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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 CT scan findings in patients with symptomatic scleroderma-related interstitial lung disease.

    PubMed

    Goldin, Jonathan G; Lynch, David A; Strollo, Diane C; Suh, Robert D; Schraufnagel, Dean E; Clements, Philip J; Elashoff, Robert M; Furst, Daniel E; Vasunilashorn, Sarinnapha; McNitt-Gray, Michael F; Brown, Mathew S; Roth, Michael D; Tashkin, Donald P

    2008-08-01

    Lung disease has become the leading cause of mortality and morbidity in scleroderma (SSc) patients. The frequency, nature, and progression of interstitial lung disease seen on high-resolution CT (HRCT) scans in patients with diffuse SSc (dcSSc) compared with those with limited SSc (lcSSc) has not been well characterized. Baseline HRCT scan images of 162 participants randomized into a National Institutes of Health-funded clinical trial were compared to clinical features, pulmonary function test measures, and BAL fluid cellularity. The extent and distribution of interstitial lung disease HRCT findings, including pure ground-glass opacity (pGGO), pulmonary fibrosis (PF), and honeycomb cysts (HCs), were recorded in the upper, middle, and lower lung zones on baseline and follow-up CT scan studies. HRCT scan findings included 92.9% PF, 49.4% pGGO, and 37.2% HCs. There was a significantly higher incidence of HCs in the three zones in lcSSc patients compared to dcSSc patients (p = 0.034, p = 0.048, and p = 0.0007, respectively). The extent of PF seen on HRCT scans was significantly negatively correlated with FVC (r = - 0.22), diffusing capacity of the lung for carbon monoxide (r = - 0.44), and total lung capacity (r = - 0.36). A positive correlation was found between pGGO and the increased number of acute inflammatory cells found in BAL fluid (r = 0.28). In the placebo group, disease progression was assessed as 30% in the upper and middle lung zones, and 45% in the lower lung zones. No difference in the progression rate was seen between lcSSc and dcSSc patients. PF and GGO were the most common HRCT scan findings in symptomatic SSc patients. HCs were seen in more than one third of cases, being more common in lcSSc vs dcSSc. There was no relationship between progression and baseline PF extent or lcSSc vs dcSSc. Clinicaltrials.gov Identifier: NCT00004563.

  3. Temporal Bone CT: Improved Image Quality and Potential for Decreased Radiation Dose Using an Ultra-High-Resolution Scan Mode with an Iterative Reconstruction Algorithm.

    PubMed

    Leng, S; Diehn, F E; Lane, J I; Koeller, K K; Witte, R J; Carter, R E; McCollough, C H

    2015-09-01

    Radiation dose in temporal bone CT imaging can be high due to the requirement of high spatial resolution. In this study, we assessed whether CT imaging of the temporal bone by using an ultra-high-resolution scan mode combined with iterative reconstruction provides higher spatial resolution and lower image noise than a z-axis ultra-high-resolution mode. Patients with baseline temporal bone CT scans acquired by using a z-axis ultra-high-resolution protocol and a follow-up scan by using the ultra-high-resolution-iterative reconstruction technique were identified. Images of left and right temporal bones were reconstructed in the axial, coronal, and Poschl planes. Three neuroradiologists assessed the spatial resolution of the following structures: round and oval windows, incudomallear and incudostapedial joints, basal turn spiral lamina, and scutum. The paired z-axis ultra-high-resolution and ultra-high-resolution-iterative reconstruction images were displayed side by side in random order, with readers blinded to the imaging protocol. Image noise was compared in ROIs over the posterior fossa. We identified 8 patients, yielding 16 sets of temporal bone images (left and right). Three sets were excluded because the patient underwent surgery between the 2 examinations. Spatial resolution was comparable (Poschl) or slightly better (axial and coronal planes) with ultra-high-resolution-iterative reconstruction than with z-axis ultra-high-resolution. A paired t test indicated that noise was significantly lower with ultra-high-resolution-iterative reconstruction than with z-axis ultra-high-resolution (P < .001), with a mean noise reduction of 37% (range, 18%-49%). The ultra-high-resolution-iterative reconstruction scan mode has similar or slightly better resolution relative to the z-axis ultra-high-resolution mode for CT of the temporal bone but significantly (P < .01) lower image noise, which may enable the dose to be reduced by approximately 50%. © 2015 by American Journal of

  4. Evaluation of the use of a tablet computer with a high-resolution display for interpreting emergency CT scans.

    PubMed

    Tewes, S; Rodt, T; Marquardt, S; Evangelidou, E; Wacker, F K; von Falck, C

    2013-11-01

    Evaluation of the potential usability of an iPad 3 with a high-resolution display in CT emergency diagnosis compared to a 3 D PACS workstation. 3 readers used a 5-point Likert scale to evaluate 40 CCT scans and 40 CTPA scans to determine the detectability of early signs of infarction in CCT or segmental and subsegmental pulmonary embolisms in CT angiography of the pulmonary arteries (CTPA) on the iPad 3 (Apple Inc., USA) using an application for image viewing (Visage Ease, Visage Imaging GmbH, Berlin) and on a 3 D PACS workstation (Visage 7.1, Visage Imaging, Berlin) using a certified monitor for image viewing. The results were compared using the Wilcoxon rank sum test, Spearman's correlation coefficient, and a kappa statistic. There was no significant difference in the median evaluations for the readings of both the CCT scans and the CTPA scans on the iPad 3 and on the workstation (p > 0.05) for all three readers. The mean Spearman's correlation coefficient for CCT and CTPA was 0.46 (± 0.2) and 0.69 (± 0.16), respectively, for the comparison iPad/PACS, 0.41 (± 0.16) and 0.68 (± 0.06), respectively, for the interobserver agreement on the iPad, and 0.35 (± 0.05) and 0.68 (± 0.10), respectively, for the interobserver agreement on the PACS. Mean kappa values for CCT of 0.52 (± 0.17) for the comparison iPad/PACS and 0.33 (± 0.16) and 0.32 (± 0.16), respectively, for the interobserver agreement on the iPad and the PACS were achieved. For CTPA average kappa values of 0.67 (± 0.19) were calculated for the comparison iPad/PACS and 0.69 (± 0.08) and 0.60 (± 0.14), respectively, for the interobserver concordance on the iPad 3 and the PACS. All differences were not statistically significant (p > 0.05). The variability of the interpretation of typical emergency scans on an iPad 3 with a high-resolution display and on a 3 D PACS workstation does not differ from the interobserver variability. © Georg Thieme Verlag KG Stuttgart · New York.

  5. High-Resolution CT Scan Findings in Familial Interstitial Pneumonia Do Not Conform to Those of Idiopathic Interstitial Pneumonia

    PubMed Central

    Lee, Ho Yun; Seo, Joon Beom; Steele, Mark P.; Schwarz, Marvin I.; Brown, Kevin K.; Loyd, James E.; Talbert, Janet L.

    2012-01-01

    Background: The aim of this study was to describe the high-resolution CT (HRCT) scan features that characterize familial interstitial pneumonia (FIP). Methods: FIP was defined by the presence of two or more cases of probable or definite idiopathic interstitial pneumonia (IIP) in individuals related within three degrees. The cases were collected consecutively from three centers. We identified 371 individuals with potential FIP from 289 families, including 340 individuals who had HRCT scans. Two chest radiologists independently reviewed the HRCT scans, scoring the extent and distribution of HRCT scan findings, and assessed the overall radiologic diagnosis. Results: HRCT scan abnormalities suggestive of IIP were present in 85% (289 of 340 subjects). The most frequent findings were reticular pattern (n = 238, 82%) and ground-glass opacity (GGO) associated with reticular abnormality (n = 231, 80%). Other changes included GGO in 116 (40%), honeycombing in 92 (32%), and micronodules in 65 (22%). In the 289 cases with evidence of IIP, the findings were diffusely distributed in the craniocaudal plane in 186 (64%), and the lower lung zones were predominantly involved in 89 (31%). In the axial plane, 194 (67%) had a subpleural distribution; 88 (30%) were diffuse. The imaging pattern was classified as definite or probable usual interstitial pneumonia (UIP) in only 62 subjects (22%) and definite or probable nonspecific interstitial pneumonia (NSIP) in 35 subjects (12%). In 160 subjects (55%), the imaging findings did not conform to previously described UIP or NSIP patterns. Conclusions: Reticulation and a mixed GGO/reticular pattern are the most common HRCT scan findings in FIP. The parenchymal abnormalities are most often diffuse in the craniocaudal dimension and have a predominantly peripheral distribution in the axial dimension. Although a radiologic UIP pattern is not uncommon, most cases do not conform to typical UIP or NSIP patterns. PMID:23364926

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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 ...

  11. Recurrent thyroid cancer diagnosis: ROC study of the effect of a high-resolution head and neck 18F-FDG PET/CT scan.

    PubMed

    Chatziioannou, Sofia N; Georgakopoulos, Alexandros T; Pianou, Nikoletta K; Kafiri, Georgia Th; Pavlou, Spyros N; Kallergi, Maria

    2014-01-01

    (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) has demonstrated significant value in the evaluation of patients with indication of recurrent thyroid cancer with negative conventional workup. The hypothesis of this study was that the addition of a dedicated, high-resolution head and neck scan (HNS) to the standard whole-body scan (WBS) improves the accuracy of the detection and diagnosis of recurrent thyroid cancer. Forty-three consecutive patients suspected for recurrent thyroid cancer, as indicated by increased tumor markers, prospectively underwent a WBS and a HNS with (18)F-FDG PET/CT. The patients were followed up to establish ground truth. A receiver operator characteristic (ROC) study with two observers was conducted to evaluate the impact of the additional HNS on the detection and diagnosis of recurrent thyroid cancer. Indices of performance included the area under the ROC curve (AUC), the number of detected abnormal foci, and the size of the detected foci without and with the HNS images. ROC results showed that the addition of the HNS to the standard WBS increased the average AUC index of performance from 0.69 to 0.96, a statistically significant difference with a confidence interval (CI) of -0.33 to -0.19. Diagnosis was also improved with the average AUC increasing from 0.79 to 0.87 but differences were not statistically significant (CI, -0.19 to 0.04). Interreader agreement was "good" in the detection task and "excellent" in the diagnostic task. The addition of the HNS increased the number of detected foci in the positive patients by an average of 37%, whereas false-positive detections in the negative patients increased by an average of 10%. Reported average maximum lesion size also increased with the HNS addition by an average of 11%. The addition of a high-resolution HNS to the standard whole-body PET/CT imaging improves readers' performance in the detection and diagnosis of recurrent thyroid cancer and

  12. 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.

  13. 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.

  14. 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 ...

  15. 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.

  16. Scanning Transmission Electron Microscopy at High Resolution

    PubMed Central

    Wall, J.; Langmore, J.; Isaacson, M.; Crewe, A. V.

    1974-01-01

    We have shown that a scanning transmission electron microscope with a high brightness field emission source is capable of obtaining better than 3 Å resolution using 30 to 40 keV electrons. Elastic dark field images of single atoms of uranium and mercury are shown which demonstrate this fact as determined by a modified Rayleigh criterion. Point-to-point micrograph resolution between 2.5 and 3.0 Å is found in dark field images of micro-crystallites of uranium and thorium compounds. Furthermore, adequate contrast is available to observe single atoms as light as silver. Images PMID:4521050

  17. 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. ...

  18. 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.

  19. Arm CT scan

    MedlinePlus

    CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... your provider should weigh this risk against the benefits of getting a correct diagnosis for a medical ...

  20. 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.

  1. 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.

  2. The theory and practice of high resolution scanning electron microscopy

    SciTech Connect

    Joy, D.C. Oak Ridge National Lab., TN )

    1990-01-01

    Recent advances in instrumentation have produced the first commercial examples of what can justifiably be called High Resolution Scanning Electron Microscopes. The key components of such instruments are a cold field emission gun, a small-gap immersion probe-forming lens, and a clean dry-pumped vacuum. The performance of these microscopes is characterized by several major features including a spatial resolution, in secondary electron mode on solid specimens, which can exceed 1nm on a routine basis; an incident probe current density of the order of 10{sup 6} amps/cm{sup 2}; and the ability to maintain these levels of performance over an accelerating voltage range of from 1 to 30keV. This combination of high resolution, high probe current, low contamination and flexible electron-optical conditions provides many new opportunitites for the application of the SEM to materials science, physics, and the life sciences. 27 refs., 14 figs.

  3. High-Resolution, Wide-Field-of-View Scanning Telescope

    NASA Technical Reports Server (NTRS)

    Sepulveda, Cesar; Wilson, Robert; Seshadri, Suresh

    2007-01-01

    A proposed telescope would afford high resolution over a narrow field of view (<0.10 ) while scanning over a total field of view nominally 16 wide without need to slew the entire massive telescope structure. The telescope design enables resolution of a 1-m-wide object in a 50- km-wide area of the surface of the Earth as part of a 200-km-wide area field of view monitored from an orbit at an altitude of 700 km. The conceptual design of this telescope could also be adapted to other applications both terrestrial and extraterrestrial in which there are requirements for telescopes that afford both wide- and narrow-field capabilities. In the proposed telescope, the scanning would be effected according to a principle similar to that of the Arecibo radio telescope, in which the primary mirror is stationary with respect to the ground and a receiver is moved across the focal surface of the primary mirror. The proposed telescope would comprise (1) a large spherical primary mirror that would afford high resolution over a narrow field of view and (2) a small displaceable optical relay segment that would be pivoted about the center of an aperture stop to effect the required scanning (see figure). Taken together, both comprise a scanning narrow-angle telescope that does not require slewing the telescope structure. In normal operation, the massive telescope structure would stare at a fixed location on the ground. The inner moveable relay optic would be pivoted to scan the narrower field of view over the wider one, making it possible to retain a fixed telescope orientation, while obtaining high-resolution images over multiple target areas during an interval of 3 to 4 minutes in the intended orbit. The pivoting relay segment of the narrow-angle telescope would include refractive and reflective optical elements, including two aspherical mirrors, to counteract the spherical aberration of the primary mirror. Overall, the combination of the primary mirror and the smaller relay optic

  4. 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.

  5. 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).

  6. 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

  7. 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.

  8. High resolution wind turbine wake measurements with a scanning lidar

    NASA Astrophysics Data System (ADS)

    Herges, T. G.; Maniaci, D. C.; Naughton, B. T.; Mikkelsen, T.; Sjöholm, M.

    2017-05-01

    High-resolution lidar wake measurements are part of an ongoing field campaign being conducted at the Scaled Wind Farm Technology facility by Sandia National Laboratories and the National Renewable Energy Laboratory using a customized scanning lidar from the Technical University of Denmark. One of the primary objectives is to collect experimental data to improve the predictive capability of wind plant computational models to represent the response of the turbine wake to varying inflow conditions and turbine operating states. The present work summarizes the experimental setup and illustrates several wake measurement example cases. The cases focus on demonstrating the impact of the atmospheric conditions on the wake shape and position, and exhibit a sample of the data that has been made public through the Department of Energy Atmosphere to Electrons Data Archive and Portal.

  9. Imaging plasmodesmata with high-resolution scanning electron microscopy.

    PubMed

    Barton, Deborah A; Overall, Robyn L

    2015-01-01

    High-resolution scanning electron microscopy (HRSEM) is an effective tool to investigate the distribution of plasmodesmata within plant cell walls as well as to probe their complex, three-dimensional architecture. It is a useful alternative to traditional transmission electron microscopy (TEM) in which plasmodesmata are sectioned to reveal their internal substructures. Benefits of adopting an HRSEM approach to studies of plasmodesmata are that the specimen preparation methods are less complex and time consuming than for TEM, many plasmodesmata within a large region of tissue can be imaged in a single session, and three-dimensional information is readily available without the need for reconstructing TEM serial sections or employing transmission electron tomography, both of which are lengthy processes. Here we describe methods to prepare plant samples for HRSEM using pre- or postfixation extraction of cellular material in order to visualize plasmodesmata embedded within plant cell walls.

  10. 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.

  11. Cardiac CT Scan

    MedlinePlus

    ... rate. Before the test, a contrast dye, often iodine, may be injected into a vein in your ... should not receive more CT scans than the number that clinical guidelines recommend. Another risk is that ...

  12. 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.

  13. CT Scans - Multiple Languages

    MedlinePlus

    ... Tomography) Scan - العربية (Arabic) Bilingual PDF Health Information Translations Chinese, Simplified (Mandarin dialect) (简体中文) Expand Section CT ( ... Chinese, Simplified (Mandarin dialect)) Bilingual PDF Health Information Translations Chinese, Traditional (Cantonese dialect) (繁體中文) Expand Section CT ( ...

  14. 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.

  15. High-resolution fully vectorial scanning Kerr magnetometer

    SciTech Connect

    Flajšman, Lukáš E-mail: urbanek@fme.vutbr.cz; Vaňatka, Marek; Urbánek, Michal E-mail: urbanek@fme.vutbr.cz; Šikola, Tomáš; Křižáková, Viola; Turčan, Igor

    2016-05-15

    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.

  16. High Resolution Helium Ion Scanning Microscopy of the Rat Kidney

    PubMed Central

    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

  17. 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

  18. Neuroendocrine Cell Hyperplasia of Infancy: Diagnosis With High-Resolution CT

    PubMed Central

    Brody, Alan S.; Guillerman, R. Paul; Hay, Thomas C.; Wagner, Brandie D.; Young, Lisa R.; Deutsch, Gail H.; Fan, Leland L.; Deterding, Robin R.

    2013-01-01

    OBJECTIVE Neuroendocrine cell hyperplasia of infancy is a form of childhood interstitial lung disease originally reported as persistent tachypnea of infancy. Reports of small series of cases and anecdotal experience have suggested that this disorder may have a consistent CT pattern. The purpose of this study was to review the CT findings in children with neuroendocrine cell hyperplasia of infancy to determine the findings at high-resolution CT, the diagnostic accuracy of CT compared with biopsy, and interrater reliability. MATERIALS AND METHODS Images from 23 CT examinations of children with biopsy-proven neuroendocrine cell hyperplasia of infancy and six CT examinations of children with other childhood interstitial lung diseases were reviewed by two pediatric radiologists with special expertise in thoracic imaging. Identifying digital data were removed, and images were reviewed without clinical data. A CT assessment form was completed for each patient. RESULTS Ground-glass opacification was the most common finding in patients with neuroendocrine cell hyperplasia of infancy. The right middle lobe and lingula were most commonly involved. Air trapping with a mosaic pattern was the second most common finding. Interrater reliability was very good with a kappa value of 0.93. The sensitivity and specificity of CT in the diagnosis of neuroendocrine cell hyperplasia of infancy were at least 78% and 100%. CONCLUSION Neuroendocrine cell hyperplasia of infancy can have a characteristic appearance on high-resolution CT scans, the imaging findings being useful in differentiating neuroendocrine cell hyperplasia of infancy from other types of childhood interstitial lung disease. The appearance aids radiologists in suggesting a specific diagnosis but does not exclude this diagnosis; in 17–22% of cases, the readers in this study did not suggest the diagnosis of neuroendocrine cell hyperplasia of infancy when it was present. PMID:20028928

  19. 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

  20. 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.

  1. 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.

  2. Cryptogenic organizing pneumonia: serial high-resolution CT findings in 22 patients.

    PubMed

    Lee, Ju Won; Lee, Kyung Soo; Lee, Ho Yun; Chung, Man Pyo; Yi, Chin A; Kim, Tae Sung; Chung, Myung Jin

    2010-10-01

    We conducted a review of serial high-resolution CT (HRCT) findings of cryptogenic organizing pneumonia (COP). Over the course of 14 years, we saw 32 patients with biopsy-confirmed COP. Serial HRCT scans were available for only 22 patients (seven men and 15 women; mean age, 52 years; median follow-up period, 8 months; range, 5-135 months). Serial CT scans were evaluated by two chest radiologists who reached a conclusion by consensus. Overall changes in disease extent were classified as cured, improved (i.e., ≥ 10% decrease in extent), not changed, or progressed (i.e., ≥ 10% increase in extent). When there were remaining abnormalities, the final follow-up CT images were analyzed to express observers' ideas regarding what type of interstitial lung disease the images most likely suggested. The two most common patterns of lung abnormality on initial scans were ground-glass opacification (86% of patients [19/22]) and consolidation (77% of patients [17/22]), distributed along the bronchovascular bundles or subpleural lungs in 13 patients (59%). In six patients (27%), the disease disappeared completely; in 15 patients (68%), the disease was decreased in extent; and in one patient (5%), no change in extent was detected on follow-up CT. When lesions remained, the final follow-up CT findings were reminiscent of fibrotic nonspecific interstitial pneumonia in 10 of 16 patients (63%). Although COP is a disease with a generally good prognosis, most patients (73%) with COP have some remaining disease seen on follow-up CT scans, and, in such cases, the lesions generally resemble a fibrotic nonspecific interstitial pneumonia pattern.

  3. 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

  4. Three-rooted premolar analyzed by high-resolution and cone beam CT.

    PubMed

    Marca, Caroline; Dummer, Paul M H; Bryant, Susan; Vier-Pelisser, Fabiana Vieira; Só, Marcus Vinicius Reis; Fontanella, Vania; Dutra, Vinicius D'avila; de Figueiredo, José Antonio Poli

    2013-07-01

    The aim of this study was to analyze the variations in canal and root cross-sectional area in three-rooted maxillary premolars between high-resolution computed tomography (μCT) and cone beam computed tomography (CBCT). Sixteen extracted maxillary premolars with three distinct roots and fully formed apices were scanned using μCT and CBCT. Photoshop CS software was used to measure root and canal cross-sectional areas at the most cervical and the most apical points of each root third in images obtained using the two tomographic computed (CT) techniques, and at 30 root sections equidistant from both root ends using μCT images. Canal and root areas were compared between each method using the Student t test for paired samples and 95 % confidence intervals. Images using μCT were sharper than those obtained using CBCT. There were statistically significant differences in mean area measurements of roots and canals between the μCT and CBCT techniques (P < 0.05). Root and canal areas had similar variations in cross-sectional μCT images and became proportionally smaller in a cervical to apical direction as the cementodentinal junction was approached, from where the area then increased apically. Although variation was similar in the roots and canals under study, CBCT produced poorer image details than μCT. Although CBCT is a strong diagnosis tool, it still needs improvement to provide accuracy in details of the root canal system, especially in cases with anatomical variations, such as the three-rooted maxillary premolars.

  5. 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).

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. High-resolution CT findings of patients with pulmonary nocardiosis

    PubMed Central

    Tsujimoto, Naoki; Saraya, Takeshi; Kikuchi, Ken; Takata, Saori; Kurihara, Yasuyuki; Hiraoka, Sayuki; Makino, Hiroshi; Yonetani, Shota; Araki, Koji; Ishii, Haruyuki; Takizawa, Hajime

    2012-01-01

    Background Opportunistic pulmonary infection with Nocardia species is rare in humans, and only a few studies have radiologically analyzed patients with pulmonary nocardiosis using high-resolution computed tomography (HRCT). Methods We retrospectively reviewed the medical records of patients with pulmonary nocardiosis at our hospital between April 2006 and December 2011 to assess HRCT and clinical findings. We also searched the medical literature for pulmonary nocardiosis reported in Japan between 2002 and 2011 for comparison. Results We identified seven patients at our institution and 33 reported infections in Japan. Four of our patients were immunocompetent, whereas the other three had impaired cellular immunity due to type 2 diabetes mellitus or having been inappropriately treated with steroid. Thoracic HRCT revealed no zonal predominance, but tropism for distribution from the middle to the peripheral area, and radiological findings of nodules, cavitation, mass, consolidations, bronchial wall thickening, septal line thickening and ground glass opacity (GGO) were evident. The main HRCT finding in our study comprised nodules (n=5, 71.4%) <30 mm and four patients had multiple nodules as described in other reports. Furthermore, we discovered a crazy paving appearance (CPA) around nodules, cavities, masses or consolidations in five patients (71.4%). Conclusions Multiple nodules distributed from the middle to the peripheral area on HRCT might reflect pulmonary nocardiosis, and CPA seemed to be a worth paying attention to the diagnosis. PMID:23205281

  14. Nonlinear histogram binning for quantitative analysis of lung tissue fibrosis in high-resolution CT data

    NASA Astrophysics Data System (ADS)

    Zavaletta, Vanessa A.; Bartholmai, Brian J.; Robb, Richard A.

    2007-03-01

    Diffuse lung diseases, such as idiopathic pulmonary fibrosis (IPF), can be characterized and quantified by analysis of volumetric high resolution CT scans of the lungs. These data sets typically have dimensions of 512 x 512 x 400. It is too subjective and labor intensive for a radiologist to analyze each slice and quantify regional abnormalities manually. Thus, computer aided techniques are necessary, particularly texture analysis techniques which classify various lung tissue types. Second and higher order statistics which relate the spatial variation of the intensity values are good discriminatory features for various textures. The intensity values in lung CT scans range between [-1024, 1024]. Calculation of second order statistics on this range is too computationally intensive so the data is typically binned between 16 or 32 gray levels. There are more effective ways of binning the gray level range to improve classification. An optimal and very efficient way to nonlinearly bin the histogram is to use a dynamic programming algorithm. The objective of this paper is to show that nonlinear binning using dynamic programming is computationally efficient and improves the discriminatory power of the second and higher order statistics for more accurate quantification of diffuse lung disease.

  15. High-resolution computed radiography by scanned luminescent toner xeroradiography

    NASA Astrophysics Data System (ADS)

    May, John W.; Lubinsky, Anthony R.

    1993-09-01

    A new computed radiography system is described in which a charged selenium photoconductive plate is exposed to x-rays to create an electrostatic latent image, developed with a luminescent toner, and scanned with a stimulating laser beam to produce emitted light, which is filtered and detected. The resulting electronic signals are processed, and converted to hard copy using a laser film printer. The system is characterized by high x-ray sensitivity and by very high spatial resolution, which makes it particularly suitable for applications such as mammography and bone radiography. The image luminescence is bright and its decay time is extremely short, enabling rapid scanning with an inexpensive laser source. Also, the electronic capture of image data permits enhancement of the displayed contrast of image structures by image processing techniques.

