; Meyer, Ernst; Wegmann, Urs; Maier, Urs; Odriozola, Aitziber Herrero; Uehli, Daniel

    2012-06-01

    State-of-the-art secondary ion mass spectrometry (SIMS) instruments allow producing 3D chemical mappings with excellent sensitivity and spatial resolution. Several important artifacts however arise from the fact that SIMS 3D mapping does not take into account the surface topography of the sample. In order to correct these artifacts, we have integrated a specially developed scanning probe microscopy (SPM) system into a commercial Cameca NanoSIMS 50 instrument. This new SPM module, which was designed as a DN200CF flange-mounted bolt-on accessory, includes a new high-precision sample stage, a scanner with a range of 100 μm in x and y direction, and a dedicated SPM head which can be operated in the atomic force microscopy (AFM) and Kelvin probe force microscopy modes. Topographical information gained from AFM measurements taken before, during, and after SIMS analysis as well as the SIMS data are automatically compiled into an accurate 3D reconstruction using the software program "SARINA," which was developed for this first combined SIMS-SPM instrument. The achievable lateral resolutions are 6 nm in the SPM mode and 45 nm in the SIMS mode. Elemental 3D images obtained with our integrated SIMS-SPM instrument on Al/Cu and polystyrene/poly(methyl methacrylate) samples demonstrate the advantages of the combined SIMS-SPM approach.

  17. High-resolution imaging of living mammalian cells bound by nanobeads-connected antibodies in a medium using scanning electron-assisted dielectric microscopy

    NASA Astrophysics Data System (ADS)

    Okada, Tomoko; Ogura, Toshihiko

    2017-02-01

    Nanometre-scale-resolution imaging technologies for liquid-phase specimens are indispensable tools in various scientific fields. In biology, observing untreated living cells in a medium is essential for analysing cellular functions. However, nanoparticles that bind living cells in a medium are hard to detect directly using traditional optical or electron microscopy. Therefore, we previously developed a novel scanning electron-assisted dielectric microscope (SE-ADM) capable of nanoscale observations. This method enables observation of intact cells in aqueous conditions. Here, we use this SE-ADM system to clearly observe antibody-binding nanobeads in liquid-phase. We also report the successful direct detection of streptavidin-conjugated nanobeads binding to untreated cells in a medium via a biotin-conjugated anti-CD44 antibody. Our system is capable of obtaining clear images of cellular organelles and beads on the cells at the same time. The direct observation of living cells with nanoparticles in a medium allowed by our system may contribute the development of carriers for drug delivery systems (DDS).

  18. Occipital Hypometabolism on FDG PET/CT Scan in a Child with Hodgkin's Lymphoma

    PubMed Central

    Tatci, Ebru; Ozmen, Ozlem; Gokcek, Atila; Demir, Haci Ahmet; Gulleroglu, Nadide Basak

    2016-01-01

    It is known that Fluorodeoxyglucose (FDG) Positron Emission/Computed Tomography (PET/CT) images may be helpful for evaluation of brain function in newborns. Here we described the fluorine-18 [18-F] FDG PET/CT imaging findings of encephalomalacia due to perinatal asphyxia in a child with refractory Hodgkin's Lymphoma (HL) who underwent PET/CT scan to stage the primary disease. Prominent hypometabolism was incidentally detected in the occipital regions bilaterally apart from the FDG uptakes in the malign lymphatic infiltrations. This case highlights the potential coexistence of a malignancy and a functional brain disorder. PMID:27965911

  19. Body surface area determined by whole-body CT scanning: need for new formulae?

    PubMed

    Villa, Chiara; Primeau, Charlotte; Hesse, Ulrik; Hougen, Hans Petter; Lynnerup, Niels; Hesse, Birger

    2017-03-01

    Calculation of the estimated body surface area (BSA) by body height and weight has been a challenge in the past centuries due to lack of a well-documented gold standard. More recently, available techniques such as 3D laser surface scanning and CT scanning may be expected to quantify the BSA in an easier and more accurate way. This study provides the first comparison between BSA obtained from post-mortem whole-body CT scans and BSA calculated by nine predictive formulae. The sample consisted of 54 male cadavers ranging from 20 to 87 years old. 3D reconstructions were generated from CT scans using Mimics software, and BSA values were automatically extracted from the program. They were compared with nine predictive equations from the literature. Remarkably, close correlations (r > 0·90) were found between BSA values from CT scans and those from the predictive formulae. A mean BSA of the 54 cadavers of 1·84-1·87 m(2) was calculated by all formulae except one, SD values varying between 0·171 and 0·223 m(2) . T-tests revealed significant differences between mean BSA values calculated with CT and three of the formulae. Regression analyses showed intercepts >(0;0) and slopes <1·0 using all predictive equations, with the CT scan determination as gold standard. It is concluded that DuBois and DuBois' equation can be safely used in normal-weight male subjects with high accuracy, but it seems likely that BSA is underestimated in underweight subjects and overestimated in overweight individuals. Creation of new formulae specific for overweight subjects and children may be needed.

  20. Achieving high-resolution soft-tissue imaging with cone-beam CT: a two-pronged approach for modulation of x-ray fluence and detector gain

    NASA Astrophysics Data System (ADS)

    Graham, S. A.; Siewerdsen, J. H.; Moseley, D. J.; Keller, H.; Shkumat, N. A.; Jaffray, D. A.

    2005-04-01

    Cone-beam computed tomography (CBCT) presents a highly promising and challenging advanced application of flat-panel detectors (FPDs). The great advantage of this adaptable technology is in the potential for sub-mm 3D spatial resolution in combination with soft-tissue detectability. While the former is achieved naturally by CBCT systems incorporating modern FPD designs (e.g., 200 - 400 um pixel pitch), the latter presents a significant challenge due to limitations in FPD dynamic range, large field of view, and elevated levels of x-ray scatter in typical CBCT configurations. We are investigating a two-pronged strategy to maximizing soft-tissue detectability in CBCT: 1) front-end solutions, including novel beam modulation designs (viz., spatially varying compensators) that alleviate detector dynamic range requirements, reduce x-ray scatter, and better distribute imaging dose in a manner suited to soft-tissue visualization throughout the field of view; and 2) back-end solutions, including implementation of an advanced FPD design (Varian PaxScan 4030CB) that features dual-gain and dynamic gain switching that effectively extends detector dynamic range to 18 bits. These strategies are explored quantitatively on CBCT imaging platforms developed in our laboratory, including a dedicated CBCT bench and a mobile isocentric C-arm (Siemens PowerMobil). Pre-clinical evaluation of improved soft-tissue visibility was carried out in phantom and patient imaging with the C-arm device. Incorporation of these strategies begin to reveal the full potential of CBCT for soft-tissue visualization, an essential step in realizing broad utility of this adaptable technology for diagnostic and image-guided procedures.

  1. Radiation exposure among patients with the highest CT scan utilization in the emergency department.

    PubMed

    Shah, Kaushal H; Slovis, Benjamin H; Runde, Dan; Godbout, Brandon; Newman, David H; Lee, Jarone

    2013-12-01

    The risk of cancer from computed tomography (CT) scan radiation is a rising concern in the medical field. Our objectives were to determine how many patients received more than ten CT scans in an academic emergency department (ED) over the course of 7 years and to quantify their radiation exposure and lifetime attributable risk of cancer. An electronic chart review was performed at our urban academic institution with an annual census of 110,000 patients. All patients who underwent a CT scan performed during ED management between the dates of January 2001 and December 2007 were identified. Specific predetermined data elements (e.g., subject demographics, type of CT scan) were extracted by two researchers blinded to hypothesis, using a preformatted data form. After identifying patients with more than ten CTs performed during the study period, radiation exposure was calculated based on accepted and reported radiation doses for the respective anatomic CTs, and lifetime attributable cancer risk was calculated based on the seventh report of the Biological Effects of Ionizing Radiation (BEIR VII) projections. Over the 7-year study period, 24,393 patients received 34,671 CT scans. The vast majority of patients (17,909) received a single CT. Twenty-six (0.1 %) patients received more than ten CTs totaling 374 scans with an average radiation exposure of 83.4 mSv. The maximum lifetime attributable risk for any individual in this cohort was 1.7 % above the baseline cancer risk. Among those undergoing CT imaging in our ED, high-exposure patients (greater than ten scans) constituted a significant minority, while more than one in four patients underwent more than one CT scan during the study period. While the presumed overall risk of radiation-induced cancer continues to be low, it is important for the emergency physician to use clinical knowledge as well as concern for the patient when utilizing radiographic imaging. Increasing attributable cancer risk may have important

  2. Extraction of the Brain from CT Head Scans Based on Domain Knowledge

    SciTech Connect

    Qian Guoyu; Luo Suhuai; Jin, Jesse; Park, Mira; Nowinski, Wieslaw L.

    2007-11-02

    We present an automatic approach for an efficient brain extraction from CT head scans. Regions of interest are first set in each slice by applying thresholding and region growing. Next, the brain candidates are extracted by using three-dimensional region growing with a variable, anatomy-dependent structuring element. Domain knowledge, including Hounsfield unit ranges, anatomy, and image acquisition parameters, is applied. The proposed method has been applied automatically to 27 CT normal and pathological scans and has shown promising results. The average sensitivity, specificity and Dice's index for 5 cases are 99.6%, 99.4% and 98.7%, respectively.

  3. High-resolution three-dimensional images from confocal scanning laser microscopy. Quantitative study and mathematical correction of the effects from bleaching and fluorescence attenuation in depth.

    PubMed

    Rigaut, J P; Vassy, J

    1991-08-01

    Three-dimensional images can be assembled by piling up consecutive confocal fluorescent images obtained by confocal scanning laser microscopy. The present work was based on three-dimensional (50-microns-deep) images at high (x, y) resolution obtained with an MRC-500 after en bloc staining of thick slices of rat liver by chromomycin A3 for nuclear DNA. The results of studies on bleaching, fluorescence excitation and emission intensities at various depths of histologic preparations are described. These effects could be evaluated separately by acquiring piled-up ("brick-stepping") and non-piled-up ("side-stepping") (x, y) images at consecutive depths and also (x, z) images. Empirical equations allowed the fitting of experimental plots of bleaching versus time, at different laser intensities and at different depths, and of fluorescence emission intensity versus depth. The main conclusions were that under our experimental conditions: (1) there was no attenuation by depth of the fluorochrome penetration, (2) there was no attenuation of the exciting beam intensity up to at least 50 microns deep, (3) there was an attenuation of the fluorescence emission intensity by depth, (4) bleaching happened equally on all planes above and below any confocal plane being studied, and (5) the fluorescence bleaching half-life was independent of depth. A mathematical correction scheme designed to compensate for bleaching and for attenuation of fluorescence emission in depth is presented. This correction is required for obtaining three-dimensional images of better quality, for optimal three-dimensional image segmentation and for any quantitative analysis based upon voxel-discretized emission intensities (gray levels)--e.g., estimating, by confocal image cytometry, textural chromatin parameters and nuclear DNA amounts.

  4. Outer contour extraction of skull from CT scan images

    NASA Astrophysics Data System (ADS)

    Ulinuha, M. A.; Yuniarno, E. M.; Nugroho, S. M. S.; Hariadi, M.

    2017-03-01

    Extraction of the outer contour of the skull is an important step in craniofacial reconstruction. The outer contour is required for surface reconstruction of the skull. In this paper, we propose a method to extract the outer contour of the skull. The extraction process consists of four stages: defining the region of interest, segmentation of the bone, noise removal and extraction of the outer contour based on scanning from the four sides of the image. The proposed method successfully extracts the outermost contour of the skull and avoids redundant data.

  5. Simulation of four-dimensional CT images from deformable registration between inhale and exhale breath-hold CT scans

    SciTech Connect

    Sarrut, David; Boldea, Vlad; Miguet, Serge; Ginestet, Chantal

    2006-03-15

    Purpose: We propose to simulate an artificial four-dimensional (4-D) CT image of the thorax during breathing. It is performed by deformable registration of two CT scans acquired at inhale and exhale breath-hold. Materials and methods: Breath-hold images were acquired with the ABC (Active Breathing Coordinator) system. Dense deformable registrations were performed. The method was a minimization of the sum of squared differences (SSD) using an approximated second-order gradient. Gaussian and linear-elastic vector field regularizations were compared. A new preprocessing step, called a priori lung density modification (APLDM), was proposed to take into account lung density changes due to inspiration. It consisted of modulating the lung densities in one image according to the densities in the other, in order to make them comparable. Simulated 4-D images were then built by vector field interpolation and image resampling of the two initial CT images. A variation in the lung density was taken into account to generate intermediate artificial CT images. The Jacobian of the deformation was used to compute voxel values in Hounsfield units. The accuracy of the deformable registration was assessed by the spatial correspondence of anatomic landmarks located by experts. Results: APLDM produced statistically significantly better results than the reference method (registration without APLDM preprocessing). The mean (and standard deviation) of distances between automatically found landmark positions and landmarks set by experts were 2.7(1.1) mm with APLDM, and 6.3(3.8) mm without. Interexpert variability was 2.3(1.2) mm. The differences between Gaussian and linear elastic regularizations were not statistically significant. In the second experiment using 4-D images, the mean difference between automatic and manual landmark positions for intermediate CT images was 2.6(2.0) mm. Conclusion: The generation of 4-D CT images by deformable registration of inhale and exhale CT images is

  6. Distribution of abdominal and pelvic Hodgkin disease: implications for CT scanning

    SciTech Connect

    Aisen, A.M.; Gross, B.H.; Glazer, G.M.; Amendola, M.A.

    1985-05-01

    Computed tomography of the abdomen and pelvis is frequently performed for the staging of abdominal and pelvic lymphoma. Certain limited CT protocols have been nearly as accurate as more complete examinations at defining the extent of lymphadenopathy and the response to therapy, with the advantages of decreased scanning time and patient radiation dose. The authors reviewed abdominal and pelvic CT scans and reports of 58 patients with Hodgkin disease to determine whether the entire abdomen and pelvis must always be scanned in such patients. Pelvic adenopathy without concurrent abdominal adenopathy was present in only one of 58 patients, and that patient presented clinically with inguinal adenopathy. These findings are supported by larger pathologic studies showing that Hodgkin disease always spreads contiguously. Patients with Hodgkin disease presenting above the diaphragm should undergo abdominal CT for staging; if the abdomen is normal, the pelvis need not be scanned. For Hodgkin patients with clinical or CT evidence of disease below the diaphragm, both abdomen and pelvis should be scanned.

  7. Lymph nodes can accurately be measured on PET-CT for lymphoma staging/restaging without a concomitant contrast enhanced CT scan.

    PubMed

    Simpson, William L; Lee, Karen M; Sosa, Ninoska; Cooper, Nancy; Scigliano, Eileen; Brody, Joshua D; Doucette, John T; Kostakoglu, Lale

    2016-05-01

    Dual imaging with both contrast enhanced CT scan and PET-CT is recommended for evaluation of lymphoma. We compared the performance in identification and size measurements of involved lymph nodes in FDG-avid lymphomas on the low dose non-contrast enhanced CT of a PET-CT scan with those on a diagnostic contrast enhanced CT scan. The size of FDG-avid lymph nodes was measured in both the short and long axis on both the low dose non-contrast CT of the PET-CT and the contrast enhanced CT by two independent readers. A total of 307 FGD avid lymph nodes were identified in 52 patients. There was no statistically significant differences in the measured size of the nodes on the non-contrast and contrast enhanced scans (p=0.21). Baseline staging and restaging of FDG-avid lymphomas can be performed with one test, PET-CT, without an accompanying contrast enhanced CT scan, with no effect on the measured nodal size.

  8. High-resolution seismic and side scan sonar imaging of active structures and Quaternary channels on the shallow shelf of Otago, southeastern New Zealand

    NASA Astrophysics Data System (ADS)

    Gorman, A. R.; Bruce, C.; Preskett, S. A.; Norris, R.; Choveaux, R.; Flemish, H.; Green, C.

    2011-12-01

    The shallow and narrow continental shelf off the coast of Otago has unique geological characteristics due to the juxtaposition of active coast-parallel contractional faults related to the nearby Pacific-Australian plate boundary and late-Miocene shield volcanism that affects the structural and sedimentological regimes of the region. For example, the offshore extent of the active Akatore Fault, a NE-SW trending reverse fault that runs along the coast SW of Dunedin, is poorly constrained to the northeast where is intersects the Dunedin Volcanic Complex. This fault is possibly associated with several other offshore coast-parallel faults based on shallow controlled-source seismic data. Historical earthquakes, including those of 1974 and 1989, are attributed these faults. The Dunedin Volcanic Complex also has impacted Quaternary erosional and sedimentation patterns on the shelf as a result of topographical features that affect drainage and sediment transport patterns. Single-channel electro-acoustic boomer seismic reflection data and side scan sonar profiles have been collected along a ~35-km-long section of the shallow shelf SW of Dunedin over the last three years. The majority of lines were collected along NW-SE azimuths (perpendicular to the coast), running from just outside the surf zone (<10 m water depth) to a maximum of 28 km offshore (~75 m water depth). Survey lines were ~250 m apart near shore and up to 5 km apart offshore. Boomer subsurface penetration is limited, primarily by the presence of multiple reflections. However, primary reflections were recorded from sub-seafloor depths of up to 100 m. Several significant structures have been imaged within the survey area, principally the Akatore and Green Island Faults. The Akatore Fault is imaged very near shore in the southern portion of the survey, and a minimum post-Miocene displacement of 55 m was calculated. Offset on the Green Island Fault, a high-angle reverse fault, was relatively well constrained to ~200

  9. Reconstructing inter annual Indonesian river discharge by high-resolution LA-ICPMS geochemistry and UV-luminescence scanning of corals

    NASA Astrophysics Data System (ADS)

    Nagtegaal, R.; Bergh, van den, G.; Pascher, K.; Jochum, K. P.; Brummer, G. A.

    2011-12-01

    Degradation of many coral reefs around the world is linked to land-based activities. Soil erosion due to land-use changes results in increased quantities of sediment to local river systems which are, in many cases, discharged directly onto the reefs systems. The Berau delta/barrier reef system, located offshore NE Kalimantan, Indonesia, is characterized by a unique and pristine reef system that exists in close proximity of the Berau river mouth. Over the last decades deforestation and mining activities have considerably increased in the region. Our project aimed to assess the impact of those land-use changes in relation to sediment supply to the reef system over the last decades. Corals archive historical sedimentation records as they entrap terrigenous sediments into their skeleton and thus can be used to identify periods of decreased or enhanced sediment supply associated with anthropogenic induced land-use changes and natural variations in freshwater discharge. We investigate cores drilled from living Porites sp. coral colonies collected in the North Eastern part of the Berau delta >20 km from the river mouth. The annually banded cores were analyzed for Ba/Ca and Y/Ca ratios using LA-ICPMS in combination with spectral luminescence scanning (SLS) as a measure for terrestrial sediment input and soil erosion. Three coral luminescence records were used to establish a 28-year composite record of sediment discharge. The year to year variability of sediment supply to the reef system is evidently regulated by the El Niño Southern Oscillation climate system (ENSO). Especially positive phases of the Nino 3.4 index (= El Niño) have a strong negative effect on the sediment supply to the reef system which clearly diminished during the El Niño years 82-83, 92 and 97-98. We also conclude that for the Berau region, Y/Ca rather than Ba/Ca correlates well with precipitation records which is supported by the relation to the spectral luminescence results. Despite the fact that

  10. The Impact of Sources of Variability on Parametric Response Mapping of Lung CT Scans

    PubMed Central

    Boes, Jennifer L.; Bule, Maria; Hoff, Benjamin A.; Chamberlain, Ryan; Lynch, David A.; Stojanovska, Jadranka; Martinez, Fernando J.; Han, Meilan K.; Kazerooni, Ella A.; Ross, Brian D.; Galbán, Craig J.

    2015-01-01

    Parametric response mapping (PRM) of inspiration and expiration computed tomography (CT) images improves the radiological phenotyping of chronic obstructive pulmonary disease (COPD). PRM classifies individual voxels of lung parenchyma as normal, emphysematous, or nonemphysematous air trapping. In this study, bias and noise characteristics of the PRM methodology to CT and clinical procedures were evaluated to determine best practices for this quantitative technique. Twenty patients of varying COPD status with paired volumetric inspiration and expiration CT scans of the lungs were identified from the baseline COPD-Gene cohort. The impact of CT scanner manufacturer and reconstruction kernels were evaluated as potential sources of variability in PRM measurements along with simulations to quantify the impact of inspiration/expiration lung volume levels, misregistration, and image spacing on PRM measurements. Negligible variation in PRM metrics was observed when CT scanner type and reconstruction were consistent and inspiration/expiration lung volume levels were near target volumes. CT scanner Hounsfield unit drift occurred but remained difficult to ameliorate. Increasing levels of image misregistration and CT slice spacing were found to have a minor effect on PRM measurements. PRM-derived values were found to be most sensitive to lung volume levels and mismatched reconstruction kernels. As with other quantitative imaging techniques, reliable PRM measurements are attainable when consistent clinical and CT protocols are implemented. PMID:26568983

  11. The Impact of Sources of Variability on Parametric Response Mapping of Lung CT Scans.

    PubMed

    Boes, Jennifer L; Bule, Maria; Hoff, Benjamin A; Chamberlain, Ryan; Lynch, David A; Stojanovska, Jadranka; Martinez, Fernando J; Han, Meilan K; Kazerooni, Ella A; Ross, Brian D; Galbán, Craig J

    2015-09-01

    Parametric response mapping (PRM) of inspiration and expiration computed tomography (CT) images improves the radiological phenotyping of chronic obstructive pulmonary disease (COPD). PRM classifies individual voxels of lung parenchyma as normal, emphysematous, or nonemphysematous air trapping. In this study, bias and noise characteristics of the PRM methodology to CT and clinical procedures were evaluated to determine best practices for this quantitative technique. Twenty patients of varying COPD status with paired volumetric inspiration and expiration CT scans of the lungs were identified from the baseline COPD-Gene cohort. The impact of CT scanner manufacturer and reconstruction kernels were evaluated as potential sources of variability in PRM measurements along with simulations to quantify the impact of inspiration/expiration lung volume levels, misregistration, and image spacing on PRM measurements. Negligible variation in PRM metrics was observed when CT scanner type and reconstruction were consistent and inspiration/expiration lung volume levels were near target volumes. CT scanner Hounsfield unit drift occurred but remained difficult to ameliorate. Increasing levels of image misregistration and CT slice spacing were found to have a minor effect on PRM measurements. PRM-derived values were found to be most sensitive to lung volume levels and mismatched reconstruction kernels. As with other quantitative imaging techniques, reliable PRM measurements are attainable when consistent clinical and CT protocols are implemented.

  12. Normalization of CT scans reconstructed with different kernels to reduce variability in emphysema measurements

    NASA Astrophysics Data System (ADS)

    Gallardo Estrella, L.; van Ginneken, B.; van Rikxoort, E. M.

    2013-03-01

    Chronic Obstructive Pulmonary Disease (COPD) is a lung disease characterized by progressive air flow limitation caused by emphysema and chronic bronchitis. Emphysema is quantified from chest computed tomography (CT) scans as the percentage of attentuation values below a fixed threshold. The emphysema quantification varies substantially between scans reconstructed with different kernels, limiting the possibilities to compare emphysema quantifications obtained from scans with different reconstruction parameters. In this paper we propose a method to normalize scans reconstructed with different kernels to have the same characteristics as scans reconstructed with a reference kernel and investigate if this normalization reduces the variability in emphysema quantification. The proposed normalization splits a CT scan into different frequency bands based on hierarchical unsharp masking. Normalization is performed by changing the energy in each frequency band to the average energy in each band in the reference kernel. A database of 15 subjects with COPD was constructed for this study. All subjects were scanned at total lung capacity and the scans were reconstructed with four different reconstruction kernels. The normalization was applied to all scans. Emphysema quantification was performed before and after normalization. It is shown that the emphysema score varies substantially before normalization but the variation diminishes after normalization.

  13. On the Role of Ultrasonography and CT Scan in the Diagnosis of Acute Appendicitis.

    PubMed

    Debnath, Jyotindu; Kumar, Rajesh; Mathur, Ankit; Sharma, Pawan; Kumar, Nikhilesh; Shridhar, Nagaraj; Shukla, Ashwani; Khanna, Shiv Pankaj

    2015-12-01

    The purposes of this study were to revisit the utility of ultrasonography (USG) as a primary imaging modality in acute appendicitis (AA) and to establish the role of CT scan as a second-line/problem-solving modality. All cases of suspected AA were referred for urgent USG. USG was done with standard protocol for appendicitis. Limited computed tomographic (CT) scan [NCCT ± CECT (IV contrast only)] was done for the lower abdomen and pelvis where sonographic findings were equivocal. One hundred and twenty-one patients were referred for USG for suspected appendicitis. Eight-four patients underwent surgery for AA based on clinical as well as imaging findings, of whom 76 had appendicitis confirmed at histopathology. Three patients were misdiagnosed (3.6 %) on USG as appendicitis. Of 76 patients of appendicitis confirmed histopathologically, 63 (82.8 %) had features of appendicitis on USG and did not require any additional imaging modality. Of 121 patients, 12 (10 %) needed CT scan because of atypical features on USG. Of these 12 patients, seven had retrocecal appendicitis, and three high-up paracolic appendicitis. USG alone had sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 81, 88, 92.6, 71.6, and 83 %, respectively. When combined with CT scan in select cases, the sensitivity, specificity, PPV, NPV, and accuracy of combined USG + CT scan were 96 % (P = 0.0014), 89 %, 93 %, 93.5 % (P = 0.0001), and 93 % (P = 0.0484), respectively. Twenty-eight (23 %) patients were given alternative diagnosis on USG. Dedicated appendiceal USG should be used as a primary imaging modality in diagnosing or excluding AA. Appendiceal CT can serve as a problem-solving modality.

  14. Interactive lung segmentation in abnormal human and animal chest CT scans

    SciTech Connect

    Kockelkorn, Thessa T. J. P. Viergever, Max A.; Schaefer-Prokop, Cornelia M.; Bozovic, Gracijela; Muñoz-Barrutia, Arrate; Rikxoort, Eva M. van; Brown, Matthew S.; Jong, Pim A. de; Ginneken, Bram van

    2014-08-15

    Purpose: Many medical image analysis systems require segmentation of the structures of interest as a first step. For scans with gross pathology, automatic segmentation methods may fail. The authors’ aim is to develop a versatile, fast, and reliable interactive system to segment anatomical structures. In this study, this system was used for segmenting lungs in challenging thoracic computed tomography (CT) scans. Methods: In volumetric thoracic CT scans, the chest is segmented and divided into 3D volumes of interest (VOIs), containing voxels with similar densities. These VOIs are automatically labeled as either lung tissue or nonlung tissue. The automatic labeling results can be corrected using an interactive or a supervised interactive approach. When using the supervised interactive system, the user is shown the classification results per slice, whereupon he/she can adjust incorrect labels. The system is retrained continuously, taking the corrections and approvals of the user into account. In this way, the system learns to make a better distinction between lung tissue and nonlung tissue. When using the interactive framework without supervised learning, the user corrects all incorrectly labeled VOIs manually. Both interactive segmentation tools were tested on 32 volumetric CT scans of pigs, mice and humans, containing pulmonary abnormalities. Results: On average, supervised interactive lung segmentation took under 9 min of user interaction. Algorithm computing time was 2 min on average, but can easily be reduced. On average, 2.0% of all VOIs in a scan had to be relabeled. Lung segmentation using the interactive segmentation method took on average 13 min and involved relabeling 3.0% of all VOIs on average. The resulting segmentations correspond well to manual delineations of eight axial slices per scan, with an average Dice similarity coefficient of 0.933. Conclusions: The authors have developed two fast and reliable methods for interactive lung segmentation in

  15. Assessment of the Diagnostic Accuracy of Limited CT Scan of Paranasal Sinuses in the Identification of Sinusitis

    PubMed Central

    Noorian, Vahid; Motaghi, Arya

    2012-01-01

    Background Paranasal sinus CT has high sensitivity and specificity for sinusitis. However, this modality is costly and involves greater radiation exposure than plain radiographs. Objectives We tried to compare 10-cut limited CT scan and standard CT scan in the diagnosis of sinusitis. Materials and Methods We conducted a cross sectional case series from August to December 2010 on 150 patients with non-randomized sampling method in academic hospitals related to medical school of Shahid Beheshti University of medical sciences. Using standard CT scan as the gold standard, the sensitivity and specificity of limited series were calculated for each sinus group. Results In our study limited CT scan had a sensitivity of 92%, specificity of 94%, positive predictive value of 90% and negative predictive value of 95%. Conclusions The limited CT scan is useful for confirming the clinical diagnosis of sinusitis. PMID:23396584

  16. Should all anticoagulated patients with head injury receive a CT scan? Decision-analysis modelling of an observational cohort

    PubMed Central

    Kuczawski, Maxine; Stevenson, Matt; Goodacre, Steve; Teare, M Dawn; Ramlakhan, Shammi; Morris, Francis; Mason, Suzanne

    2016-01-01

    Objectives It is not currently clear whether all anticoagulated patients with a head injury should receive CT scanning or only those with evidence of traumatic brain injury (eg, loss of consciousness or amnesia). We aimed to determine the cost-effectiveness of CT for all compared with selective CT use for anticoagulated patients with a head injury. Design Decision-analysis modelling of data from a multicentre observational study. Setting 33 emergency departments in England and Scotland. Participants 3566 adults (aged ≥16 years) who had suffered blunt head injury, were taking warfarin and underwent selective CT scanning. Main outcome measures Estimated expected benefits in terms of quality-adjusted life years (QALYs) were the entire cohort to receive a CT scan; estimated increased costs of CT and also the potential cost implications associated with patient survival and improved health. These values were used to estimate the cost per QALY of implementing a strategy of CT for all patients compared with observed practice based on guidelines recommending selective CT use. Results Of the 1420 of 3534 patients (40%) who did not receive a CT scan, 7 (0.5%) suffered a potentially avoidable head injury-related adverse outcome. If CT scanning had been performed in all patients, appropriate treatment could have gained 3.41 additional QALYs but would have incurred £193 149 additional treatment costs and £130 683 additional CT costs. The incremental cost-effectiveness ratio of £94 895/QALY gained for unselective compared with selective CT use is markedly above the threshold of £20–30 000/QALY used by the UK National Institute for Care Excellence to determine cost-effectiveness. Conclusions CT scanning for all anticoagulated patients with head injury is not cost-effective compared with selective use of CT scanning based on guidelines recommending scanning only for those with evidence of traumatic brain injury. Trial registration number NCT 02461498. PMID

  17. Geometry-constraint-scan imaging for in-line phase contrast micro-CT.

    PubMed

    Fu, Jian; Yu, Guangyuan; Fan, Dekai

    2014-01-01

    X-ray phase contrast computed tomography (CT) uses the phase shift that x-rays undergo when passing through matter, rather than their attenuation, as the imaging signal and may provide better image quality in soft-tissue and biomedical materials with low atomic number. Here a geometry-constraint-scan imaging technique for in-line phase contrast micro-CT is reported. It consists of two circular-trajectory scans with x-ray detector at different positions, the phase projection extraction method with the Fresnel free-propagation theory and the filter back-projection reconstruction algorithm. This method removes the contact-detector scan and the pure phase object assumption in classical in-line phase contrast Micro-CT. Consequently it relaxes the experimental conditions and improves the image contrast. This work comprises a numerical study of this technique and its experimental verification using a biomedical composite dataset measured at an x-ray tube source Micro-CT setup. The numerical and experimental results demonstrate the validity of the presented method. It will be of interest for a wide range of in-line phase contrast Micro-CT applications in biology and medicine.

  18. Multienergy CT acquisition and reconstruction with a stepped tube potential scan

    SciTech Connect

    Shen, Le; Xing, Yuxiang

    2015-01-15

    Purpose: Based on an energy-dependent property of matter, one may obtain a pseudomonochromatic attenuation map, a material composition image, an electron-density distribution, and an atomic number image using a dual- or multienergy computed tomography (CT) scan. Dual- and multienergy CT scans broaden the potential of x-ray CT imaging. The development of such systems is very useful in both medical and industrial investigations. In this paper, the authors propose a new dual- and multienergy CT system design (segmental multienergy CT, SegMECT) using an innovative scanning scheme that is conveniently implemented on a conventional single-energy CT system. The two-step-energy dual-energy CT can be regarded as a special case of SegMECT. A special reconstruction method is proposed to support SegMECT. Methods: In their SegMECT, a circular trajectory in a CT scan is angularly divided into several arcs. The x-ray source is set to a different tube voltage for each arc of the trajectory. Thus, the authors only need to make a few step changes to the x-ray energy during the scan to complete a multienergy data acquisition. With such a data set, the image reconstruction might suffer from severe limited-angle artifacts if using conventional reconstruction methods. To solve the problem, they present a new prior-image-based reconstruction technique using a total variance norm of a quotient image constraint. On the one hand, the prior extracts structural information from all of the projection data. On the other hand, the effect from a possibly imprecise intensity level of the prior can be mitigated by minimizing the total variance of a quotient image. Results: The authors present a new scheme for a SegMECT configuration and establish a reconstruction method for such a system. Both numerical simulation and a practical phantom experiment are conducted to validate the proposed reconstruction method and the effectiveness of the system design. The results demonstrate that the proposed Seg

  19. Study Finds Small Increase in Cancer Risk after Childhood CT Scans

    Cancer.gov

    A study published in the June 6, 2012, issue of The Lancet shows that radiation exposure from computed tomography (CT) scans in childhood results in very small but increased risks of leukemia and brain tumors in the first decade after exposure.

  20. Automatic Segmentation and Quantification of White and Brown Adipose Tissues from PET/CT Scans.

    PubMed

    Hussein, Sarfaraz; Green, Aileen; Watane, Arjun; Reiter, David; Chen, Xinjian; Papadakis, Georgios Z; Wood, Bradford; Cypess, Aaron; Osman, Medhat; Bagci, Ulas

    2016-12-06

    In this paper, we investigate the automatic detection of white and brown adipose tissues using Positron Emission Tomography/ Computed Tomography (PET/CT) scans, and develop methods for the quantification of these tissues at the whole-body and body-region levels. We propose a patient-specific automatic adiposity analysis system with two modules. In the first module, we detect white adipose tissue (WAT) and its two sub-types from CT scans: Visceral Adipose Tissue (VAT) and Subcutaneous Adipose Tissue (SAT). This process relies conventionally on manual or semi-automated segmentation, leading to inefficient solutions. Our novel framework addresses this challenge by proposing an unsupervised learning method to separate VAT from SAT in the abdominal region for the clinical quantification of central obesity. This step is followed by a context driven label fusion algorithm through sparse 3D Conditional Random Fields (CRF) for volumetric adiposity analysis. In the second module, we automatically detect, segment, and quantify brown adipose tissue (BAT) using PET scans because unlike WAT, BAT is metabolically active. After identifying BAT regions using PET, we perform a co-segmentation procedure utilizing asymmetric complementary information from PET and CT. Finally, we present a new probabilistic distance metric for differentiating BAT from non-BAT regions. Both modules are integrated via an automatic body-region detection unit based on one-shot learning. Experimental evaluations conducted on 151 PET/CT scans achieve state-of-the-art performances in both central obesity as well as brown adiposity quantification.

  1. An anatomically shaped lower body model for CT scanning of cadaver femurs.

    PubMed

    Tanck, Esther; Deenen, J C W; Huisman, Henk Jan; Kooloos, Jan G; Huizenga, Henk; Verdonschot, Nico

    2010-01-21

    Bone specific, CT-based finite element (FE) analyses have great potential to accurately predict the fracture risk of deteriorated bones. However, it has been shown that differences exist between FE-models of femora scanned in a water basin or scanned in situ within the human body, as caused by differences in measured bone mineral densities (BMD). In this study we hypothesized that these differences can be reduced by re-creating the patient CT-conditions by using an anatomically shaped physical model of the lower body. BMD distributions were obtained from four different femora that were scanned under three conditions: (1) in situ within the cadaver body, (2) in a water basin and (3) in the body model. The BMD of the three scanning protocols were compared at two locations: proximally, in the trabecular bone of the femoral head, and in the cortical bone of the femoral shaft. Proximally, no significant differences in BMD were found between the in situ scans and the scans in the body model, whereas the densities from the water basin scans were on average 10.8% lower than in situ. In the femoral shaft the differences between the three scanning protocols were insignificant. In conclusion, the body model better approached the in situ situation than a water basin. Future studies can use this body model to mimic patient situations and to develop protocols to improve the performance of the FE-models in actual patients.

  2. Pancreatic Cancer Tumor Size on CT Scan Versus Pathologic Specimen: Implications for Radiation Treatment Planning

    SciTech Connect

    Arvold, Nils D.; Niemierko, Andrzej; Mamon, Harvey J.; Hong, Theodore S.