  16. High-resolution Josephson spectroscopy with a scanning tunneling microscope

    NASA Astrophysics Data System (ADS)

    Randeria, Mallika T.; Feldman, Benjamin E.; Drozdov, Ilya K.; Yazdani, Ali

    2015-03-01

    Conventional scanning tunneling microscopy (STM) measurements use a normal metal tip to probe local quasi-particle density of states with atomic resolution. Using a superconducting tip to conduct spectroscopy significantly boosts the energy resolution of the measurements, thus expanding the STM capabilities. Moreover, superconducting tips make it possible to probe superconductivity via the Josephson effect, which provides a direct measure of the local superconducting order parameter. Therefore, scanning Josephson spectroscopy measurements have the potential to characterize of a wide variety of superconducting materials on the atomic scale. I will present superconducting Pb tip measurements performed at temperatures below 250mK in a dilution refrigerator STM. By controlling the junction resistance, we are able to explore a wide range of tunneling regimes. Josephson measurements on Pb samples exhibit features including multiple Andreev reflections, and I will discuss the extension of these techniques to study atomic scale variations in Josephson current.

  17. High-resolution thermal scanning for hot-strip mills

    NASA Astrophysics Data System (ADS)

    Holmsten, Dag; Houis, Rene

    1990-03-01

    Until recently, very few choices were available to a hot-strip mill operator desiringinfrared scanning. Measurements were often made using either portable non linescanning/imaging systems or slow linescanners originally designed for cement applications.3 Since then, important changes have taken place and the summer/fall of 1989 saw the introduction of no less than four different opto-mechanical linescanners as well as the increasing use at high object temperatures of various near-IR (CCD) linear-arrays in lieu of more traditional (mid) IR scanners. In comparison to earlier systems most, if not all, scanners provided higher spatial resolution (typically 2000 IR-points per line), higher scanning rate (typically20 - 100 Hz) and drastically improved measurement accuracy (at least for the opto-mechanical scanners, see below). This article will outline some of the results obtained in a typical steel mill environment with one of the highperformance linescanners of the new breed, and comments will be made on the emerging CCD-technology. For those interested in other line scanning applications with different object characteristics and surface temperature, some indications will also be given of the possibility to project the results obtained on other usages.

  18. Detecting metastasis of gastric carcinoma using high-resolution micro-CT system: in vivo small animal study

    NASA Astrophysics Data System (ADS)

    Liu, Junting; Tian, Jie; Liang, Jimin; Li, Xiangsi; Yang, Xiang; Chen, Xiaofeng; Chen, Yi; Zhou, Yuanfang; Wang, Xiaorui

    2011-03-01

    Immunocytochemical and immunofluorescence staining are used for identifying the characteristics of metastasis in traditional ways. Micro-computed tomography (micro-CT) is a useful tool for monitoring and longitudinal imaging of tumor in small animal in vivo. In present study, we evaluated the feasibility of the detection for metastasis of gastric carcinoma by high-resolution micro-CT system with omnipaque accumulative enhancement method in the organs. Firstly, a high-resolution micro-CT ZKKS-MCT-sharp micro-CT was developed by our research group and Guangzhou Zhongke Kaisheng Medical Technology Co., Ltd. Secondly, several gastric carcinoma models were established through inoculating 2x106 BGC-823 gastric carcinoma cells subcutaneously. Thirdly, micro-CT scanning was performed after accumulative enhancement method of intraperitoneal injection of omnipaque contrast agent containing 360 mg iodine with a concentration of 350 mg I/ml. Finally, we obtained high-resolution anatomical information of the metastasis in vivo in a BALB/c NuNu nude mouse, the 3D tumor architecture is revealed in exquisite detail at about 35 μm spatial resolution. In addition, the accurate shape and volume of the micrometastasis as small as 0.78 mm3 can be calculated with our software. Overall, our data suggest that this imaging approach and system could be used to enhance the understanding of tumor proliferation, metastasis and could be the basis for evaluating anti-tumor therapies.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Mineral volume and morphology in carotid plaque specimens using high-resolution MRI and CT.

    PubMed

    Wolf, Ronald L; Wehrli, Suzanne L; Popescu, Andra M; Woo, John H; Song, Hee Kwon; Wright, Alexander C; Mohler, Emile R; Harding, John D; Zager, Eric L; Fairman, Ronald M; Golden, Michael A; Velazquez, Omaida C; Carpenter, Jeffrey P; Wehrli, Felix W

    2005-08-01

    High-resolution MRI methods have been used to evaluate carotid artery atherosclerotic plaque content. The purpose of this study was to assess the performance of high-resolution MRI in evaluation of the quantity and pattern of mineral deposition in carotid endarterectomy (CEA) specimens, with quantitative micro-CT as the gold standard. High-resolution MRI and CT were compared in 20 CEA specimens. Linear regression comparing mineral volumes generated from CT (VCT) and MRI (VMRI) data demonstrated good correlation using simple thresholding (VMRI=-0.01+0.98VCT; R2=0.90; threshold=4xnoise) and k-means clustering methods (VMRI=-0.005+1.38VCT; R2=0.93). Bone mineral density (BMD) and bone mineral content (BMC [mineral mass]) were calculated for CT data and BMC verified with ash weight. Patterns of mineralization like particles, granules, and sheets were more clearly depicted on CT. Mineral volumes generated from MRI or CT data were highly correlated. CT provided a more detailed depiction of mineralization patterns and provided BMD and BMC in addition to mineral volume. The extent of mineralization as well as the morphology may ultimately be useful in assessing plaque stability.

  5. Renal stone characterization using high resolution imaging mode on a photon counting detector CT system

    NASA Astrophysics Data System (ADS)

    Ferrero, A.; Gutjahr, R.; Henning, A.; Kappler, S.; Halaweish, A.; Abdurakhimova, D.; Peterson, Z.; Montoya, J.; Leng, S.; McCollough, C.

    2017-03-01

    In addition to the standard-resolution (SR) acquisition mode, a high-resolution (HR) mode is available on a research photon-counting-detector (PCD) whole-body CT system. In the HR mode each detector consists of a 2x2 array of 0.225 mm x 0.225 mm subpixel elements. This is in contrast to the SR mode that consists of a 4x4 array of the same subelements, and results in 0.25 mm isotropic resolution at iso-center for the HR mode. In this study, we quantified ex vivo the capabilities of the HR mode to characterize renal stones in terms of morphology and mineral composition. Forty pure stones - 10 uric acid (UA), 10 cystine (CYS), 10 calcium oxalate monohydrate (COM) and 10 apatite (APA) - and 14 mixed stones were placed in a 20 cm water phantom and scanned in HR mode, at radiation dose matched to that of routine dual-energy stone exams. Data from micro CT provided a reference for the quantification of morphology and mineral composition of the mixed stones. The area under the ROC curve was 1.0 for discriminating UA from CYS, 0.89 for CYS vs COM and 0.84 for COM vs APA. The root mean square error (RMSE) of the percent UA in mixed stones was 11.0% with a medium-sharp kernel and 15.6% with the sharpest kernel. The HR showed qualitatively accurate characterization of stone morphology relative to micro CT.

  6. 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.

  7. 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

  8. Body CT (CAT Scan)

    MedlinePlus

    ... during the procedure. Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images and ... may increase the risk of an unusual adverse effect. Women should always inform their physician and the ...

  9. 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, ...

  10. 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 ...

  11. 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.

  12. 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.

  13. Reversed halo sign on high-resolution CT of cryptogenic organizing pneumonia: diagnostic implications.

    PubMed

    Kim, Sang Jin; Lee, Kyung Soo; Ryu, Young Hoon; Yoon, Young Cheol; Choe, Kyu Ok; Kim, Tae Sung; Sung, Ki Jun

    2003-05-01

    The aim of our study was to evaluate the usefulness of the reversed halo sign on high-resolution CT in the diagnosis of cryptogenic organizing pneumonia. Between 1996 and 2001, we saw 31 patients with biopsy-proven cryptogenic organizing pneumonia. During the same period, we also saw 30 patients with non-cryptogenic organizing pneumonia diseases, from which cryptogenic organizing pneumonia should be differentiated: Wegener's granulomatosis (n = 14), diffuse bronchioloalveolar carcinoma (n = 10), chronic eosinophilic pneumonia (n = 5), and Churg-Strauss syndrome (n = 1). Two independent observers analyzed CT findings and recorded how frequently the so-called reversed halo sign (central ground-glass opacity and surrounding air-space consolidation of crescentic and ring shape) was seen on high-resolution CT. The most common patterns of parenchymal abnormalities of cryptogenic organizing pneumonia were ground-glass opacity (28/31 patients, 90%) and consolidation (27/31, 87%). The ground-glass opacity pattern showed random distribution, and the consolidation pattern showed subpleural or peribronchovascular (20/27 patients, 74%) distribution with predominance in the middle or lower lung zone. The reversed CT halo sign was seen in six (19%) of 31 patients with cryptogenic organizing pneumonia and in none of the patients with the diseases that needed to be differentiated from cryptogenic organizing pneumonia on CT. The reversed halo sign, although seen only in one fifth of patients with the disease, appears relatively specific to make a diagnosis of cryptogenic organizing pneumonia on CT.

  14. 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.

  15. 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.

  16. 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.

  17. High-resolution dynamic imaging and quantitative analysis of lung cancer xenografts in nude mice using clinical PET/CT

    PubMed Central

    Wang, Ying Yi; Wang, Kai; Xu, Zuo Yu; Song, Yan; Wang, Chu Nan; Zhang, Chong Qing; Sun, Xi Lin; Shen, Bao Zhong

    2017-01-01

    Considering the general application of dedicated small-animal positron emission tomography/computed tomography is limited, an acceptable alternative in many situations might be clinical PET/CT. To estimate the feasibility of using clinical PET/CT with [F-18]-fluoro-2-deoxy-D-glucose for high-resolution dynamic imaging and quantitative analysis of cancer xenografts in nude mice. Dynamic clinical PET/CT scans were performed on xenografts for 60 min after injection with [F-18]-fluoro-2-deoxy-D-glucose. Scans were reconstructed with or without SharpIR method in two phases. And mice were sacrificed to extracting major organs and tumors, using ex vivo γ-counting as a reference. Strikingly, we observed that the image quality and the correlation between the all quantitive data from clinical PET/CT and the ex vivo counting was better with the SharpIR reconstructions than without. Our data demonstrate that clinical PET/CT scanner with SharpIR reconstruction is a valuable tool for imaging small animals in preclinical cancer research, offering dynamic imaging parameters, good image quality and accurate data quatification. PMID:28881772

  18. High-resolution dynamic imaging and quantitative analysis of lung cancer xenografts in nude mice using clinical PET/CT.

    PubMed

    Wang, Ying Yi; Wang, Kai; Xu, Zuo Yu; Song, Yan; Wang, Chu Nan; Zhang, Chong Qing; Sun, Xi Lin; Shen, Bao Zhong

    2017-08-08

    Considering the general application of dedicated small-animal positron emission tomography/computed tomography is limited, an acceptable alternative in many situations might be clinical PET/CT. To estimate the feasibility of using clinical PET/CT with [F-18]-fluoro-2-deoxy-D-glucose for high-resolution dynamic imaging and quantitative analysis of cancer xenografts in nude mice. Dynamic clinical PET/CT scans were performed on xenografts for 60 min after injection with [F-18]-fluoro-2-deoxy-D-glucose. Scans were reconstructed with or without SharpIR method in two phases. And mice were sacrificed to extracting major organs and tumors, using ex vivo γ-counting as a reference. Strikingly, we observed that the image quality and the correlation between the all quantitive data from clinical PET/CT and the ex vivo counting was better with the SharpIR reconstructions than without. Our data demonstrate that clinical PET/CT scanner with SharpIR reconstruction is a valuable tool for imaging small animals in preclinical cancer research, offering dynamic imaging parameters, good image quality and accurate data quatification.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  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. 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

  5. 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.

  6. Precise 3D dimensional metrology using high-resolution x-ray computed tomography (μCT)

    NASA Astrophysics Data System (ADS)

    Brunke, Oliver; Santillan, Javier; Suppes, Alexander

    2010-09-01

    measurement and the CT method of measurement within the same CT data set. A comparison of these results to the data obtained by means of CT shows that state of the art high resolution CT can provide measurement accuracy on the order of established coordinate measurement techniques.

  7. 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.

  8. Investigation of a Dedicated, High Resolution PET/CT Scanner for Staging and Treatment Planning of Head and Neck Cancer

    NASA Astrophysics Data System (ADS)

    Raylman, Raymond R.; Stolin, Alexander V.; Sompalli, Prashanth; Randall, Nicole Bunda; Martone, Peter F.; Clinthorne, Neal H.

    2015-10-01

    Staging of head and neck cancer (HNC) is often hindered by the limited resolution of standard whole body PET scanners, which can make it challenging to detect small areas of metastatic disease in regional lymph nodes and accurately delineate tumor boundaries. In this investigation, the performance of a proposed high resolution PET/CT scanner designed specifically for imaging of the head and neck region was explored. The goal is to create a dedicated PET/CT system that will enhance the staging and treatment of HNCs. Its performance was assessed by simulating the scanning of a three-dimensional Rose-Burger contrast phantom. To extend the results from the simulation studies, an existing scanner with a similar geometry to the dedicated system and a whole body, clinical PET/CT scanner were used to image a Rose-Burger contrast phantom and a phantom simulating the neck of an HNC patient (out-of-field-of-view sources of activity were not included). Images of the contrast detail phantom acquired with Breast-PET/CT and simulated head and neck scanner both produced object contrasts larger than the images created by the clinical scanner. Images of a neck phantom acquired with the Breast-PET/CT scanner permitted the identification of all of the simulated metastases, while it was not possible to identify any of the simulated metastasis with the clinical scanner. The initial results from this study demonstrate the potential benefits of high-resolution PET systems for improving the diagnosis and treatment of HNC.

  9. Reversible bronchial dilatation in children: comparison of serial high-resolution computer tomography scans of the lungs.

    PubMed

    Gaillard, E A; Carty, H; Heaf, D; Smyth, R L

    2003-09-01

    Bronchiectasis is generally considered irreversible in the adult population, largely based on studies employing bronchography in cases with a significant clinical history. It is assumed, that the same is true for children. Few studies have examined the natural history of bronchiectasis in children and diagnostic criteria on high-resolution computer tomography of the lungs are derived from studies on adults. Frequently, bronchiectasis is reported in children in cases where localised bronchial dilatation is present, incorrectly labelling these children with an irreversible life-long condition. to evaluate changes in appearance of bronchial dilatation, unrelated to cystic fibrosis in children, as assessed by sequential high-resolution computer tomography (HRCT) of the lungs. The scans of 22 children with a radiological diagnosis of bronchiectasis, seen at Alder Hey Children's Hospital between 1994 and 2000, who had at least two CT scans of the lungs were reviewed by a single radiologist, who was blinded to the original report. Following a median scan interval of 21 months (range 2-43), bronchial dilatation resolved completely in six children and there was improvement in appearances in a further eight, with medical treatment alone. A radiological diagnosis of bronchiectasis should be considered with caution in children as diagnostic criteria derived from studies in adults have not been validated in children and the condition is generally considered irreversible.

  10. High-resolution CT assessment of the pediatric airways: structure and function

    NASA Astrophysics Data System (ADS)

    Kramer, Sandra S.; Hoffman, Eric A.; Amirav, Israel

    1994-05-01

    The airway has always been a central focus for respiratory pathology in infants and children. Imaging of the larynx, trachea, and the central bronchi can be readily accomplished by radiographic or conventional CT techniques. Newer high resolution CT (HRCT) techniques have extended our view of the bronchi peripherally to the limits of scanner resolution, i.e., to bronchial generations 7 - 9, and rapid volumetric CT data acquisitions have made it possible to follow the same lung anatomic level through the rapidly occurring changes in a series of experimental protocols. These techniques together with a custom designed computer software program for image display and analysis have enabled us to objectively study changes in airway caliber and lung density that occurred in an animal mode of airway reactivity and thereby relate structure with function in the airways.

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

    PubMed Central

    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.

    2014-01-01

    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. PMID:24434734

  12. 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.

  13. Photon-Counting CT: High-Resolution Imaging of Coronary Stents.

    PubMed

    Mannil, Manoj; Hickethier, Tilman; von Spiczak, Jochen; Baer, Matthias; Henning, André; Hertel, Madeleine; Schmidt, Bernhard; Flohr, Thomas; Maintz, David; Alkadhi, Hatem

    2017-09-23

    The aim of this study was to investigate computed tomography (CT) imaging characteristics of coronary stents using a novel photon-counting detector (PCD) in comparison with a conventional energy-integrating detector (EID). In this in vitro study, 18 different coronary stents were expanded in plastic tubes of 3 mm diameter, were filled with contrast agent (diluted to an attenuation of 250 Hounsfield units [HU] at 120 kVp), and were sealed. Stents were placed in an oil-filled custom phantom calibrated to an attenuation of -100 HU at 120 kVp for resembling pericardial fat. The phantom was positioned in the gantry at 2 different angles at 0 degree and 90 degrees relative to the z axis, and was imaged in a research dual-source PCD-CT scanner. Detector subsystem "A" used a standard 64-row EID, while detector subsystem "B" used a PCD, allowing high-resolution scanning (detector pixel-size 0.250 × 0.250 mm in the isocenter). Images were obtained from both detector systems at identical tube voltage (100 kVp) and tube current-time product (100 mA), and were both reconstructed using a typical convolution kernel for stent imaging (B46f) and using the same reconstruction parameters. Two independent, blinded readers evaluated in-stent visibility and measured noise, intraluminal stent diameter, and in-stent attenuation for each detector subsystem. Differences in noise, intraluminal stent diameter, and in-stent attenuation where tested using a paired t test; differences in subjective in-stent visibility were evaluated using a Wilcoxon signed-rank test. Best results for in-stent visibility, noise, intraluminal stent diameter, and in-stent attenuation in EID and PCD were observed at 0-degree phantom position along the z axis, suggesting higher in-plane compared with through-plane resolution. Subjective in-stent visibility was superior in coronary stent images obtained from PCD compared with EID (P < 0.001). Mean in-stent diameter was 28.8% and 8.4% greater in PCD (0.85 ± 0.24 mm

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

    SciTech Connect

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

    1986-09-10

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. High Resolution Multi-Detector CT Aided Tissue Analysis and Quantification of Lung Fibrosis

    PubMed Central

    Zavaletta, Vanessa A.; Bartholmai, Brian J.; Robb, Richard A

    2009-01-01

    Rational and Objectives Volumetric high-resolution scans can be acquired of the lungs with multi-detector CT (MDCT). Such scans have potential to facilitate useful visualization, characterization, and quantification of the extent of diffuse lung diseases, such as Usual Interstitial Pneumonitis or Idiopathic Pulmonary Fibrosis (UIP/IPF). There is a need to objectify, standardize and improve the accuracy and repeatability of pulmonary disease characterization and quantification from such scans. This paper presents a novel texture analysis approach toward classification and quantification of various pathologies present in lungs with UIP/IPF. The approach integrates a texture matching method with histogram feature analysis. Materials and Methods Patients with moderate UIP/IPF were scanned on a Lightspeed 8-detector GE CT scanner (140kVp, 250mAs). Images were reconstructed with 1.25mm slice thickness in a high-frequency sparing algorithm (BONE) with 50% overlap and a 512 × 512 axial matrix, (0.625 mm3 voxels). Eighteen scans were used in this study. Each dataset is pre-processed which includes segmentation of the lungs and the broncho-vascular trees. Two types of analysis were performed, first an analysis of independent volume of interests (VOIs) and second an analysis of whole lung datasets. 1.) Fourteen of the eighteen scans were used to create a database of independent 15×15×15 cubic voxel VOIs. The VOIs were selected by experts as having greater than 70% of the defined class. The database was composed of the following: Honeycombing (# of VOIs 337), Reticular (130), Ground glass (148), Normal (240), and Emphysema (54). This database was used to develop our algorithm. Three progressively challenging classification experiments were designed to test our algorithm. All three experiments were performed using a 10-fold cross validation method for error estimation. Experiment 1 consisted of a two class discrimination: Normal and Abnormal. Experiment 2 consisted of a four

  20. Compton Scattering in Clinical PET/CT With High Resolution Half Ring PET Insert Device

    PubMed Central

    Komarov, Sergey A.; Wu, Heyu; Keesing, Daniel B.; O'Sullivan, Joseph A.; Tai, Yuan-Chuan

    2011-01-01

    The integration of a high resolution PET insert into a conventional PET system can significantly improve the resolution and the contrast of its images within a reduced imaging field of view. For the rest of the scanner imaging field of view, the insert is a highly attenuating and scattering media. In order to use all available coincidence events (including coincidences between 2 detectors in the original scanner, namely the scanner-scanner coincidences), appropriate scatter and attenuation corrections have to be implemented. In this work, we conducted a series of Monte Carlo simulations to estimate the composition of the scattering background and the importance of the scatter correction. We implemented and tested the Single Scatter Simulation (SSS) algorithm for a hypothetical system and show good agreement between the estimated scatter using SSS and Monte Carlo simulated scatter contribution. We further applied the SSS to estimate scatter contribution from an existing prototype PET insert for a clinical PET/CT scanner. The results demonstrated the applicability of SSS to estimate the scatter contribution within a clinical PET/CT system even when there is a high resolution half ring PET insert device in its imaging field of view. PMID:21552470

  1. 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

  2. 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

  3. Ribbon scanning confocal for high-speed high-resolution volume imaging of brain

    PubMed Central

    Rose, Annika H.; Gibson, Gregory A.; Gardner, Christina L.; Sun, Chengqun; Reed, Douglas S.; Lam, L. K. Metthew; St. Croix, Claudette M.; Strick, Peter L.; Klimstra, William B.; Watkins, Simon C.

    2017-01-01

    Whole-brain imaging is becoming a fundamental means of experimental insight; however, achieving subcellular resolution imagery in a reasonable time window has not been possible. We describe the first application of multicolor ribbon scanning confocal methods to collect high-resolution volume images of chemically cleared brains. We demonstrate that ribbon scanning collects images over ten times faster than conventional high speed confocal systems but with equivalent spectral and spatial resolution. Further, using this technology, we reconstruct large volumes of mouse brain infected with encephalitic alphaviruses and demonstrate that regions of the brain with abundant viral replication were inaccessible to vascular perfusion. This reveals that the destruction or collapse of large regions of brain micro vasculature may contribute to the severe disease caused by Venezuelan equine encephalitis virus. Visualization of this fundamental impact of infection would not be possible without sampling at subcellular resolution within large brain volumes. PMID:28686653

  4. High-resolution and high-speed CT in industry and research

    NASA Astrophysics Data System (ADS)

    Zabler, S.; Fella, C.; Dietrich, A.; Nachtrab, F.; Salamon, Michael; Voland, V.; Ebensperger, T.; Oeckl, S.; Hanke, R.; Uhlmann, N.

    2012-10-01

    The application of industrial CT covers many orders of magnitude of object sizes, ranging from freight containers (few meters) down to liquid foams (i.e. for food industry) or even parts of insects which are only several hundreds of micrometers in size. Similarly, the specifications for acquisition speed extend over some orders of magnitude, from hours to sub-second CT. We present the current technology in terms of X-ray sources and detectors, along with numerous applications from industry and materials research: e.g. industrial high-speed CT of car pistons, in situ micro-CT of milk foam decay at micrometer spatial resolution and 8 s scan time, as well as ex situ scans of tensile tested Nickel-alloys. The Fraunhofer Development Center X-ray Technology (Fürth, Germany) and the Chair of X-ray Microscopy (University Würzburg, Germany) are currently working on extending the technological limits, demonstrated, e,g. by the development of advanced X-ray detectors or a new inhouse CT system which comprises a high-brilliance liquid metal jet anode.

  5. High-Resolution SPECT-CT/MR Molecular Imaging of Angiogenesis in the Vx2 Model

    PubMed Central

    Lijowski, Michal; Caruthers, Shelton; Hu, Grace; Zhang, Huiying; Scott, Michael J.; Williams, Todd; Erpelding, Todd; Schmieder, Anne H.; Kiefer, Garry; Gulyas, Gyongyi; Athey, Phillip S.; Gaffney, Patrick J.; Wickline, Samuel A.; Lanza, Gregory M.

    2009-01-01

    Background The use of antiangiogenic therapy in conjunction with traditional chemotherapy is becoming increasingly in cancer management, but the optimal benefit of these targeted pharmaceuticals has been limited to a subset of the population treated. Improved imaging probes that permit sensitive detection and high-resolution characterization of tumor angiogenesis could improve patient risk-benefit stratification. Objectives The overarching objective of these experiments was to develop a dual modality αvβ3-targeted nanoparticle molecular imaging agent that affords sensitive nuclear detection in conjunction with high-resolution MR characterization of tumor angiogenesis. Materials and Methods In part 1, New Zealand white rabbits (n = 21) bearing 14d Vx2 tumor received either αvβ3-targeted 99mTc nanoparticles at doses of 11, 22, or 44 MBq/kg, nontargeted 99mTc nanoparticles at 22 MBq/kg, or αvβ3-targeted 99mTc nanoparticles (22 MBq/kg) competitively inhibited with unlabeled αvβ3-nanoparticles. All animals were imaged dynamically over 2 hours with a planar camera using a pinhole collimator. In part 2, the effectiveness of αvβ3-targeted 99mTc nanoparticles in the Vx2 rabbit model was demonstrated using clinical SPECT-CT imaging techniques. Next, MR functionality was incorporated into αvβ3-targeted 99mTc nanoparticles by inclusion of lipophilic gadolinium chelates into the outer phospholipid layer, and the concept of high sensitivity – high-resolution detection and characterization of tumor angiogenesis was shown using sequential SPECT-CT and MR molecular imaging with 3D neovascular mapping. Results αvβ3-Targeted 99mTc nanoparticles at 22 MBq/kg produced the highest tumor-to-muscle contrast ratio (8.56 ± 0.13, TMR) versus the 11MBq/kg (7.32 ± 0.12) and 44 MBq/kg (6.55 ± 0.07) doses, (P < 0.05). TMR of nontargeted particles at 22.2 MBq/kg (5.48 ± 0.09) was less (P < 0.05) than the equivalent dosage of αvβ3-targeted 99mTc nanoparticles. Competitively

  6. High-resolution CT findings of Mycobacterium avium-intracellulare complex pulmonary disease: correlation with pulmonary function test results.