    2011-08-01

    Purpose: Pancreatic cancer primary tumor size measurements are often discordant between computed tomography (CT) and pathologic specimen after resection. Dimensions of the primary tumor are increasingly relevant in an era of highly conformal radiotherapy. Methods and Materials: We retrospectively evaluated 97 consecutive patients with resected pancreatic cancer at two Boston hospitals. All patients had CT scans before surgical resection. Primary endpoints were maximum dimension (in millimeters) of the primary tumor in any direction as reported by the radiologist on CT and by the pathologist for the resected gross fresh specimen. Endoscopic ultrasound (EUS) findings were analyzed if available. Results: Of the patients, 87 (90%) had preoperative CT scans available for review and 46 (47%) had EUS. Among proximal tumors (n = 69), 40 (58%) had pathologic duodenal invasion, which was seen on CT in only 3 cases. The pathologic tumor size was a median of 7 mm larger compared with CT size for the same patient (range, -15 to 43 mm; p < 0.0001), with 73 patients (84%) having a primary tumor larger on pathology than CT. Endoscopic ultrasound was somewhat more accurate, with pathologic tumor size being a median of only 5 mm larger compared with EUS size (range, -15 to 35 mm; p = 0.0003). Conclusions: Computed tomography scans significantly under-represent pancreatic cancer tumor size compared with pathologic specimens in resectable cases. We propose a clinical target volume expansion formula for the primary tumor based on our data. The high rate of pathologic duodenal invasion suggests a risk of duodenal undercoverage with highly conformal radiotherapy.

  3. Use of CA-125 Tests and CT Scans for Surveillance in Ovarian Cancer

    PubMed Central

    Esselen, Katharine M.; Cronin, Angel M.; Bixel, Kristin; Bookman, Michael A.; Burger, Robert A.; Cohn, David E.; Cristea, Mihaela; Griggs, Jennifer J.; Levenback, Charles F.; Mantia-Smaldone, Gina; Meyer, Larissa A.; Matulonis, Ursula A.; Niland, Joyce C.; Sun, Charlotte; O’Malley, David M.; Wright, Alexi A.

    2016-01-01

    Importance A 2009 randomized clinical trial (RCT) demonstrated that using CA-125 tests for routine surveillance in ovarian cancer increases chemotherapy use and decreases patients’ quality of life without improving survival, compared with clinical observation. The Society of Gynecologic Oncology guidelines categorize CA-125 testing as “optional” and discourage the use of radiographic imaging for routine surveillance. To date, few studies have examined their use in clinical practice. Objective To examine the use of CA-125 tests and CT scans in clinical practice before and after the 2009 RCT and estimate the economic impact of surveillance testing. Design Prospective cohort of women diagnosed with ovarian cancer between 2004-2011 and followed through 2012. Setting Six National Cancer Institute-Designated Cancer Centers. Participants 1,241 women with ovarian cancer in clinical remission after completion of primary cytoreductive surgery and chemotherapy. Main Outcome Measures Use of CA-125 tests and CT scans before and after 2009 (n=1,241). Secondary outcomes included: the time from CA-125 doubling to retreatment among women who experienced a rise in CA-125 (n=511) before and after 2009, and the costs associated with surveillance testing using 2016 Medicare reimbursement rates. Results Use of CA-125 testing and CT scans was very similar over the study period. During 12 months of surveillance, the cumulative incidence of 3 or more CA-125 tests was 86% in 2004-2009 versus 91% in 2010-2012 (P=.95), and the cumulative incidence of more than 1 CT scan was 81% (2004-2009) versus 78% (2010-2012) (P=.50). Among women who experienced a CA-125 doubling (n=511), there was no significant difference in the time to retreatment with chemotherapy before and after 2009 (median: 2.8 months vs. 3.5 months, P=.40). Over a 12-month period, there were a mean of 4.6 CA-125 tests and 1.7 CT scans per patient, resulting in a United States population surveillance cost estimate of $1

  4. Neck evaluation with barium-enhanced radiographs and CT scans after supraglottic subtotal laryngectomy.

    PubMed

    Niemeyer, J H; Balfe, D M; Hayden, R E

    1987-02-01

    Supraglottic subtotal laryngectomy (SSL) is a radical, yet voice-conserving, surgical procedure commonly performed for carcinoma of the supraglottic larynx. The pharyngograms and computed tomographic (CT) scans of 35 patients obtained after SSL were evaluated retrospectively. These examinations reliably demonstrated the changes in anatomy caused by removal of the epiglottis, aryepiglottic folds, and false vocal cords. Fourteen patients had documented recurrence of cancer; five mucosal, nine extramucosal. Three of five macroscopic mucosal recurrences in the larynx/pharynx were detected on the barium pharyngograms; the two mucosal lesions not seen were in the base of the tongue and tonsillar fossa. CT enabled detection of five of five recurrences and was superior to pharyngography in demonstrating the soft-tissue extent of disease. CT findings mimicking recurrence were seen in two patients: one with diffuse histiocytic lymphoma; the second, with benign hyperkeratosis. Barium and CT examinations are useful adjuncts to the clinical examination in detecting recurrent squamous cell carcinoma in patients following SSL.

  5. "High-precision, reconstructed 3D model" of skull scanned by conebeam CT: Reproducibility verified using CAD/CAM data.

    PubMed

    Katsumura, Seiko; Sato, Keita; Ikawa, Tomoko; Yamamura, Keiko; Ando, Eriko; Shigeta, Yuko; Ogawa, Takumi

    2016-01-01

    Computed tomography (CT) scanning has recently been introduced into forensic medicine and dentistry. However, the presence of metal restorations in the dentition can adversely affect the quality of three-dimensional reconstruction from CT scans. In this study, we aimed to evaluate the reproducibility of a "high-precision, reconstructed 3D model" obtained from a conebeam CT scan of dentition, a method that might be particularly helpful in forensic medicine. We took conebeam CT and helical CT images of three dry skulls marked with 47 measuring points; reconstructed three-dimensional images; and measured the distances between the points in the 3D images with a computer-aided design/computer-aided manufacturing (CAD/CAM) marker. We found that in comparison with the helical CT, conebeam CT is capable of reproducing measurements closer to those obtained from the actual samples. In conclusion, our study indicated that the image-reproduction from a conebeam CT scan was more accurate than that from a helical CT scan. Furthermore, the "high-precision reconstructed 3D model" facilitates reliable visualization of full-sized oral and maxillofacial regions in both helical and conebeam CT scans.

  6. High-resolution ultrasound evaluation of experimental brain abscess evolution: comparison with computed tomography and neuropathology

    SciTech Connect

    Enzmann, D.R.; Britt, R.H.; Lyons, B.; Carroll, B.; Wilson, D.A.; Buxton, J.

    1982-01-01

    Computed tomographic (CT) and high-resolution ultrasound (HRUS) imaging of experimental brain abscess were correlated with neuropathologic findings in nine mongrel dogs. The HRUS scan was more sensitive to different histologic features than the CT scan but both accurately delineated the evolution of the experimental brain abscess. All stages of abscess evolution were characterized by an appearance of an echogenic rim with a hypoechoic center. In the early stages the echogenicity of the abscess was related primarily to marked cellular infiltration while in the late stages extensive collagen deposition correlated closely with the echo pattern. The size of the abscess in the cerebritis stages appeared smaller on the HRUS scan than on the CT scan because the latter modality detected the extensive cerebritis around the developing necrotic center whereas the HRUS scan did not. This discrepancy disappeared in the capsule stages. The HRUS scan provided a more accurate depiction of the neuropathologic characteristics of the necrotic center than did the CT scan. Healing of the abscess, indicated by a decrease in size of the hypoechoic center, was accurately detected by the HRUS scan.

  7. Analysis of chromosome translocation frequency after a single CT scan in adults

    PubMed Central

    Abe, Yu; Miura, Tomisato; Yoshida, Mitsuaki A.; Ujiie, Risa; Kurosu, Yumiko; Kato, Nagisa; Katafuchi, Atsushi; Tsuyama, Naohiro; Kawamura, Fumihiko; Ohba, Takashi; Inamasu, Tomoko; Shishido, Fumio; Noji, Hideyoshi; Ogawa, Kazuei; Yokouchi, Hiroshi; Kanazawa, Kenya; Ishida, Takashi; Muto, Satoshi; Ohsugi, Jun; Suzuki, Hiroyuki; Ishikawa, Tetsuo; Kamiya, Kenji; Sakai, Akira

    2016-01-01

    We recently reported an increase in dicentric chromosome (DIC) formation after a single computed tomography (CT) scan (5.78–60.27 mSv: mean 24.24 mSv) and we recommended analysis of 2000 metaphase cells stained with Giemsa and centromere-FISH for dicentric chromosome assay (DCA) in cases of low-dose radiation exposure. In the present study, we analyzed the frequency of chromosome translocations using stored Carnoy's-fixed lymphocyte specimens from the previous study; these specimens were from 12 patients who were subject to chromosome painting of Chromosomes 1, 2 and 4. Chromosomes 1, 2 and 4 were analyzed in ∼5000 cells, which is equivalent to the whole-genome analysis of almost 2000 cells. The frequency of chromosome translocation was higher than the number of DICs formed, both before and after CT scanning. The frequency of chromosome translocations tended to be higher, but not significantly higher, in patients with a treatment history compared with patients without such a history. However, in contrast to the results for DIC formation, the frequency of translocations detected before and after the CT scan did not differ significantly. Therefore, analysis of chromosome translocation may not be a suitable assay for detecting chromosome aberrations in cases of low-dose radiation exposure from a CT scan. A significant increase in the frequency of chromosome translocations was not likely to be detected due to the high baseline before the CT scan; the high and variable frequency of translocations was probably due to multiple confounding factors in adults. PMID:26874116

  8. Analysis of chromosome translocation frequency after a single CT scan in adults.

    PubMed

    Abe, Yu; Miura, Tomisato; Yoshida, Mitsuaki A; Ujiie, Risa; Kurosu, Yumiko; Kato, Nagisa; Katafuchi, Atsushi; Tsuyama, Naohiro; Kawamura, Fumihiko; Ohba, Takashi; Inamasu, Tomoko; Shishido, Fumio; Noji, Hideyoshi; Ogawa, Kazuei; Yokouchi, Hiroshi; Kanazawa, Kenya; Ishida, Takashi; Muto, Satoshi; Ohsugi, Jun; Suzuki, Hiroyuki; Ishikawa, Tetsuo; Kamiya, Kenji; Sakai, Akira

    2016-06-01

    We recently reported an increase in dicentric chromosome (DIC) formation after a single computed tomography (CT) scan (5.78-60.27 mSv: mean 24.24 mSv) and we recommended analysis of 2000 metaphase cells stained with Giemsa and centromere-FISH for dicentric chromosome assay (DCA) in cases of low-dose radiation exposure. In the present study, we analyzed the frequency of chromosome translocations using stored Carnoy's-fixed lymphocyte specimens from the previous study; these specimens were from 12 patients who were subject to chromosome painting of Chromosomes 1, 2 and 4. Chromosomes 1, 2 and 4 were analyzed in ∼5000 cells, which is equivalent to the whole-genome analysis of almost 2000 cells. The frequency of chromosome translocation was higher than the number of DICs formed, both before and after CT scanning. The frequency of chromosome translocations tended to be higher, but not significantly higher, in patients with a treatment history compared with patients without such a history. However, in contrast to the results for DIC formation, the frequency of translocations detected before and after the CT scan did not differ significantly. Therefore, analysis of chromosome translocation may not be a suitable assay for detecting chromosome aberrations in cases of low-dose radiation exposure from a CT scan. A significant increase in the frequency of chromosome translocations was not likely to be detected due to the high baseline before the CT scan; the high and variable frequency of translocations was probably due to multiple confounding factors in adults.

  9. Self-guided clinical cases for medical students based on postmortem CT scans of cadavers.

    PubMed

    Bohl, Michael; Francois, Webster; Gest, Thomas

    2011-07-01

    In the summer of 2009, we began full body computed tomography (CT) scanning of the pre-embalmed cadavers in the University of Michigan Medical School (UMMS) dissection lab. We theorized that implementing web-based, self-guided clinical cases based on postmortem CT (PMCT) scans would result in increased student appreciation for the clinical relevance of anatomy, increased knowledge of cross-sectional anatomy, and increased ability to identify common pathologies on CT scans. The PMCT scan of each cadaver was produced as a DICOM dataset, and then converted into a Quicktime movie file using Osirix software. Clinical cases were researched and written by the authors, and consist of at least one Quicktime movie of a PMCT scan surrounded by a novel navigation interface. To assess the value of these clinical cases we surveyed medical students at UMMS who are currently using the clinical cases in their coursework. Students felt the clinical cases increased the clinical relevance of anatomy (mean response 7.77/10), increased their confidence finding anatomical structures on CT (7.00/10), and increased their confidence recognizing common pathologies on CT (6.17/10). Students also felt these clinical cases helped them synthesize material from numerous courses into an overall picture of a given disease process (7.01/10). These results support the conclusion that our clinical cases help to show students why the anatomy they are learning is foundational to their other coursework. We would recommend the use of similar clinical cases to any medical school utilizing cadaver dissection as a primary teaching method in anatomy education.

  10. High resolution hypernuclear spectroscopy

    SciTech Connect

    F. Garibaldi

    2005-02-01

    Hypernuclear spectroscopy provides fundamental information for understanding the effective ?-Nucleon interaction. Jefferson Laboratory experiment E94-107 was designed to perform high resolution hypernuclear spectroscopy by electroproduction of strangeness in four 1p-shell nuclei: 12C, 9Be, 16O, and 7Li. The first part of the experiment on 12C and 9Be has been performed in January and April-May 2004 in Hall A at Jefferson Lab. Significant modifications were made to the standard Hall A apparatus for this challenging experiment: two septum magnets and a RICH detector have been added to get reasonable counting rates and excellent particle identification, as required for the experiment. A description of the apparatus and the preliminary analysis results are presented here.

  11. High resolution ultrasonic densitometer

    SciTech Connect

    Dress, W.B.

    1983-01-01

    The velocity of torsional stress pulses in an ultrasonic waveguide of non-circular cross section is affected by the temperature and density of the surrounding medium. Measurement of the transit times of acoustic echoes from the ends of a sensor section are interpreted as level, density, and temperature of the fluid environment surrounding that section. This paper examines methods of making these measurements to obtain high resolution, temperature-corrected absolute and relative density and level determinations of the fluid. Possible applications include on-line process monitoring, a hand-held density probe for battery charge state indication, and precise inventory control for such diverse fluids as uranium salt solutions in accountability storage and gasoline in service station storage tanks.

  12. Achieving routine submillisievert CT scanning: report from the summit on management of radiation dose in CT.

    PubMed

    McCollough, Cynthia H; Chen, Guang Hong; Kalender, Willi; Leng, Shuai; Samei, Ehsan; Taguchi, Katsuyuki; Wang, Ge; Yu, Lifeng; Pettigrew, Roderic I

    2012-08-01

    This Special Report presents the consensus of the Summit on Management of Radiation Dose in Computed Tomography (CT) (held in February 2011), which brought together participants from academia, clinical practice, industry, and regulatory and funding agencies to identify the steps required to reduce the effective dose from routine CT examinations to less than 1 mSv. The most promising technologies and methods discussed at the summit include innovations and developments in x-ray sources; detectors; and image reconstruction, noise reduction, and postprocessing algorithms. Access to raw projection data and standard data sets for algorithm validation and optimization is a clear need, as is the need for new, clinically relevant metrics of image quality and diagnostic performance. Current commercially available techniques such as automatic exposure control, optimization of tube potential, beam-shaping filters, and dynamic z-axis collimators are important, and education to successfully implement these methods routinely is critically needed. Other methods that are just becoming widely available, such as iterative reconstruction, noise reduction, and postprocessing algorithms, will also have an important role. Together, these existing techniques can reduce dose by a factor of two to four. Technical advances that show considerable promise for additional dose reduction but are several years or more from commercial availability include compressed sensing, volume of interest and interior tomography techniques, and photon-counting detectors. This report offers a strategic roadmap for the CT user and research and manufacturer communities toward routinely achieving effective doses of less than 1 mSv, which is well below the average annual dose from naturally occurring sources of radiation.

  13. Variation compensation and analysis on diaphragm curvature analysis for emphysema quantification on whole lung CT scans

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Barr, R. Graham; Yankelevitz, David F.; Henschke, Claudia I.

    2010-03-01

    CT scans allow for the quantitative evaluation of the anatomical bases of emphysema. Recently, a non-density based geometric measurement of lung diagphragm curvature has been proposed as a method for the quantification of emphysema from CT. This work analyzes variability of diaphragm curvature and evaluates the effectiveness of a compensation methodology for the reduction of this variability as compared to emphysema index. Using a dataset of 43 scan-pairs with less than a 100 day time-interval between scans, we find that the diaphragm curvature had a trend towards lower overall variability over emphysema index (95% CI:-9.7 to + 14.7 vs. -15.8 to +12.0), and that the variation of both measures was reduced after compensation. We conclude that the variation of the new measure can be considered comparable to the established measure and the compensation can reduce the apparent variation of quantitative measures successfully.

  14. Computed Tomography (CT) Scanning Facilitates Early Identification of Neonatal Cystic Fibrosis Piglets

    PubMed Central

    Guillon, Antoine; Chevaleyre, Claire; Barc, Celine; Berri, Mustapha; Adriaensen, Hans; Lecompte, François; Villemagne, Thierry; Pezant, Jérémy; Delaunay, Rémi; Moënne-Loccoz, Joseph; Berthon, Patricia; Bähr, Andrea; Wolf, Eckhard; Klymiuk, Nikolai; Attucci, Sylvie; Ramphal, Reuben; Sarradin, Pierre; Buzoni-Gatel, Dominique; Si-Tahar, Mustapha; Caballero, Ignacio

    2015-01-01

    Background Cystic Fibrosis (CF) is the most prevalent autosomal recessive disease in the Caucasian population. A cystic fibrosis transmembrane conductance regulator knockout (CFTR-/-) pig that displays most of the features of the human CF disease has been recently developed. However, CFTR-/- pigs presents a 100% prevalence of meconium ileus that leads to death in the first hours after birth, requiring a rapid diagnosis and surgical intervention to relieve intestinal obstruction. Identification of CFTR-/- piglets is usually performed by PCR genotyping, a procedure that lasts between 4 to 6 h. Here, we aimed to develop a procedure for rapid identification of CFTR-/- piglets that will allow placing them under intensive care soon after birth and immediately proceeding with the surgical correction. Methods and Principal Findings Male and female CFTR+/- pigs were crossed and the progeny was examined by computed tomography (CT) scan to detect the presence of meconium ileus and facilitate a rapid post-natal surgical intervention. Genotype was confirmed by PCR. CT scan presented a 94.4% sensitivity to diagnose CFTR-/- piglets. Diagnosis by CT scan reduced the birth-to-surgery time from a minimum of 10 h down to a minimum of 2.5 h and increased the survival of CFTR-/- piglets to a maximum of 13 days post-surgery as opposed to just 66 h after later surgery. Conclusion CT scan imaging of meconium ileus is an accurate method for rapid identification of CFTR-/- piglets. Early CT detection of meconium ileus may help to extend the lifespan of CFTR-/- piglets and, thus, improve experimental research on CF, still an incurable disease. PMID:26600426

  15. Automatic lung nodule matching for the follow-up in temporal chest CT scans

    NASA Astrophysics Data System (ADS)

    Hong, Helen; Lee, Jeongjin; Shin, Yeong Gil

    2006-03-01

    We propose a fast and robust registration method for matching lung nodules of temporal chest CT scans. Our method is composed of four stages. First, the lungs are extracted from chest CT scans by the automatic segmentation method. Second, the gross translational mismatch is corrected by the optimal cube registration. This initial registration does not require extracting any anatomical landmarks. Third, initial alignment is step by step refined by the iterative surface registration. To evaluate the distance measure between surface boundary points, a 3D distance map is generated by the narrow-band distance propagation, which drives fast and robust convergence to the optimal location. Fourth, nodule correspondences are established by the pairs with the smallest Euclidean distances. The results of pulmonary nodule alignment of twenty patients are reported on a per-center-of mass point basis using the average Euclidean distance (AED) error between corresponding nodules of initial and follow-up scans. The average AED error of twenty patients is significantly reduced to 4.7mm from 30.0mm by our registration. Experimental results show that our registration method aligns the lung nodules much faster than the conventional ones using a distance measure. Accurate and fast result of our method would be more useful for the radiologist's evaluation of pulmonary nodules on chest CT scans.