    PubMed

    Song, Jong Woon; Koh, Won-Jung; Lee, Kyung Soo; Lee, Ji Young; Chung, Myung Jin; Kim, Tae Sung; Kwon, O Jung

    2008-10-01

    The purpose of our study was to analyze the high-resolution CT findings of the nodular bronchiectatic form of Mycobacterium avium-intracellulare complex (MAC) pulmonary disease and to correlate the extent of high-resolution CT findings with pulmonary function test (PFT) results. From January 2005 through December 2005, we identified 47 patients (mean age, 58 +/- 13 years; age range, 24-72 years; male-female ratio, 11:36) with the nodular bronchiectatic form of MAC pulmonary disease who underwent both high-resolution CT and PFTs. High-resolution CT findings were reviewed retrospectively in terms of the presence and extent of bronchiectasis, cellular or inflammatory bronchiolitis (centrilobular small nodules and tree-in-bud signs), cavity, nodule, and other findings. The extent of the abnormalities seen on high-resolution CT was scored by modifying the cystic fibrosis scoring system proposed by Helbich and coworkers. The scores were correlated with PFT results using Spearman's correlation coefficient. On high-resolution CT, the three most frequently observed patterns of parenchymal abnormalities were, in decreasing order of frequency, cellular bronchiolitis (n = 47, 100%), bronchiectasis (n = 46, 98%), and consolidation (n = 27, 57%). The total CT score showed a significant correlation with the residual volume-total lung capacity (RV/TLC) ratio (r = 0.572, p < 0.001), forced expiratory volume in 1 second (FEV(1)) value (r = -0.426, p = 0.003), forced vital capacity (FVC) value (r = -0.360, p = 0.013), peak expiratory flow value (r = -0.352, p = 0.015), and peak expiratory flow between 25% and 75% of the forced vital capacity (FEF(25-75%)) (r = -0.289, p = 0.049). CT scoring of pulmonary abnormalities correlates with measures of functional impairment in patients with MAC pulmonary disease.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. CT densities in delayed iodine hepatic scanning

    SciTech Connect

    Perkerson, R.B. Jr.; Erwin, B.C.; Baumgartner, B.R.; Phillips, V.M.; Torres, W.E.; Clements, J.L. Jr.; Gedgaudas-McClees, K.; Bernardino, M.E.

    1985-05-01

    Sixty patients underwent CT scanning of the liver prior to, immediately after, and four hours after intravenous administration of 60% meglumine diatrizoate. Twenty patients received a 50 ml bolus of contrast material, 20 received 100 ml, and 20 received 200 ml. In each group, delayed CT scanning safely raised the inherent density of the liver significantly. Thus, delayed scanning with doses presently used in abdominal and neurological CT examinations may be helpful in detecting hepatic lesions.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. High-resolution CT of the sternoclavicular joint and first costochondral synchondrosis in asymptomatic individuals.

    PubMed

    De Maeseneer, Michel; Lenchik, Leon; Buls, Nico; Boulet, Cedric; Döring, Seema; de Mey, Johan; Willekens, Inneke

    2016-09-01

    To assess CT features of the sternoclavicular joint (SCJ) and first costochondral junction in asymptomatic patients. In 66 patients transverse and coronal oblique high-resolution multiple detector CT images of the SCJ and first costochondral junction were obtained. Images were reviewed by consensus of two radiologists. Joint space width was measured at three levels, and osteophytes, geodes, and erosions were evaluated. Variants and degree of ossification were noted. Statistical analysis consisted of Shapiro-Wilk test, Pearson's test, and paired sample t test. There were 34 men and 32 women with a mean age of 60 years (age range, 17-98 years). The width of the joint spaces showed a normal distribution. There was no significant difference between the left and right sides. On coronal images the joint space was wider superiorly and on transverse images posteriorly. There was a trend toward decreasing joint space with age, although it did not reach significance (p > 0.05). Clavicular osteophytes were seen in 16 out of 66 patients (24 %) and sternal osteophytes in 16 out of 66 patients. Clavicular geodes were seen in 10 out of 66 patients (15 %) and sternal geodes in 14 out of 66 patients (14 %). No erosions were seen. Clefts of the first costochondral junction were seen in 31 out of 66 patients (47 %). In asymptomatic patients, there is no significant asymmetry of the SCJ. The joint spaces did not significantly decrease with age, although such a trend could be observed. Pronounced joint space narrowing with large geodes and osteophytes was not seen. Clefts of the first costochondral junction are common and not significant.

  19. PET/CT and High Resolution CT as potential imaging biomarkers associated with treatment outcomes in MDR-TB

    PubMed Central

    Chen, Ray Y.; Dodd, Lori E.; Lee, Myungsun; Paripati, Praveen; Hammoud, Dima A.; Mountz, James M.; Jeon, Doosoo; Zia, Nadeem; Zahiri, Homeira; Coleman, M. Teresa; Carroll, Matthew W.; Lee, Jong Doo; Jeong, Yeon Joo; Herscovitch, Peter; Lahouar, Saher; Tartakovsky, Michael; Rosenthal, Alexander; Somaiyya, Sandeep; Lee, Soyoung; Goldfeder, Lisa C.; Cai, Ying; Via, Laura E.; Park, Seung-Kyu; Cho, Sang-Nae; Barry, Clifton E.

    2017-01-01

    Definitive clinical trials of new chemotherapies for tuberculosis (TB) treatment require following subjects until at least six months after treatment discontinuation to assess for durable cure, making these trials expensive and lengthy. Surrogate endpoints relating to treatment failure and relapse are currently limited to sputum microbiology, which has limited sensitivity and specificity. In this study we prospectively assessed radiographic changes using 2-deoxy-2-[18F]-fluoro-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) at two months and six months (CT only) in a cohort of subjects with multidrug-resistant (MDR) TB who were treated with second-line TB therapy for two years and then followed for an additional six months. CT scans were read semi-quantitatively by radiologists and computationally evaluated using custom software to provide volumetric assessment of TB-associated abnormalities. CT scans at six months assessed by readers were predictive of outcomes but not two months and changes in computed abnormal volumes were predictive at both time points. Quantitative changes in FDG uptake two months after starting treatment were associated with long-term outcomes. In this cohort, some radiologic markers were more sensitive than conventional sputum microbiology in distinguishing successful from unsuccessful treatment. These results support the potential of imaging biomarkers as possible surrogate endpoints in clinical trials of new TB drug regimens. Larger cohorts confirming these results are needed. PMID:25473034

  20. 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.

  1. 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.

  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. [Chest high resolution CT features of extrinsic allergic alveolitis and its diagnostic value].

    PubMed

    Ban, Cheng-jun; Dai, Hua-ping; Zhang, Shu; Zhang, Lei; Ye, Qiao; Zhu, Min

    2010-04-27

    To summarize the chest high-resolution CT (HRCT) features of the patients with extrinsic allergic alveolitis (EAA). We analyzed the images of chest HRCT of 34 patients diagnosed as EAA at our hospital from February 2001 to August 2009. All patients had a history of environmental exposure. The duration of intermittent or continuous antigen exposure was from 3 months to 13 years. Two patients showed acute clinical manifestations. There were 22 sub-acute and 10 chronic cases. Acute EAA was characterized by ground-glass opacities, air trapping and/or mosaic sign on HRCT. The HRCT features of subacute EAA included patchy ground-glass opacities with mosaic sign (n = 11, 50.0%) and diffusely distributed centrilobular nodules (n = 7, 31.8%) with mosaic sign (n = 4, 18.2%). All patients with chronic EAA had reticular and honeycombing lesions on HRCT. There were 3 cases with ground-glass opacities, 3 with mosaic sign, and 3 with centrilobular nodules. The typical findings of chest HRCT are helpful for making a diagnosis and differential diagnosis of EAA.

  4. 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.

  5. 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).

  6. 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

  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. 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.

  9. 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.

  10. Near-Field Scanning Optical Microscopy for High-Resolution Membrane Studies

    PubMed Central

    Huckabay, Heath A.; Armendariz, Kevin P.; Newhart, William H.; Wildgen, Sarah M.; Dunn, Robert C.

    2012-01-01

    The desire to directly probe biological structures on the length scales that they exist has driven the steady development of various high-resolution microscopy techniques. Among these, optical microscopy and, in particular, fluorescence-based approaches continue to occupy dominant roles in biological studies given their favorable attributes. Fluorescence microscopy is both sensitive and specific, is generally noninvasive toward biological samples, has excellent temporal resolution for dynamic studies, and is relatively inexpensive. Light-based microscopies can also exploit a myriad of contrast mechanisms based on spectroscopic signatures, energy transfer, polarization, and lifetimes to further enhance the specificity or information content of a measurement. Historically, however, spatial resolution has been limited to approximately half the wavelength due to the diffraction of light. Near-field scanning optical microscopy (NSOM) is one of several optical approaches currently being developed that combines the favorable attributes of fluorescence microscopy with superior spatial resolution. NSOM is particularly well suited for studies of both model and biological membranes and application to these systems is discussed. PMID:23086886

  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. 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.

  13. Quantitative analysis of high-resolution computed tomography scans in severe asthma subphenotypes

    PubMed Central

    Gupta, Sumit; Siddiqui, Salman; Haldar, Pranab; Entwisle, James J; Mawby, Dean; Wardlaw, Andrew J; Bradding, Peter; Pavord, Ian D; Green, Ruth H

    2010-01-01

    Background Severe asthma is a heterogeneous condition. Airway remodelling is a feature of severe asthma and can be determined by the assessment of high-resolution computed tomography (HRCT) scans. The aim of this study was to assess whether airway remodelling is restricted to specific subphenotypes of severe asthma. Methods A retrospective analysis was performed of HRCT scans from subjects who had attended a single-centre severe asthma clinic between 2003 and 2008. The right upper lobe apical segmental bronchus (RB1) dimensions were measured and the clinical and sputum inflammatory characteristics associated with RB1 geometry were assessed by univariate and multivariate regression analyses. Longitudinal sputum data were available and were described as area under the time curve (AUC). Comparisons were made in RB1 geometry across subjects in four subphenotypes determined by cluster analysis, smokers and non-smokers, and subjects with and without persistent airflow obstruction. Results Ninety-nine subjects with severe asthma and 16 healthy controls were recruited. In the subjects with severe asthma the RB1 percentage wall area (%WA) was increased (p=0.009) and lumen area (LA)/body surface area (BSA) was decreased (p=0.008) compared with controls but was not different across the four subphenotypes. Airway geometry was not different between smokers and non-smokers and RB1 %WA was increased in those with persistent airflow obstruction. RB1 %WA in severe asthma was best associated with airflow limitation and persistent neutrophilic airway inflammation (model R2=0.27, p=0.001). Conclusions Airway remodelling of proximal airways occurs in severe asthma and is associated with impaired lung function and neutrophilic airway inflammation. PMID:20805170

  14. 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.

  15. 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.

  16. 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

  17. High-resolution scanning tunneling microscopy of fully hydrated ripple-phase bilayers.

    PubMed

    Woodward, J T; Zasadzinski, J A

    1997-02-01

    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 P beta' 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 to soft biological materials; the technique is substrate-free, and the conductive and chemically uniform replicas make image interpretation simple and direct.

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. The use of pretest probability increases the value of high-resolution CT in diagnosing usual interstitial pneumonia.

    PubMed

    Brownell, Robert; Moua, Teng; Henry, Travis S; Elicker, Brett M; White, Darin; Vittinghoff, Eric; Jones, Kirk D; Urisman, Anatoly; Aravena, Carlos; Johannson, Kerri A; Golden, Jeffrey A; King, Talmadge E; Wolters, Paul J; Collard, Harold R; Ley, Brett

    2017-05-01

    Recent studies have suggested that non-definitive patterns on high-resolution CT (HRCT) scan provide sufficient diagnostic specificity to forgo surgical lung biopsy in the diagnosis of idiopathic pulmonary fibrosis (IPF). The objective of this study was to determine test characteristics of non-definitive HRCT patterns for identifying histopathological usual interstitial pneumonia (UIP). Patients with biopsy-proven interstitial lung disease (ILD) and non-definitive HRCT scans were identified from two academic ILD centres. Test characteristics for HRCT patterns as predictors of UIP on surgical lung biopsy were derived and validated in independent cohorts. In the derivation cohort, 64/385 (17%) had possible UIP pattern on HRCT; 321/385 (83%) had inconsistent with UIP pattern. 113/385 (29%) patients had histopathological UIP pattern in the derivation cohort. Possible UIP pattern had a specificity of 91.2% (95% CI 87.2% to 94.3%) and a positive predictive value (PPV) of 62.5% (95% CI 49.5% to 74.3%) for UIP pattern on surgical lung biopsy. The addition of age, sex and total traction bronchiectasis score improved the PPV. Inconsistent with UIP pattern demonstrated poor PPV (22.7%, 95% CI 18.3% to 27.7%). HRCT pattern specificity was nearly identical in the validation cohort (92.7%, 95% CI 82.4% to 98.0%). The substantially higher prevalence of UIP pattern in the validation cohort improved the PPV of HRCT patterns. A possible UIP pattern on HRCT has high specificity for UIP on surgical lung biopsy, but PPV is highly dependent on underlying prevalence. Adding clinical and radiographic features to possible UIP pattern on HRCT may provide sufficient probability of histopathological UIP across prevalence ranges to change clinical decision-making. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  3. Upscaling of Heterogeneous Porous Rocks Using High Resolution Hydrogeophysical Scanning Measurements

    NASA Astrophysics Data System (ADS)

    Bussod, G. Y.; Svyatskiy, D.; Zyvoloski, G.; Boitnott, G. N.; Lichtner, P. C.; Moulton, J. D.

    2009-12-01

    This research is part of a DOE SBIR project that combines physical properties measurements on consolidated and unconsolidated subsurface lithologies, with numerical and effective media models that describe subsurface contaminant flow and transport. This paper presents results from an application of a new high-resolution methodology for the laboratory characterization of hydrogeophysical properties on core and field samples. The methodology is used to constrain contaminant flow and transport models for both unsaturated and saturated subsurface conditions. Spatially integrated fine-scale scanning (mm-cm resolution) of permeabilities, ultrasonic velocities and electrical conductivities on core and field samples are used to quantify heterogeneities at the smallest continuum scale. Through application of numerical and effective medium upscaling techniques, the scans provide a means to assign hydrogeophysical properties and model parameters at scales more appropriate to field applications, while preserving the physical influence of fine scale heterogeneities that cannot be explicitly modeled. The methodology is being applied to several contaminated DOE sites at LANL, NM, Hanford, WA and Rifle, CO. We illustrate that fine- and meso- scale heterogeneities (mm-m) can cause significant saturation dependent anisotropy in hydrogeophysical properties (e.g., electrical conductivity and relative permeability). These effects are captured in our upscaling methodology to provide more accurate model parameters used in representation of the contaminated subsurface. Through a series of examples, we show how quantification of the fine scale heterogeneities of a particular flow unit can be used to constrain upscaled model properties at the meter scale. We show that as a result of these heterogeneities, the change in scale from centimeters to meters requires a change in character of the capillary pressure / relative permeability relationships. As an example, we find that after applying

  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 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

  6. 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

  7. High-resolution imaging of magnetic fields using scanning superconducting quantum interference device (SQUID) microscopy

    NASA Astrophysics Data System (ADS)

    Fong de Los Santos, Luis E.

    Development of a scanning superconducting quantum interference device (SQUID) microscope system with interchangeable sensor configurations for imaging magnetic fields of room-temperature (RT) samples with sub-millimeter resolution. The low-critical-temperature (Tc) niobium-based monolithic SQUID sensor is mounted in the tip of a sapphire rod and thermally anchored to the cryostat helium reservoir. A 25 mum sapphire window separates the vacuum space from the RT sample. A positioning mechanism allows adjusting the sample-to-sensor spacing from the top of the Dewar. I have achieved a sensor-to-sample spacing of 100 mum, which could be maintained for periods of up to 4 weeks. Different SQUID sensor configurations are necessary to achieve the best combination of spatial resolution and field sensitivity for a given magnetic source. For imaging thin sections of geological samples, I used a custom-designed monolithic low-Tc niobium bare SQUID sensor, with an effective diameter of 80 mum, and achieved a field sensitivity of 1.5 pT/Hz1/2 and a magnetic moment sensitivity of 5.4 x 10-18 Am2/Hz1/2 at a sensor-to-sample spacing of 100 mum in the white noise region for frequencies above 100 Hz. Imaging action currents in cardiac tissue requires higher field sensitivity, which can only be achieved by compromising spatial resolution. I developed a monolithic low-Tc niobium multiloop SQUID sensor, with sensor sizes ranging from 250 mum to 1 mm, and achieved sensitivities of 480 - 180 fT/Hz1/2 in the white noise region for frequencies above 100 Hz, respectively. For all sensor configurations, the spatial resolution was comparable to the effective diameter and limited by the sensor-to-sample spacing. Spatial registration allowed us to compare high-resolution images of magnetic fields associated with action currents and optical recordings of transmembrane potentials to study the bidomain nature of cardiac tissue or to match petrography to magnetic field maps in thin sections of

  8. 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.

  9. 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

  10. Defect detection on hardwood logs using high resolution three-dimensional laser scan data

    Treesearch

    Liya Thomas; Lamine Mili; Clifford A. Shaffer; Ed Thomas; Ed Thomas

    2004-01-01

    The location, type, and severity of external defects on hardwood logs and skills are the primary indicators of overall log quality and value. External defects provide hints about the internal log characteristics. Defect data would improve the sawyer's ability to process logs such that a higher valued product (lumber) is generated. Using a high-resolution laser log...

  11. 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.

  12. Characterising the Geomorphology of Forested Floodplains Using High Resolution Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Sear, D. A.; Brasington, J.; Darby, S. E.

    2007-12-01

    Forested floodplain environments represent the undisturbed land cover of most temperate and tropical river systems, but they are under threat from human resource management (Hughes et al., 2005, FLOBAR II Project report). A scientific understanding of forest floodplain processes therefore has relevance to ecosystem conservation and restoration, and the interpretation of pre-historic river and floodplain evolution. Empirical research has highlighted how overbank flows are relatively shallow and strongly modified by floodplain topography and the presence of vegetation and organic debris on the woodland floor [Jeffries et al., 2003, Geomorphology, 51, 61-80; Millington and Sear, 2007, Earth. Surf. Proc. Landforms, 32, doi: 10.1002/esp.1552]. In such instances flow blockage and diversions are common, and there is the possibility of frequent switches from sub-critical to locally super-critical flow. Such conditions also favour turbulence generation, both by wakes and by shear. Consequently, the floodplain terrain (where we take 'terrain' to include the underlying topography, root structures, and organic debris) plays a key role in modulating the processes of erosion and sedimentation that underpin the physical habitat diversity and hydraulic characteristics of complex wooded floodplain surfaces. However, despite the importance of these issues, as yet there are no formal, quantitative, descriptions of the highly complex and spatially diverse micro- and meso-topography that appears to be characteristic of forested floodplain surfaces. To address this gap, we have undertaken detailed surveys on a small floodplain reach within the Highland Water Research Catchment (HWRC: see http://www.geog.soton.ac.uk/research/nfrc/default.asp), which is a UK national reference site for lowland floodplain forest streams. This involved the deployment of a Leica ScanStation terrestrial laser-scanner from 14 setups and ranges of less than 30 m to acquire an extremely high resolution, accurate

  13. Asbestosis and other pulmonary fibrosis in asbestos-exposed workers: high-resolution CT features with pathological correlations.

    PubMed

    Arakawa, Hiroaki; Kishimoto, Takumi; Ashizawa, Kazuto; Kato, Katsuya; Okamoto, Kenzo; Honma, Koichi; Hayashi, Seiji; Akira, Masanori

    2016-05-01

    The purpose was to identify distinguishing CT features of pathologically diagnosed asbestosis, and correlate diagnostic confidence with asbestos body burden. Thirty-three workers (mean age at CT: 73 years) with clinical diagnoses of asbestosis, who were autopsied (n = 30) or underwent lobectomy (n = 3), were collected. Two radiologists independently scored high-resolution CT images for various CT findings and the likelihood of asbestosis was scored. Two pathologists reviewed the pathology specimens and scored the confidence of their diagnoses. Asbestos body count was correlated with CT and pathology scores. Pathologically, 15 cases were diagnosed as asbestosis and 18 cases with various lung fibroses other than asbestosis. On CT, only the score of the subpleural curvilinear lines was significantly higher in asbestosis (p = 0.03). Accuracy of CT diagnosis of asbestosis with a high confidence ranged from 0.73 to 0.79. Asbestos body count positively correlated with CT likelihood of asbestosis (r = 0.503, p = 0.003), and with the confidence level of pathological diagnosis (r = 0.637, p < 0.001). Subpleural curvilinear lines were the only clue for the diagnosis of asbestosis. However, this was complicated by other lung fibrosis, especially at low asbestos body burden. • Various patterns of pulmonary fibrosis occurred in asbestos-exposed workers. • The fibre burden in lungs paralleled confident CT diagnosis of asbestosis. • The fibre burden in lungs paralleled confident pathological diagnosis of asbestosis. • Subpleural curvilinear lines were an important CT finding favouring asbestosis.

  14. 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

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

    PubMed

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

    2015-07-03

    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.

  16. Automatic high-resolution infarct detection using volumetric multiphase dual-energy CT.

    PubMed

    Sandfort, Veit; Kwan, Alan C; Elumogo, Comfort; Vigneault, Davis M; Symons, Rolf; Pourmorteza, Amir; Rice, Kelly; Davies-Venn, Cynthia; Ahlman, Mark A; Liu, Chia-Ying; Zimmerman, Stefan L; Bluemke, David A

    Late contrast enhancement CT (LCE-CT) visualizes the presence of myocardial infarcts. Differentiation of the contrast-enhanced infarct from blood pool is challenging. We developed a novel method using data from first pass CT angiography (CTA) imaging to enable automatic infarct detection. A canine model of myocardial infarction was produced in 11 animals. Two months later, first pass CTA (90 kVp) and LCE-CT (dual energy 90 kVp/150 kVp tin filtered) were performed. Late gadolinium enhancement MRI was used as reference standard. The CTA and LCE-CT were co-registered using a fully automatic non-rigid method based on curved B-splines. The method allowed for limited elastic deformation and the considerable differences in attenuation between first-pass and delayed image. The blood pool was easily identified on the CTA image by high attenuation. Because CTA and LCE-CT were registered, the blood pool segmentation can be directly transferred to the LCE-CT - thereby solving the key problem of infarct/blood pool differentiation. The remaining segmentation of infarcted vs. noninfarcted myocardium was performed using a threshold. Automatic and MRI-guided expert segmentations of LCE-CT infarcts were compared to each other on volume and area basis (intraclass correlation coefficient, ICC) and on voxel basis (dice similarity coefficient, DSC between automatic and expert CT segmentation). CT infarct volumes were compared with the reference standard MRI. The infarcts were mainly subendocardial (81%) and relatively small (median MRI infarct mass 7.4 g). The automatic segmentation showed excellent agreement with expert segmentation on volume and area measurements (ICC = 0.96 and 0.87, respectively). DSC showed moderately good agreement (DSC = 0.47). Compared to MRI there was modest agreement (ICC = 0.62) and excellent correlation (R = 0.9). Manual interaction was less than 1 min per exam. We propose an automatic method for infarct segmentation on LCE-CT using multiphase CT

  17. A dataset describing brooding in three species of South African brittle stars, comprising seven high-resolution, micro X-ray computed tomography scans.

    PubMed

    Landschoff, Jannes; Du Plessis, Anton; Griffiths, Charles L

    2015-01-01

    Brooding brittle stars have a special mode of reproduction whereby they retain their eggs and juveniles inside respiratory body sacs called bursae. In the past, studying this phenomenon required disturbance of the sample by dissecting the adult. This caused irreversible damage and made the sample unsuitable for future studies. Micro X-ray computed tomography (μCT) is a promising technique, not only to visualise juveniles inside the bursae, but also to keep the sample intact and make the dataset of the scan available for future reference. Seven μCT scans of five freshly fixed (70 % ethanol) individuals, representing three differently sized brittle star species, provided adequate image quality to determine the numbers, sizes and postures of internally brooded young, as well as anatomy and morphology of adults. No staining agents were necessary to achieve high-resolution, high-contrast images, which permitted visualisations of both calcified and soft tissue. The raw data (projection and reconstruction images) are publicly available for download from GigaDB. Brittle stars of all sizes are suitable candidates for μCT imaging. This explicitly adds a new technique to the suite of tools available for studying the development of internally brooded young. The purpose of applying the technique was to visualise juveniles inside the adult, but because of the universally good quality of the dataset, the images can also be used for anatomical or comparative morphology-related studies of adult structures.

  18. 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.

  19. Data-fusion of high resolution X-ray CT, SEM and EDS for 3D and pseudo-3D chemical and structural characterization of sandstone.

    PubMed

    De Boever, Wesley; Derluyn, Hannelore; Van Loo, Denis; Van Hoorebeke, Luc; Cnudde, Veerle

    2015-07-01

    When dealing with the characterization of the structure and composition of natural stones, problems of representativeness and choice of analysis technique almost always occur. Since feature-sizes are typically spread over the nanometer to centimeter range, there is never one single technique that allows a rapid and complete characterization. Over the last few decades, high resolution X-ray CT (μ-CT) has become an invaluable tool for the 3D characterization of many materials, including natural stones. This technique has many important advantages, but there are also some limitations, including a tradeoff between resolution and sample size and a lack of chemical information. For geologists, this chemical information is of importance for the determination of minerals inside samples. We suggest a workflow for the complete chemical and structural characterization of a representative volume of a heterogeneous geological material. This workflow consists of combining information derived from CT scans at different spatial resolutions with information from scanning electron microscopy and energy-dispersive X-ray spectroscopy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. 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

  1. 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.

  2. Evaluation of high-resolution melting (HRM) for mutation scanning of selected exons of the CFTR gene.

    PubMed

    Krenková, P; Norambuena, P; Stambergová, A; Macek, M

    2009-01-01

    Hereby we present evaluation of high-resolution melting for mutation scanning applied to the cystic fibrosis transmembrane conductance regulator gene. High resolution melting was used for mutation scanning of selected samples derived from cystic fibrosis patients with a known cystic fibrosis transmembrane conductance regulator genotype. We tested 19 different disease-causing cystic fibrosis transmembrane conductance regulator mutant genotypes located within six exons of the cystic fibrosis transmembrane conductance regulator gene (4, 7, 10, 11, 14b and 22). Normalized melting curves of tested samples were compared to sequenced-verified wildtype samples. Determined mutations are as follows: p.F508del, p.I507del, p.G551D, p.R347P, c.1717- 1G>A, c.621+1G>T, p.Y122X, p.I336K, p.R553X, c.2789+5G>A, c.574delA, c.1811+1G>C, p.L1335F, p.L1335P, p.L1324P and p.M470V and represent minimally 76.5 % of all cystic fibrosis alleles detected in the Czech cystic fibrosis population. All analysed samples with mutant genotypes were unambiguously distinguished from wild-type samples. High-resolution melting analysis enabled reliable detection of all single-nucleotide polymorphism classes and 1- or 3- base pair deletions. We examined the specificity, sensitivity and precision of this methodology. High-resolution melting analysis is an economical, sensitive and specific close-tube method and has a high utility for the detection of unknown mutations in cystic fibrosis DNA diagnostics.

  3. High-resolution imaging of murine myocardial infarction with delayed-enhancement cine micro-CT.

    PubMed

    Nahrendorf, Matthias; Badea, Cristian; Hedlund, Laurence W; Figueiredo, Jose-Luiz; Sosnovik, David E; Johnson, G Allan; Weissleder, Ralph

    2007-06-01

    The objective of this study was to determine the feasibility of delayed-enhancement micro-computed tomography (microCT) imaging to quantify myocardial infarct size in experimental mouse models. A total of 20 mice were imaged 5 or 35 days after surgical ligation of the left coronary artery or sham surgery (n=6 or 7 per group). We utilized a prototype microCT that covers a three-dimensional (3D) volume with an isotropic spatial resolution of 100 microm. A series of image acquisitions were started after a 200 microl bolus of a high-molecular-weight blood pool CT agent to outline the ventricles. CT imaging was continuously performed over 60 min, while an intravenous constant infusion with iopamidol 370 was started at a dosage of 1 ml/h. Thirty minutes after the initiation of this infusion, signal intensity in Hounsfield units was significantly higher in the infarct than in the remote, uninjured myocardium. Cardiac morphology and motion were visualized with excellent contrast and in fine detail. In vivo CT determination of infarct size at the midventricular level was in good agreement with ex vivo staining with triphenyltetrazolium chloride [5 days post-myocardial infarction (MI): r(2)=0.86, P<0.01; 35 days post-MI: r(2)=0.92, P<0.01]. In addition, we detected significant left ventricular remodeling consisting of left ventricular dilation and decreased ejection fraction. 3D cine microCT reliably and rapidly quantifies infarct size and assesses murine anatomy and physiology after coronary ligation, despite the small size and fast movement of the mouse heart. This efficient imaging tool is a valuable addition to the current phenotyping armamentarium and will allow rapid testing of novel drugs and cell-based interventions in murine models.

  4. High Resolution Imaging of Murine Myocardial Infarction With Delayed Enhancement and Cine Micro-CT

    PubMed Central

    Nahrendorf, Matthias; Badea, Cristian; Hedlund, Laurence W; Figueiredo, Jose-Luiz; Sosnovik, David E.; Johnson, G Allan; Weissleder, Ralph

    2009-01-01

    Objective To determine the feasibility of delayed enhancement µCT imaging to quantify myocardial infarct size in experimental mouse models. Methods and Results A total of 20 mice were imaged 5 or 35 days after surgical ligation of the left coronary artery, or sham surgery (n=6–7 per group). We utilized a prototype εCT which covers a 3D volume with an isotropic spatial resolution of 100 µm. A series of image acquisitions were started after a 200 µL bolus of a high molecular weight blood pool CT agent to outline the ventricles. CT imaging was continuously performed over 60 minutes, while an intravenous constant infusion with iopamidol 370 was started at a dosage of 1 mL/h. Thirty minutes after the initiation of this infusion, signal intensity in Hounsfild Units was significantly higher in the infarct than in the remote, uninjured myocardium. Cardiac morphology and motion was visualized with excellent contrast and in fine detail. In vivo CT determination of infarct extension and transmurality was in good agreement with ex vivo staining with triphenyltetrazolium chloride (5 days post MI: r2= 0.86, p < 0.01; 35 days post MI r2=0.92, p < 0.01). In addition, we detected significant left ventricular remodeling consisting of left ventricular dilation and decreased ejection fraction. Conclusion 3D cine µCT reliably and rapidly quantifies infarct size and assesses murine anatomy and physiology after coronary ligation, despite the small size and the fast movement of the mouse heart. This efficient imaging tool is a valuable addition to the current phenotyping armamentarium and will allow rapid testing of novel drugs and cell based interventions in murine models. PMID:17322414

  5. High-resolution CT findings of primary lung cancer with cavitation: a comparison between adenocarcinoma and squamous cell carcinoma.

    PubMed

    Kunihiro, Y; Kobayashi, T; Tanaka, N; Matsumoto, T; Okada, M; Kamiya, M; Ueda, K; Kawano, H; Matsunaga, N

    2016-11-01

    To evaluate the high-resolution computed tomography (CT) findings of primary lung cancer with cavitation and compare the findings in adenocarcinoma and squamous cell carcinoma. The high-resolution CT findings of tumours with cavitation were retrospectively evaluated in 60 patients. Forty-seven of the lesions were diagnosed as adenocarcinomas; 13 were diagnosed as squamous cell carcinomas. The diameters of the tumour and cavity, the maximum thickness of the cavity wall, shape of the cavity wall, the number of cavities, and the presence of ground-glass opacity, bronchial obstruction, intratumoural bronchiectasis, emphysema, and honeycombing were evaluated. The mechanisms of cavity formation were examined according to the pathological features. The maximum thickness of the cavity wall was significantly greater in squamous cell carcinomas than in adenocarcinomas (p=0.002). Ground-glass opacity and intratumoural bronchiectasis were significantly more common in adenocarcinomas than in squamous cell carcinomas (p<0.001 and p=0.040, respectively). Regarding the pathological findings, intratumoural bronchiectasis with or without alveolar wall destruction contributed to a significant difference between adenocarcinoma and squamous cell carcinoma (p<0.001; odds ratio [OR], 20.35; 95% confidence interval [CI], 3.87-107.10). The cavity wall tends to be thicker in squamous cell carcinomas than in adenocarcinomas. The presence of ground-glass opacity and intratumoural bronchiectasis is strongly suggestive of adenocarcinoma. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  6. 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.

  7. Monte Carlo simulations of a high-resolution X-ray CT system for industrial applications

    NASA Astrophysics Data System (ADS)

    Miceli, A.; Thierry, R.; Flisch, A.; Sennhauser, U.; Casali, F.; Simon, M.

    2007-12-01

    An X-ray computed tomography (CT) model based on the GEANT4 Monte Carlo code was developed for simulation of a cone-beam CT system for industrial applications. The full simulation of the X-ray tube, object, and area detector was considered. The model was validated through comparison with experimental measurements of different test objects. There is good agreement between the simulated and measured projections. To validate the model we reduced the beam aperture of the X-ray tube, using a source-collimator, to decrease the scattered radiation from the CT system structure and from the walls of the X-ray shielding room. The degradation of the image contrast using larger beam apertures is also shown. Thereafter, the CT model was used to calculate the spatial distribution and the magnitude of the scattered radiation from different objects. It has been assessed that the scatter-to-primary ratio (SPR) is below 5% for small aluminum objects (approx. 5 cm path length), and in the case of large aluminum objects (approx. 20 cm path length) it can reach up to a factor of 3 in the region corresponding to the maximum path length. Therefore, the scatter from the object significantly affects quantitative accuracy. The model was also used to evaluate the degradation of the image contrast due to the detector box.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Spectral deblurring: an algorithm for high-resolution, hybrid spectral CT

    NASA Astrophysics Data System (ADS)

    Clark, D. P.; Badea, C. T.

    2015-03-01

    We are developing a hybrid, dual-source micro-CT system based on the combined use of an energy integrating (EID) x-ray detector and a photon counting x-ray detector (PCXD). Due to their superior spectral resolving power, PCXDs have the potential to reduce radiation dose and to enable functional and molecular imaging with CT. In most current PCXDs, however, spatial resolution and field of view are limited by hardware development and charge sharing effects. To address these problems, we propose spectral deblurring—a relatively simple algorithm for increasing the spatial resolution of hybrid, spectral CT data. At the heart of the algorithm is the assumption that the underlying CT data is piecewise constant, enabling robust recovery in the presence of noise and spatial blur by enforcing gradient sparsity. After describing the proposed algorithm, we summarize simulation experiments which assess the trade-offs between spatial resolution, contrast, and material decomposition accuracy given realistic levels of noise. When the spatial resolution between imaging chains has a ratio of 5:1, spectral deblurring results in a 52% increase in the material decomposition accuracy of iodine, gadolinium, barium, and water vs. linear interpolation. For a ratio of 10:1, a realistic representation of our hybrid imaging system, a 52% improvement was also seen. Overall, we conclude that the performance breaks down around high frequency and low contrast structures. Following the simulation experiments, we apply the algorithm to ex vivo data acquired in a mouse injected with an iodinated contrast agent and surrounded by vials of iodine, gadolinium, barium, and water.

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

    PubMed

    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.

  14. 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.

  15. 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.

  16. 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

  17. Lung nodule volume quantification and shape differentiation with an ultra-high resolution technique on a photon counting detector CT system

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

    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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. High-resolution CT findings of pulmonary tuberculosis in liver transplant patients.

    PubMed

    Schuhmacher Neto, R; Giacomelli, I L; Schuller Nin, C; da Silva Moreira, J; Comaru Pasqualotto, A; Marchiori, E; Loureiro Irion, K; Hochhegger, B

    2017-10-01

    To assess the high-resolution computed tomography (HRCT) findings in liver transplant patients diagnosed with pulmonary Mycobacterium tuberculosis infection. The HRCT findings from 19 patients diagnosed with pulmonary tuberculosis infection after liver transplantation were reviewed. The patients included were 12 men and seven women, age range 23-65 years; mean age 57 years. The diagnosis was established with Mycobacterium tuberculosis detection in bronchoalveolar lavage, sputum, or biopsy. HRCT images were reviewed independently by two observers who reached a consensus decision. The HRCT findings were classified as (1) miliary nodules; (2) cavitation and centrilobular tree-in-bud nodules; (3) ground-glass attenuation and consolidation; and (4) mediastinal lymph node enlargement. The time between the transplantation and the diagnosis of pulmonary tuberculosis ranged from 7 to 153 days with an average of 79 days. The main HRCT pattern was cavitation and centrilobular tree-in-bud nodules (79%) followed by mediastinal lymph node enlargement (10.4%), ground-glass attenuation or consolidation (5.2%) and miliary nodules (5.2%). None of the patients presented pleural effusion. The cavitation and centrilobular tree-in-bud nodules pattern had upper lobe predominance, and ground-glass attenuation and consolidation pattern had middle lobe/lingular segment predominance. The main HRCT pattern of pulmonary tuberculosis in liver transplant patients was cavitation and centrilobular tree-in-bud nodules. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  5. 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.

  6. 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.

  7. 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

  8. High-resolution extremity cone-beam CT with a CMOS detector: task-based optimization of scintillator thickness

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

    Purpose: CMOS x-ray detectors offer small pixel sizes and low electronic noise that may support the development of novel high-resolution imaging applications of cone-beam CT (CBCT). We investigate the effects of CsI scintillator thickness on the performance of CMOS detectors in high resolution imaging tasks, in particular in quantitative imaging of bone microstructure in extremity CBCT. Methods: A scintillator thickness-dependent cascaded systems model of CMOS x-ray detectors was developed. Detectability in low-, high- and ultra-high resolution imaging tasks (Gaussian with FWHM of 250 μm, 80 μm and 40 μm, respectively) was studied as a function of scintillator thickness using the theoretical model. Experimental studies were performed on a CBCT test bench equipped with DALSA Xineos3030 CMOS detectors (99 μm pixels) with CsI scintillator thicknesses of 400 μm and 700 μm, and a 0.3 FS compact rotating anode x-ray source. The evaluation involved a radiographic resolution gauge (0.6-5.0 lp/mm), a 127 μm tungsten wire for assessment of 3D resolution, a contrast phantom with tissue-mimicking inserts, and an excised fragment of human tibia for visual assessment of fine trabecular detail. Results: Experimental studies show 35% improvement in the frequency of 50% MTF modulation when using the 400 μm scintillator compared to the standard nominal CsI thickness of 700 μm. Even though the high-frequency DQE of the two detectors is comparable, theoretical studies show a 14% to 28% increase in detectability index (d'2) of high- and ultra- high resolution tasks, respectively, for the detector with 400 μm CsI compared to 700 μm CsI. Experiments confirm the theoretical findings, showing improvements with the adoption of 400 μm panel in the visibility of the radiographic pattern (2x improvement in peak-to-through distance at 4.6 lp/mm) and a 12.5% decrease in the FWHM of the tungsten wire. Reconstructions of the tibial plateau reveal enhanced visibility of trabecular

  9. 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.

  10. 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

  11. High resolution characterizations of fine structure of semiconductor device and material using scanning nonlinear dielectric microscopy

    NASA Astrophysics Data System (ADS)

    Cho, Yasuo

    2017-10-01

    Scanning nonlinear dielectric microscopy (SNDM) can easily distinguish the dopant type (PN) and has a wide dynamic range of sensitivity from low to high concentrations of dopants, because it has a high sensitivity to capacitance variation on the order of 10‑22 F/\\sqrt{\\text{Hz}} . It is also applicable to the analysis of compound semiconductors with much lower signal levels than Si. We can avoid misjudgments from the two-valued function (contrast reversal) problem of dC/dV signals. Under an ultrahigh-vacuum condition, SNDM has atomic resolution. As the extended versions of SNDM, super-higher-order SNDM, local-deep-level transient spectroscopy, noncontact SNDM, and scanning nonlinear dielectric potentiometory have been developed and introduced. The favorable features of SNDM originate from its significantly high sensitivity.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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

  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. 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.

  5. High-Resolution Laser Scanning Reveals Plant Architectures that Reflect Universal Network Design Principles.

    PubMed

    Conn, Adam; Pedmale, Ullas V; Chory, Joanne; Navlakha, Saket

    2017-07-26

    Transport networks serve critical functions in biological and engineered systems, and yet their design requires trade-offs between competing objectives. Due to their sessile lifestyle, plants need to optimize their architecture to efficiently acquire and distribute resources while also minimizing costs in building infrastructure. To understand how plants resolve this design trade-off, we used high-precision three-dimensional laser scanning to map the architectures of tomato, tobacco, or sorghum plants grown in several environmental conditions and through multiple developmental time points, scanning in total 505 architectures from 37 plants. Using a graph-theoretic algorithm that we developed to evaluate design strategies, we find that plant architectures lie along the Pareto front between two simple length-based objectives-minimizing total branch length and minimizing nutrient transport distance-thereby conferring a selective fitness advantage for plant transport processes. The location along the Pareto front can distinguish among species and conditions, suggesting that during evolution, natural selection may employ common network design principles despite different optimization trade-offs. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Dual-resolution image reconstruction for region-of-interest CT scan

    NASA Astrophysics Data System (ADS)

    Jin, S. O.; Shin, K. Y.; Yoo, S. K.; Kim, J. G.; Kim, K. H.; Huh, Y.; Lee, S. Y.; Kwon, O.-K.

    2014-07-01

    In ordinary CT scan, so called full field-of-view (FFOV) scan, in which the x-ray beam span covers the whole section of the body, a large number of projections are necessary to reconstruct high resolution images. However, excessive x-ray dose is a great concern in FFOV scan. Region-of-interest (ROI) scan is a method to visualize the ROI in high resolution while reducing the x-ray dose. But, ROI scan suffers from bright-band artifacts which may hamper CT-number accuracy. In this study, we propose an image reconstruction method to eliminate the band artifacts in the ROI scan. In addition to the ROI scan with high sampling rate in the view direction, we get FFOV projection data with much lower sampling rate. Then, we reconstruct images in the compressed sensing (CS) framework with dual resolutions, that is, high resolution in the ROI and low resolution outside the ROI. For the dual-resolution image reconstruction, we implemented the dual-CS reconstruction algorithm in which data fidelity and total variation (TV) terms were enforced twice in the framework of adaptive steepest descent projection onto convex sets (ASD-POCS). The proposed method has remarkably reduced the bright-band artifacts at around the ROI boundary, and it has also effectively suppressed the streak artifacts over the entire image. We expect the proposed method can be greatly used for dual-resolution imaging with reducing the radiation dose, artifacts and scan time.

  7. CT scans through metal scanning technique versus hardware composition.

    PubMed

    Haramati, N; Staron, R B; Mazel-Sperling, K; Freeman, K; Nickoloff, E L; Barax, C; Feldman, F

    1994-01-01

    Streak artifact on CT scans of metal containing areas has been a long standing problem. Although several artifact reducing methods have been used to improve image quality, most have been limited by requiring specialized equipment or lengthy complex calculations that are not automated. Others have shown that increasing the beam energy results in increased thickness of metal that may be imaged by CT without severe image degradation. We have studied the image quality of bone surrounding metal both with titanium and cobalt-chrome prostheses using various scanning techniques. In a double blind fashion, 28 radiology residents and attendings were surveyed as to the best technique for imaging bone detail surrounding metal. A series of images was arranged of an implanted titanium prosthesis, a cobalt-chrome prosthesis and a pelvis repaired with stainless steel pelvic reconstruction plates. Scans were performed using three techniques: 120 kVp, 170 mA, 2 s, 360 degrees rotation, 140 kVp, 140 mA, 3 s, 360 degrees rotation, 140 kVp, 140 mA, 4 s, 420 degrees rotation. Titanium was superior to cobalt-chrome (p < .0001 Wilcoxon Signed Rank Test). No advantage was noted for higher kVp or increased scan arc of 420 degrees compared to the standard 360 degrees. Titanium allows improved bone detail surround the metal than CT cobalt-chrome. We have found no advantage to using either high kVp or a 420 degrees scan arc to improve the image quality of bone surrounded by metal.

  8. High-resolution characterization of multiferroic heterojunction using aberration-corrected scanning transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Yuan, Zhoushen; Ruan, Jieji; Xie, Lin; Pan, Xiaoqing; Wu, Di; Wang, Peng

    2017-04-01

    Multiferroic tunnel junctions have been considered as potential candidates for nonvolatile memory devices. Understanding the atomic structure at the interface is crucial for optimizing the performances in such oxide electronics. Spatially resolved electron energy loss spectroscopy (EELS) combined with aberration-corrected scanning transmission electron microscopy is employed to measure the compositional profiles across the interfaces of different layers with atomic resolution. Two-dimensional elemental imaging with atomic resolution is demonstrated, and the influences of the interface sharpness, the terminal layer, and cation intermixing are investigated. An asymmetric sublattice intermixing at the Pr0.8Ca0.2MnO3/BaTiO3/La0.7Sr0.3MnO3 interface is observed, which can affect the local Mn valence and coupling. The reduction in the Mn valence at the interface is further studied using EELS near-edge fine structures.

  9. 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.

  10. Fusion of high resolution remote sensing images and terrestrial laser scanning for improved biomass estimation of maize

    NASA Astrophysics Data System (ADS)

    Hütt, C.; Schiedung, H.; Tilly, N.; Bareth, G.

    2014-09-01

    In this study, images from the satellite system WorldView-2 in combination with terrestrial laser scanning (TLS) over a maize field in Germany are investigated. Simultaneously to the measurements a biomass field campaigns was carried out. From the point clouds of the terrestrial laser scanning campaigns crop surface models (CSM) from each scanning date were calculate to model plant growth over time. These results were resampled to match the spatial resolution of the WorldView-2 images, which had to orthorectified using a high resolution digital elevation model and atmosphere corrected using the ATCOR Software package. A high direct correlation of the NDVI calculated from the WorldView-2 sensor and the dry biomass was found in the beginning of June. At the same date, the heights from laser scanning can also explain a certain amount of the biomass variation (r2 = 0.6). By combining the NDVI from WorldView-2 and the height from the laser scanner with a linear model, the R2 reaches higher values of 0.86. To further understand the relationship between CSM derived crop heights and reflection indices, a comparison on a pixel basis was performed. Interestingly, the correlation of the NDVI and the crop height is rather low at the beginning of June (r2 = 0,4, n = 1857) and increases significantly (R2 = 0,79, N = 1857) at a later stage.

  11. 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.

  12. 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.

  13. 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.

  14. 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).

  15. 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.

  16. 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.

  17. 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

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

    PubMed

    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

    2016-09-08

    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. Copyright © 2016 Zackrisson et al.

  19. 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.

  20. 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.

  1. 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.

  2. Detailed methodology for high resolution scanning electron microscopy (SEM) of murine malaria parasitized-erythrocytes.

    PubMed

    Hayakawa, Eri H; Matsuoka, Hiroyuki

    2016-10-01

    Scanning electron microscopy (SEM) is a powerful tool used to investigate object surfaces and has been widely applied in both material science and biology. With respect to the study of malaria, SEM revealed that erythrocytes infected with Plasmodium falciparum, a human parasite, display 'knob-like' structures on their surface comprising parasitized proteins. However, detailed methodology for SEM studies of malaria parasites is lacking in the literature making such studies challenging. Here, we provide a step-by-step guide to preparing Plasmodium-infected erythrocytes from two mouse strains for SEM analysis with minimal structural deterioration. We tested three species of murine malaria parasites, P. berghei, P. yoelii, and P. chabaudi, as well as non-parasitized human erythrocytes and P. falciparum-infected erythrocytes for comparisons. Our data demonstrated that the surface structures of parasitized erythrocytes between the three species of murine parasites in the two different strains of mice were indistinguishable and no surface alterations were observed in P. falciparum-erythrocytes. Our SEM observations contribute towards an understanding of the molecular mechanisms of parasite maturation in the erythrocyte cytoplasm and, along with future studies using our detailed methodology, may help to gain insight into the clinical phenomena of human malaria. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  3. Comparison of high resolution terrestrial laser scanning and terrestrial photogrammetry for modeling applications

    NASA Astrophysics Data System (ADS)

    Özdemir, Samed; Bayrak, Temel

    2016-04-01

    3D documentation of cultural heritage and engineering projects is an important matter. These documentation applications, requires highest possible accuracy and detail to represent the actual surface correctly. Terrestrial photogrammetric method which is employed to produce 3D models to day, now can obtain dense point clouds thanks to advancements in computer technology. Terrestrial laser scanners gained popularity in the last decade because of their high capacity and today they are being widely used in many applications. However every application has its own requirements that depend on the type of application, modeling environment, accuracy and budget limitations. This means, for every application highest accuracy instruments are not always best, considering the facts that mentioned before. In this study, laser scanner and terrestrial photogrammetric methods' spatial and model accuracies investigated under various conditions which include measuring targets at different instrument to object distances then investigating the accuracy of these measurements, modeling an irregular shaped surface to compare two surfaces volume and surface areas, at last comparing dimensions of known geometrical shaped small objects. Also terrestrial laser scanners and terrestrial photogrammetric methods most suitable application conditions investigated in terms of cost, time, mobility and accuracy. Terrestrial laser scanner has the ability to, measure distances under cm accuracy and directly measuring 3D world but there is also some drawbacks like sensitive, bulky and expensive equipment. When it comes to terrestrial photogrammetry, it has above cm accuracy, comparatively fast (considering the image acquisition stage), inexpensive but it can be affected by the coarse geometry, surface texture and the environmental lighting. Key Words: Accuracy, Comparison, Model, Terrestrial Photogrammetry, Terrestrial Laser Scanning,.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. High-resolution Terrestrial Laser Scanning surveys for quantifying surface ruptures of the 2016 seismic sequence in Central Italy

    NASA Astrophysics Data System (ADS)

    Bornemann, Pierrick; Point, Julien; Skupinski, Grzegorz; Stumpf, André; Malet, Jean-Philippe; van der Woerd, Jérôme; Fleury, Jules; Benedetti, Lucilla; Pérouse, Eugénie; Rizza, Magali; Tesson, Jim

    2017-04-01

    From August to October 2016, a sequence of seismic events took place in Central Italy. Major shocks occurred on August 24 (Mw=6.0), October 26 (Mw= 5.9) and October 30 (Mw=6.5). The events created surface ruptures particularly visible along the southern segment of the Monte Vettore fault with vertical co-seismic deformation along the fault plane reaching up to 2.2 m (cumulated after the October 30 earthquake). The surface ruptures affected morphological features (gullies) and surficial formations (colluvial and talus deposits) which makes them suitable markers for quantifying the co-seismic displacement. High resolution terrestrial laser scans were acquired on rupture outcrops after each of the two largest events using a long-range RIEGL VZ-2000 device during two campaigns in September and November 2016. Further, very-high resolution optical satellite imagery (tri-stereo Pléiades, 50 cm spatial resolution) were acquired before and after the October 30 event, and digital surface models were calculated with the DSM-OPT service of the ESA GeoHazard Exploitation Platform. We present the long-range (1.0 to 1.5 km) terrestrial laser scanner point clouds acquired along the largest rupture trace on four areas of the Monte Vettore Western and Southern slopes. We document the geometry of the surface ruptures at high point cloud density (up to 1500 pts.m-2) for an approximate length of 4.2km and an approximate area of 9.6 km2. The laser scanner point clouds are co-registered and georeferenced using GNSS RTK surveys on reference targets. High-resolution surface models are created for each dataset, by meshing the point clouds. For two areas, bi-temporal point clouds are available allowing the quantification of the spatial variability of the vertical deformation. The high-resolution topographic measurements allow (1) quantifying the vertical displacement caused by the October 30th shock and (2) comparing the accuracy of the different surveying methods. The vertical displacement

  11. TEM based high resolution and low-dose scanning electron nanodiffraction technique for nanostructure imaging and analysis.