  16. High Resolution Doppler Imager

    NASA Technical Reports Server (NTRS)

    Hays, Paul B.

    1999-01-01

    This report summarizes the accomplishments of the High Resolution Doppler Imager (HRDI) on UARS spacecraft during the period 4/l/96 - 3/31/99. During this period, HRDI operation, data processing, and data analysis continued, and there was a high level of vitality in the HRDI project. The HRDI has been collecting data from the stratosphere, mesosphere, and lower thermosphere since instrument activation on October 1, 1991. The HRDI team has stressed three areas since operations commenced: 1) operation of the instrument in a manner which maximizes the quality and versatility of the collected data; 2) algorithm development and validation to produce a high-quality data product; and 3) scientific studies, primarily of the dynamics of the middle atmosphere. There has been no significant degradation in the HRDI instrument since operations began nearly 8 years ago. HRDI operations are fairly routine, although we have continued to look for ways to improve the quality of the scientific product, either by improving existing modes, or by designing new ones. The HRDI instrument has been programmed to collect data for new scientific studies, such as measurements of fluorescence from plants, measuring cloud top heights, and lower atmosphere H2O.

  17. Determination of stature from skeletal and skull measurements by CT scan evaluation.

    PubMed

    Giurazza, Francesco; Del Vescovo, Riccardo; Schena, Emiliano; Battisti, Sofia; Cazzato, Roberto Luigi; Grasso, Francesco Rosario; Silvestri, Sergio; Denaro, Vincenzo; Zobel, Bruno Beomonte

    2012-10-10

    The aim of this article is to find a correlation between height and femur/skull measurements through Computed Tomography (CT) scans and derive regression equations for total skeletal height estimation in the Caucasian population. We selected 200 Caucasian patients from March 2010 to July 2011 who had to perform a CT scan for cancer restaging. The mean age is 64.5 years. Both sexes are represented by the same number of persons. Patients have executed a total body CT scan with contrast; once scan accomplished, we measured height through a digital scales. We analyzed CT scans of each patient, obtaining multiplanar reconstruction in sagittal and coronal planes with 1mm of thickness, and we measured 10 diameters of skull and femur. Then we performed a single and a multiple regression analysis considering the three diameters that better correlated with height. The skeletal diameters with the highest correlation coefficients with stature were femur lengths, length of cranial base (Ba-N), and distance from the posterior extremity of the cranial base to the inferior point of the nasal bone (Ba-NB). Although both femur and skull are skeletal segments used for stature estimation, in our sample femur gave stronger correlation with height than skull. h=35.7+1.48·BaN+2.32·BaNB+2.53·FEM and h=3.06·FEM+72.6 are the formulae that provided the most accurate stature assessment using multiple and single regression analysis respectively.

  18. A novel sedimentological method based on CT-scanning: Use for tomographic characterization of the Galicia Interior Basin

    NASA Astrophysics Data System (ADS)

    Mena, Anxo; Francés, Guillermo; Pérez-Arlucea, Marta; Aguiar, Pablo; Barreiro-Vázquez, José Daniel; Iglesias, Alfredo; Barreiro-Lois, Andrés

    2015-05-01

    Non-destructive techniques of core analysis, especially of marine cores, are being broadly employed for sedimentary, paleoceanographic and paleoclimate research. In particular, Computed Tomography scanning (CT-scanning) allows acquisition of 3D and 2D images, according to desired planes, and thus the identification of sedimentary structures, large grains and their distributions as well as direct measurements of material densities. The most significant contribution of this technique is the possibility of getting results before opening the core. In this work CT-scan data obtained for five cores from the Galicia Interior Basin (GIB, NW Peninsula Iberia) are presented and discussed, focussing on (1) methodology of the CT-scan use, (2) tomographic description of sedimentary facies identified in the GIB, (3) treatment of the numeric data obtained with CT-scanning using specific software (anidoC), and (4) comparison of tomographic data with data obtained by conventional methodologies of core analysis. The most singular feature of GIB cores is the presence of Ice Rafted Debris (IRD) deposited during late Pleistocene Heinrich Events (HE), which can be easily recognized using the CT-scan by the presence of high radio-density grains immersed in a low radio-density matrix. Comparison of CT-scan data with analytical sedimentary data and HE proxies performed on the cores validates the CT-scanning method as a powerful tool to improve correlations, identify well-constrained events, and make more accurate basin reconstructions without opening all the cores in an oceanographic study.

  19. CT scan

    MedlinePlus

    ... type of contrast given into a vein contains iodine. If you have an iodine allergy, a type of contrast may cause nausea ... steroids before the test. Your kidneys help remove iodine from the body. You may need to receive ...

  20. TU-F-18A-06: Dual Energy CT Using One Full Scan and a Second Scan with Very Few Projections

    SciTech Connect

    Wang, T; Zhu, L

    2014-06-15

    Purpose: The conventional dual energy CT (DECT) requires two full CT scans at different energy levels, resulting in dose increase as well as imaging errors from patient motion between the two scans. To shorten the scan time of DECT and thus overcome these drawbacks, we propose a new DECT algorithm using one full scan and a second scan with very few projections by preserving structural information. Methods: We first reconstruct a CT image on the full scan using a standard filtered-backprojection (FBP) algorithm. We then use a compressed sensing (CS) based iterative algorithm on the second scan for reconstruction from very few projections. The edges extracted from the first scan are used as weights in the Objectives: function of the CS-based reconstruction to substantially improve the image quality of CT reconstruction. The basis material images are then obtained by an iterative image-domain decomposition method and an electron density map is finally calculated. The proposed method is evaluated on phantoms. Results: On the Catphan 600 phantom, the CT reconstruction mean error using the proposed method on 20 and 5 projections are 4.76% and 5.02%, respectively. Compared with conventional iterative reconstruction, the proposed edge weighting preserves object structures and achieves a better spatial resolution. With basis materials of Iodine and Teflon, our method on 20 projections obtains similar quality of decomposed material images compared with FBP on a full scan and the mean error of electron density in the selected regions of interest is 0.29%. Conclusion: We propose an effective method for reducing projections and therefore scan time in DECT. We show that a full scan plus a 20-projection scan are sufficient to provide DECT images and electron density with similar quality compared with two full scans. Our future work includes more phantom studies to validate the performance of our method.

  1. Laryngeal carcinoma: high-resolution computed tomography and thick anatomic sections

    SciTech Connect

    Reid, M.H.

    1984-06-01

    High-resolution 2-mm thick sequential CT scans of 23 patients with primary laryngeal carcinoma were reviewed to judge the value of CT in early tumor detection and the ability of CT to establish tumor extent reliably, particularly early cartilage invasion. In tumors large enough to be imaged, there were no false negatives. False-positive results for clearly identified tumors were related to the interpretation of tumor on CT where only edema was present at surgery. Both early and gross cartilage invasion were well correlated with surgically resected specimen sections. Early cartilage involvement by tumor can be detected by the development of a fenestrated chrondral margin. Other benign expansive cartilage processes, such as occur with chondromas, have calcified cartilage fragment distributions that are out of proportion to any soft-tissue mass present.

  2. Intracranial myeloid metaplasia: diagnosis by CT and Fe52 scans and treatment by cranial irradiation

    SciTech Connect

    Cornfield, D.B.; Shipkin, P.; Alavi, A.; Becker, J.; Peyster, R.

    1983-11-01

    A patient with longstanding agnogenic myeloid metaplasia developed a progressive dementia. CT scanning demonstrated multiple intracranial masses, and a Fe/sub 52/ bone marrow scan demonstrated erythroid activity within the masses and confirmed the suspicion of extra-medullary hematopoiesis. A potentially hazardous biopsy was avoided, and a course of cranial irradiation was administered, resulting in regression of the masses and clearing of the patient's dementia. Fe/sub 52/ scintigraphy provides a specific and useful diagnostic approach which may eliminate the need for invasive procedures.

  3. Association Between a Quantitative CT Scan Measure of Brain Edema and Outcome After Cardiac Arrest

    PubMed Central

    Metter, Robert B.; Rittenberger, Jon C.; Guyette, Francis X.; Callaway, Clifton W.

    2011-01-01

    Background Cerebral edema is one physical change associated with brain injury and decreased survival after cardiac arrest. Edema appears on computed tomography (CT) scan of the brain as decreased x-ray attenuation by gray matter. This study tested whether the gray matter attenuation to white matter attenuation ratio (GWR) was associated with survival and functional recovery. Methods Subjects were patients hospitalized after cardiac arrest at a single institution between 1/1/2005 and 7/30/2010. Subjects were included if they had non-traumatic cardiac arrest and a non-contrast CT scan within 24 hours after cardiac arrest. Attenuation (Hounsfield Units) was measured in gray matter (caudate nucleus, putamen, thalamus, and cortex) and in white matter (internal capsule, corpus callosum and centrum semiovale). The GWR was calculated for basal ganglia and cerebrum. Outcomes included survival and functional status at hospital discharge. Results For 680 patients, 258 CT scans were available, but 18 were excluded because of hemorrhage (10), intravenous contrast (3) or technical artifact (5), leaving 240 CT scans for analysis. Lower GWR values were associated with lower initial Glasgow Coma Scale motor score. Overall survival was 36%, but decreased with decreasing GWR. The average of basal ganglia and cerebrum GWR provided the best discrimination. Only 2/58 subjects with average GWR<1.20 survived and both were treated with hypothermia. The association of GWR with functional outcome was completely explained by mortality when GWR<1.20. Conclusions Subjects with severe cerebral edema, defined by GWR<1.20, have very low survival with conventional care, including hypothermia. GWR estimates pre-treatment likelihood of survival after cardiac arrest. PMID:21592642

  4. Quantitative characterization of endothelial cell morphologies depending on shear stress in different blood vessels of domestic pigs using a focused ion beam and high resolution scanning electron microscopy (FIB-SEM).

    PubMed

    Pham, Tam Thanh; Maenz, Stefan; Lüdecke, Claudia; Schmerbauch, Christoph; Settmacher, Utz; Jandt, Klaus D; Bossert, Jörg; Zanow, Jürgen

    2015-04-01

    Microstructured surfaces mimicking the endothelial cell (EC) morphology is a new approach to improve the blood compatibility of synthetic vascular grafts. The ECs are capable of changing their shapes depending on different shear conditions. However, the quantitative correlation between EC morphology and shear stress has not yet been investigated statistically. The aim of this study was to quantitatively investigate the morphology of ECs in dependence on the shear stress. Blood flow rates in different types of natural blood vessels (carotid, renal, hepatic and iliac arteries) originated from domestic pigs were first measured in vivo to calculate the shear stresses. The EC morphologies were quantitatively characterized ex vivo by imaging with high resolution scanning electron microscopy (SEM) and cross-sectioning of the cells using a state-of-the-art focused ion beam (FIB). The relationships between EC geometrical parameters and shear stress were statistically analyzed and found to be exponential. ECs under high shear stress conditions had a longer length and narrower width, i.e. a higher aspect ratio, while the cell height was smaller compared to low shear conditions. Based on these results, suitable and valid geometrical parameters of microstructures mimicking EC can be derived for various shear conditions in synthetic vascular grafts to optimize blood compatibility.

  5. Morphometric and high resolution scanning electron microscopy analysis of low-level laser therapy and latex protein (Hevea brasiliensis) administration following a crush injury of the sciatic nerve in rats.

    PubMed

    Dias, Fernando J; Issa, João Paulo M; Coutinho-Netto, Joaquim; Fazan, Valéria P S; Sousa, Luiz Gustavo; Iyomasa, Mamie M; Papa, Paula C; Watanabe, Ii-Sei

    2015-02-15

    This study evaluated the effect of low-level laser therapy (LLLT; 15 J/cm(2)) and a latex protein (F1) on a crush injury of the sciatic (ischiadicus) nerve. Seventy-two rats (male, 250 g) were divided into 6 groups: CG, control; EG, exposed nerve; IG, injured nerve without treatment; LG, injured nerve with LLLT; HG, injured nerve with F1; and LHG, injured nerve with LLLT and F1. After 4 or 8 weeks, the animals were euthanized and samples of the sciatic nerve were collected for morphometric and high-resolution scanning electron microscopy (HRSEM) analysis. After 4 weeks, the morphometry revealed improvements in the treated animals, and the HG appeared to be the most similar to the CG; after 8 weeks, the injured groups showed improvements compared to the previous period, and the results of the treatment groups were more similar to one another. At HRSEM after 4 weeks, the treated groups were similar and showed improvement compared to the IG; after 8 weeks, the LHG and HG had the best results. In conclusion, the treatments resulted in improvement after the nerve injury, and this recovery was time-dependent. In addition, the use of the F1 resulted in the best morphometric and ultrastructural findings.

  6. Spinal uptake mimicking metastasis in SPECT/CT bone scan in a patient with superior vena cava obstruction.

    PubMed

    Rager, Olivier; Nkoulou, René; Garibotto, Valentina; Boudabbous, Sana; Arditi, Daniel

    2013-11-01

    A 46-year-old female patient with a mediastinal neuroendocrine carcinoma complicated by superior vena cava syndrome was referred for a bone metastatic workup. Bone scan with SPECT/CT showed several vertebral fixations without alterations on the unenhanced CT, but a CT scan with injection of contrast media showed vertebral densities matched to the lesions described on the SPECT/CT. This pattern confirmed presence of collateral paths through vertebral veins due to superior vena cava syndrome. Lack of metastases was confirmed by MRI.

  7. 3D segmentation of abdominal aorta from CT-scan and MR images.

    PubMed

    Duquette, Anthony Adam; Jodoin, Pierre-Marc; Bouchot, Olivier; Lalande, Alain

    2012-06-01

    We designed a generic method for segmenting the aneurismal sac of an abdominal aortic aneurysm (AAA) both from multi-slice MR and CT-scan examinations. It is a semi-automatic method requiring little human intervention and based on graph cut theory to segment the lumen interface and the aortic wall of AAAs. Our segmentation method works independently on MRI and CT-scan volumes and has been tested on a 44 patient dataset and 10 synthetic images. Segmentation and maximum diameter estimation were compared to manual tracing from 4 experts. An inter-observer study was performed in order to measure the variability range of a human observer. Based on three metrics (the maximum aortic diameter, the volume overlap and the Hausdorff distance) the variability of the results obtained by our method is shown to be similar to that of a human operator, both for the lumen interface and the aortic wall. As will be shown, the average distance obtained with our method is less than one standard deviation away from each expert, both for healthy subjects and for patients with AAA. Our semi-automatic method provides reliable contours of the abdominal aorta from CT-scan or MRI, allowing rapid and reproducible evaluations of AAA.

  8. Classification of pulmonary emphysema from chest CT scans using integral geometry descriptors

    NASA Astrophysics Data System (ADS)

    van Rikxoort, E. M.; Goldin, J. G.; Galperin-Aizenberg, M.; Brown, M. S.

    2011-03-01

    To gain insight into the underlying pathways of emphysema and monitor the effect of treatment, methods to quantify and phenotype the different types of emphysema from chest CT scans are of crucial importance. Current standard measures rely on density thresholds for individual voxels, which is influenced by inspiration level and does not take into account the spatial relationship between voxels. Measures based on texture analysis do take the interrelation between voxels into account and therefore might be useful for distinguishing different types of emphysema. In this study, we propose to use Minkowski functionals combined with rotation invariant Gaussian features to distinguish between healthy and emphysematous tissue and classify three different types of emphysema. Minkowski functionals characterize binary images in terms of geometry and topology. In 3D, four Minkowski functionals are defined. By varying the threshold and size of neighborhood around a voxel, a set of Minkowski functionals can be defined for each voxel. Ten chest CT scans with 1810 annotated regions were used to train the method. A set of 108 features was calculated for each training sample from which 10 features were selected to be most informative. A linear discriminant classifier was trained to classify each voxel in the lungs into a subtype of emphysema or normal lung. The method was applied to an independent test set of 30 chest CT scans with varying amounts and types of emphysema with 4347 annotated regions of interest. The method is shown to perform well, with an overall accuracy of 95%.

  9. High Resolution Formaldehyde Photochemistry

    NASA Astrophysics Data System (ADS)

    Ernest, C. T.; Bauer, D.; Hynes, A. J.

    2010-12-01

    Formaldehyde (HCHO) is the most abundant and most important organic carbonyl compound in the atmosphere. The sources of formaldehyde are the oxidation of methane, isoprene, acetone, and other volatile organic compounds (VOCs); fossil fuel combustion; and biomass burning. The dominant loss mechanism for formaldehyde is photolysis which occurs via two pathways: (R1) HCHO + hv → HCO + H (R2) HCHO + hv → H2 + CO The first pathway (R1) is referred to as the radical channel, while the second pathway (R2) is referred to as the molecular channel. The products of both pathways play a significant role in atmospheric chemistry. The CO that is produced in the molecular channel undergoes further oxidation to produce CO2. Under atmospheric conditions, the H atom and formyl radical that are produced in the radical channel undergo rapid reactions with O2 to produce the hydroperoxyl radical (HO2) via (R3) and (R4). (R3) HCO + O2 → HO2 + CO (R4) H + O2 → HO2 Thus, for every photon absorbed, the photolysis of formaldehyde can contribute one CO2 molecule to the global greenhouse budget or two HO2 radicals to the tropospheric HOx (OH + HO2) cycle. The HO2 radicals produced during formaldehyde photolysis have also been implicated in the formation of photochemical smog. The HO2 radicals act as radical chain carriers and convert NO to NO2, which ultimately results in the catalytic production of O3. Constraining the yield of HO2 produced via HCHO photolysis is essential for improving tropospheric chemistry models. In this study, both the absorption cross section and the quantum yield of the radical channel (R1) were measured at high resolution over the tropospherically relevant wavelength range 304-330 nm. For the cross section measurements a narrow linewidth Nd:YAG pumped dye laser was used with a multi-pass cell. Partial pressures of HCHO were kept below 0.3 torr. Simultaneous measurement of OH LIF in a flame allowed absolute calibration of the wavelength scale. Pressure

  10. Carotid plaque characterization using CT and MRI scans for synergistic image analysis

    NASA Astrophysics Data System (ADS)

    Getzin, Matthew; Xu, Yiqin; Rao, Arhant; Madi, Saaussan; Bahadur, Ali; Lennartz, Michelle R.; Wang, Ge

    2014-09-01

    Noninvasive determination of plaque vulnerability has been a holy grail of medical imaging. Despite advances in tomographic technologies , there is currently no effective way to identify vulnerable atherosclerotic plaques with high sensitivity and specificity. Computed tomography (CT) and magnetic resonance imaging (MRI) are widely used, but neither provides sufficient information of plaque properties. Thus, we are motivated to combine CT and MRI imaging to determine if the composite information can better reflect the histological determination of plaque vulnerability. Two human endarterectomy specimens (1 symptomatic carotid and 1 stable femoral) were imaged using Scanco Medical Viva CT40 and Bruker Pharmascan 16cm 7T Horizontal MRI / MRS systems. μCT scans were done at 55 kVp and tube current of 70 mA. Samples underwent RARE-VTR and MSME pulse sequences to measure T1, T2 values, and proton density. The specimens were processed for histology and scored for vulnerability using the American Heart Association criteria. Single modality-based analyses were performed through segmentation of key imaging biomarkers (i.e. calcification and lumen), image registration, measurement of fibrous capsule, and multi-component T1 and T2 decay modeling. Feature differences were analyzed between the unstable and stable controls, symptomatic carotid and femoral plaque, respectively. By building on the techniques used in this study, synergistic CT+MRI analysis may provide a promising solution for plaque characterization in vivo.

  11. Metabolite localization by atmospheric pressure high-resolution scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging in whole-body sections and individual organs of the rove beetle Paederus riparius.

    PubMed

    Bhandari, Dhaka Ram; Schott, Matthias; Römpp, Andreas; Vilcinskas, Andreas; Spengler, Bernhard

    2015-03-01

    Mass spectrometry imaging provides for non-targeted, label-free chemical imaging. In this study, atmospheric pressure high-resolution scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging (AP-SMALDI MSI) was used for the first time to describe the chemical distribution of the defensive compounds pederin, pseudopederin, and pederon in tissue sections (16 μm thick) of the rove beetle Paederus riparius. The whole-insect tissue section was scanned with a 20-μm step size. Mass resolution of the orbital trapping mass spectrometer was set to 100,000 at m/z 200. Additionally, organ-specific compounds were identified for brain, nerve cord, eggs, gut, ovaries, and malpighian tubules. To confirm the distribution of the specific compounds, individual organs from the insect were dissected, and MSI experiments were performed on the dissected organs. Three ganglia of the nerve cord, with a dimension of 250-500 μm, were measured with 10-μm spatial resolution. High-quality m/z images, based on high spatial resolution and high mass accuracy were generated. These features helped to assign mass spectral peaks with high confidence. Mass accuracy of the imaging experiments was <3 ppm root mean square error, and mapping of different compound classes from a single experiment was possible. This approach improved the understanding of the biochemistry of P. riparius. Concentration differences and distributions of pederin and its analogues could be visualized in the whole-insect section. Without any labeling, we assigned key lipids for specific organs to describe their location in the body and to identify morphological structures with a specificity higher than with staining or immunohistology methods.

  12. WE-EF-207-07: Dual Energy CT with One Full Scan and a Second Sparse-View Scan Using Structure Preserving Iterative Reconstruction (SPIR)

    SciTech Connect

    Wang, T; Zhu, L

    2015-06-15

    Purpose: Conventional dual energy CT (DECT) reconstructs CT and basis material images from two full-size projection datasets with different energy spectra. To relax the data requirement, we propose an iterative DECT reconstruction algorithm using one full scan and a second sparse-view scan by utilizing redundant structural information of the same object acquired at two different energies. Methods: We first reconstruct a full-scan CT image using filtered-backprojection (FBP) algorithm. The material similarities of each pixel with other pixels are calculated by an exponential function about pixel value differences. We assume that the material similarities of pixels remains in the second CT scan, although pixel values may vary. An iterative method is designed to reconstruct the second CT image from reduced projections. Under the data fidelity constraint, the algorithm minimizes the L2 norm of the difference between pixel value and its estimation, which is the average of other pixel values weighted by their similarities. The proposed algorithm, referred to as structure preserving iterative reconstruction (SPIR), is evaluated on physical phantoms. Results: On the Catphan600 phantom, SPIR-based DECT method with a second 10-view scan reduces the noise standard deviation of a full-scan FBP CT reconstruction by a factor of 4 with well-maintained spatial resolution, while iterative reconstruction using total-variation regularization (TVR) degrades the spatial resolution at the same noise level. The proposed method achieves less than 1% measurement difference on electron density map compared with the conventional two-full-scan DECT. On an anthropomorphic pediatric phantom, our method successfully reconstructs the complicated vertebra structures and decomposes bone and soft tissue. Conclusion: We develop an effective method to reduce the number of views and therefore data acquisition in DECT. We show that SPIR-based DECT using one full scan and a second 10-view scan can

  13. High resolution time interval meter

    DOEpatents

    Martin, A.D.

    1986-05-09

    Method and apparatus are provided for measuring the time interval between two events to a higher resolution than reliability available from conventional circuits and component. An internal clock pulse is provided at a frequency compatible with conventional component operating frequencies for reliable operation. Lumped constant delay circuits are provided for generating outputs at delay intervals corresponding to the desired high resolution. An initiation START pulse is input to generate first high resolution data. A termination STOP pulse is input to generate second high resolution data. Internal counters count at the low frequency internal clock pulse rate between the START and STOP pulses. The first and second high resolution data are logically combined to directly provide high resolution data to one counter and correct the count in the low resolution counter to obtain a high resolution time interval measurement.

  14. Refractory Epilepsy-MRI, EEG and CT scan, a Correlative Clinical Study

    PubMed Central

    Nikodijevic, Dijana; Baneva–Dolnenec, Natalija; Petrovska-Cvetkovska, Dragana; Caparoska, Daniela

    2016-01-01

    OBJECTIVES: Refractory epilepsies (RE), as well as, the surgically correctable syndromes, are of great interest, since they affect the very young population of children and adolescents. The early diagnosis and treatment are very important in preventing the psychosocial disability. Therefore MRI and EEG are highly sensitive methods in the diagnosis and localization of epileptogenic focus, but also in pre-surgical evaluation of these patients. The aim of our study is to correlate the imaging findings of EEG, MRI and CT scan in refractory symptomatic epilepsies, and to determine their specificity in detecting the epileptogenic focus. METHODS: The study was prospective with duration of over two years, open-labelled, and involved a group of 37 patients that had been evaluated and diagnosed as refractory epilepsy patients. In the evaluation the type and frequency of seizures were considered, together with the etiologic factors and their association, and finally the risk for developing refractory epilepsy was weighted. EEG and MRI findings and CT scan results were evaluated for their specificity and sensitivity in detecting the epileptogenic focus, and the correlation between them was analyzed. RESULTS: Regarding the type of seizures considered in our study, the patients with PCS (partial complex seizures) dominated, as opposed to those with generalized seizures (GS) (D=1.178, p < 0.05). Positive MRI findings were registered in 28 patients (75.7%). Most of them were patients with hippocampal sclerosis, 12 (42.8%), and also they were found to have the highest risk of developing refractory epilepsy (RE) (Odds ratio = 5.7), and the highest association between the etiologic factor and refractory epilepsy (p < 0.01). In detecting the epileptogenic focus, a significant difference was found (p < 0.01) between MRI and CT scan findings, especially in patients with hippocampal sclerosis and cerebral malformations. There was a strong correlation between the MRI findings and the

  15. CT Enterography

    MedlinePlus

    ... obstructions and Crohn’s disease. CT scanning is fast, painless, noninvasive and accurate. CT enterography is better able ... the benefits vs. risks? Benefits CT scanning is painless, noninvasive and accurate. A major advantage of CT ...

  16. Hierarchical pictorial structures for simultaneously localizing multiple organs in volumetric pre-scan CT

    NASA Astrophysics Data System (ADS)

    Montillo, Albert; Song, Qi; Das, Bipul; Yin, Zhye

    2015-03-01

    Parsing volumetric computed tomography (CT) into 10 or more salient organs simultaneously is a challenging task with many applications such as personalized scan planning and dose reporting. In the clinic, pre-scan data can come in the form of very low dose volumes acquired just prior to the primary scan or from an existing primary scan. To localize organs in such diverse data, we propose a new learning based framework that we call hierarchical pictorial structures (HPS) which builds multiple levels of models in a tree-like hierarchy that mirrors the natural decomposition of human anatomy from gross structures to finer structures. Each node of our hierarchical model learns (1) the local appearance and shape of structures, and (2) a generative global model that learns probabilistic, structural arrangement. Our main contribution is twofold. First we embed the pictorial structures approach in a hierarchical framework which reduces test time image interpretation and allows for the incorporation of additional geometric constraints that robustly guide model fitting in the presence of noise. Second we guide our HPS framework with the probabilistic cost maps extracted using random decision forests using volumetric 3D HOG features which makes our model fast to train and fast to apply to novel test data and posses a high degree of invariance to shape distortion and imaging artifacts. All steps require approximate 3 mins to compute and all organs are located with suitably high accuracy for our clinical applications such as personalized scan planning for radiation dose reduction. We assess our method using a database of volumetric CT scans from 81 subjects with widely varying age and pathology and with simulated ultra-low dose cadaver pre-scan data.

  17. National Survey of Radiation Dose and Image Quality in Adult CT Head Scans in Taiwan

    PubMed Central

    Lin, Chung-Jung; Mok, Greta S. P.; Tsai, Mang-Fen; Tsai, Wei-Ta; Yang, Bang-Hung; Tu, Chun-Yuan; Wu, Tung-Hsin

    2015-01-01

    Introduction The purpose of the present study was to evaluate the influence of different variables on radiation dose and image quality based on a national database. Materials and Methods Taiwan’s Ministry of Health and Welfare requested all radiology departments to complete a questionnaire for each of their CT scanners. Information gathered included all scanning parameters for CT head scans. For the present analysis, CT machines were divided into three subgroups: single slice CT (Group A); multi-detector CT (MDCT) with 2-64 slices (Group B); and MDCT with more than 64 slices (Group C). Correlations between computed tomography dose index (CTDI) and signal-to-noise ratio (SNR) with cumulated tube rotation number (CTW(n)) and cumulated tube rotation time (CTW(s)), and sub group analyses of CTDI and SNR across the three groups were performed. Results CTDI values demonstrated a weak correlation (r = 0.33) with CTW(n) in Group A. SNR values demonstrated a weak negative correlation (r = -0.46) with CTW(n) in Group C. MDCT with higher slice numbers used more tube potential resulting in higher effective doses. There were both significantly lower CTDI and SNR values in helical mode than in axial mode in Group B, but not Group C. Conclusion CTW(n) and CTW(s) did not influence radiation output. Helical mode is more often used in MDCT and results in both lower CTDI and SNR compared to axial mode in MDCT with less than 64 slices. PMID:26125549

  18. A measurement-based generalized source model for Monte Carlo dose simulations of CT scans

    NASA Astrophysics Data System (ADS)

    Ming, Xin; Feng, Yuanming; Liu, Ransheng; Yang, Chengwen; Zhou, Li; Zhai, Hezheng; Deng, Jun

    2017-03-01

    The goal of this study is to develop a generalized source model for accurate Monte Carlo dose simulations of CT scans based solely on the measurement data without a priori knowledge of scanner specifications. The proposed generalized source model consists of an extended circular source located at x-ray target level with its energy spectrum, source distribution and fluence distribution derived from a set of measurement data conveniently available in the clinic. Specifically, the central axis percent depth dose (PDD) curves measured in water and the cone output factors measured in air were used to derive the energy spectrum and the source distribution respectively with a Levenberg–Marquardt algorithm. The in-air film measurement of fan-beam dose profiles at fixed gantry was back-projected to generate the fluence distribution of the source model. A benchmarked Monte Carlo user code was used to simulate the dose distributions in water with the developed source model as beam input. The feasibility and accuracy of the proposed source model was tested on a GE LightSpeed and a Philips Brilliance Big Bore multi-detector CT (MDCT) scanners available in our clinic. In general, the Monte Carlo simulations of the PDDs in water and dose profiles along lateral and longitudinal directions agreed with the measurements within 4%/1 mm for both CT scanners. The absolute dose comparison using two CTDI phantoms (16 cm and 32 cm in diameters) indicated a better than 5% agreement between the Monte Carlo-simulated and the ion chamber-measured doses at a variety of locations for the two scanners. Overall, this study demonstrated that a generalized source model can be constructed based only on a set of measurement data and used for accurate Monte Carlo dose simulations of patients’ CT scans, which would facilitate patient-specific CT organ dose estimation and cancer risk management in the diagnostic and therapeutic radiology.

  19. Pulmonary nodule registration in serial CT scans based on rib anatomy and nodule template matching

    PubMed Central

    Shi, Jiazheng; Sahiner, Berkman; Chan, Heang-Ping; Hadjiiski, Lubomir; Zhou, Chuan; Cascade, Philip N.; Bogot, Naama; Kazerooni, Ella A.; Wu, Yi-Ta; Wei, Jun

    2009-01-01

    An automated method is being developed in order to identify corresponding nodules in serial thoracic CT scans for interval change analysis. The method uses the rib centerlines as the reference for initial nodule registration. A spatially adaptive rib segmentation method first locates the regions where the ribs join the spine, which define the starting locations for rib tracking. Each rib is tracked and locally segmented by expectation-maximization. The ribs are automatically labeled, and the centerlines are estimated using skeletonization. For a given nodule in the source scan, the closest three ribs are identified. A three-dimensional (3D) rigid affine transformation guided by simplex optimization aligns the centerlines of each of the three rib pairs in the source and target CT volumes. Automatically defined control points along the centerlines of the three ribs in the source scan and the registered ribs in the target scan are used to guide an initial registration using a second 3D rigid affine transformation. A search volume of interest (VOI) is then located in the target scan. Nodule candidate locations within the search VOI are identified as regions with high Hessian responses. The initial registration is refined by searching for the maximum cross-correlation between the nodule template from the source scan and the candidate locations. The method was evaluated on 48 CT scans from 20 patients. Experienced radiologists identified 101 pairs of corresponding nodules. Three metrics were used for performance evaluation. The first metric was the Euclidean distance between the nodule centers identified by the radiologist and the computer registration, the second metric was a volume overlap measure between the nodule VOIs identified by the radiologist and the computer registration, and the third metric was the hit rate, which measures the fraction of nodules whose centroid computed by the computer registration in the target scan falls within the VOI identified by the

  20. A new CT collimator for producing two simultaneous overlapping slices from one scan. [for biomedical applications

    NASA Technical Reports Server (NTRS)

    Kwoh, Y. S.; Glenn, W. V., Jr.; Reed, I. S.; Truong, T. K.

    1981-01-01

    A new CT collimator is developed which is capable of producing two simultaneous successive overlapping images from a single scan. The collimator represents a modification of the standard EMI 5005 collimator achieved by alternately masking one end or portions of both ends of the X-ray detectors at a 13-mm beamwidth so that a set of 540 filtered projections is obtained for each scan which can be separated into two sets of interleaved projections corresponding to views 3 mm apart. Tests have demonstrated that the quality of the images produced from these two projections almost equals the quality of those produced by the standard collimator from two separate scans. The new collimator may thus be used to achieve a speed improvement in the generation of overlapping sections as well as a reduction in X-ray dosage.

  1. A Survey of Pediatric CT Protocols and Radiation Doses in South Korean Hospitals to Optimize the Radiation Dose for Pediatric CT Scanning.

    PubMed

    Hwang, Jae-Yeon; Do, Kyung-Hyun; Yang, Dong Hyun; Cho, Young Ah; Yoon, Hye-Kyung; Lee, Jin Seong; Koo, Hyun Jung

    2015-12-01

    Children are at greater risk of radiation exposure than adults because the rapidly dividing cells of children tend to be more radiosensitive and they have a longer expected life time in which to develop potential radiation injury. Some studies have surveyed computed tomography (CT) radiation doses and several studies have established diagnostic reference levels according to patient age or body size; however, no survey of CT radiation doses with a large number of patients has yet been carried out in South Korea. The aim of the present study was to investigate the radiation dose in pediatric CT examinations performed throughout South Korea. From 512 CT (222 brain CT, 105 chest CT, and 185 abdominopelvic CT) scans that were referred to our tertiary hospital, a dose report sheet was available for retrospective analysis of CT scan protocols and dose, including the volumetric CT dose index (CTDIvol), dose-length product (DLP), effective dose, and size-specific dose estimates (SSDE). At 55.2%, multiphase CT was the most frequently performed protocol for abdominopelvic CT. Tube current modulation was applied most often in abdominopelvic CT and chest CT, accounting for 70.1% and 62.7%, respectively. Regarding the CT dose, the interquartile ranges of the CTDIvol were 11.1 to 22.5 (newborns), 16.6 to 39.1 (≤1 year), 14.6 to 41.7 (2-5 years), 23.5 to 44.1 (6-10 years), and 31.4 to 55.3 (≤15 years) for brain CT; 1.3 to 5.7 (≤1 year), 3.9 to 6.8 (2-5 years), 3.9 to 9.3 (6-10 years), and 7.7 to 13.8 (≤15 years) for chest CT; and 4.0 to 7.5 (≤1 year), 4.2 to 8.9 (2-5 years), 5.7 to 12.4 (6-10 years), and 7.6 to 16.6 (≤15 years) for abdominopelvic CT. The SSDE and CTDIvol were well correlated for patients <5 years old, whereas the CTDIvol was lower in patients ≥6 years old. Our study describes the various parameters and dosimetry metrics of pediatric CT in South Korea. The CTDIvol, DLP, and effective dose were generally lower than in German and UK surveys, except in

  2. CT Scan Does Not Differentiate Patients with Hepatopulmonary Syndrome from Other Patients with Liver Disease

    PubMed Central

    Prabhudesai, Vikramaditya; Castel, Helene; Gupta, Samir

    2016-01-01

    Background Hepatopulmonary syndrome (HPS) is defined by liver dysfunction, intrapulmonary vascular dilatations, and impaired oxygenation. The gold standard for detection of intrapulmonary vascular dilatations in HPS is contrast echocardiography. However, two small studies have suggested that patients with HPS have larger segmental pulmonary arterial diameters than both normal subjects and normoxemic subjects with cirrhosis, when measured by CT. We sought to compare CT imaging-based pulmonary vasodilatation in patients with HPS, patients with liver dysfunction without HPS, and matching controls on CT imaging. Methods We performed a retrospective cohort study at two quaternary care Canadian HPS centers. We analyzed CT thorax scans in 23 patients with HPS, 29 patients with liver dysfunction without HPS, and 52 gender- and age-matched controls. We measured the artery-bronchus ratios (ABRs) in upper and lower lung zones, calculated the “delta ABR” by subtracting the upper from the lower ABR, compared these measurements between groups, and correlated them with clinically relevant parameters (partial pressure of arterial oxygen, alveolar-arterial oxygen gradient, macroaggregated albumin shunt fraction, and diffusion capacity). We repeated measurements in patients with post-transplant CTs. Results Patients had significantly larger lower zone ABRs and delta ABRs than controls (1.20 +/- 0.19 versus 0.98 +/- 0.10, p<0.01; and 0.12 +/- 0.17 versus -0.06 +/- 0.10, p<0.01, respectively). However, there were no significant differences between liver disease patients with and without HPS, nor any significant correlations between CT measurements and clinically relevant parameters. There were no significant changes in ABRs after liver transplantation (14 patients). Conclusions Basilar segmental artery-bronchus ratios are larger in patients with liver disease than in normal controls, but this vasodilatation is no more severe in patients with HPS. CT does not distinguish patients