    PubMed

    Kim, Kyou-Hyun; Xing, Hui; Zuo, Jian-Min; Zhang, Peng; Wang, Haifeng

    2015-04-01

    We report a high resolution and low-dose scanning electron nanodiffraction (SEND) technique for nanostructure analysis. The SEND patterns are recorded in a transmission electron microscope (TEM) using a low-brightness ∼2 nm electron beam with a LaB6 thermionic source obtained by a large demagnification of the condenser 1 lens. The diffraction pattern is directly recorded using a CCD camera optimized for low-dose imaging. A custom script was developed for calibration and automated data acquisition. The performance of low-dose SEND is evaluated using nanostructured Au as a test sample for the quality of diffraction patterns, sample stability and probe size. We demonstrate that our method provides an effective and robust way for recording diffraction patterns from nanometer-sized grains. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. 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.

  13. 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

  14. 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

  15. 3D printing for orthopedic applications: from high resolution cone beam CT images to life size physical models

    NASA Astrophysics Data System (ADS)

    Jackson, Amiee; Ray, Lawrence A.; Dangi, Shusil; Ben-Zikri, Yehuda K.; Linte, Cristian A.

    2017-03-01

    With increasing resolution in image acquisition, the project explores capabilities of printing toward faithfully reflecting detail and features depicted in medical images. To improve safety and efficiency of orthopedic surgery and spatial conceptualization in training and education, this project focused on generating virtual models of orthopedic anatomy from clinical quality computed tomography (CT) image datasets and manufacturing life-size physical models of the anatomy using 3D printing tools. Beginning with raw micro CT data, several image segmentation techniques including thresholding, edge recognition, and region-growing algorithms available in packages such as ITK-SNAP, MITK, or Mimics, were utilized to separate bone from surrounding soft tissue. After converting the resulting data to a standard 3D printing format, stereolithography (STL), the STL file was edited using Meshlab, Netfabb, and Meshmixer. The editing process was necessary to ensure a fully connected surface (no loose elements), positive volume with manifold geometry (geometry possible in the 3D physical world), and a single, closed shell. The resulting surface was then imported into a "slicing" software to scale and orient for printing on a Flashforge Creator Pro. In printing, relationships between orientation, print bed volume, model quality, material use and cost, and print time were considered. We generated anatomical models of the hand, elbow, knee, ankle, and foot from both low-dose high-resolution cone-beam CT images acquired using the soon to be released scanner developed by Carestream, as well as scaled models of the skeletal anatomy of the arm and leg, together with life-size models of the hand and foot.

  16. Slit-scan flow cytometry for consistent high resolution DNA analysis of X- and Y-chromosome bearing sperm.

    PubMed

    Rens, W; Welch, G R; Houck, D W; van Oven, C H; Johnson, L A

    1996-10-01

    This paper describes the application of slit-scan flow cytometry for accurate DNA analysis of X- and Y-chromosome bearing sperm. The introduction of the slit-scanning technique was initiated to improve the consistency in resolution of the X and Y population from donor to donor. An optimal resolution is essential for high purity sorting of X and Y sperm, as the difference in DNA content is small (3-4%) in most mammals. This difference is the discriminatory parameter for the flow cytometric sorting of the two populations. Our approach was to focus on the role of the sperm tail in the detection process. Slit-scan flow cytometric analysis allows the whole sperm to be spatially analyzed along the direction of flow. Sperm were stained with Dansyl Lysine, a UV excitable fluorescent membrane dye, which stained the head, midpiece, and principal piece. Analysis of these stained sperm showed that there was no difference between the relative number of sperm that travel headfirst or tailfirst through the detection zone of the flow cytometer. The influence of sperm with coiled tails on DNA analysis was also investigated. The proportion of sperm with coiled tails influences semen quality. The standard X-Y separation procedure uses Hoechst 33342, which stains all intact sperm, both living and dead. Propidium iodide was added to discriminate the dead sperm population. Slit-scan analysis showed that measurement of a sample containing a high proportion of living sperm with coiled tails results in an inferior DNA histogram and reduced X-Y resolution. Sperm with coiled tails can result in a lower detected fluorescence intensity, but the reason for this is unclear. Slit-scan flow cytometry allows exclusion of sperm with coiled tails from the analysis, resulting in a restoration of high resolution of X- and Y-chromosome bearing sperm populations.

  17. 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

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. CT scan correlates of gesture recognition.

    PubMed Central

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

    1983-01-01

    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. Images PMID:6644319

  3. 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

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

    PubMed

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

    2013-03-01

    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. 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. 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). 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 distributions did not differ

  5. 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.

  6. 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.

  7. 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

  8. 3D assessment of cortical bone porosity and tissue mineral density using high-resolution µCT: effects of resolution and threshold method.

    PubMed

    Palacio-Mancheno, Paolo E; Larriera, Adriana I; Doty, Stephen B; Cardoso, Luis; Fritton, Susannah P

    2014-01-01

    Current micro-computed tomography (µCT) systems allow scanning bone at resolutions capable of three-dimensional (3D) characterization of intracortical vascular porosity and osteocyte lacunae. However, the scanning and reconstruction parameters along with the image segmentation method affect the accuracy of the measurements. In this study, the effects of scanning resolution and image threshold method in quantifying small features of cortical bone (vascular porosity, vascular canal diameter and separation, lacunar porosity and density, and tissue mineral density) were analyzed. Cortical bone from the tibia of Sprague-Dawley rats was scanned at 1-µm and 4-µm resolution, reconstructions were density-calibrated, and volumes of interest were segmented using approaches based on edge-detection or histogram analysis. In 1-µm resolution scans, the osteocyte lacunar spaces could be visualized, and it was possible to separate the lacunar porosity from the vascular porosity. At 4-µm resolution, the vascular porosity and vascular canal diameter were underestimated, and osteocyte lacunae were not effectively detected, whereas the vascular canal separation and tissue mineral density were overestimated compared to 1-µm resolution. Resolution had a much greater effect on the measurements than did threshold method, showing partial volume effects at resolutions coarser than 2 µm in two separate analyses, one of which assessed the effect of resolution on an object of known size with similar architecture to a vascular pore. Although there was little difference when using the edge-detection versus histogram-based threshold approaches, edge-detection was somewhat more effective in delineating canal architecture at finer resolutions (1-2 µm). In addition, use of a high-resolution (1 µm) density-based threshold on lower resolution (4 µm) density-calibrated images was not effective in improving the lower-resolution measurements. In conclusion, if measuring cortical vascular

  9. 3D Assessment of Cortical Bone Porosity and Tissue Mineral Density Using High-Resolution Micro-CT: Effects of Resolution and Threshold Method

    PubMed Central

    Palacio-Mancheno, Paolo E.; Larriera, Adriana I.; Doty, Stephen B.; Cardoso, Luis; Fritton, Susannah P.

    2013-01-01

    Current micro-CT systems allow scanning bone at resolutions capable of three-dimensional characterization of intracortical vascular porosity and osteocyte lacunae. However, the scanning and reconstruction parameters along with the image segmentation method affect the accuracy of the measurements. In this study, the effects of scanning resolution and image threshold method in quantifying small features of cortical bone (vascular porosity, vascular canal diameter and separation, lacunar porosity and density, and tissue mineral density) were analyzed. Cortical bone from the tibia of Sprague-Dawley rats was scanned at 1-µm and 4-µm resolutions, reconstructions were density-calibrated, and volumes of interest were segmented using approaches based on edge-detection or histogram analysis. With 1-µm resolution scans, the osteocyte lacunar spaces could be visualized, and it was possible to separate the lacunar porosity from the vascular porosity. At 4-µm resolution, the vascular porosity and vascular canal diameter were underestimated, and osteocyte lacunae were not effectively detected, whereas the vascular canal separation and tissue mineral density were overestimated compared to 1-µm resolution. Resolution had a much greater effect on the measurements than did threshold method, with partial volume effects at resolutions coarser than 2 µm demonstrated in two separate analyses, one of which assessed the effect of resolution on an object of known size with similar architecture to a vascular pore. Although there was little difference when using the edge-detection versus histogram-based threshold approaches, edge-detection was somewhat more effective in delineating canal architecture at finer resolutions (1 – 2 µm). In addition, use of a high-resolution (1-µm) density-based threshold on lower resolution (4-µm) density-calibrated images was not effective in improving the lower-resolution measurements. In conclusion, if measuring cortical vascular microarchitecture

  10. 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

  11. 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.

  12. 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.

  13. Comparison of human lung tissue mass measurements from ex vivo lungs and high resolution CT software analysis.

    PubMed

    Henne, Erik; Anderson, Joseph C; Lowe, Norma; Kesten, Steven

    2012-05-14

    Quantification of lung tissue via analysis of computed tomography (CT) scans is increasingly common for monitoring disease progression and for planning of therapeutic interventions. The current study evaluates the quantification of human lung tissue mass by software analysis of a CT to physical tissue mass measurements. Twenty-two ex vivo lungs were scanned by CT and analyzed by commercially available software. The lungs were then dissected into lobes and sublobar segments and weighed. Because sublobar boundaries are not visually apparent, a novel technique of defining sublobar segments in ex vivo tissue was developed. The tissue masses were then compared to measurements by the software analysis. Both emphysematous (n = 14) and non-emphysematous (n = 8) bilateral lungs were evaluated. Masses (Mean ± SD) as measured by dissection were 651 ± 171 g for en bloc lungs, 126 ± 60 g for lobar segments, and 46 ± 23 g for sublobar segments. Masses as measured by software analysis were 598 ± 159 g for en bloc lungs, 120 ± 58 g for lobar segments, and 45 ± 23 g for sublobar segments. Correlations between measurement methods was above 0.9 for each segmentation level. The Bland-Altman analysis found limits of agreement at the lung, lobe and sublobar levels to be -13.11% to -4.22%, -13.59% to 4.24%, and -45.85% to 44.56%. The degree of concordance between the software mass quantification to physical mass measurements provides substantial evidence that the software method represents an appropriate non-invasive means to determine lung tissue mass.

  14. CT Scans Might Help Gauge Heart Attack Risk

    MedlinePlus

    ... fullstory_167148.html CT Scans Might Help Gauge Heart Attack Risk Researchers aim to identify vulnerable patients before ... into irreversible plaque could potentially help cardiologists prevent heart attacks, the scientists said. "Currently, CT only tells you ...

  15. Efficient cross-section preparation method for high-resolution imaging of hard polymer composites with a scanning electron microscope.

    PubMed

    Brodusch, N; Yourdkhani, M; Hubert, P; Gauvin, R

    2015-11-01

    Characterization of distribution and arrangement of filler particles in polymer composites is of primary importance to understand and maximize their mechanical, electrical and thermal properties. An innovative procedure that allows reliable and straightforward preparation of cross-sections of polymer composites with the use of mechanical polishing, ion beam etching and soft gaseous etching is presented in this paper. Because of the inherent difference between the organic amorphous matrix and the inorganic crystalline nature of composite fillers, the removal of matrix layers at the surface of the cross-section at the expense of the inorganic materials allowed characterizing the composite filler particles structure and distribution over the surface. Since beam broadening did not occur before the beam hit the nanoparticles, high-resolution imaging in the scanning electron microscope was possible and true dimensions and orientation of the particles were observed. This provided more flexibility in selecting the primary beam voltage; especially, the use of low beam energy greatly improved the image contrast and reduced charging effects resulting from the primary electron beam bombardment. It was shown that only polymers with a carbonated main chain could be etched selectively by the gaseous etching process. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  16. Imaging Single Virus Particles on the Surface of Cell Membranes by High-Resolution Scanning Surface Confocal Microscopy

    PubMed Central

    Shevchuk, Andrew I.; Hobson, Phil; Lab, Max J.; Klenerman, David; Krauzewicz, Nina; Korchev, Yuri E.

    2008-01-01

    We have developed a high-resolution scanning surface confocal microscopy technique capable of imaging single virus-like particles (VLPs) on the surfaces of cells topographically and by fluorescence. The technique combines recently published single-molecule-resolution ion-conductance microscopy that acquires topographical data with confocal microscopy providing simultaneous fluorescent imaging. In our experiments we have demonstrated that the cell membrane exhibits numerous submicrometer-sized surface structures that could be topographically confused with virus particles. However, simultaneous acquisition of confocal images allows the positions of fluorescently tagged particles to be identified. Using this technique, we have, for the first time, visualized single polyoma VLPs adsorbed onto the cell membrane. Observed VLPs had a mean width of 108 ± 16 nm. The particles were randomly distributed across the cell membrane, and no specific interactions were seen with cell membrane structures such as microvilli. These experiments demonstrate the utility of this new microscope for imaging the interactions of nanoparticles with the cell surface to provide novel insights into the earliest interactions of viruses and other nanoparticles such as gene therapy vectors with the cell. PMID:18199668

  17. 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.

  18. 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

  19. Characterization of the nuclear envelope, pore complexes, and dense lamina of mouse liver nuclei by high resolution scanning electron microscopy

    PubMed Central

    1977-01-01

    We have used high resolution scanning electron microscopy (SEM) to study the nuclear envelope components of isolated mouse liver nuclei. The surfaces of intact nuclei are covered by closely packed ribosomes which are distinguishable by SEM from nuclear pore complexes. After removal of nuclear membranes with the nonionic detergent Triton X-100, the pore complexes remain attached to an underlying, peripheral nuclear lamina, as described by others. The surface of this dense lamina is composed of particulate granules, 75-150 A in diameter, which are contiguous over the entire periphery. We did not observe the pore-to- pore fibril network suggested by other investigators, but such a structure might be the framework upon which the dense lamina is formed. Morphometric analysis of pores and pore complexes shows their size, structure, and density to be similar to that of other mammalian cells. In addition, several types of pore complex-associated structures, not previously reported by other electron microscope (EM) techniques, are observed by SEM. Our studies suggest that the major role of the dense lamina is associated with the distribution, stability, and perhaps, biogenesis of nuclear pore complexes. Treatment of isolated nuclei with a combination of Triton X-100 and sodium deoxycholate removes membranes, dense lamina, and nuclear pore complexes. The resulting "chromatin nuclei" retain their integrity despite the absence of any limiting peripheral structures. PMID:556616

  20. 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.

  1. 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

  2. High-resolution 18F-FDG PET/CT for assessing disease activity in rheumatoid and psoriatic arthritis: findings of a prospective pilot study

    PubMed Central

    Ferrero, Andrea; Godinez, Felipe; Yang, Kai; Shelton, David K; Hunter, John C; Naguwa, Stanley M; Boone, John M; Raychaudhuri, Siba P; Badawi, Ramsey D

    2016-01-01

    Objective: Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) commonly affect the small joints of the wrist and hand. We evaluated the performance of a new, high-resolution extremity positron emission tomography (PET)/CT scanner for characterizing and quantifying pathologies associated with the two arthritides in the wrist and hand joints. Methods: Patients with RA or PsA underwent fluorine-18 fludeoxyglucose (18F-FDG) PET/CT wrist and hand imaging, respectively, on the high-resolution scanner. Calibrated CT images and co-registered PET images were reconstructed. PET/CT was derived for the radiocarpal and pisiform–triquetral compartments, joints with erosive changes, sites of synovitis or tenosynovitis and the nail bed and were correlated with clinical and MRI findings. Results: Significantly elevated 18F-FDG uptake was measured for the radiocarpal and pisiform–triquetral compartments and at sites of bone erosion, synovitis, pannus and oedema, compared with unaffected joints (p < 0.05) in patients with RA, consistent with their clinical findings. In patients with PsA, significantly elevated 18F-FDG uptake was measured for joints with synovitis compared with unaffected joints (p < 0.05), with patterns of 18F-FDG uptake along the tendons, at the enthesis and in the nail bed, consistent with tenosynovitis, enthesitis and nail dystrophy, respectively. Conclusion: High-resolution 18F-FDG PET/CT imaging of the wrist and hand is feasible in an RA or PsA patient cohort and is capable of providing quantifiable measures of disease activity (synovitis, enthesitis, oedema and bone destruction). Advances in knowledge: High-resolution PET/CT imaging shows promise as a tool for understanding the pathogenesis of the arthritic process and for non-invasive, objective assessment of RA or PsA severity and therapy selection. PMID:27109738

  3. 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

  4. 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.

  5. 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.

  6. High-resolution imaging of the retinal nerve fiber layer in normal eyes using adaptive optics scanning laser ophthalmoscopy.

    PubMed

    Takayama, Kohei; Ooto, Sotaro; Hangai, Masanori; Arakawa, Naoko; Oshima, Susumu; Shibata, Naohisa; Hanebuchi, Masaaki; Inoue, Takashi; Yoshimura, Nagahisa

    2012-01-01

    To conduct high-resolution imaging of the retinal nerve fiber layer (RNFL) in normal eyes using adaptive optics scanning laser ophthalmoscopy (AO-SLO). AO-SLO images were obtained in 20 normal eyes at multiple locations in the posterior polar area and a circular path with a 3-4-mm diameter around the optic disc. For each eye, images focused on the RNFL were recorded and a montage of AO-SLO images was created. AO-SLO images for all eyes showed many hyperreflective bundles in the RNFL. Hyperreflective bundles above or below the fovea were seen in an arch from the temporal periphery on either side of a horizontal dividing line to the optic disc. The dark lines among the hyperreflective bundles were narrower around the optic disc compared with those in the temporal raphe. The hyperreflective bundles corresponded with the direction of the striations on SLO red-free images. The resolution and contrast of the bundles were much higher in AO-SLO images than in red-free fundus photography or SLO red-free images. The mean hyperreflective bundle width around the optic disc had a double-humped shape; the bundles at the temporal and nasal sides of the optic disc were narrower than those above and below the optic disc (P<0.001). RNFL thickness obtained by optical coherence tomography correlated with the hyperreflective bundle widths on AO-SLO (P<0.001) AO-SLO revealed hyperreflective bundles and dark lines in the RNFL, believed to be retinal nerve fiber bundles and Müller cell septa. The widths of the nerve fiber bundles appear to be proportional to the RNFL thickness at equivalent distances from the optic disc.

  7. 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.

  8. 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

  9. 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.

  10. Computed Tomography (CT) Scans and Cancer

    MedlinePlus

    ... Funding Find NCI funding for small business innovation, technology transfer, and contracts Training Cancer Training at NCI ( ... improve CT or new uses of CT imaging technology. Some of these clinical trials are run by ...

  11. Ultrafast CT scanning of an oak log for internal defects

    Treesearch

    Francis G. Wagner; Fred W. Taylor; Douglas S. Ladd; Charles W. McMillin; Fredrick L. Roder

    1989-01-01

    Detecting internal defects in sawlogs and veneer logs with computerized tomographic (CT) scanning is possible, but has been impractical due to the long scanning time required. This research investigated a new scanner able to acquire 34 cross-sectional log scans per second. This scanning rate translates to a linear log feed rate of 85 feet (25.91 m) per minute at one...

  12. CT scan utilization patterns in pediatric patients with recurrent headache.

    PubMed

    DeVries, Andrea; Young, Paul C; Wall, Eric; Getchius, Thomas ScD; Li, Chia-hsuan; Whitney, John; Rosenberg, Alan

    2013-07-01

    Although unnecessary for children with headache and normal history, computed tomography (CT) scans are widely used. This study sought to determine current practice patterns of neuroimaging to diagnose pediatric headache in a variety of treatment settings and to identify factors associated with increased use of neuroimaging. This retrospective claims analysis included children (aged 3–17 years) with ≥2 medical claims for headache. The primary outcome was CT scan utilization on or after first presentation with headache in a physician’s office or emergency department (ED). Of 15 836 patients, 26% (4034 patients; mean age: 11.8 years) had ≥1 CT scan, 74% within 1 month of index diagnosis. Patients with ED visits were 4 times more likely to undergo a CT scan versus those without ED visits (P < .001 [95% confidence interval: 3.9–4.8]). However, even outside the ED, use of CT scans remained widespread. Two-thirds of patients with CT scans had no ED use.Among patients with no ED utilization, >20% received a CT scan during the study period. Evaluation by a neurologist was strongly associated with a lower likelihood of CT scan compared with other provider specialties (odds ratio: 0.37; P < .01 [95% confidence interval: 0.30–0.46]). Use of CT scans to diagnose pediatric headache remains high despite existing guidelines, low diagnostic yield, and high potential risk. Implementing quality improvement initiatives to ensure that CT scans in children are performed only when truly indicated will reduce unnecessary exposure to ionizing radiation and associated cancer risks.

  13. Tropospheric Carbon Monoxide Measurements from the Scanning High-resolution Interferometer Sounder during SAFARI 2000 on September 7, 2000

    NASA Astrophysics Data System (ADS)

    McMillan, W. W.; McCourt, M. L.; Sparling, L.; Lukovich, J.; Revercomb, H.; Knuteson, R.; Antonelli, P.

    2002-05-01

    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 September 7, 2000, as part of the SAFARI 2000 international field campaign. CO retrievals were performed utilizing a portion of the CO 1--0 vibration-rotation band centered at 2142~wn with an algorithm previously demonstrated for the SHIS predecessor HIS instrument. On this flight, enhancements in tropospheric column CO were seen in the vicinity of a controlled burn in the Timbavati Game Reserve near Kruger National Park 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 on the other side of the waning baroclinic westerly wave responsible for driving the river of smoke. Quantitative comparisons are presented with in situ measurements from five different instruments flying on two other aircraft, the University of Washington Convair-580 and South Africa JRB, in the vicinity of the Timbavati fire. Measured tropospheric CO columns (extrapolated from 337 mb to 100 mb) of 2.1 x 1018 cm-2 in background air and up to 1.5 x 1019 cm-2 in the smoke plume agree extremely well with SHIS retrieved tropospheric CO columns of 2.3 +/- 0.25 x 1018 cm-2 over background air near the fire and 1.5 +/- 0.35 x 1019 cm-2 over the smoke plume. Qualitative inter-comparisons are presented for 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. 13 SHIS flights remain to be studied in detail with more comparisons to in situ measurements and eventual use of the full suite of SHIS CO retrievals for validation of the MOPITT instrument onboard the NASA Terra satellite.

  14. High-resolution room-temperature sample scanning superconducting quantum interference device microscope configurable for geological and biomagnetic applications

    NASA Astrophysics Data System (ADS)

    Fong, L. E.; Holzer, J. R.; McBride, K. K.; Lima, E. A.; Baudenbacher, F.; Radparvar, M.

    2005-05-01

    We have developed a scanning superconducting quantum interference device (SQUID) microscope system with interchangeable sensor configurations for imaging magnetic fields of room-temperature (RT) samples with submillimeter resolution. The low-critical-temperature (Tc) niobium-based monolithic SQUID sensors are mounted on the tip of a sapphire and thermally anchored to the helium reservoir. A 25μm sapphire window separates the vacuum space from the RT sample. A positioning mechanism allows us to adjust the sample-to-sensor spacing from the top of the Dewar. We achieved a sensor-to-sample spacing of 100μm, which could be maintained for periods of up to four weeks. Different SQUID sensor designs are necessary to achieve the best combination of spatial resolution and field sensitivity for a given source configuration. For imaging thin sections of geological samples, we used a custom-designed monolithic low-Tc niobium bare SQUID sensor, with an effective diameter of 80μm, and achieved a field sensitivity of 1.5pT/Hz1/2 and a magnetic moment sensitivity of 5.4×10-18Am2/Hz1/2 at a sensor-to-sample spacing of 100μm in the white noise region for frequencies above 100Hz. Imaging action currents in cardiac tissue requires a higher field sensitivity, which can only be achieved by compromising spatial resolution. We developed a monolithic low-Tc niobium multiloop SQUID sensor, with sensor sizes ranging from 250μm to 1mm, and achieved sensitivities of 480-180fT /Hz1/2 in the white noise region for frequencies above 100Hz, respectively. For all sensor configurations, the spatial resolution was comparable to the effective diameter and limited by the sensor-to-sample spacing. Spatial registration allowed us to compare high-resolution images of magnetic fields associated with action currents and optical recordings of transmembrane potentials to study the bidomain nature of cardiac tissue or to match petrography to magnetic field maps in thin sections of geological samples.

  15. 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.

  16. [Volumetric CT scanning: 2D and 3D reconstruction].

    PubMed

    Ferretti, G-R; Jankowski, A

    2010-12-01

    This review aims to present the 2D and 3D reconstructions derived from high-resolution volume CT acquisitions and to illustrate their thoracic applications, as well as showing the interest and limitations of these techniques. We present new applications for computer-assisted detection (CAD) and tools for quantification of pulmonary lesions. Copyright © 2010 SPLF. Published by Elsevier Masson SAS. All rights reserved.

  17. 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.

  18. Intracranial extramedullary hematopoiesis. CT and bone marrow scan findings

    SciTech Connect

    Urman, M.; O'Sullivan, R.A.; Nugent, R.A.; Lentle, B.C. )

    1991-06-01

    This case concerns a patient with intracranial extramedullary hematopoiesis (EH) suspected on a CT scan and subsequently confirmed with In-111 chloride and Tc-99m SC bone marrow scans. The bone marrow scans also provided additional information by demonstrating other sites of EH in the paravertebral tissues and bone marrow expansion into the distal extremities.

  19. 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

  20. 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.

  1. Direct Observation of Iron-Induced Conformational Changes of Mitochondrial DNA by High-Resolution Field-Emission in-Lens Scanning Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Yaffee, Marcus; Walter, Patrick; Richter, Christoph; Muller, Martin

    1996-05-01

    When respiring rat liver mitochondria are incubated in the presence of Fe(III) gluconate, their DNA (mtDNA) relaxes from the supercoiled to the open circular form dependent on the iron dose. Anaerobiosis or antioxidants fail to completely inhibit the unwinding. High-resolution field-emission in-lens scanning electron microscopy imaging, in concert with backscattered electron detection, pinpoints nanometer-range iron colloids bound to mtDNA isolated from iron-exposed mitochondria. High-resolution field-emission in-lens scanning electron microscopy with backscattered electron detection imaging permits simultaneous detailed visual analysis of DNA topology, iron dose-dependent mtDNA unwinding, and assessment of iron colloid formation on mtDNA strands.