  3. A Fast Experimental Scanner for Proton CT: Technical Performance and First Experience with Phantom Scans

    PubMed Central

    Johnson, Robert P.; Bashkirov, Vladimir; DeWitt, Langley; Giacometti, Valentina; Hurley, Robert F.; Piersimoni, Pierluigi; Plautz, Tia E.; Sadrozinski, Hartmut F.-W.; Schubert, Keith; Schulte, Reinhard; Schultze, Blake; Zatserklyaniy, Andriy

    2016-01-01

    We report on the design, fabrication, and first tests of a tomographic scanner developed for proton computed tomography (pCT) of head-sized objects. After extensive preclinical testing, pCT is intended to be employed in support of proton therapy treatment planning and pre-treatment verification in patients undergoing particle-beam therapy. The scanner consists of two silicon-strip telescopes that track individual protons before and after the phantom, and a novel multistage scintillation detector that measures a combination of the residual energy and range of the proton, from which we derive the water equivalent path length (WEPL) of the protons in the scanned object. The set of WEPL values and the associated paths of protons passing through the object over a 360° angular scan are processed by an iterative, parallelizable reconstruction algorithm that runs on modern GP-GPU hardware. In order to assess the performance of the scanner, we have performed tests with 200 MeV protons from the synchrotron of the Loma Linda University Medical Center and the IBA cyclotron of the Northwestern Medicine Chicago Proton Center. Our first objective was calibration of the instrument, including tracker channel maps and alignment as well as the WEPL calibration. Then we performed the first CT scans on a series of phantoms. The very high sustained rate of data acquisition, exceeding one million protons per second, allowed a full 360° scan to be completed in less than 10 minutes, and reconstruction of a CATPHAN 404 phantom verified accurate reconstruction of the proton relative stopping power in a variety of materials. PMID:27127307

  4. Location registration and recognition (LRR) for serial analysis of nodules in lung CT scans.

    PubMed

    Sofka, Michal; Stewart, Charles V

    2010-06-01

    In the clinical workflow for lung cancer management, the comparison of nodules between CT scans from subsequent visits by a patient is necessary for timely classification of pulmonary nodules into benign and malignant and for analyzing nodule growth and response to therapy. The algorithm described in this paper takes (a) two temporally-separated CT scans, I(1) and I(2), and (b) a series of nodule locations in I(1), and for each location it produces an affine transformation that maps the locations and their immediate neighborhoods from I(1) to I(2). It does this without deformable registration and without initialization by global affine registration. Requiring the nodule locations to be specified in only one volume provides the clinician more flexibility in investigating the condition of the lung. The algorithm uses a combination of feature extraction, indexing, refinement, and decision processes. Together, these processes essentially "recognize" the neighborhoods. We show on lung CT scans that our technique works at near interactive speed and that the median alignment error of 134 nodules is 1.70mm compared to the error 2.14mm of the Diffeomorphic Demons algorithm, and to the error 3.57mm of the global nodule registration with local refinement. We demonstrate on the alignment of 250 nodules, that the algorithm is robust to changes caused by cancer progression and differences in breathing states, scanning procedures, and patient positioning. Our algorithm may be used both for diagnosis and treatment monitoring of lung cancer. Because of the generic design of the algorithm, it might also be used in other applications that require fast and accurate mapping of regions.

  5. Automatic classication of pulmonary function in COPD patients using trachea analysis in chest CT scans

    NASA Astrophysics Data System (ADS)

    van Rikxoort, E. M.; de Jong, P. A.; Mets, O. M.; van Ginneken, B.

    2012-03-01

    Chronic Obstructive Pulmonary Disease (COPD) is a chronic lung disease that is characterized by airflow limitation. COPD is clinically diagnosed and monitored using pulmonary function testing (PFT), which measures global inspiration and expiration capabilities of patients and is time-consuming and labor-intensive. It is becoming standard practice to obtain paired inspiration-expiration CT scans of COPD patients. Predicting the PFT results from the CT scans would alleviate the need for PFT testing. It is hypothesized that the change of the trachea during breathing might be an indicator of tracheomalacia in COPD patients and correlate with COPD severity. In this paper, we propose to automatically measure morphological changes in the trachea from paired inspiration and expiration CT scans and investigate the influence on COPD GOLD stage classification. The trachea is automatically segmented and the trachea shape is encoded using the lengths of rays cast from the center of gravity of the trachea. These features are used in a classifier, combined with emphysema scoring, to attempt to classify subjects into their COPD stage. A database of 187 subjects, well distributed over the COPD GOLD stages 0 through 4 was used for this study. The data was randomly divided into training and test set. Using the training scans, a nearest mean classifier was trained to classify the subjects into their correct GOLD stage using either emphysema score, tracheal shape features, or a combination. Combining the proposed trachea shape features with emphysema score, the classification performance into GOLD stages improved with 11% to 51%. In addition, an 80% accuracy was achieved in distinguishing healthy subjects from COPD patients.

  6. A Fast Experimental Scanner for Proton CT: Technical Performance and First Experience with Phantom Scans.

    PubMed

    Johnson, Robert P; Bashkirov, Vladimir; DeWitt, Langley; Giacometti, Valentina; Hurley, Robert F; Piersimoni, Pierluigi; Plautz, Tia E; Sadrozinski, Hartmut F-W; Schubert, Keith; Schulte, Reinhard; Schultze, Blake; Zatserklyaniy, Andriy

    2016-02-01

    We report on the design, fabrication, and first tests of a tomographic scanner developed for proton computed tomography (pCT) of head-sized objects. After extensive preclinical testing, pCT is intended to be employed in support of proton therapy treatment planning and pre-treatment verification in patients undergoing particle-beam therapy. The scanner consists of two silicon-strip telescopes that track individual protons before and after the phantom, and a novel multistage scintillation detector that measures a combination of the residual energy and range of the proton, from which we derive the water equivalent path length (WEPL) of the protons in the scanned object. The set of WEPL values and the associated paths of protons passing through the object over a 360° angular scan are processed by an iterative, parallelizable reconstruction algorithm that runs on modern GP-GPU hardware. In order to assess the performance of the scanner, we have performed tests with 200 MeV protons from the synchrotron of the Loma Linda University Medical Center and the IBA cyclotron of the Northwestern Medicine Chicago Proton Center. Our first objective was calibration of the instrument, including tracker channel maps and alignment as well as the WEPL calibration. Then we performed the first CT scans on a series of phantoms. The very high sustained rate of data acquisition, exceeding one million protons per second, allowed a full 360° scan to be completed in less than 10 minutes, and reconstruction of a CATPHAN 404 phantom verified accurate reconstruction of the proton relative stopping power in a variety of materials.

  7. In vitro dose measurements in a human cadaver with abdomen/pelvis CT scans

    SciTech Connect

    Zhang, Da; Padole, Atul; Li, Xinhua; Singh, Sarabjeet; Khawaja, Ranish Deedar Ali; Lira, Diego; Shi, Jim Q.; Otrakji, Alexi; Kalra, Mannudeep K.; Liu, Bob; Liu, Tianyu; Xu, X. George

    2014-09-15

    Purpose: To present a study of radiation dose measurements with a human cadaver scanned on a clinical CT scanner. Methods: Multiple point dose measurements were obtained with high-accuracy Thimble ionization chambers placed inside the stomach, liver, paravertebral gutter, ascending colon, left kidney, and urinary bladder of a human cadaver (183 cm in height and 67.5 kg in weight) whose abdomen/pelvis region was scanned repeatedly with a multidetector row CT. The flat energy response and precision of the dosimeters were verified, and the slight differences in each dosimeter's response were evaluated and corrected to attain high accuracy. In addition, skin doses were measured for radiosensitive organs outside the scanned region with OSL dosimeters: the right eye, thyroid, both nipples, and the right testicle. Three scan protocols were used, which shared most scan parameters but had different kVp and mA settings: 120-kVp automA, 120-kVp 300 mA, and 100-kVp 300 mA. For each protocol three repeated scans were performed. Results: The tube starting angle (TSA) was found to randomly vary around two major conditions, which caused large fluctuations in the repeated point dose measurements: for the 120-kVp 300 mA protocol this angle changed from approximately 110° to 290°, and caused 8% − 25% difference in the point dose measured at the stomach, liver, colon, and urinary bladder. When the fluctuations of the TSA were small (within 5°), the maximum coefficient of variance was approximately 3.3%. The soft tissue absorbed doses averaged from four locations near the center of the scanned region were 27.2 ± 3.3 and 16.5 ± 2.7 mGy for the 120 and 100-kVp fixed-mA scans, respectively. These values were consistent with the corresponding size specific dose estimates within 4%. The comparison of the per-100-mAs tissue doses from the three protocols revealed that: (1) dose levels at nonsuperficial locations in the TCM scans could not be accurately deduced by simply scaling the

  8. In vitro dose measurements in a human cadaver with abdomen/pelvis CT scans

    PubMed Central

    Zhang, Da; Padole, Atul; Li, Xinhua; Singh, Sarabjeet; Khawaja, Ranish Deedar Ali; Lira, Diego; Liu, Tianyu; Shi, Jim Q.; Otrakji, Alexi; Kalra, Mannudeep K.; Xu, X. George; Liu, Bob

    2014-01-01

    Purpose: To present a study of radiation dose measurements with a human cadaver scanned on a clinical CT scanner. Methods: Multiple point dose measurements were obtained with high-accuracy Thimble ionization chambers placed inside the stomach, liver, paravertebral gutter, ascending colon, left kidney, and urinary bladder of a human cadaver (183 cm in height and 67.5 kg in weight) whose abdomen/pelvis region was scanned repeatedly with a multidetector row CT. The flat energy response and precision of the dosimeters were verified, and the slight differences in each dosimeter's response were evaluated and corrected to attain high accuracy. In addition, skin doses were measured for radiosensitive organs outside the scanned region with OSL dosimeters: the right eye, thyroid, both nipples, and the right testicle. Three scan protocols were used, which shared most scan parameters but had different kVp and mA settings: 120-kVp automA, 120-kVp 300 mA, and 100-kVp 300 mA. For each protocol three repeated scans were performed. Results: The tube starting angle (TSA) was found to randomly vary around two major conditions, which caused large fluctuations in the repeated point dose measurements: for the 120-kVp 300 mA protocol this angle changed from approximately 110° to 290°, and caused 8% − 25% difference in the point dose measured at the stomach, liver, colon, and urinary bladder. When the fluctuations of the TSA were small (within 5°), the maximum coefficient of variance was approximately 3.3%. The soft tissue absorbed doses averaged from four locations near the center of the scanned region were 27.2 ± 3.3 and 16.5 ± 2.7 mGy for the 120 and 100-kVp fixed-mA scans, respectively. These values were consistent with the corresponding size specific dose estimates within 4%. The comparison of the per-100-mAs tissue doses from the three protocols revealed that: (1) dose levels at nonsuperficial locations in the TCM scans could not be accurately deduced by simply scaling the

  9. Cervical CT scan-guided epidural blood patches for spontaneous intracranial hypotension.

    PubMed

    Maingard, Julian; Giles, Lauren; Marriott, Mark; Phal, Pramit M

    2015-12-01

    We describe two patients with spontaneous intracranial hypotension (SIH), presenting with postural headache due to C1-C2 cerebrospinal fluid (CSF) leak. Both patients were refractory to lumbar epidural blood patching (EBP), and subsequently underwent successful CT scan-guided cervical EBP. SIH affects approximately 1 in 50,000 patients, with females more frequently affected. Its associated features are variable, and as such, misdiagnosis is common. Therefore, imaging plays an important role in the diagnostic workup of SIH and can include MRI of the brain and spine, CT myelogram, and radionuclide cisternography. In patients with an established diagnosis and confirmed CSF leak, symptoms will usually resolve with conservative management. However, in a select subgroup of patients, the symptoms are refractory to medical management and require more invasive therapies. In patients with cervical leaks, EBP in the cervical region is an effective management approach, either in close proximity to, or directly targeting a dural defect. CT scan-guided cervical EBP is an effective treatment approach in refractory SIH, and should be considered in those patients who are refractory to conservative management.

  10. Growth of an Ultrathin Zirconia Film on Pt3Zr Examined by High-Resolution X-ray Photoelectron Spectroscopy, Temperature-Programmed Desorption, Scanning Tunneling Microscopy, and Density Functional Theory

    PubMed Central

    2014-01-01

    Ultrathin (∼3 Å) zirconium oxide films were grown on a single-crystalline Pt3Zr(0001) substrate by oxidation in 1 × 10–7 mbar of O2 at 673 K, followed by annealing at temperatures up to 1023 K. The ZrO2 films are intended to serve as model supports for reforming catalysts and fuel cell anodes. The atomic and electronic structure and composition of the ZrO2 films were determined by synchrotron-based high-resolution X-ray photoelectron spectroscopy (HR-XPS) (including depth profiling), low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), and density functional theory (DFT) calculations. Oxidation mainly leads to ultrathin trilayer (O–Zr–O) films on the alloy; only a small area fraction (10–15%) is covered by ZrO2 clusters (thickness ∼0.5–10 nm). The amount of clusters decreases with increasing annealing temperature. Temperature-programmed desorption (TPD) of CO was utilized to confirm complete coverage of the Pt3Zr substrate by ZrO2, that is, formation of a closed oxide overlayer. Experiments and DFT calculations show that the core level shifts of Zr in the trilayer ZrO2 films are between those of metallic Zr and thick (bulklike) ZrO2. Therefore, the assignment of such XPS core level shifts to substoichiometric ZrOx is not necessarily correct, because these XPS signals may equally well arise from ultrathin ZrO2 films or metal/ZrO2 interfaces. Furthermore, our results indicate that the common approach of calculating core level shifts by DFT including final-state effects should be taken with care for thicker insulating films, clusters, and bulk insulators. PMID:25688293

  11. Growth of an Ultrathin Zirconia Film on Pt3Zr Examined by High-Resolution X-ray Photoelectron Spectroscopy, Temperature-Programmed Desorption, Scanning Tunneling Microscopy, and Density Functional Theory.

    PubMed

    Li, Hao; Choi, Joong-Il Jake; Mayr-Schmölzer, Wernfried; Weilach, Christian; Rameshan, Christoph; Mittendorfer, Florian; Redinger, Josef; Schmid, Michael; Rupprechter, Günther

    2015-02-05

    Ultrathin (∼3 Å) zirconium oxide films were grown on a single-crystalline Pt3Zr(0001) substrate by oxidation in 1 × 10(-7) mbar of O2 at 673 K, followed by annealing at temperatures up to 1023 K. The ZrO2 films are intended to serve as model supports for reforming catalysts and fuel cell anodes. The atomic and electronic structure and composition of the ZrO2 films were determined by synchrotron-based high-resolution X-ray photoelectron spectroscopy (HR-XPS) (including depth profiling), low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), and density functional theory (DFT) calculations. Oxidation mainly leads to ultrathin trilayer (O-Zr-O) films on the alloy; only a small area fraction (10-15%) is covered by ZrO2 clusters (thickness ∼0.5-10 nm). The amount of clusters decreases with increasing annealing temperature. Temperature-programmed desorption (TPD) of CO was utilized to confirm complete coverage of the Pt3Zr substrate by ZrO2, that is, formation of a closed oxide overlayer. Experiments and DFT calculations show that the core level shifts of Zr in the trilayer ZrO2 films are between those of metallic Zr and thick (bulklike) ZrO2. Therefore, the assignment of such XPS core level shifts to substoichiometric ZrO x is not necessarily correct, because these XPS signals may equally well arise from ultrathin ZrO2 films or metal/ZrO2 interfaces. Furthermore, our results indicate that the common approach of calculating core level shifts by DFT including final-state effects should be taken with care for thicker insulating films, clusters, and bulk insulators.

  12. High-resolution 3D structural and optical analyses of hybrid or composite materials by means of scanning probe microscopy combined with the ultramicrotome technique: an example of application to engineering of liquid crystals doped with fluorescent quantum dots

    NASA Astrophysics Data System (ADS)

    Mochalov, Konstantin E.; Efimov, Anton E.; Bobrovsky, Alexey Yu.; Agapov, Igor I.; Chistyakov, Anton A.; Oleinikov, Vladimir A.; Nabiev, Igor

    2013-05-01

    Combination of nanometer-scale 3D structural analysis with optical characterization of the same material is a challenging task. Its results may be important for nanophotonics, materials science, and quality control. We have developed a new technique for complementary high-resolution structural and optical characterization followed by optical spectroscopic and microscopic measurements accompanied by reconstruction of the 3D structure in the same area of the sample. The 3D structure is reconstructed by combination of ultramicrotomic and SPM techniques allowing the study of the 3D distribution of implanted nanoparticles and their effect on the matrix structure. The combination of scanning probe nanotomography (SPN) and optical microspectroscopy makes it possible to direct estimate how the 3D structural characteristics of materials affect their macroscopic optical properties. The technique developed has been applied to the engineering of materials made from cholesteric liquid crystals and fluorescent quantum dots (QDs). These materials permit photochemical patterning and image recording through the changes in the dissymmetry factor of circular polarization of QD emission. The differences in the polarisation images and morphological characteristics of the liquid crystal matrix have proved to be correlated with the arrangement of the areas of homogeneous distribution and nonhomogeneous clustering of QDs. The reconstruction of the 3D structure of the liquid crystal matrix in the areas of homogeneous QD distribution has shown that QDs embedded into cholesteric liquid crystal matrices do not perturb their periodic planar texture. The combined optical/SPM/ultramicrotome technique will be indispensable for evaluating the effects of inorganic nanoparticles on the organisation of organic and liquid crystal matrices, biomedical materials, cells, and tissues.

  13. TH-C-18A-11: Investigating the Minimum Scan Parameters Required to Generate Free-Breathing Fast-Helical CT Scans Without Motion-Artifacts

    SciTech Connect

    Thomas, D; Neylon, J; Dou, T; Jani, S; Lamb, J; Low, D; Tan, J

    2014-06-15

    Purpose: A recently proposed 4D-CT protocol uses deformable registration of free-breathing fast-helical CT scans to generate a breathing motion model. In order to allow accurate registration, free-breathing images are required to be free of doubling-artifacts, which arise when tissue motion is greater than scan speed. This work identifies the minimum scanner parameters required to successfully generate free-breathing fast-helical scans without doubling-artifacts. Methods: 10 patients were imaged under free breathing conditions 25 times in alternating directions with a 64-slice CT scanner using a low dose fast helical protocol. A high temporal resolution (0.1s) 4D-CT was generated using a patient specific motion model and patient breathing waveforms, and used as the input for a scanner simulation. Forward projections were calculated using helical cone-beam geometry (800 projections per rotation) and a GPU accelerated reconstruction algorithm was implemented. Various CT scanner detector widths and rotation times were simulated, and verified using a motion phantom. Doubling-artifacts were quantified in patient images using structural similarity maps to determine the similarity between axial slices. Results: Increasing amounts of doubling-artifacts were observed with increasing rotation times > 0.2s for 16×1mm slice scan geometry. No significant increase in doubling artifacts was observed for 64×1mm slice scan geometry up to 1.0s rotation time although blurring artifacts were observed >0.6s. Using a 16×1mm slice scan geometry, a rotation time of less than 0.3s (53mm/s scan speed) would be required to produce images of similar quality to a 64×1mm slice scan geometry. Conclusion: The current generation of 16 slice CT scanners, which are present in most Radiation Oncology departments, are not capable of generating free-breathing sorting-artifact-free images in the majority of patients. The next generation of CT scanners should be capable of at least 53mm/s scan speed

  14. A case of pulmonary artery intimal sarcoma diagnosed with multislice CT scan with 3D reconstruction.

    PubMed

    Choi, Eui-Young; Yoon, Young-Won; Kwon, Hyuck Moon; Kim, Dongsoo; Park, Byung-Eun; Hong, Yoo-Sun; Koo, Ja-Seung; Kim, Tae-Hoon; Kim, Hyun-Seung

    2004-06-30

    Pulmonary artery intimal sarcoma is a rare highly lethal disease, with additional retrograde extension to pulmonic valve and right ventricle being an extremely rare condition. It is frequently mistaken for pulmonary thromboembolism. We report a case of 64-year-old woman with progressive dyspnea initially suspected and treated for pulmonary thromboembolism. Her helical chest CT scan with 3 dimensional (3D) reconstruction combined with echocardiography revealed a compacting main pulmonary artery mass extending to the right ventricular outflow tract and the right pulmonary artery. After excision of the mass, the patient's condition improved dramatically, and the pathologic findings revealed pulmonary intimal sarcoma. This report emphasizes that helical chest CT with 3D reconstruction can be an important tool to differentiate the characteristics of pulmonary artery lesions, such as intimal sarcoma and thromboembolism.

  15. Implant planning and placement using optical scanning and cone beam CT technology.

    PubMed

    van der Zel, Jef M

    2008-08-01

    There is a growing interest in minimally invasive implant therapy as a standard prosthodontic treatment, providing complete restoration of occlusal function. A new treatment method (CADDIMA), which combines both computerized tomographic (CT) and optical laser-scan data for planning and design of surgical guides, implant abutments, and prosthetic devices, is described. Imaging using a "NewTom 3G" cone beam CT scanner and a modified laser triangulation scanner "D200c" is discussed, as are impression and surgical guide fabrication, which allow for flapless, precise implant placement and an accurate provisional prosthesis. The new approach gives the operator full control over the design of the implant prosthesis for planning of proper occlusal relations and shows promise for further evaluation.

  16. Cerebral blood flow and brain atrophy correlated by xenon contrast CT scanning

    SciTech Connect

    Kitagawa, Y.; Meyer, J.S.; Tanahashi, N.; Rogers, R.L.; Tachibana, H.; Kandula, P.; Dowell, R.E.; Mortel, K.F.

    1985-11-01

    Correlations between cerebral blood flow (CBF) measured during stable xenon contrast CT scanning and standard CT indices of brain atrophy were investigated in the patients with senile dementia of Alzheimer type, multi-infarct dementia and idiopathic Parkinson's disease. Compared to age-matched normal volunteers, significant correlations were found in patients with idiopathic Parkinson's disease between cortical and subcortical gray matter blood flow and brain atrophy estimated by the ventricular body ratio, and mild to moderate brain atrophy were correlated with stepwise CBF reductions. However, in patients with senile dementia of Alzheimer type and multi-infarct dementia, brain atrophy was not associated with stepwise CBF reductions. Overall correlations between brain atrophy and reduced CBF were weak. Mild degrees of brain atrophy are not always associated with reduced CBF.

  17. A multicenter, randomized controlled trial of immediate total-body CT scanning in trauma patients (REACT-2)

    PubMed Central

    2012-01-01

    Background Computed tomography (CT) scanning has become essential in the early diagnostic phase of trauma care because of its high diagnostic accuracy. The introduction of multi-slice CT scanners and infrastructural improvements made total-body CT scanning technically feasible and its usage is currently becoming common practice in several trauma centers. However, literature provides limited evidence whether immediate total-body CT leads to better clinical outcome then conventional radiographic imaging supplemented with selective CT scanning in trauma patients. The aim of the REACT-2 trial is to determine the value of immediate total-body CT scanning in trauma patients. Methods/design The REACT-2 trial is an international, multicenter randomized clinical trial. All participating trauma centers have a multi-slice CT scanner located in the trauma room or at the Emergency Department (ED). All adult, non-pregnant, severely injured trauma patients according to predefined criteria will be included. Patients in whom direct scanning will hamper necessary cardiopulmonary resuscitation or who require an immediate operation because of imminent death (both as judged by the trauma team leader) are excluded. Randomization will be computer assisted. The intervention group will receive a contrast-enhanced total-body CT scan (head to pelvis) during the primary survey. The control group will be evaluated according to local conventional trauma imaging protocols (based on ATLS guidelines) supplemented with selective CT scanning. Primary outcome will be in-hospital mortality. Secondary outcomes are differences in mortality and morbidity during the first year post trauma, several trauma work-up time intervals, radiation exposure, general health and quality of life at 6 and 12 months post trauma and cost-effectiveness. Discussion The REACT-2 trial is a multicenter randomized clinical trial that will provide evidence on the value of immediate total-body CT scanning during the primary

  18. Construction and analysis of a head CT-scan database for craniofacial reconstruction.

    PubMed

    Tilotta, Françoise; Richard, Frédéric; Glaunès, Joan; Berar, Maxime; Gey, Servane; Verdeille, Stéphane; Rozenholc, Yves; Gaudy, J F

    2009-10-30

    This paper is devoted to the construction of a complete database which is intended to improve the implementation and the evaluation of automated facial reconstruction. This growing database is currently composed of 85 head CT-scans of healthy European subjects aged 20-65 years old. It also includes the triangulated surfaces of the face and the skull of each subject. These surfaces are extracted from CT-scans using an original combination of image-processing techniques which are presented in the paper. Besides, a set of 39 referenced anatomical skull landmarks were located manually on each scan. Using the geometrical information provided by triangulated surfaces, we compute facial soft-tissue depths at each known landmark positions. We report the average thickness values at each landmark and compare our measures to those of the traditional charts of [J. Rhine, C.E. Moore, Facial Tissue Thickness of American Caucasoïds, Maxwell Museum of Anthropology, Albuquerque, New Mexico, 1982] and of several recent in vivo studies [M.H. Manhein, G.A. Listi, R.E. Barsley, et al., In vivo facial tissue depth measurements for children and adults, Journal of Forensic Sciences 45 (1) (2000) 48-60; S. De Greef, P. Claes, D. Vandermeulen, et al., Large-scale in vivo Caucasian facial soft tissue thickness database for craniofacial reconstruction, Forensic Science International 159S (2006) S126-S146; R. Helmer, Schödelidentifizierung durch elektronische bildmischung, Kriminalistik Verlag GmbH, Heidelberg, 1984].

  19. Semi-automated method to measure pneumonia severity in mice through computed tomography (CT) scan analysis

    NASA Astrophysics Data System (ADS)

    Johri, Ansh; Schimel, Daniel; Noguchi, Audrey; Hsu, Lewis L.

    2010-03-01

    Imaging is a crucial clinical tool for diagnosis and assessment of pneumonia, but quantitative methods are lacking. Micro-computed tomography (micro CT), designed for lab animals, provides opportunities for non-invasive radiographic endpoints for pneumonia studies. HYPOTHESIS: In vivo micro CT scans of mice with early bacterial pneumonia can be scored quantitatively by semiautomated imaging methods, with good reproducibility and correlation with bacterial dose inoculated, pneumonia survival outcome, and radiologists' scores. METHODS: Healthy mice had intratracheal inoculation of E. coli bacteria (n=24) or saline control (n=11). In vivo micro CT scans were performed 24 hours later with microCAT II (Siemens). Two independent radiologists scored the extent of airspace abnormality, on a scale of 0 (normal) to 24 (completely abnormal). Using the Amira 5.2 software (Mercury Computer Systems), a histogram distribution of voxel counts between the Hounsfield range of -510 to 0 was created and analyzed, and a segmentation procedure was devised. RESULTS: A t-test was performed to determine whether there was a significant difference in the mean voxel value of each mouse in the three experimental groups: Saline Survivors, Pneumonia Survivors, and Pneumonia Non-survivors. It was found that the voxel count method was able to statistically tell apart the Saline Survivors from the Pneumonia Survivors, the Saline Survivors from the Pneumonia Non-survivors, but not the Pneumonia Survivors vs. Pneumonia Non-survivors. The segmentation method, however, was successfully able to distinguish the two Pneumonia groups. CONCLUSION: We have pilot-tested an evaluation of early pneumonia in mice using micro CT and a semi-automated method for lung segmentation and scoring system. Statistical analysis indicates that the system is reliable and merits further evaluation.

  20. Optic nerve sheath diameter measurements by CT scan in ventriculoperitoneal shunt obstruction.

    PubMed

    Zaidi, Syed Javed H; Yamamoto, Loren G

    2014-08-01

    The objective of the study was to determine differences in optic nerve sheath diameter (ONSD) measurements taken from computed tomography (CT) scans of patients with ventriculoperitoneal shunt (VPS) obstruction versus controls. Inpatients 0-15 years with confirmed VPS obstruction requiring neurosurgical intervention were identified using ICD9 codes. ONSDs, orbit, cranium, and foramen magnum sizes were measured on their pre-surgical CT. Controls included cases at times when their VPS was not obstructed and age and gender matched patients with a CT scan done in the emergency room for head trauma (normal CT findings). Paired T-tests were used for both case-control comparisons. In order to compare the optic nerve sheath size more accurately, the ONSD width was divided by the width of the orbit and by the foramen magnum (antero-posterior) length. Twenty patients were identified with 25 events of VPS obstruction. The right ONSD (RON) was chosen to study. RON/orbit width and RON/foramen magnum diameter for the VPS obstruction versus self-controls, were 0.22 and 0.22, compared to 0.19 and 0.18, respectively, for the non-obstructed self-controls (P = .044 and P = .008, respectively). The same measurements for the VPS obstruction versus age and gender matched controls were 0.22 and 0.21 for the VPS obstruction cases, respectively, compared to 0.17 and 0.16, respectively for the age and gender matched controls (P < .001 and P < .001, respectively). This data confirms that the optic nerve diameter increases during a VPS obstruction. ONSD measurements by ultrasound could add to the evaluation for VPS obstruction.

  1. Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

    2014-09-01

    With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

  2. Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation.

    PubMed

    Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

    2014-09-21

    With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

  3. 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.

  4. Quantitative assessment of emphysema from whole lung CT scans: comparison with visual grading

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Apanosovich, Tatiyana V.; Wang, Jianwei; Yankelevitz, David F.; Henschke, Claudia I.

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema and for visual assessment by radiologists of the extent present in the lungs. Several measures have been introduced for the quantification of the extent of disease directly from CT data in order to add to the qualitative assessments made by radiologists. In this paper we compare emphysema index, mean lung density, histogram percentiles, and the fractal dimension to visual grade in order to evaluate the predictability of radiologist visual scoring of emphysema from low-dose CT scans through quantitative scores, in order to determine which measures can be useful as surrogates for visual assessment. All measures were computed over nine divisions of the lung field (whole lung, individual lungs, and upper/middle/lower thirds of each lung) for each of 148 low-dose, whole lung scans. In addition, a visual grade of each section was also given by an expert radiologist. One-way ANOVA and multinomial logistic regression were used to determine the ability of the measures to predict visual grade from quantitative score. We found that all measures were able to distinguish between normal and severe grades (p<0.01), and between mild/moderate and all other grades (p<0.05). However, no measure was able to distinguish between mild and moderate cases. Approximately 65% prediction accuracy was achieved from using quantitative score to predict visual grade, with 73% if mild and moderate cases are considered as a single class.

  5. [Paraclinical diagnostic procedures in micro- and macrotraumas of the shoulder. Indications for echography and CT scanning].

    PubMed

    Annaert, J M; Peetrons, P; Famaey, J P

    1990-03-01

    A careful physical examination is absolutely necessary as a first evaluation of all disorders of the shoulder before performing any imaging technique that must be chosen according to the kind of suspected pathology. The best indications for performing an arthroscanner are the intraarticular lesions such as injuries of the glenoid labrum and of the articular capsule. Echography is the most performing technique for bicipital and rotator cuff tendinitis. CT scan helps to understand the antero-internal retro-coracoidal impingment syndromes as well as uninterpretable bone lesions at standard radiography. Arthrography and arthro-pneumo-tomography are very useful for presurgical assessment of rotator cuff tears.

  6. Microcomputer-based image processing system for CT/MRI scans: II. Expert system

    NASA Astrophysics Data System (ADS)

    Kwok, John C. K.; Yu, Peter K. N.; Cheng, Andrew Y. S.; Ho, Wai-Chin

    1991-06-01

    A microcomputer-based image processing system is used to digitize and process serial sections of CT/MRI scan and reconstruct three-dimensional images of brain structures and brain lesions. The images grabbed also serve as templates and different vital regions with different risk values are also traced out for 3D reconstruction. A knowledge-based system employing rule-based programming has been built to help identifying brain lesions and to help planning trajectory for operations. The volumes of the lesions are also automatically determined. Such system is very useful for medical skills archival, tumor size monitoring, survival and outcome forecasting, and consistent neurosurgical planning.

  7. Effective one step-iterative fiducial marker-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    We previously introduced three different fiducial marker-based correction methods (2D projection shifting, 2D projection warping, and 3D image warping) for patients' involuntary motion in the lower body during weight-bearing Carm CT scanning. The 3D warping method performed better than 2D methods since it could more accurately take into account the lower body motion in 3D. However, as the 3D warping method applies different rotational and translational movement to the reconstructed image for each projection frame, distance-related weightings were slightly twisted and thus result in overlaying background noise over the entire image. In order to suppress background noise and artifacts (e.g. metallic marker-caused streaks), the 3D warping method has been improved by incorporating bilateral filtering and a Landwebertype iteration in one step. A series of projection images of five healthy volunteers standing at various flexion angles were acquired using a C-arm cone-beam CT system with a flat panel. A horizontal scanning trajectory of the C-arm was calibrated to generate projection matrices. Using the projection matrices, the static reference marker coordinates in 3D were estimated and used for the improved 3D warping method. The improved 3D warping method effectively reduced background noise down below the noise level of 2D methods and also eliminated metal-generated streaks. Thus, improved visibility of soft tissue structures (e.g. fat and muscle) was achieved while maintaining sharp edges at bone-tissue interfaces. Any high resolution weight-bearing cone-beam CT system can apply this method for motion compensation.

  8. Preliminary evaluation of optical CT scanning versus MRI for nPAG gel dosimetry: The Ghent experience

    NASA Astrophysics Data System (ADS)

    Vandecasteele, Jan; DeDeene, Yves

    2009-05-01

    The aim of this study was to evaluate fast laser-scanning optical CT versus MRI for an nPAG gel dosimeter in terms of accuracy and precision. Three small cylindrical volumetric gel phantoms were fabricated and irradiated with photon beams. The gel dosimeters were scanned with an MR scanner and an in house developed laser scanning optical CT scanner. A comparison between MRI and optical CT scanning was performed based on the reconstructed images. Preliminary results show a fair correspondence in the MRI acquired and optical CT acquired dose maps. Still, ringing artifacts contaminate the reconstructed optical CT images. These may be related to sub-pixel misalignments between the blank projection and the acquired transmission projection of the gel phantom. Another artifact may be caused by refraction near the edges of the field. Further optimisation of our optical CT scanner is required to obtain the same accuracy as with MRI. To make a comparison between the two imaging modalities in terms of precision, the intrinsic dose precision on readout (IPD) was calculated which is independent of spatial resolution and acquisition time. It is shown that optical CT has a better intrinsic dose precision.