  2. Quantifying the impact of µCT-scanning of human fossil teeth on ESR age results.

    PubMed

    Duval, Mathieu; Martín-Francés, Laura

    2017-05-01

    Fossil human teeth are nowadays systematically CT-scanned by palaeoanthropologists prior to any further analysis. It has been recently demonstrated that this noninvasive technique has, in most cases, virtually no influence on ancient DNA preservation. However, it may have nevertheless an impact on other techniques, like Electron Spin Resonance (ESR) dating, by artificially ageing the apparent age of the sample. To evaluate this impact, we µCT-scanned several modern enamel fragments following the standard analytical procedures employed by the Dental Anthropology Group at CENIEH, Spain, and then performed ESR dose reconstruction for each of them. The results of our experiment demonstrate that the systematic high-resolution µCT-scanning of fossil hominin remains introduces a nonnegligible X-ray dose into the tooth enamel, equivalent to 15-30 Gy depending on the parameters used. This dose may be multiplied by a factor of ∼8 if no metallic filter is used. However, this dose estimate cannot be universally extrapolated to any µCT-scan experiment but has instead to be specifically assessed for each device and set of parameters employed. The impact on the ESR age results is directly dependent on the magnitude of the geological dose measured in fossil enamel but could potentially lead to an age overestimation up to 40% in case of Late Pleistocene samples, if not taken into consideration. © 2017 Wiley Periodicals, Inc.

  3. Full-Body CT Scans - What You Need to Know

    MedlinePlus

    ... Radiation-Emitting Products Radiation-Emitting Products and Procedures Medical Imaging Medical X-ray Imaging Full-Body CT Scans - ... cancer, cardiac disease, and other abnormalities, clinics and medical imaging facilities nationwide are touting a new service for ...

  4. 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.

  5. Analysis of bromotryptophan and hydroxyproline modifications by high-resolution, high-accuracy precursor ion scanning utilizing fragment ions with mass-deficient mass tags.

    PubMed

    Steen, Hanno; Mann, Matthias

    2002-12-15

    Protein modifications are often detected by precursor ion scanning. When quadrupole TOF mass spectrometers are used for precursor ion scanning with high-resolution, high-accuracy fragment ion selection, "reporter" ions are required to have a unique mass within +/-0.04 Da or less instead of +/-0.5 Da on triple quadrupole mass spectrometers, the traditional instrument used for precursor ion scanning. Thus, characteristic fragment ions can be utilized even if other fragment ions have the same nominal mass as long as the characteristic fragment ions are slightly mass deficient as compared to the other fragments, i.e., when they have an inherent mass-deficient mass tag. Here, the immonium ions of bromotryptophan and hydroxyproline are described as two fragment ions characteristic for tryptophan-brominated and proline-hydroxylated peptides, respectively. The "reporter" ion of trytophan-brominated peptides is highly mass deficient due to the presence of bromine, thereby allowing the selective detection of these species and the distinction from other dipeptidic a-, b-, and y-fragment ions by high-resolution, high-accuracy precursor ion scanning. This strategy also enables the differentiation between precursors giving rise to the oxygen-containing immonium ion of hydroxyproline and precursors of the immonium ions of near-ubiquitous leucine/isoleucine. Both immonium ions have the same nominal mass of 86 Da, but the exact masses differ by less than 0.04 Da. High-resolution, high-accuracy precursor ion scanning enabled the identification of proline-hydroxylated and tryptophan-brominated species and the directed analysis of species carrying these modifications in a highly complex Conus textile conotoxin mixture. This lead to the characterization of one novel C. textile conotoxin containing a bromotryptophan residue and one novel C. textile conotoxin carrying two hydroxyproline residues.

  6. Abdominal CT scanning in critically ill surgical patients.

    PubMed Central

    Norwood, S H; Civetta, J M

    1985-01-01

    Clinical parameters, intensive care unit (ICU) course, abdominal computed tomography (CT) scans, and the clinical decisions of 53 critically ill patients were reviewed to determine the influence of the CT scan. No scans were positive before the eighth day. Sensitivity was 48% and specificity, 64%. Seventeen (23%) scans of the 72 provided beneficial results: eight localized abscesses that were drained; nine were negative and not operated on. Five (7%) scans provided detrimental information: scan negative with abscess discovered or scan positive but negative laparotomy. Fifty (70%) scans were either of no help or not used in management. The mortality rate was 50% when CT led to an intervention, and 47% in the entire group. Hospital charges were +33,408. Personnel time and cost were 497 hours and +3658; of the total +37,066, 77% (+28,541) could be considered wasted. From these data, it was concluded that CT scans should be used to confirm abscesses, not to search for a source of sepsis. PMID:4015222

  7. Quantitative analysis of high-resolution, contrast-enhanced, cone-beam CT for the detection of intracranial in-stent hyperplasia.

    PubMed

    Flood, Thomas F; van der Bom, Imramsjah M J; Strittmatter, Lara; Puri, Ajit S; Hendricks, Gregory M; Wakhloo, Ajay K; Gounis, Matthew J

    2015-02-01

    Intracranial in-stent hyperplasia is a stroke-associated complication that requires routine surveillance. To compare the results of in vivo experiments to determine the accuracy and precision of in-stent hyperplasia measurements obtained with modified C-arm contrast-enhanced, cone-beam CT (CE-CBCT) imaging with those obtained by 'gold standard' histomorphometry. Additionally, to carry out clinical analyses comparing this CE-CBCT protocol with digital subtraction angiography (DSA). A non-binned CE-CBCT protocol (VasoCT) was used that acquires x-ray images with a small field-of-view and applies a full-scale reconstruction algorithm providing high-resolution three-dimensional (3D) imaging with 100 µm isotropic voxels. In an vivo porcine model, VasoCT cross-sectional area measurements were compared with gold standard vessel histology. VasoCT and DSA were used to calculate in-stent stenosis in 23 imaging studies. Porcine VasoCT cross-sectional stent, lumen, and in-stent hyperplasia areas strongly correlated with histological measurements (r(2)=0.97, 0.93, 0.90; slope=1.14, 1.07, and 0.76, respectively; p<0.0001). Clinical VasoCT percentage stenosis correlated well with DSA percentage stenosis (r(2)=0.84; slope=0.76), and the two techniques were free of consistent bias (Bland-Altman, bias=3.29%; 95% CI -14.75% to 21.33%). An illustrative clinical case demonstrated the advantages of VasoCT, including 3D capability and non-invasive IV contrast administration, for detection of in-stent hyperplasia. C-arm VasoCT is a high-resolution 3D capable imaging technique that has been validated in an animal model for measurement of in-stent tissue growth. Successful clinical implementation of the protocol was performed in a small case series. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  8. Large-Volume Reconstruction of Brain Tissue from High-Resolution Serial Section Images Acquired by SEM-Based Scanning Transmission Electron Microscopy

    PubMed Central

    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. PMID:23086880

  9. 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.

  10. Indications for CT scanning in minor head injuries: a review.

    PubMed

    Żyluk, Andrzej

    2015-01-01

    To determine indications for performing head CT following minor head injuries, which allow reducing number of imaging. Based on 15 articles dedicated to this topic, the clinical decision rules were systematically analysed. The Canadian Computed Tomography Head Rule was found to be the most reliable instrument meeting these criteria, characterised by excellent sensitivity of 100% and fairly good specificity of 48-77%. Remaining scales, although very sensitive, showed poor ability to reduce number of "unnecessary" CT scans. Features most predictive for intracranial injuries included: disorientation, abnormal alertness, somnolentia and neurological deficits. Patients with no loss of consciousness and in normal physical condition need only clinical assessment. Indications to head CT scanning are determined by decision rules presented in the article. Use of clinical decision rules may have effect on reducing number of head CT scanning performed "just in a case". Copyright © 2015 Polish Neurological Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  11. 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. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Multistage 8.2 kyr event revealed through high-resolution XRF core scanning of Cuban sinkhole sediments

    NASA Astrophysics Data System (ADS)

    Peros, Matthew; Collins, Shawn; G'Meiner, Anna Agosta; Reinhardt, Eduard; Pupo, Felipe Matos

    2017-07-01

    We use sediments from a flooded sinkhole (Cenote Jennifer) in northern Cuba to provide new, well-dated, high-resolution evidence for the 8.2 kyr event. From 7600 to 8700 cal yr B.P. the sinkhole contained shallow, low-salinity water, which supported a marsh dominated by cattail and grass. Peaks in Cl and Br—occurring at 8150, 8200, and 8250 cal yr B.P.—are attributable to increased evaporation due to regional drying associated with the 8.2 kyr event. The three peaks in these elements also closely correspond to the greyscale record from the Cariaco Basin, indicative of increased upwelling in the southern Caribbean Sea at this time, supporting the notion of a multistage 8.2 kyr event. Our work provides new data that help to clarify the initiation, behavior, and impacts of the 8.2 kyr event in the northern tropics.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. An evaluation of cranial CT scanning in clinical psychiatry.

    PubMed

    Colohan, H; O'Callaghan, E; Larkin, C; Waddington, J L

    1989-07-01

    From 6,300 psychiatric admissions over a 37 month period, all 54 patient referrals for CT were identified and their charts reviewed. CT influenced diagnosis, management or prognosis in 11.7 percent of patients scanned. There was poor correlation between organicity on CT scan and findings on physical examination, laboratory testing, EEG and psychological testing. The mental state examination was the single significant correlate of CT abnormality. We suggest that the use of a formalised mental state examination such as the Mini Mental State, in addition to the usual clinical assessment of mental state, may improve the accuracy of prediction of abnormality on CT scan. The introduction of X-ray computed tomography (CT) is recognised to be one of the most important innovations in the recent history of clinical medicine. In neurology the value of a non-invasive technique for examining the intracranial contents was quickly realised in the areas of diagnosis, particularly in the detection of vascular accidents and tumours. CT has also attained a significant place in psychiatry. In research studies, it has provided important information on schizophrenia, alcoholism and chronic organic reactions. The place of CT in clinical psychiatry is less clear. As its availability has increased, such scans are being requested with increasing frequency in psychiatric patients. Cranial CT is a highly sensitive diagnostic procedure which, when used unselectively, may result in the discovery of incidental findings. Until recently, a function of the psychiatrist in relation to diagnosis was to first seek to distinguish symptoms produced by organic pathology from those produced by functional illness.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. 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.

  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. Multimodality thoracic imaging of juvenile systemic sclerosis: emphasis on clinical correlation and high-resolution CT of pulmonary fibrosis.

    PubMed

    Valeur, Natalie S; Stevens, Anne M; Ferguson, Mark R; Effmann, Eric L; Iyer, Ramesh S

    2015-02-01

    OBJECTIVE. Juvenile systemic sclerosis is a rare multisystem autoimmune disorder characterized by vasculopathy and multiorgan fibrosis. Cardiopulmonary complications are the leading cause of morbidity and mortality. Although pulmonary fibrosis is the complication that is most common and well described, cardiovascular and esophageal involvement may also be observed. In this article, common thoracic findings in juvenile systemic sclerosis will be discussed. We will focus on chest CT, including CT findings of pulmonary fibrosis and associated grading methods, as well as cardiac MRI and esophageal imaging. CONCLUSION. Radiologists play a pivotal role in the initial diagnosis and follow-up evaluation of pediatric patients with systemic sclerosis. Treatment decisions and prognostic assessment are directly related to imaging findings along with clinical evaluation.

  5. 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 ...

  6. 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.

  7. 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.

  8. Co-registration of high resolution MRI scans with partial brain coverage in non-human primates

    PubMed Central

    Lecoeur, Jérémy; Wang, Feng; chen, Li Min; Li, Rui; Avison, Malcom J.; Dawant, Benoit M.

    2012-01-01

    Dynamic structural and functional remodeling of the Central Nervous System occurs throughout the lifespan of the organism from the molecular to the systems level. MRI offers several advantages to observe this phenomenon: it is non-invasive and non-destructive, the contrast can be tuned to interrogate different tissue properties and imaging resolution can range from cortical columns to whole brain networks in the same session. To measure these changes reliably, functional maps generated over time with high resolution fMRI need to be registered accurately. This article presents a new method for the automatic registration of thin cortical MR volumes that are aligned with the functional maps. These acquisitions focus on the primary somato-sensory cortex, a region in the anterior parietal part of the brain, responsible for fine touch and proprioception. Currently, these slabs are acquired in approximately the same orientation from acquisition to acquisition and then registered by hand. Because they only cover a small portion of the cortex, their direct automatic registration is difficult. To address this issue, we propose a method relying on an intermediate image, acquired with a surface coil that covers a larger portion of the head to which the slabs can be registered. Because images acquired with surface coils suffer from severe intensity attenuation artifact, we also propose a method to register these. The results from data sets obtained with 3 squirrel monkeys show a registration accuracy of 30 micrometers.). PMID:24236222

  9. Towards non-invasive high-resolution 3D nano-tomography by ultrasonic scanning probe microscopy

    NASA Astrophysics Data System (ADS)

    Sharahi, Hossein J.; Shekhawat, Gajendra; Dravid, Vinayak; Egberts, Philip; Kim, Seonghwan

    2017-07-01

    Nanoscale imaging techniques that can be used to visualize and characterize local aggregations of the embedded nanoparticulates with sufficient resolution have attracted a great deal of interest. Ultrasonic scanning probe microscopy (SPM) and its derivatives are nondestructive techniques that can be used to elucidate subsurface nanoscale features and mechanical properties. Although many different ultrasonic methods have been used for subsurface imaging, the mechanisms and crucial parameters associated with the contrast formation in subsurface imaging are still unclear. Here, the impact of mechanical properties of the nanoparticulates/matrix, size of the nanoparticulates, buried depth of the nanoparticulates, and the ultrasonic excitation frequency on the developed ultrasonic SPM images have been investigated. To verify our theoretical model, experimental measurements of scanning near-field ultrasound holography (SNFUH) have been recreated in our theoretical analysis to reveal comparable variations in phase contrast measured in SNFUH while scanning over the nanoparticulates embedded in bacteria.

  10. Initial results of a new generation dual source CT system using only an in-plane comb filter for ultra-high resolution temporal bone imaging.

    PubMed

    Meyer, Mathias; Haubenreisser, Holger; Raupach, Rainer; Schmidt, Bernhard; Lietzmann, Florian; Leidecker, Christianne; Allmendinger, Thomas; Flohr, Thomas; Schad, Lothar R; Schoenberg, Stefan O; Henzler, Thomas

    2015-01-01

    To prospectively evaluate radiation dose and image quality of a third generation dual-source CT (DSCT) without z-axis filter behind the patient for temporal bone CT. Forty-five patients were either examined on a first, second, or third generation DSCT in an ultra-high-resolution (UHR) temporal bone-imaging mode. On the third generation DSCT system, the tighter focal spot of 0.2 mm(2) removes the necessity for an additional z-axis-filter, leading to an improved z-axis radiation dose efficiency. Images of 0.4 mm were reconstructed using standard filtered-back-projection or iterative reconstruction (IR) technique for previous generations of DSCT and a novel IR algorithm for the third generation DSCT. Radiation dose and image quality were compared between the three DSCT systems. The statistically significantly highest subjective and objective image quality was evaluated for the third generation DSCT when compared to the first or second generation DSCT systems (all p < 0.05). Total effective dose was 63%/39% lower for the third generation examination as compared to the first and second generation DSCT. Temporal bone imaging without z-axis-UHR-filter and a novel third generation IR algorithm allows for significantly higher image quality while lowering effective dose when compared to the first two generations of DSCTs. • Omitting the z-axis-filter allows a reduction in radiation dose of 50% • A smaller focal spot of 0.2 mm (2) significantly improves spatial resolution • Ultra-high-resolution temporal-bone-CT helps to gain diagnostic information of the middle/inner ear.

  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. Laser microbeam CT scanning of dosimetry gels

    NASA Astrophysics Data System (ADS)

    Maryanski, Marek J.; Ranade, Manisha K.

    2001-06-01

    A novel design of an optical tomographic scanner is described that can be used for 3D mapping of optical attenuation coefficient within translucent cylindrical objects with spatial resolution on the order of 100 microns. Our scanner design utilizes the cylindrical geometry of the imaged object to obtain the desired paths of the scanning light rays. A rotating mirror and a photodetector are placed at two opposite foci of the translucent cylinder that acts as a cylindrical lens. A He-Ne laser beam passes first through a focusing lens and then is reflected by the rotating mirror, so as to scan the interior of the cylinder with focused and parallel paraxial rays that are subsequently collected by the photodetector to produce the projection data, as the cylinder rotates in small angle increments between projections. Filtered backprojection is then used to reconstruct planar distributions of optical attenuation coefficient in the cylinder. Multiplanar scans are used to obtain a complete 3D tomographic reconstruction. Among other applications, the scanner can be used in radiation therapy dosimetry and quality assurance for mapping 3D radiation dose distributions in various types of tissue-equivalent gel phantoms that change their optical attenuation coefficients in proportion to the absorbed radiation dose.

  14. 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.

  15. 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.

  16. 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.

  17. SU-C-207A-01: A Novel Maximum Likelihood Method for High-Resolution Proton Radiography/proton CT

    SciTech Connect

    Collins-Fekete, C; Schulte, R; Beaulieu, L; Seco, J

    2016-06-15

    Purpose: Multiple Coulomb scattering is the largest contributor to blurring in proton imaging. Here we tested a maximum likelihood least squares estimator (MLLSE) to improve the spatial resolution of proton radiography (pRad) and proton computed tomography (pCT). Methods: The object is discretized into voxels and the average relative stopping power through voxel columns defined from the source to the detector pixels is optimized such that it maximizes the likelihood of the proton energy loss. The length spent by individual protons in each column is calculated through an optimized cubic spline estimate. pRad images were first produced using Geant4 simulations. An anthropomorphic head phantom and the Catphan line-pair module for 3-D spatial resolution were studied and resulting images were analyzed. Both parallel and conical beam have been investigated for simulated pRad acquisition. Then, experimental data of a pediatric head phantom (CIRS) were acquired using a recently completed experimental pCT scanner. Specific filters were applied on proton angle and energy loss data to remove proton histories that underwent nuclear interactions. The MTF10% (lp/mm) was used to evaluate and compare spatial resolution. Results: Numerical simulations showed improvement in the pRad spatial resolution for the parallel (2.75 to 6.71 lp/cm) and conical beam (3.08 to 5.83 lp/cm) reconstructed with the MLLSE compared to averaging detector pixel signals. For full tomographic reconstruction, the improved pRad were used as input into a simultaneous algebraic reconstruction algorithm. The Catphan pCT reconstruction based on the MLLSE-enhanced projection showed spatial resolution improvement for the parallel (2.83 to 5.86 lp/cm) and conical beam (3.03 to 5.15 lp/cm). The anthropomorphic head pCT displayed important contrast gains in high-gradient regions. Experimental results also demonstrated significant improvement in spatial resolution of the pediatric head radiography. Conclusion: The

  18. Single-cell resolution in high-resolution synchrotron X-ray CT imaging with gold nanoparticles.

    PubMed

    Schültke, Elisabeth; Menk, Ralf; Pinzer, Bernd; Astolfo, Alberto; Stampanoni, Marco; Arfelli, Fulvia; Harsan, Laura-Adela; Nikkhah, Guido

    2014-01-01

    Gold nanoparticles are excellent intracellular markers in X-ray imaging. Having shown previously the suitability of gold nanoparticles to detect small groups of cells with the synchrotron-based computed tomography (CT) technique both ex vivo and in vivo, it is now demonstrated that even single-cell resolution can be obtained in the brain at least ex vivo. Working in a small animal model of malignant brain tumour, the image quality obtained with different imaging modalities was compared. To generate the brain tumour, 1 × 10(5) C6 glioma cells were loaded with gold nanoparticles and implanted in the right cerebral hemisphere of an adult rat. Raw data were acquired with absorption X-ray CT followed by a local tomography technique based on synchrotron X-ray absorption yielding single-cell resolution. The reconstructed synchrotron X-ray images were compared with images obtained by small animal magnetic resonance imaging. The presence of gold nanoparticles in the tumour tissue was verified in histological sections.

  19. Systematic Assessment of Survey Scan and MS2-Based Abundance Strategies for Label-Free Quantitative Proteomics Using High-Resolution MS Data

    PubMed Central

    2015-01-01

    Survey-scan-based label-free method have shown no compelling benefit over fragment ion (MS2)-based approaches when low-resolution mass spectrometry (MS) was used, the growing prevalence of high-resolution analyzers may have changed the game. This necessitates an updated, comparative investigation of these approaches for data acquired by high-resolution MS. Here, we compared survey scan-based (ion current, IC) and MS2-based abundance features including spectral-count (SpC) and MS2 total-ion-current (MS2-TIC), for quantitative analysis using various high-resolution LC/MS data sets. Key discoveries include: (i) study with seven different biological data sets revealed only IC achieved high reproducibility for lower-abundance proteins; (ii) evaluation with 5-replicate analyses of a yeast sample showed IC provided much higher quantitative precision and lower missing data; (iii) IC, SpC, and MS2-TIC all showed good quantitative linearity (R2 > 0.99) over a >1000-fold concentration range; (iv) both MS2-TIC and IC showed good linear response to various protein loading amounts but not SpC; (v) quantification using a well-characterized CPTAC data set showed that IC exhibited markedly higher quantitative accuracy, higher sensitivity, and lower false-positives/false-negatives than both SpC and MS2-TIC. Therefore, IC achieved an overall superior performance than the MS2-based strategies in terms of reproducibility, missing data, quantitative dynamic range, quantitative accuracy, and biomarker discovery. PMID:24635752

  20. Systematic assessment of survey scan and MS2-based abundance strategies for label-free quantitative proteomics using high-resolution MS data.

    PubMed

    Tu, Chengjian; Li, Jun; Sheng, Quanhu; Zhang, Ming; Qu, Jun

    2014-04-04

    Survey-scan-based label-free method have shown no compelling benefit over fragment ion (MS2)-based approaches when low-resolution mass spectrometry (MS) was used, the growing prevalence of high-resolution analyzers may have changed the game. This necessitates an updated, comparative investigation of these approaches for data acquired by high-resolution MS. Here, we compared survey scan-based (ion current, IC) and MS2-based abundance features including spectral-count (SpC) and MS2 total-ion-current (MS2-TIC), for quantitative analysis using various high-resolution LC/MS data sets. Key discoveries include: (i) study with seven different biological data sets revealed only IC achieved high reproducibility for lower-abundance proteins; (ii) evaluation with 5-replicate analyses of a yeast sample showed IC provided much higher quantitative precision and lower missing data; (iii) IC, SpC, and MS2-TIC all showed good quantitative linearity (R(2) > 0.99) over a >1000-fold concentration range; (iv) both MS2-TIC and IC showed good linear response to various protein loading amounts but not SpC; (v) quantification using a well-characterized CPTAC data set showed that IC exhibited markedly higher quantitative accuracy, higher sensitivity, and lower false-positives/false-negatives than both SpC and MS2-TIC. Therefore, IC achieved an overall superior performance than the MS2-based strategies in terms of reproducibility, missing data, quantitative dynamic range, quantitative accuracy, and biomarker discovery.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Iodine and freeze-drying enhanced high-resolution MicroCT imaging for reconstructing 3D intraneural topography of human peripheral nerve fascicles.

    PubMed

    Yan, Liwei; Guo, Yongze; Qi, Jian; Zhu, Qingtang; Gu, Liqiang; Zheng, Canbin; Lin, Tao; Lu, Yutong; Zeng, Zitao; Yu, Sha; Zhu, Shuang; Zhou, Xiang; Zhang, Xi; Du, Yunfei; Yao, Zhi; Lu, Yao; Liu, Xiaolin

    2017-08-01

    The precise annotation and accurate identification of the topography of fascicles to the end organs are prerequisites for studying human peripheral nerves. In this study, we present a feasible imaging method that acquires 3D high-resolution (HR) topography of peripheral nerve fascicles using an iodine and freeze-drying (IFD) micro-computed tomography (microCT) method to greatly increase the contrast of fascicle images. The enhanced microCT imaging method can facilitate the reconstruction of high-contrast HR fascicle images, fascicle segmentation and extraction, feature analysis, and the tracing of fascicle topography to end organs, which define fascicle functions. The complex intraneural aggregation and distribution of fascicles is typically assessed using histological techniques or MR imaging to acquire coarse axial three-dimensional (3D) maps. However, the disadvantages of histological techniques (static, axial manual registration, and data instability) and MR imaging (low-resolution) limit these applications in reconstructing the topography of nerve fascicles. Thus, enhanced microCT is a new technique for acquiring 3D intraneural topography of the human peripheral nerve fascicles both to improve our understanding of neurobiological principles and to guide accurate repair in the clinic. Additionally, 3D microstructure data can be used as a biofabrication model, which in turn can be used to fabricate scaffolds to repair long nerve gaps. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Metal artifact reduction of CT scans to improve PET/CT.

    PubMed

    van der Vos, Charlotte S; Arens, Anne Ij; Hamill, Jim; Hofmann, Christian; Panin, Vladimir Y; Meeuwis, Antoi Pw; Visser, Eric P; de Geus-Oei, Lioe-Fee

    2017-05-10

    In recent years different metal artifact reduction (MAR) methods have been developed for computed tomography (CT). These methods have only recently been introduced for positron emission tomography/computed tomography (PET/CT) even though they could be beneficial for interpretation, segmentation and quantification of the PET/CT images. In this study, phantom and patient scans were analyzed visually and quantitatively to measure the effect on PET images of iterative metal artifact reduction (iMAR) of CT data. Methods The phantom consisted of two types of hip prostheses in a solution of (18)F-flurodeoxyglucose ((18)F-FDG) and water. (18)F-FDG PET/CT scans of 14 patients with metal implants (either dental implants, hip prostheses, shoulder prostheses or pedicle screws) and (68)Ga-labeled prostate-specific membrane antigen ((68)Ga-PSMA) PET/CT scans of 7 patients with hip prostheses were scored by two experienced nuclear medicine physicians to analyze clinical relevance. For all patients a lesion was located in the field of view of the metal implant. Phantom and patients were scanned in an mCT PET/CT scanner (Siemens Healthcare). The standard low-dose CTs were processed with the iMAR algorithm. The PET data were reconstructed using attenuation correction provided by both standard CT and iMAR-processed CT. Results For the phantom scans cold artifacts were visible on the PET image. There was a 30% deficit in (18)F-FDG concentration, which was restored by iMAR processing, indicating that metal artifacts on CT images induce quantification errors in PET data. The iMAR algorithm was useful for most patients. When iMAR was used the confidence in interpretation increased or stayed the same, with an average improvement of 28±20% (scored on a scale of 0-100% confidence). The standardized uptake value (SUV) increase or decrease depended on the type of metal artifact. The mean difference in absolute values of SUVmean of the lesions was 3.5±3.3%. Conclusion The iMAR algorithm

  11. A High Resolution Genome-Wide Scan for Significant Selective Sweeps: An Application to Pooled Sequence Data in Laying Chickens

    PubMed Central

    Qanbari, Saber; Strom, Tim M.; Haberer, Georg; Weigend, Steffen; Gheyas, Almas A.; Turner, Frances; Burt, David W.; Preisinger, Rudolf; Gianola, Daniel; Simianer, Henner

    2012-01-01

    In most studies aimed at localizing footprints of past selection, outliers at tails of the empirical distribution of a given test statistic are assumed to reflect locus-specific selective forces. Significance cutoffs are subjectively determined, rather than being related to a clear set of hypotheses. Here, we define an empirical p-value for the summary statistic by means of a permutation method that uses the observed SNP structure in the real data. To illustrate the methodology, we applied our approach to a panel of 2.9 million autosomal SNPs identified from re-sequencing a pool of 15 individuals from a brown egg layer line. We scanned the genome for local reductions in heterozygosity, suggestive of selective sweeps. We also employed a modified sliding window approach that accounts for gaps in the sequence and increases scanning resolution by moving the overlapping windows by steps of one SNP only, and suggest to call this a “creeping window” strategy. The approach confirmed selective sweeps in the region of previously described candidate genes, i.e. TSHR, PRL, PRLHR, INSR, LEPR, IGF1, and NRAMP1 when used as positive controls. The genome scan revealed 82 distinct regions with strong evidence of selection (genome-wide p-value<0.001), including genes known to be associated with eggshell structure and immune system such as CALB1 and GAL cluster, respectively. A substantial proportion of signals was found in poor gene content regions including the most extreme signal on chromosome 1. The observation of multiple signals in a highly selected layer line of chicken is consistent with the hypothesis that egg production is a complex trait controlled by many genes. PMID:23209582

  12. Analysis of Multilayer Devices for Superconducting Electronics by High-Resolution Scanning Transmission Electron Microscopy and Energy Dispersive Spectroscopy

    DOE PAGES

    Missert, Nancy; Kotula, Paul G.; Rye, Michael; ...

    2017-02-15

    We used a focused ion beam to obtain cross-sectional specimens from both magnetic multilayer and Nb/Al-AlOx/Nb Josephson junction devices for characterization by scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDX). An automated multivariate statistical analysis of the EDX spectral images produced chemically unique component images of individual layers within the multilayer structures. STEM imaging elucidated distinct variations in film morphology, interface quality, and/or etch artifacts that could be correlated to magnetic and/or electrical properties measured on the same devices.

  13. 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

  14. A system for high resolution 3D mapping using laser radar and requiring no beam scanning mechanisms

    NASA Astrophysics Data System (ADS)

    Rademacher, Paul

    1988-06-01

    The inherently high angular and range resolution capabilities associated with radar systems operating at optical frequencies are at once a blessing and a curse. Standard implementations consist of very narrow field of view optical receivers operating in conjunction with laser transmitters or even narrower illumination beamwidth. While high angular resolution is thus achieved, mechanical scanning is required to gather data over extended fields of view. The many laser pulse transmissions necessary to cover the entire field of view increase the detectability of the system by enemy sensors. A system concept is proposed which, through the use of a single laser transmitter and multiple optical receivers, largely eliminate these deficiencies. Complete 3D data over a broad angular field of view and depth of field can be gathered based upon the reflections from a single transmitted laser pulse. Covert operation is enhanced as a result of the sparse laser transmissions required. The eye safety characteristics of the system are also enhanced. Proprietary coding of optical shutters in each of the multiple optical receivers permits the number of such receivers to be reduced to a very practical few. An alternative configuration of the system reduces the number of receivers required to one, at the expense of increased data acquisition time. The multiple receiver configuration is simply a parallel processing implementation of the single receiver approach. While data rate is reduced by the single receiver configuration, it still greatly exceeds that of scanning systems, and hardware complexity is also reduced significantly.

  15. High resolution imaging of the distribution and permeability of methyl viologen dication in bovine articular cartilage using scanning electrochemical microscopy.

    PubMed

    Gonsalves, M; Macpherson, J V; O'Hare, D; Winlove, C P; Unwin, P R

    2001-11-15

    Scanning electrochemical microscopy (SECM) has been used in the induced transfer (SECMIT) mode to image the permeability of a probe cation, methyl viologen (MV(2+)), in samples of articular cartilage. An ultramicroelectrode (UME), scanned just above the surface of a sample, is used to amperometrically detect the probe solute. The resulting depletion of MV(2+) in solution induces the transfer of this cation from the sample into the solution for detection at the UME. The current provides quantitative information on local permeability, provided that the sample-UME distance is known. It is shown that the necessary topographical information can be obtained using the amperometric response for the oxidation of Ru(CN)(4-)(6), which does not permeate into the cartilage matrix. This procedure was validated by marking samples in situ, after electrochemical imaging, with subsequent examination by ex situ interferometry and optical microscopy. Wide variations in the permeability of MV(2+) have been detected by SECMIT. These observations represent the first demonstration of the inhomogeneous permeability of a cation in cartilage on a micrometre scale. The permeability maps show similar features to the proteoglycan distribution, identified by toluidine blue staining, and it is likely that proteoglycans are the main determinant of MV(2+) permeability in articular cartilage.

  16. A Prospective Evaluation of High-Resolution CT Parameters in Predicting Extracorporeal Shockwave Lithotripsy Success for Upper Urinary Tract Calculi.

    PubMed

    Abdelhamid, Mahmoud; Mosharafa, Ashraf A; Ibrahim, Hamdy; Selim, Hany M; Hamed, Mohamed; Elghoneimy, Mohamed N; Salem, Hosny K; Abdelazim, Mohamed S; Badawy, Hesham

    2016-11-01

    To evaluate the ability of noncontrast CT parameters (stone size, stone attenuation, and skin-to-stone distance [SSD]) to predict the outcome of extracorporeal shockwave lithotripsy (SWL) in a prospective cohort of patients with renal and upper ureteric stones. Patients with stones 5 to 20 mm were prospectively enrolled from 2011 to 2014. Patients had NCCT with recording of stone size, stone mean attenuation, and SSD, as well as various stone and patient parameters. The numbers of needed sessions as well as the final outcome were determined, with SWL failure defined as residual fragments >3 mm. Predictors of SWL failure were assessed by multiple regression analysis. Two hundred twenty patients (mean ± standard deviation [SD] age 41.5 ± 12.4 years) underwent SWL. Mean ± SD stone size was 11.3 ± 4.1 mm, while mean ± SD stone attenuation was 795.1 ± 340.4 HU. Mean ± SD SSD was 9.4 ± 2.1 cm. The average number of sessions was 1.64. SWL was effective in 186 (84.5%) patients (group A), while 34 (15.5%) patients had significant residual fragments (>3 mm). On univariate analysis, predictors of SWL failure included stone attenuation >1000 HU, older age, higher body mass index, higher attenuation value, larger stone size, and longer SSD. Increased SSD and higher stone attenuation retained their significance as independent predictors of SWL failure (p < 0.05) on multiple regression analysis both after first session and as final SWL outcome. A positive correlation was found between number of SWL sessions and mean stone attenuation (r = 0.6, p < 0.001) and SSD (r = 4, p < 0.001). Stone mean attenuation and SSD on noncontrast CT are significant independent predictors of SWL outcome in patients with renal and ureteric stones. These parameters should be included in clinical decision algorithms for patients with urolithiasis. For patients with stones having mean attenuation of >1000 HU and/or large SSDs, alternatives to

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. MicroCT for high-resolution imaging of ectopic pheochromocytoma tumors in the liver of nude mice.

    PubMed

    Ohta, Shoichiro; Lai, Edwin W; Morris, John C; Bakan, Douglas A; Klaunberg, Brenda; Cleary, Susannah; Powers, James F; Tischler, Arthur S; Abu-Asab, Mones; Schimel, Daniel; Pacak, Karel

    2006-11-01

    Successful outcomes for patients with cancer often depend on the early detection of tumor and the prompt initiation of active therapy. Despite major advances in the treatment of many cancers, early-stage lesions often go undetected due to the suboptimal resolution of current anatomical and functional imaging modalities. This limitation also applies to preclinical animal tumor models that are crucial for the evaluation and development of new therapeutic approaches to cancer. We report a new mouse model of metastatic pheochromocytoma, generated using tail vein injection of the mouse pheochromocytoma cell (MPC) line that reproducibly generated multiple liver tumors in the animals. Furthermore, we show that in vivo microCT imaging enhanced using a hepatobiliary-specific contrast agent, glyceryl-2-oleyl-1,3-di-7-(3-amino-2,4,6-triiodophenyl)-heptanoate (DHOG), detected tumors as small as 0.35 mm as early as 4 weeks after the injection of the tumor cells. This model may be useful for in vivo studies of tumor biology and for development of new strategies to treat metastatic pheochromocytoma.

  3. MicroCT for high-resolution imaging of ectopic pheochromocytoma tumors in the liver of nude mice

    PubMed Central

    Ohta, Shoichiro; Lai, Edwin W.; Morris, John C.; Bakan, Douglas A.; Klaunberg, Brenda; Cleary, Susannah; Powers, James F.; Tischler, Arthur S.; Abu-Asab, Mones; Schimel, Daniel; Pacak, Karel

    2008-01-01

    Successful outcomes for patients with cancer often depend on the early detection of tumor and the prompt initiation of active therapy. Despite major advances in the treatment of many cancers, early-stage lesions often go undetected due to the suboptimal resolution of current anatomical and functional imaging modalities. This limitation also applies to preclinical animal tumor models that are crucial for the evaluation and development of new therapeutic approaches to cancer. We report a new mouse model of metastatic pheochromocytoma, generated using tail vein injection of the mouse pheochromocytoma cell (MPC) line that reproducibly generated multiple liver tumors in the animals. Furthermore, we show that in vivo microCT imaging enhanced using a hepatobiliary-specific contrast agent, glyceryl-2-oleyl-1,3-di-7-(3-amino-2,4,6-triiodophenyl)-heptanoate (DHOG), detected tumors as small as 0.35 mm as early as 4 weeks after the injection of the tumor cells. This model may be useful for in vivo studies of tumor biology and for development of new strategies to treat metastatic pheochromocytoma. PMID:16841334

  4. 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.

  5. 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.

  6. 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.

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

    PubMed

    Larsson, Daniel H; Lundström, Ulf; Westermark, Ulrica K; Arsenian Henriksson, Marie; Burvall, Anna; Hertz, Hans M

    2013-02-01

    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. 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 ∼7 μm x-ray spots, providing high spatial resolution in absorption imaging and high spatial coherence for the phase-contrast imaging. High-resolution absorption imaging is demonstrated on mice with CT, showing 50 μm 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. 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.

  8. 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.

  9. A Method to Monitor Seasonal Inundation States Using High Resolution ALOS PALSAR ScanSAR Observations in Alaksa

    NASA Astrophysics Data System (ADS)

    Azarderakhsh, M.; McDonald, K. C.; Moghaddam, M.; Whitcomb, J.

    2015-12-01

    Inland water extent is crucial to enhancing our knowledge about the biogeochemical transitions, carbon dynamics and prediction of boreal-arctic ecosystem. However, in high latitute regions inundation is directly affected by the timing of freeze and thaw conditions at the surface. In other words, these two features (i.e. freeze/thaw and inundation analysis) are interconnected and should be considered simultaneously in understanding hydrological and carbon cycles. One of advantages of L-band microwave satellite observation over optical observation is to penetrate to the clouds and vegetation to detect inundated areas. A recent study usese fine-beam mode of PALSAR observation Fine Beam Data (FBD) with resolution of up to 12m as well as ground based land cover using Random Forest Classification method to classify different types of wetlands over Alaska. However, these observations are not frequent and it makes the seasonal and inter-annual studies challenging. We employ PALSAR ScanSAR mode data with more frequent temporal coverage of up to 40 days along with the static map dervied from FBD data to study the timing of the inundation for these wetland classes for 2007- 2010 years period. This study has the advantage of providing freeze-thaw states to detect the timing of active season and then to provide timing of inundated surfaces. Traditional approaches normalize ScanSAR mode data with varying incidence angle to far angle using either histogram method or linear fit methods. We use a unique method that uses the angle dependency of different land cover types to detect inundated surfaces especially the ones that are mixed with vegetation. The seasonal and temporal inundation and freeze/thaw states maps are generated which agree well with previous studies, ancillary data, and ground observations over different land-cover classes. The results of this study benefits hydrological and carbon cycle studies as an important source of carbon uptake in arctic regions. Moreover

  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. Time delay study of a CT simulator in respiratory gated CT scanning

    SciTech Connect

    Guan Huaiqun

    2006-04-15

    In respiratory-gated radiotherapy (RGRT), if the time delay in a computed tomography (CT) simulator and that in a linear accelerator (Linac) are different, the simulation and the treatment cannot be synchronized. In this study, we presented a technique to measure the time delay of the AcQSim CT simulator (Philips Medical Systems, Cleveland, OH) using Varian's Real-Time Positioning Management (RPM) system (Varian Medical Systems, Palo Alto, CA). A respiratory gating platform (REF 91150, Standard Imaging, Inc., Middleton, MI) was first set at the position of amplitude maximum (phase 0). Then a ball of 1.3 cm diameter was put on the platform and set at the CT laser. A single axial scan was acquired across the center of the ball without motion. Then the motion was turned on and single axial scans gated at different phases were acquired with a very narrow gating window. The time between the phase giving a good estimate of the ball and phase 0 is the overall delay time. We found that for AcQSim CT, the overall delay for a single axial scan (with 1 s scan time) is 1.75 s. For multiple axial scans, the overall delay is 1.75 s for the first scan and 0.75 s for the subsequent ones. This demonstrated that the CT mechanical startup delay is 1 s. After the first axial scan, the overall delay per scan is less because CT gantry continuously spins and no mechanical delay exists. We call the overall delay without mechanical part the scanning delay, which basically equals half the scan time (0.5 s for 1 s scan time) plus the gating pulse triggering delay (250 ms). The delays were also verified using metal balls of 1.5 mm diameter set at the amplitude minimum (phase 180, initially). We note that it is the scanning delay rather than the triggering delay that should be compensated when doing motion-synchronized radiotherapy. The current interface between the RPM system and the AcQSim CT does not compensate for this scanning delay.

  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. Near-field scanning optical microscopy in liquid for high resolution single molecule detection on dendritic cells.

    PubMed

    Koopman, M; Cambi, A; de Bakker, B I; Joosten, B; Figdor, C G; van Hulst, N F; Garcia-Parajo, M F

    2004-08-27

    Clustering of cell surface receptors into micro-domains in the plasma membrane is an important mechanism for regulating cellular functions. Unfortunately, these domains are often too small to be resolved with conventional optical microscopy. Near-field scanning optical microscopy (NSOM) is a relatively new technique that combines ultra high optical resolution, down to 70 nm, with single molecule detection sensitivity. As such, the technique holds great potential for direct visualisation of domains at the cell surface. Yet, NSOM operation under liquid conditions is far from trivial. In this contribution, we show that the performance of NSOM can be extended to measurements in liquid environments using a diving bell concept. For the first time, individual fluorescent molecules on the membrane of cells in solution are imaged with a spatial resolution of 90 nm. Furthermore, using this technique we have been able to directly visualise nanometric sized domains of the C-type lectin DC-SIGN on the membrane of dendritic cells, both in air and in liquid.

  15. 3D documentation of footwear impressions and tyre tracks in snow with high resolution optical surface scanning.

    PubMed

    Buck, Ursula; Albertini, Nicola; Naether, Silvio; Thali, Michael J

    2007-09-13

    The three-dimensional documentation of footwear and tyre impressions in snow offers an opportunity to capture additional fine detail for the identification as present photographs. For this approach, up to now, different casting methods have been used. Casting of footwear impressions in snow has always been a difficult assignment. This work demonstrates that for the three-dimensional documentation of impressions in snow the non-destructive method of 3D optical surface scanning is suitable. The new method delivers more detailed results of higher accuracy than the conventional casting techniques. The results of this easy to use and mobile 3D optical surface scanner were very satisfactory in different meteorological and snow conditions. The method is also suitable for impressions in soil, sand or other materials. In addition to the side by side comparison, the automatic comparison of the 3D models and the computation of deviations and accuracy of the data simplify the examination and delivers objective and secure results. The results can be visualized efficiently. Data exchange between investigating authorities at a national or an international level can be achieved easily with electronic data carriers.

  16. 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.

  17. 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

  18. High-resolution photoreceptor imaging in idiopathic macular telangiectasia type 2 using adaptive optics scanning laser ophthalmoscopy.

    PubMed

    Ooto, Sotaro; Hangai, Masanori; Takayama, Kohei; Arakawa, Naoko; Tsujikawa, Akitaka; Koizumi, Hideki; Oshima, Susumu; Yoshimura, Nagahisa

    2011-07-25

    To study pathologic changes in the photoreceptors in eyes with idiopathic macular telangiectasia (MacTel) type 2 using adaptive optics scanning laser ophthalmoscopy (AO-SLO). Thirteen eyes with nonproliferative MacTel type 2 and 10 normal eyes underwent a full ophthalmologic examination, spectral-domain optical coherence tomography (SD-OCT), and imaging with an original prototype AO-SLO system. All eyes with MacTel type 2 were examined with fluorescein angiography (FA), fundus autofluorescence (FAF), confocal blue reflectance (CBR), and fundus-monitoring microperimetry (MP). All eyes with MacTel type 2 had ring-like dark areas and/or small patchy regions on AO-SLO images; significantly lower cone density than that of normal eyes in each hemisphere at 0.5 mm from the foveal center; an area with parafoveal reflectance in CBR that was larger than the hyperfluorescence area in FA, the area of increased FAF, the dark areas on AO-SLO, and the area of decreased retinal sensitivity on MP. Dark areas on AO-SLO roughly corresponded to the leakage area in FA, but dark areas were also seen in areas without FA leakage in 11 eyes, including an eye with the earliest clinical signs of MacTel. Visual acuity and retinal sensitivity correlated with mean cone density 0.5 mm from the center of the fovea. In eyes with MacTel type 2, AO-SLO revealed unique dark regions in the cone mosaic and decreased cone density that was associated with decreased vision, even in areas with normal vasculature, which suggests that this feature represents early neuronal changes involved in the pathogenesis of MacTel type 2.

  19. High-resolution imaging of retinal nerve fiber bundles in glaucoma using adaptive optics scanning laser ophthalmoscopy.

    PubMed

    Takayama, Kohei; Ooto, Sotaro; Hangai, Masanori; Ueda-Arakawa, Naoko; Yoshida, Sachiko; Akagi, Tadamichi; Ikeda, Hanako Ohashi; Nonaka, Atsushi; Hanebuchi, Masaaki; Inoue, Takashi; Yoshimura, Nagahisa

    2013-05-01

    To detect pathologic changes in retinal nerve fiber bundles in glaucomatous eyes seen on images obtained by adaptive optics (AO) scanning laser ophthalmoscopy (AO SLO). Prospective cross-sectional study. Twenty-eight eyes of 28 patients with open-angle glaucoma and 21 normal eyes of 21 volunteer subjects underwent a full ophthalmologic examination, visual field testing using a Humphrey Field Analyzer, fundus photography, red-free SLO imaging, spectral-domain optical coherence tomography, and imaging with an original prototype AO SLO system. The AO SLO images showed many hyperreflective bundles suggesting nerve fiber bundles. In glaucomatous eyes, the nerve fiber bundles were narrower than in normal eyes, and the nerve fiber layer thickness was correlated with the nerve fiber bundle widths on AO SLO (P < .001). In the nerve fiber layer defect area on fundus photography, the nerve fiber bundles on AO SLO were narrower compared with those in normal eyes (P < .001). At 60 degrees on the inferior temporal side of the optic disc, the nerve fiber bundle width was significantly lower, even in areas without nerve fiber layer defect, in eyes with glaucomatous eyes compared with normal eyes (P = .026). The mean deviations of each cluster in visual field testing were correlated with the corresponding nerve fiber bundle widths (P = .017). AO SLO images showed reduced nerve fiber bundle widths both in clinically normal and abnormal areas of glaucomatous eyes, and these abnormalities were associated with visual field defects, suggesting that AO SLO may be useful for detecting early nerve fiber bundle abnormalities associated with loss of visual function. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Rapid, high-resolution measurement of leaf area and leaf orientation using terrestrial LiDAR scanning data

    NASA Astrophysics Data System (ADS)

    Bailey, Brian N.; Mahaffee, Walter F.

    2017-06-01

    The rapid evolution of high performance computing technology has allowed for the development of extremely detailed models of the urban and natural environment. Although models can now represent sub-meter-scale variability in environmental geometry, model users are often unable to specify the geometry of real domains at this scale given available measurements. An emerging technology in this field has been the use of terrestrial LiDAR scanning data to rapidly measure the three-dimensional geometry of trees, such as the distribution of leaf area. However, current LiDAR methods suffer from the limitation that they require detailed knowledge of leaf orientation in order to translate projected leaf area into actual leaf area. Common methods for measuring leaf orientation are often tedious or inaccurate, which places constraints on the LiDAR measurement technique. This work presents a new method to simultaneously measure leaf orientation and leaf area within an arbitrarily defined volume using terrestrial LiDAR data. The novelty of the method lies in the direct measurement of the fraction of projected leaf area G from the LiDAR data which is required to relate projected leaf area to total leaf area, and in the new way in which radiation transfer theory is used to calculate leaf area from the LiDAR data. The method was validated by comparing LiDAR-measured leaf area to (1) ‘synthetic’ or computer-generated LiDAR data where the exact area was known, and (2) direct measurements of leaf area in the field using destructive sampling. Overall, agreement between the LiDAR and reference measurements was very good, showing a normalized root-mean-squared-error of about 15% for the synthetic tests, and 13% in the field.

  1. Scanning ion conductance microscopy: a convergent high-resolution technology for multi-parametric analysis of living cardiovascular cells

    PubMed Central

    Miragoli, Michele; Moshkov, Alexey; Novak, Pavel; Shevchuk, Andrew; Nikolaev, Viacheslav O.; El-Hamamsy, Ismail; Potter, Claire M. F.; Wright, Peter; Kadir, S.H. Sheikh Abdul; Lyon, Alexander R.; Mitchell, Jane A.; Chester, Adrian H.; Klenerman, David; Lab, Max J.; Korchev, Yuri E.; Harding, Sian E.; Gorelik, Julia

    2011-01-01

    Cardiovascular diseases are complex pathologies that include alterations of various cell functions at the levels of intact tissue, single cells and subcellular signalling compartments. Conventional techniques to study these processes are extremely divergent and rely on a combination of individual methods, which usually provide spatially and temporally limited information on single parameters of interest. This review describes scanning ion conductance microscopy (SICM) as a novel versatile technique capable of simultaneously reporting various structural and functional parameters at nanometre resolution in living cardiovascular cells at the level of the whole tissue, single cells and at the subcellular level, to investigate the mechanisms of cardiovascular disease. SICM is a multimodal imaging technology that allows concurrent and dynamic analysis of membrane morphology and various functional parameters (cell volume, membrane potentials, cellular contraction, single ion-channel currents and some parameters of intracellular signalling) in intact living cardiovascular cells and tissues with nanometre resolution at different levels of organization (tissue, cellular and subcellular levels). Using this technique, we showed that at the tissue level, cell orientation in the inner and outer aortic arch distinguishes atheroprone and atheroprotected regions. At the cellular level, heart failure leads to a pronounced loss of T-tubules in cardiac myocytes accompanied by a reduction in Z-groove ratio. We also demonstrated the capability of SICM to measure the entire cell volume as an index of cellular hypertrophy. This method can be further combined with fluorescence to simultaneously measure cardiomyocyte contraction and intracellular calcium transients or to map subcellular localization of membrane receptors coupled to cyclic adenosine monophosphate production. The SICM pipette can be used for patch-clamp recordings of membrane potential and single channel currents. In

  2. 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

  3. An automatic approach for 3D registration of CT scans

    NASA Astrophysics Data System (ADS)

    Hu, Yang; Saber, Eli; Dianat, Sohail; Vantaram, Sreenath Rao; Abhyankar, Vishwas

    2012-03-01

    CT (Computed tomography) is a widely employed imaging modality in the medical field. Normally, a volume of CT scans is prescribed by a doctor when a specific region of the body (typically neck to groin) is suspected of being abnormal. The doctors are required to make professional diagnoses based upon the obtained datasets. In this paper, we propose an automatic registration algorithm that helps healthcare personnel to automatically align corresponding scans from 'Study' to 'Atlas'. The proposed algorithm is capable of aligning both 'Atlas' and 'Study' into the same resolution through 3D interpolation. After retrieving the scanned slice volume in the 'Study' and the corresponding volume in the original 'Atlas' dataset, a 3D cross correlation method is used to identify and register various body parts.

  4. 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.

  5. 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.

  6. 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.