  9. Morphometry of the primate bony labyrinth: a new method based on high-resolution computed tomography.

    PubMed Central

    Spoor, F; Zonneveld, F

    1995-01-01

    A method is described for taking accurate measurements of the bony labyrinth of humans and other primates using high-resolution computed tomography (CT). The measurements comprise 8 dimensions, 14 orientations and 2 indices of the labyrinth, as well as 7 orientations of related structures of the petrous pyramid. Comparison of the measurements taken from CT scans with those taken from subsequently made casts and cryosections demonstrates that the method is sufficiently accurate to permit the morphometric analysis of labyrinthine size and shape. Since the CT method is nondestructive, fast and easy to perform, it is applicable to large samples and to rare or precious anthropological specimens. Images Fig. 1 Fig. 2 Fig. 4 PMID:7649826

  10. Computerized lung nodule detection on screening CT scans: performance on juxta-pleural and internal nodules

    NASA Astrophysics Data System (ADS)

    Sahiner, Berkman; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Zhou, Chuan; Wei, Jun

    2006-03-01

    We are developing a computer-aided detection (CAD) system for lung nodules in thoracic CT volumes. Our CAD system includes an adaptive 3D pre-screening algorithm to segment suspicious objects, and a false-positive (FP) reduction stage to classify the segmented objects as true nodules or normal lung structures. We found that the effectiveness of the FP reduction stage was limited by the different characteristics of the objects in the internal and the juxta-pleural (JP) regions. The purpose of this study was to evaluate object characteristics in the internal and JP regions of a lung CT scan, and to develop different FP reduction classifiers for JP and internal objects. Our FP reduction technique utilized shape, grayscale, and gradient features, as well as the scores of a newly-developed neural network trained on the eigenvalues of the Hessian matrix in a volume of interest containing the suspicious object. We designed an algorithm to automatically label the objects as internal or JP. Based on a training set of 75 CT scans containing internal and JP nodules, two FP classifiers were trained separately for objects in the two types of lung regions. The system performance was evaluated on an independent test set of 27 low dose screening scans. An experienced chest radiologist identified 64 solid nodules (mean diameter: 5.3 mm, range: 3.0-12.9 mm) on the test cases, of which 33 were internal and 31 were JP. Our adaptive 3D prescreening algorithm detected 28 internal and 29 JP nodules. At 80% sensitivity, the average number of FPs was 3.9 and 9.7 in the internal and JP regions per scan, respectively. In comparison, a classifier designed to work on both types of nodules had an average of 29.4 FPs per scan at the same sensitivity. Our results indicate that it is more effective to use two different classifiers for JP and internal nodules because of their different characteristics. FPs in the JP region were more difficult to distinguish from true nodules. Further investigation

  11. Extracting information from previous full-dose CT scan for knowledge-based Bayesian reconstruction of current low-dose CT images

    PubMed Central

    Zhang, Hao; Han, Hao; Liang, Zhengrong; Hu, Yifan; Liu, Yan; Moore, William; Ma, Jianhua; Lu, Hongbing

    2015-01-01

    Markov random field (MRF) model has been widely employed in edge-preserving regional noise smoothing penalty to reconstruct piece-wise smooth images in the presence of noise, such as in low-dose computed tomography (LdCT). While it preserves edge sharpness, its regional smoothing may sacrifice tissue image textures, which have been recognized as useful imaging biomarkers, and thus it may compromise clinical tasks such as differentiating malignant vs. benign lesions, e.g., lung nodules or colon polyps. This study aims to shift the edge-preserving regional noise smoothing paradigm to texture-preserving framework for LdCT image reconstruction while retaining the advantage of MRF’s neighborhood system on edge preservation. Specifically, we adapted the MRF model to incorporate the image textures of muscle, fat, bone, lung, etc. from previous full-dose CT (FdCT) scan as a priori knowledge for texture-preserving Bayesian reconstruction of current LdCT images. To show the feasibility of the proposed reconstruction framework, experiments using clinical patient scans were conducted. The experimental outcomes showed a dramatic gain by the a priori knowledge for LdCT image reconstruction using the commonly-used Haralick texture measures. Thus, it is conjectured that the texture-preserving LdCT reconstruction has advantages over the edge-preserving regional smoothing paradigm for texture-specific clinical applications. PMID:26561284

  12. Adapted Treatment Guided by Interim PET-CT Scan in Advanced Hodgkin’s Lymphoma

    PubMed Central

    Johnson, Peter; Federico, Massimo; Kirkwood, Amy; Fosså, Alexander; Berkahn, Leanne; Carella, Angelo; d’Amore, Francesco; Enblad, Gunilla; Franceschetto, Antonella; Fulham, Michael; Luminari, Stefano; O’Doherty, Michael; Patrick, Pip; Roberts, Thomas; Sidra, Gamal; Stevens, Lindsey; Smith, Paul; Trotman, Judith; Viney, Zaid; Radford, John; Barrington, Sally

    2016-01-01

    Background We tested interim positron-emission tomography–computed tomography (PET-CT) as a measure of early response to chemotherapy in order to guide treatment for patients with advanced Hodgkin’s lymphoma. Methods Patients with newly diagnosed advanced classic Hodgkin’s lymphoma underwent a baseline PET-CT scan, received two cycles of ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) chemotherapy, and then underwent an interim PET-CT scan. Images were centrally reviewed with the use of a 5-point scale for PET findings. Patients with negative PET findings after two cycles were randomly assigned to continue ABVD (ABVD group) or omit bleomycin (AVD group) in cycles 3 through 6. Those with positive PET findings after two cycles received BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone). Radiotherapy was not recommended for patients with negative findings on interim scans. The primary outcome was the difference in the 3-year progression-free survival rate between randomized groups, a noninferiority comparison to exclude a difference of 5 or more percentage points. Results A total of 1214 patients were registered; 937 of the 1119 patients (83.7%) who underwent an interim PET-CT scan according to protocol had negative findings. With a median follow-up of 41 months, the 3-year progression-free survival rate and overall survival rate in the ABVD group were 85.7% (95% confidence interval [CI], 82.1 to 88.6) and 97.2% (95% CI, 95.1 to 98.4), respectively; the corresponding rates in the AVD group were 84.4% (95% CI, 80.7 to 87.5) and 97.6% (95% CI, 95.6 to 98.7). The absolute difference in the 3-year progression-free survival rate (ABVD minus AVD) was 1.6 percentage points (95% CI, −3.2 to 5.3). Respiratory adverse events were more severe in the ABVD group than in the AVD group. BEACOPP was given to the 172 patients with positive findings on the interim scan, and 74.4% had negative findings on a third

  13. Three-dimensional dosimetry of small megavoltage radiation fields using radiochromic gels and optical CT scanning.

    PubMed

    Babic, Steven; McNiven, Andrea; Battista, Jerry; Jordan, Kevin

    2009-04-21

    The dosimetry of small fields as used in stereotactic radiotherapy, radiosurgery and intensity-modulated radiation therapy can be challenging and inaccurate due to partial volume averaging effects and possible disruption of charged particle equilibrium. Consequently, there exists a need for an integrating, tissue equivalent dosimeter with high spatial resolution to avoid perturbing the radiation beam and artificially broadening the measured beam penumbra. In this work, radiochromic ferrous xylenol-orange (FX) and leuco crystal violet (LCV) micelle gels were used to measure relative dose factors (RDFs), percent depth dose profiles and relative lateral beam profiles of 6 MV x-ray pencil beams of diameter 28.1, 9.8 and 4.9 mm. The pencil beams were produced via stereotactic collimators mounted on a Varian 2100 EX linear accelerator. The gels were read using optical computed tomography (CT). Data sets were compared quantitatively with dosimetric measurements made with radiographic (Kodak EDR2) and radiochromic (GAFChromic EBT) film, respectively. Using a fast cone-beam optical CT scanner (Vista), corrections for diffusion in the FX gel data yielded RDFs that were comparable to those obtained by minimally diffusing LCV gels. Considering EBT film-measured RDF data as reference, cone-beam CT-scanned LCV gel data, corrected for scattered stray light, were found to be in agreement within 0.5% and -0.6% for the 9.8 and 4.9 mm diameter fields, respectively. The validity of the scattered stray light correction was confirmed by general agreement with RDF data obtained from the same LCV gel read out with a laser CT scanner that is less prone to the acceptance of scattered stray light. Percent depth dose profiles and lateral beam profiles were found to agree within experimental error for the FX gel (corrected for diffusion), LCV gel (corrected for scattered stray light), and EBT and EDR2 films. The results from this study reveal that a three-dimensional dosimetry method utilizing

  14. Sensitivity calibration procedures in optical-CT scanning of BANG®3 polymer gel dosimeters

    PubMed Central

    Xu, Y.; Wuu, Cheng-Shie; Maryanski, Marek J.

    2010-01-01

    The dose response of the BANG®3 polymer gel dosimeter (MGS Research Inc., Madison, CT) was studied using the OCTOPUS™ laser CT scanner (MGS Research Inc., Madison, CT). Six 17 cm diameter and 12 cm high Barex cylinders, and 18 small glass vials were used to house the gel. The gel phantoms were irradiated with 6 and 10 MV photons, as well as 12 and 16 MeV electrons using a Varian Clinac 2100EX. Three calibration methods were used to obtain the dose response curves: (a) Optical density measurements on the 18 glass vials irradiated with graded doses from 0 to 4 Gy using 6 or 10 MV large field irradiations; (b) optical-CT scanning of Barex cylinders irradiated with graded doses (0.5, 1, 1.5, and 2 Gy) from four adjacent 4×4 cm2 photon fields or 6×6 cm2 electron fields; and (c) percent depth dose (PDD) comparison of optical-CT scans with ion chamber measurements for 6×6 cm2, 12 and 16 MeV electron fields. The dose response of the BANG®3 gel was found to be linear and energy independent within the uncertainties of the experimental methods (about 3%). The slopes of the linearly fitted dose response curves (dose sensitivities) from the four field irradiations (0.0752±3%, 0.0756±3%, 0.0767±3%, and 0.0759±3% cm−1 Gy−1) and the PDD matching methods (0.0768±3% and 0.0761±3% cm−1 Gy−1) agree within 2.2%, indicating a good reproducibility of the gel dose response within phantoms of the same geometry. The dose sensitivities from the glass vial approach are different from those of the cylindrical Barex phantoms by more than 30%, owing probably to the difference in temperature inside the two types of phantoms during gel formation and irradiation, and possible oxygen contamination of the glass vial walls. The dose response curve obtained from the PDD matching approach with 16 MeV electron field was used to calibrate the gel phantom irradiated with the 12 MeV, 6×6 cm2 electron field. Three-dimensional dose distributions from the gel measurement and the Eclipse

  15. Evaluation of image and dose according to I-dose technique when performing a CT scan

    NASA Astrophysics Data System (ADS)

    Ryu, S. W.; Lee, H. K.; Cho, J. H.

    2015-06-01

    In this study, we applied the iterative reconstruction technique to improve image quality (I-dose) and evaluated its usability by analyzing the quality of the resulting image and evaluating the dose. To perform the scans, we fixed the uniform module (CTP 486's section) 4 on the table of the computed tomography (CT) device with the American association of physicists in medicine (AAPM) phantom and located it in the center where the X-rays could be generated by using a razor beam. Then, we set up the conditions of 120 kilovoltage peak (kVp), 150 milliampere second (mAs), collimation 4 × 0.625 mm, and a standard YA (Y-Sharp) filter. Next, we formed two groups: Group A in which I-dose was not applied and Group B in which I-dose was applied. According to the rod in the middle, after fixing the location of (A) at 12 o'clock, (B) at 3 o'clock, (C) at 6 o'clock, and (D) at 9 o'clock to evaluate the image quality, the CT number was measured and the noise level was analyzed. Using the AAPM phantom with doses of 50, 100, 200, 250, and 300 mAs by 80, 100, and 120 kVp, a dose analysis was performed. After scanning, the CT numbers and noise level were measured 20 times as a function of the I-dose levels (1-7). After applying I-dose at 6, 9, 12, and 3 o'clock, when a higher I-dose was applied, a lower noise level was measured. As a result, it was found that when applying I-dose to the AAPM phantom, the higher the level of I-dose, the lower the level of noise. When applying I-dose, the dose can be reduced by 60%. When I-dose is applied when taking CT scans in a clinical study, it is possible to lower the dose and lower the noise level.

  16. A reappraisal of adult thoracic and abdominal surface anatomy via CT scan in Chinese population.

    PubMed

    Shen, Xin-Hua; Su, Bai-Yan; Liu, Jing-Juan; Zhang, Gu-Muyang; Xue, Hua-Dan; Jin, Zheng-Yu; Mirjalili, S Ali; Ma, Chao

    2016-03-01

    Accurate surface anatomy is essential for safe clinical practice. There are numerous inconsistencies in clinically important surface markings among and within contemporary anatomical reference texts. The aim of this study was to investigate key thoracic and abdominal surface anatomy landmarks in living Chinese adults using computed tomography (CT). A total of 100 thoracic and 100 abdominal CT scans were examined. Our results indicated that the following key surface landmarks differed from current commonly-accepted descriptions: the positions of the tracheal bifurcation, azygos vein termination, and pulmonary trunk bifurcation (all below the plane of the sternal angle at vertebral level T5-T6 in most individuals); the superior vena cava formation and junction with the right atrium (most often behind the 1st and 4th intercostal spaces, respectively); and the level at which the inferior vena cava and esophagus traverse the diaphragm (T10 and T11, respectively). The renal arteries were most commonly at L1; the midpoint of the renal hila was most frequently at L2; the 11th rib was posterior to the left kidney in only 29% of scans; and the spleen was most frequently located between the 10th and 12th ribs. A number of significant sex- and age-related differences were noted. The Chinese population was also compared with western populations on the basis of published reports. Reappraisal of surface anatomy using modern imaging tools in vivo will provide both quantitative and qualitative evidence to facilitate the clinical application of these key surface landmarks.

  17. Fully automatic anatomical, pathological, and functional segmentation from CT scans for hepatic surgery

    NASA Astrophysics Data System (ADS)

    Soler, Luc; Delingette, Herve; Malandain, Gregoire; Montagnat, Johan; Ayache, Nicholas; Clement, Jean-Marie; Koehl, Christophe; Dourthe, Olivier; Mutter, Didier; Marescaux, Jacques

    2000-06-01

    To facilitate hepatic surgical planning, we have developed a new system for the automatic 3D delineation of anatomical and pathological hepatic structures from a spiral CT scan. This system also extracts functional information useful for surgery planning, such as portal vein labeling and anatomical segment delineation following the conventional Couinaud definition. From a 2 mm thick enhanced spiral CT scan, a first stage automatically delineates the skin, bones, lungs and kidneys, by combining the use of thresholding, mathematical morphological methods and distance maps. Next, a reference 3D model is immerged in the image and automatically deformed to the liver contour. Then an automatic Gaussians fitting on the imaging histogram allows to threshold the intensities of parenchyma, vessels and lesions. The next stage improves this first classification by an original topological and geometrical analysis, providing an automatic and precise delineation of lesions and veins. Finally, a topological and geometrical analysis based on medical knowledge provides the hepatic functional information invisible in medical imaging: portal vein labeling and hepatic anatomical segments. Clinical validation performed on more than 30 patients shows that this method allows a delineation of anatomical structures, often more sensitive and more specific than manual delineation by a radiologist.

  18. Imaging Non-Specific Wrist Pain: Interobserver Agreement and Diagnostic Accuracy of SPECT/CT, MRI, CT, Bone Scan and Plain Radiographs

    PubMed Central

    Huellner, Martin W.; Bürkert, Alexander; Strobel, Klaus; Pérez Lago, María del Sol; Werner, Lennart; Hug, Urs; von Wartburg, Urs; Seifert, Burkhardt; Veit-Haibach, Patrick

    2013-01-01

    Purpose Chronic hand and wrist pain is a common clinical issue for orthopaedic surgeons and rheumatologists. The purpose of this study was 1. To analyze the interobserver agreement of SPECT/CT, MRI, CT, bone scan and plain radiographs in patients with non-specific pain of the hand and wrist, and 2. to assess the diagnostic accuracy of these imaging methods in this selected patient population. Materials and Methods Thirty-two consecutive patients with non-specific pain of the hand or wrist were evaluated retrospectively. All patients had been imaged by plain radiographs, planar early-phase imaging (bone scan), late-phase imaging (SPECT/CT including bone scan and CT), and MRI. Two experienced and two inexperienced readers analyzed the images with a standardized read-out protocol. Reading criteria were lesion detection and localisation, type and etiology of the underlying pathology. Diagnostic accuracy and interobserver agreement were determined for all readers and imaging modalities. Results The most accurate modality for experienced readers was SPECT/CT (accuracy 77%), followed by MRI (56%). The best performing, though little accurate modality for inexperienced readers was also SPECT/CT (44%), followed by MRI and bone scan (38% each). The interobserver agreement of experienced readers was generally high in SPECT/CT concerning lesion detection (kappa 0.93, MRI 0.72), localisation (kappa 0.91, MRI 0.75) and etiology (kappa 0.85, MRI 0.74), while MRI yielded better results on typification of lesions (kappa 0.75, SPECT/CT 0.69). There was poor agreement between experienced and inexperienced readers in SPECT/CT and MRI. Conclusions SPECT/CT proved to be the most helpful imaging modality in patients with non-specific wrist pain. The method was found reliable, providing high interobserver agreement, being outperformed by MRI only concerning the typification of lesions. We believe it is beneficial to integrate SPECT/CT into the diagnostic imaging algorithm of chronic wrist

  19. Computerized lung nodule detection: comparison of performance for low-dose and standard-dose helical CT scans

    NASA Astrophysics Data System (ADS)

    Armato, Samuel G., III; Giger, Maryellen L.; Doi, Kunio; Bick, Ulrich; MacMahon, Heber

    2001-07-01

    The vast amount of image data acquired during a computed tomography (CT) scan makes lung nodule detection a burdensome task. Moreover, the growing acceptance of low-dose CT for lung cancer screening promises to further impact radiologists' workloads. Therefore, we have developed a computerized method to automatically analyze structures within a CT scan and identify those structures that represent lung nodules. Gray-level thresholding is performed to segment the lungs in each section to produce a segmented lung volume, which is then iteratively thresholded. At each iteration, remaining voxels are grouped into contiguous three-dimensional structures. Structures that satisfy a volume criterion then become nodule candidates. The set of nodule candidates is subjected to feature analysis. To distinguish candidates representing nodule and non-nodule structures, a rule-based approach is combined with an automated classifier. This method was applied to 43 standard-dose (diagnostic) CT scans and 13 low-dose CT scans. The method achieved an overall detection sensitivity of 71% with 1.5 false-positive detections per section on the standard-dose database and 71% sensitivity with 1.2 false-positive detections per section on the low-dose database. This automated method demonstrates promising performance in its ability to accurately detect lung nodules in standard-dose and low-dose CT images.

  20. Moving metal artifact reduction in cone-beam CT scans with implanted cylindrical gold markers

    SciTech Connect

    Toftegaard, Jakob Fledelius, Walther; Worm, Esben S.; Poulsen, Per R.; Seghers, Dieter; Huber, Michael; Brehm, Marcus; Elstrøm, Ulrik V.

    2014-12-15

    Purpose: Implanted gold markers for image-guided radiotherapy lead to streaking artifacts in cone-beam CT (CBCT) scans. Several methods for metal artifact reduction (MAR) have been published, but they all fail in scans with large motion. Here the authors propose and investigate a method for automatic moving metal artifact reduction (MMAR) in CBCT scans with cylindrical gold markers. Methods: The MMAR CBCT reconstruction method has six steps. (1) Automatic segmentation of the cylindrical markers in the CBCT projections. (2) Removal of each marker in the projections by replacing the pixels within a masked area with interpolated values. (3) Reconstruction of a marker-free CBCT volume from the manipulated CBCT projections. (4) Reconstruction of a standard CBCT volume with metal artifacts from the original CBCT projections. (5) Estimation of the three-dimensional (3D) trajectory during CBCT acquisition for each marker based on the segmentation in Step 1, and identification of the smallest ellipsoidal volume that encompasses 95% of the visited 3D positions. (6) Generation of the final MMAR CBCT reconstruction from the marker-free CBCT volume of Step 3 by replacing the voxels in the 95% ellipsoid with the corresponding voxels of the standard CBCT volume of Step 4. The MMAR reconstruction was performed retrospectively using a half-fan CBCT scan for 29 consecutive stereotactic body radiation therapy patients with 2–3 gold markers implanted in the liver. The metal artifacts of the MMAR reconstructions were scored and compared with a standard MAR reconstruction by counting the streaks and by calculating the standard deviation of the Hounsfield units in a region around each marker. Results: The markers were found with the same autosegmentation settings in 27 CBCT scans, while two scans needed slightly changed settings to find all markers automatically in Step 1 of the MMAR method. MMAR resulted in 15 scans with no streaking artifacts, 11 scans with 1–4 streaks, and 3 scans