  7. Correlation between IVC dimensions and volume status on CT scan.

    PubMed

    Miraflor, Emily; Yeung, Louise; Strumwasser, Aaron; Sadjadi, Javid; Victorino, Gregory P

    2011-10-01

    End points of resuscitation in trauma patients are difficult to define. The size of the inferior vena cava (IVC) on CT scan may accurately indicate volume status and guide resuscitation efforts. Our hypothesis was that IVC "flatness" on CT scan reflects volume status in hemodynamically normal trauma patients. The study population was drawn from a database of trauma patients who had abdominal CT scans and lactate levels drawn on arrival. Lactate was chosen as a marker of volume status since hypotensive patients were unlikely to undergo CT. Anteroposterior (AP) and transverse (TV) diameters of the IVC were measured at the suprarenal and infrarenal locations. A flatness index was calculated for each location (TV ÷ AP) and this value was correlated with heart rate, blood pressure, and lactate. There was no difference in IVC flatness at the suprarenal or infrarenal position for patients with an elevated lactate compared with those with a normal lactate: 1.54 ± 0.18 versus 1.43 ± 0.08 (P = 0.2) suprarenal and 1.54 ± 0.46 versus 1.68 ± 0.58 (P = 0.4) infrarenal. IVC flatness at the suprarenal location weakly correlated with blood pressure (r = -0.29). IVC flatness did not correlate with blood pressure at the infrarenal location (r = -0.1). IVC flatness did not correlate with heart rate (P > 0.3) or age (P > 0.2). These results did not demonstrate a correlation between IVC flatness and the markers of intravascular volume of heart rate, blood pressure, or lactate. IVC flatness on CT scan is not a valid indicator of volume status in hemodynamically normal trauma patients. Copyright © 2011 Elsevier Inc. All rights reserved.

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

    PubMed Central

    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. PMID:27351925

  9. 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.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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-1 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-1) at various radiation doses (1.2, 2.4 and 3.6 mGy) and then CT images were reconstructed using the filtered-back-projection (FBP) technique and the 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 task-based modulation transfer function (MTF). Both the 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 the FBP reconstruction for low contrast target. For high contrast target, the TFIR was substantially superior to the FBP reconstruction in terms of spatial resolution. In addition, TFIR was able to achieve a factor of 1.6-1.8 increase in CNR, depending on the target contrast level. This study demonstrates that the TFIR can reduce the required radiation dose by a factor of two-thirds for a CT image reconstruction compared to the 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 system and it takes approximately 10 s to reconstruct a single-slice CT image

  12. 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

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

    PubMed

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

    2014-10-21

    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(-1) 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(-1)) at various radiation doses (1.2, 2.4 and 3.6 mGy) and then CT images were reconstructed using the filtered-back-projection (FBP) technique and the 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 task-based modulation transfer function (MTF). Both the 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 the FBP reconstruction for low contrast target. For high contrast target, the TFIR was substantially superior to the FBP reconstruction in terms of spatial resolution. In addition, TFIR was able to achieve a factor of 1.6-1.8 increase in CNR, depending on the target contrast level. This study demonstrates that the TFIR can reduce the required radiation dose by a factor of two-thirds for a CT image reconstruction compared to the 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 system and it takes approximately 10 s to reconstruct a single-slice CT image

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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

    2017-05-01

    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. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  3. 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

  4. CT scan range estimation using multiple body parts detection: let PACS learn the CT image content.

    PubMed

    Wang, Chunliang; Lundström, Claes

    2016-02-01

    The aim of this study was to develop an efficient CT scan range estimation method that is based on the analysis of image data itself instead of metadata analysis. This makes it possible to quantitatively compare the scan range of two studies. In our study, 3D stacks are first projected to 2D coronal images via a ray casting-like process. Trained 2D body part classifiers are then used to recognize different body parts in the projected image. The detected candidate regions go into a structure grouping process to eliminate false-positive detections. Finally, the scale and position of the patient relative to the projected figure are estimated based on the detected body parts via a structural voting. The start and end lines of the CT scan are projected to a standard human figure. The position readout is normalized so that the bottom of the feet represents 0.0, and the top of the head is 1.0. Classifiers for 18 body parts were trained using 184 CT scans. The final application was tested on 136 randomly selected heterogeneous CT scans. Ground truth was generated by asking two human observers to mark the start and end positions of each scan on the standard human figure. When compared with the human observers, the mean absolute error of the proposed method is 1.2% (max: 3.5%) and 1.6% (max: 5.4%) for the start and end positions, respectively. We proposed a scan range estimation method using multiple body parts detection and relative structure position analysis. In our preliminary tests, the proposed method delivered promising results.

  5. 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.

  6. Ultrahigh vacuum scanning force/scanning tunneling microscope: Application to high-resolution imaging of Si(111)7 × 7

    NASA Astrophysics Data System (ADS)

    Olsson, L.; Wigren, R.; Erlandsson, R.

    1996-06-01

    We present a combined scanning force/scanning tunneling microscope (SFM/STM) operating in ultrahigh vacuum using a fiber-optic laser interferometer to detect the lever deflection. As force microscope it operates in ac and dc mode with commercial (Si, Si3N4) or individually made (W) cantilevers. Samples and cantilevers can be inserted without breaking the vacuum using a load-lock system. The force sensor includes a novel three-dimensional micropositioner based on the piezoelectric slider principle. The system includes standard surface analytical techniques (low-energy electron diffraction/Auger, prepared for x-ray photoelectron spectroscopy) and is equipped for mass spectroscopic detection of reaction products from catalytic surfaces at elevated temperature. Tips are cleaned in situ using electron bombardment. By using tungsten cantilevers with a high spring constant (k=100-200 N/m), it is possible to switch directly between STM and SFM operation. As reference surface we have used the Si(111)7×7 reconstruction, prepared by in situ flashing to 1150 °C, which is imaged at atomic resolution using STM as well as ac-mode SFM.

  7. High resolution measurement of earthquake impacts on rock slope stability and damage using pre- and post-earthquake terrestrial laser scans

    NASA Astrophysics Data System (ADS)

    Hutchinson, Lauren; Stead, Doug; Rosser, Nick

    2017-04-01

    Understanding the behaviour of rock slopes in response to earthquake shaking is instrumental in response and relief efforts following large earthquakes as well as to ongoing risk management in earthquake affected areas. Assessment of the effects of seismic shaking on rock slope kinematics requires detailed surveys of the pre- and post-earthquake condition of the slope; however, at present, there is a lack of high resolution monitoring data from pre- and post-earthquake to facilitate characterization of seismically induced slope damage and validate models used to back-analyze rock slope behaviour during and following earthquake shaking. Therefore, there is a need for additional research where pre- and post- earthquake monitoring data is available. This paper presents the results of a direct comparison between terrestrial laser scans (TLS) collected in 2014, the year prior to the 2015 earthquake sequence, with that collected 18 months after the earthquakes and two monsoon cycles. The two datasets were collected using Riegl VZ-1000 and VZ-4000 full waveform laser scanners with high resolution (c. 0.1 m point spacing as a minimum). The scans cover the full landslide affected slope from the toe to the crest. The slope is located in Sindhupalchok District, Central Nepal which experienced some of the highest co-seismic and post-seismic landslide intensities across Nepal due to the proximity to the epicenters (<20 km) of both of the main aftershocks on April 26, 2015 (M 6.7) and May 12, 2015 (M7.3). During the 2015 earthquakes and subsequent 2015 and 2016 monsoons, the slope experienced rockfall and debris flows which are evident in satellite imagery and field photographs. Fracturing of the rock mass associated with the seismic shaking is also evident at scales not accessible through satellite and field observations. The results of change detection between the TLS datasets with an emphasis on quantification of seismically-induced slope damage is presented. Patterns in the

  8. Direct use of CT scans for hyperthermia treatment planning

    SciTech Connect

    James, B.J.; Sullivan, D.M. )

    1992-08-01

    In the field of deep regional hyperthermia cancer therapy, the BSD-2000 Hyperthermia System is one of the most widely used devices. Because of the complexity of the treatment process, computer modeling has long been viewed as a desirable means of planning patient treatments. Patient-specific, three-dimensional computer modeling for treatment planning in the BSD-2000 has been in clinical use at this institution for two years. Two of the persistent problems have been the large amount of time needed to create the patient model from a computed tomography (CT) scan, and the lack of a way to view the large amounts of data that comprise the output of treatment plan, i.e., the specific absorption rate (SAR) at 20 000 to 30 000 cells. Here the authors present a method that obtains the dielectric properties needed for hyperthermia treatment planning directly from the CT image with minimum operator interaction, a process which takes about a half day and is more accurate. Comparison is made with the previous method of drawing contours around the different tissue types. They further describe a method which displays the output as iso-SAR contours directly over the CT scan of the patient.

  9. 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

  10. Structural analysis of PTCDA monolayers on epitaxial graphene with ultra-high vacuum scanning tunneling microscopy and high-resolution X-ray reflectivity

    NASA Astrophysics Data System (ADS)

    Emery, Jonathan D.; Wang, Qing Hua; Zarrouati, Marie; Fenter, Paul; Hersam, Mark C.; Bedzyk, Michael J.

    2011-09-01

    Epitaxial graphene, grown by thermal decomposition of the SiC (0001) surface, is a promising material for future applications due to its unique and superlative electronic properties. However, the innate chemical passivity of graphene presents challenges for integration with other materials for device applications. Here, we present structural characterization of epitaxial graphene functionalized by the organic semiconductor perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA). A combination of ultra-high vacuum scanning tunneling microscopy (STM) and high-resolution X-ray reflectivity (XRR) is used to extract lateral and vertical structures of 0, 1, and 2 monolayer (ML) PTCDA on epitaxial graphene. Both Fienup-based phase-retrieval algorithms and model-based least-squares analyses of the XRR data are used to extract an electron density profile that is interpreted in terms of a stacking sequence of molecular layers with specific interlayer spacings. Features in the STM and XRR analysis indicate long-range molecular ordering and weak π-π* interactions binding PTCDA molecules to the graphene surface. The high degree of both lateral and vertical ordering of the self-assembled film demonstrates PTCDA functionalization as a viable route for templating graphene for the growth and deposition of additional materials required for next-generation electronics and sensors.

  11. 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.

  12. 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.

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

    PubMed Central

    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. PMID:26578896

  14. 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.

  15. Hydration Effects on Skin Microstructure as Probed by High-Resolution Cryo-Scanning Electron Microscopy and Mechanistic Implications to Enhanced Transcutaneous Delivery of Biomacromolecules

    PubMed Central

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

    2010-01-01

    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. PMID:19582754

  16. 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.

  17. 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.

  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. 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.

  20. Automated detection of bone metastatic changes using serial CT scans.

    PubMed

    Oh, Jihun; Kim, Gyehyun; Lee, Jaesung; Cheon, Minsu; Park, Yongsup; Kim, Sewon; Yi, Jonghyon; Lee, Ho Yun

    2017-06-01

    Bone metastases resulting from a primary tumor invasion to the bone are common and cause significant morbidity in advanced cancer patients. Although the detection of bone metastases is often straightforward, it is difficult to identify their spread and track their changes, particularly in early stages. This paper presents a novel method that automatically finds the changes in appearance and the progress of bone metastases using longitudinal CT images. In contrast to previous methods based on nodule detection within a specific bone site in an individual CT scan, the approach in the present study is based on the subtraction between two registered CT volumes. The volumes registered using the proposed weighted-Demons registration and symmetric warping were subtracted with minimizing noise, and the Jacobian and false positive suppressions were performed to reduce false alarms. The proposed method detects the changes in bone metastases within 3min for entire chest bone structures covering the spine, ribs, and sternum. The method was validated based on 3-fold cross validation using the radiologists' markings of 459 lesions in 24 subjects and was performed with a sensitivity of 92.59%, a false positive volume of 2.58%, and 9.71 false positives per patient. Note that 113 lesions (24%) missed by the radiologists were identified by the present system and confirmed to be true metastases. Indeed, three patients diagnosed initially as normal, having no metastatic difference, by radiologists were found to be abnormal using the proposed system. Automatic detection method of bone metastatic changes in the entire chest bone was developed. Weighted Demons, symmetric warping, following false positive suppressions, and their parallel computing implementation enabled precise and fast computation of delicate changes in serial CT scans. The cross validation proved that this method can be quite useful for assisting radiologists in sensing minute metastatic changes from early stage

  1. a 530-590 GHZ Schottky Heterodyne Receiver for High-Resolution Molecular Spectroscopy with Lille's Fast-Scan Fully Solid-State DDS Spectrometer

    NASA Astrophysics Data System (ADS)

    Pienkina, A.; Margulès, L.; Motiyenko, R. A.; Wiedner, Martina C.; Maestrini, Alain; Defrance, Fabien

    2017-06-01

    Laboratory spectroscopy, especially at THz and mm-wave ranges require the advances in instrumentation techniques to provide high resolution of the recorded spectra with precise frequency measurement that facilitates the mathematical treatment. We report the first implementation of a Schottky heterodyne receiver, operating at room temperature and covering the range between 530 and 590 GHz, for molecular laboratory spectroscopy. A 530-590 GHz non-cryogenic Schottky solid-state receiver was designed at LERMA, Observatoire de Paris and fabricated in partnership with LPN- CNRS (Laboratoire de Photonique et de Nanostructures), and was initially developed for ESA Jupiter Icy Moons Explorer (JUICE), intended to observe Jupiter and its icy moon atmospheres. It is based on a sub-harmonic Schottky diode mixer, designed and fabricated at LERMA-LPN, pumped by a Local Oscillator (LO), consisting of a frequency Amplifier/Multiplier chains (AMCs) from RPG (Radiometer Physics GmBh). The performance of the receiver was demonstrated by absorption spectroscopy of CH_3CH_2CN with Lille's fast-scan DDS spectrometer. A series of test measurements showed the receiver's good sensitivity, stability and frequency accuracy comparable to those of 4K QMC bolometers, thus making room-temperature Schottky receiver a competitive alternative to 4K QMC bolometers to laboratory spectroscopy applications. We will present the first results with such a combination of a compact room temperature Schottky heterodyne receiver and a fast-scan DDS spectrometer. J. Treuttel, L. Gatilova, A. Maestrini et al., 2016, IEEE Trans. Terahertz Science and Tech., 6, 148-155. This work was funded by the French ANR under the Contract No. ANR-13-BS05-0008-02 IMOLABS.

  2. 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

  3. 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.

  4. Visual anatomical lung CT scan assessment of lung recruitability.

    PubMed

    Chiumello, Davide; Marino, Antonella; Brioni, Matteo; Menga, Federica; Cigada, Irene; Lazzerini, Marco; Andrisani, Maria C; Biondetti, Pietro; Cesana, Bruno; Gattinoni, Luciano

    2013-01-01

    The computation of lung recruitability in acute respiratory distress syndrome (ARDS) is advocated to set positive end-expiratory pressure (PEEP) for preventing lung collapse. The quantitative lung CT scan, obtained by manual image processing, is the reference method but it is time consuming. The aim of this study was to evaluate the accuracy of a visual anatomical analysis compared with a quantitative lung CT scan analysis in assessing lung recruitability. Fifty sets of two complete lung CT scans of ALI/ARDS patients computing lung recruitment were analyzed. Lung recruitability computed at an airway pressure of 5 and 45 cm H(2)O was defined as the percentage decrease in the collapsed/consolidated lung parenchyma assessed by two expert radiologists using a visual anatomical analysis and as the decrease in not aerated lung regions using a quantitative analysis computed by dedicated software. Lung recruitability was 11.3 % (interquartile range 7.39-16.41) and 15.5 % (interquartile range 8.18-21.43) with the visual anatomical and quantitative analysis, respectively. In the Bland-Altman analysis, the bias and agreement bands between the visual anatomical and quantitative analysis were -2.9 % (-11.8 to +5.9 %). The ROC curve showed that the optimal cutoff values for the visual anatomical analysis in predicting high versus low lung recruitability was 8.9 % (area under the ROC curve 0.9248, 95 % CI 0.8550-0.9946). Considering this cutoff, the sensitivity, specificity, and diagnostic accuracy were 0.96, 0.76, and 0.86, respectively. Visual anatomical analysis can classify patients into those with high and low lung recruitability allowing more intensivists to get access to lung recruitability assessment.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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).

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. Rheumatoid arthritis-associated interstitial lung disease: lung inflammation evaluated with high resolution computed tomography scan is correlated to rheumatoid arthritis disease activity.

    PubMed

    Pérez-Dórame, Renzo; Mejía, Mayra; Mateos-Toledo, Heidegger; Rojas-Serrano, Jorge

    2015-01-01

    To describe the association between rheumatoid arthritis disease activity (RA) and interstitial lung damage (inflammation and fibrosis), in a group of patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD). A retrospective study of RA patients with interstitial lung disease (restrictive pattern in lung function tests and evidence of interstitial lung disease in high resolution computed tomography (HRCT)). Patients were evaluated to exclude other causes of pulmonary disease. RA disease activity was measured with the CDAI index. Interstitial lung inflammation and fibrosis were determined by Kazerooni scale. We compared Kazerooni ground-glass score with the nearest CDAI score to HRCT date scan of the first medical evaluation at our institution. In nine patients, we compared the first ground-glass score with a second one after treatment with DMARDs and corticosteroids. Spearman's rank correlation coefficient was used to evaluate association between RA disease activity and the Kazerooni ground-glass and fibrosis scores. Thirty-four patients were included. A positive correlation between CDAI and ground-glass scores was found (rs=0.3767, P<0.028). Fibrosis and CDAI scores were not associated (rs=-0.0747, P<0.6745). After treatment, a downward tendency in the ground-glass score was observed (median [IQR]): (2.33 [2,3] vs. 2 [1.33-2.16]), P<0.056, along with a lesser CDAI score (27 [8-43] vs. 9 [5-12]), P<0.063. There is a correlation between RA disease activity and ground-glass appearance in the HRCT of RA-ILD patients. These results suggest a positive association between RA disease activity and lung inflammation in RA-ILD. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

  2. 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.

  3. 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.

  4. 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.

    PubMed

    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.

  5. 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.

  6. Impact of PET-CT scan on management in upper gastrointestinal malignancy.

    PubMed

    Sharma, Aditya; Young, Michael

    2016-07-01

    Curative treatments of upper gastrointestinal (UGI) cancers carry significant morbidity and mortality. Therefore, accurate pre-treatment staging is important. PET-CT scan is an expensive modality, and not readily available in New Zealand. The aim of this study was to describe how PET-CT scan influences management in UGI cancer. This retrospective descriptive study included patients with UGI cancer with no evidence of metastatic disease on IV contrast CT scan, and those medically fit for curative treatment. Patients then underwent PET-CT scan. We defined influence or change in management if PET-CT showed metastatic disease or other lesions requiring further investigation. Seventy-nine patients were identified for the purposes of this study. Fifty-nine (74.7%) had CT scan showing no evidence of metastatic disease. Of these, PET-CT scan influenced management in 14 patients (23.7%) and found distant metastasis in eight patients (13.6%). The remaining 20 of 79 patients (25.3%) had CT scan showing indeterminate lesions. Of these, PET-CT scan influenced management in eight patients (40%), with metastatic disease seen in seven patients (35%). Our study confirms the value of PET-CT scan in pre-operative staging of UGI cancer. It had a greater impact on patients with intermediate lesions on staging CT.

  7. 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

  8. Yttrium-90 internal pair production imaging using first generation PET/CT provides high-resolution images for qualitative diagnostic purposes

    PubMed Central

    Kao, Y H; Tan, E H; Lim, K Y; Ng, C E; Goh, S W

    2012-01-01

    Yttrium-90 (90Y) internal pair production can be imaged by positron emission tomography (PET)/CT and is superior to bremsstrahlung single-photon emission CT/CT for evaluating hepatic 90Y microsphere biodistribution. We illustrate a case of 90Y imaging using first generation PET/CT technology, producing high-quality images for qualitative diagnostic purposes. PMID:21976634

  9. 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

  10. 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.

  11. 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.

  12. 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)

  13. Measurements of Epidural Space Depth Using Preexisting CT Scans Correlate with Loss of Resistance Depth during Thoracic Epidural Catheter Placement

    PubMed Central

    Greene, Nathaniel H.; Cobb, Benjamin G.; Linnau, Ken F.; Kent, Christopher D.

    2015-01-01

    Background. Thoracic epidural catheters provide the best quality postoperative pain relief for major abdominal and thoracic surgical procedures, but placement is one of the most challenging procedures in the repertoire of an anesthesiologist. Most patients presenting for a procedure that would benefit from a thoracic epidural catheter have already had high resolution imaging that may be useful to assist placement of a catheter. Methods. This retrospective study used data from 168 patients to examine the association and predictive power of epidural-skin distance (ESD) on computed tomography (CT) to determine loss of resistance depth acquired during epidural placement. Additionally, the ability of anesthesiologists to measure this distance was compared to a radiologist, who specializes in spine imaging. Results. There was a strong association between CT measurement and loss of resistance depth (P < 0.0001); the presence of morbid obesity (BMI > 35) changed this relationship (P = 0.007). The ability of anesthesiologists to make CT measurements was similar to a gold standard radiologist (all individual ICCs > 0.9). Conclusions. Overall, this study supports the examination of a recent CT scan to aid in the placement of a thoracic epidural catheter. Making use of these scans may lead to faster epidural placements, fewer accidental dural punctures, and better epidural blockade. PMID:25628654

  14. 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

  15. 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.

  16. 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

  17. High-resolution electron microscope

    NASA Technical Reports Server (NTRS)

    Nathan, R.

    1977-01-01

    Employing scanning transmission electron microscope as interferometer, relative phases of diffraction maximums can be determined by analysis of dark field images. Synthetic aperture technique and Fourier-transform computer processing of amplitude and phase information provide high resolution images at approximately one angstrom.

  18. 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

  19. 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

  20. 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.

  1. Slowing the increase in the population dose resulting from CT scans.

    PubMed

    Brenner, D J

    2010-12-01

    The annual number of CT scans in the U.S. is now over 70 million. The concern is that organ doses from CT are typically far larger than those from conventional X-ray examinations, and there is epidemiological evidence of a small but significant increased cancer risk at typical CT doses. Because CT is a superb diagnostic tool and because individual CT risks are small, when a CT scan is clinically indicated, the CT benefit/risk balance is by far in the patient's favor. Nevertheless, CT should operate under the ALARA (As Low As Reasonably Achievable) principle, and opportunities exist to reduce the significant population dose associated with CT without compromising patient care. The first opportunity is to reduce the dose per scan, and improved technology has much potential here. The second opportunity is selective replacement of CT with other modalities, such as for many head and spinal examinations (with MRI), and for diagnosing appendicitis (selective use of ultrasound + CT). Finally, a fraction of CT scans could be avoided entirely, as indicated by CT decision rules: Clinical decision rules for CT use represent a powerful approach for slowing down the increase in CT use, because they have the potential to overcome some of the major factors that result in some CT scans being undertaken when they are potentially not clinically helpful. In the U.S. and potentially elsewhere, legislative approaches are a possible option, to improve quality control and reduce clinically unneeded CT use, and it is also possible that upcoming changes in heath care economics will tend to slow the increase in such CT use.

  2. 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.

  3. 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

  4. Weightbearing CT scan of severe flexible pes planus deformities.

    PubMed

    Ferri, Melanie; Scharfenberger, Angela V; Goplen, Gord; Daniels, Timothy R; Pearce, Dawn

    2008-02-01

    The three-dimensional relationships of the bones in the foot in a flatfoot deformity are difficult to assess with standard radiographs. CT scans demonstrate these relationships but are typically made in a nonweightbearing mode. Our objective was to assess the use of a weightbearing CT apparatus to image the feet in patients with severe flexible pes planus deformities and to better define the anatomical changes that occur. A specialized device was designed and constructed to simulate weightbearing to the feet during CT examination. Eighteen normal feet and 30 painful severe and flexible pes planus feet were imaged in both the non weightbearing and weightbearing states, set at 50% of body weight. Several measurements of intertarsal relationships were made of the pes planus and normal feet. Navicular floor to skin distance, forefoot arch angle, and subtalar joint subluxation were measured in the coronal plane in both the weightbearing and nonweightbearing states. T-tests were used to analyze measurements of navicular floor to skin distance and forefoot arch angle. The weightbearing device had a significant effect on foot configuration for both normal and pes planus feet (p = 0.0008) and (p < 0.0001) respectively for both floor to skin distance and forefoot arch angle. There was a significant difference between normal feet and pes planus feet with regard to the forefoot arch angle in the nonweightbearing (p = 0.02) and weightbearing states (p = 0.01). Four of the pes planus patients had evidence of subtalar joint subluxation which was more pronounced in the weightbearing state. There was no significant difference between the navicular floor to skin distance in the normal versus pes planus feet in either the non weightbearing (p = 0.05) or the weightbearing states (p = 0.07). A device was designed and constructed to apply a weightbearing load equal to that of 50% body weight with minimal to no patient discomfort. The resultant effects on foot configuration were

  5. 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

  6. 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.

  7. Use of PET/CT scanning in cancer patients: technical and practical considerations

    PubMed Central

    2005-01-01

    This overview of the oncologic applications of positron emission tomography (PET) focuses on the technical aspects and clinical applications of a newer technique: the combination of a PET scanner and a computed tomography (CT) scanner in a single (PET/CT) device. Examples illustrate how PET/CT contributes to patient care and improves upon the previous state-of-the-art method of comparing a PET scan with a separate CT scan. Finally, the author presents some of the results from studies of PET/CT imaging that are beginning to appear in the literature. PMID:16252023

  8. 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

  9. 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.

  10. Thoracic CT scanning for mediastinal Hodgkin's disease: results and therapeutic implications

    SciTech Connect

    Rostock, R.A.; Siegelman, S.S.; Lenhard, R.E.; Wharam, M.D.; Order, S.E.

    1983-10-01

    Thoracic CT scans were performed on 42 newly diagnosed patients with Hodgkin's disease. Five of 10 patients with negative chest X ray (CXR) had abnormal thoracic CT scans. Among the remaining 32 patients with mediastinal Hodgkin's disease (MHD) on CXR, pericardial (Ep) and chest wall invasion (Ec) were the two most common sites of involvement which were detectable by CT scan alone. Ep and Ec accounted for 16 of 19 of the changes in treatment portal or philosophy based on CT scan findings. Because of the high risk of cardiac or pulmonary radiation toxicity in Ep or Ec, radiation treatment alone may be inadequate. Treatment of mediastinal Hodgkin's disease is reviewed here. The use of CT scans for identification of Ep, Ec, and other abnormalities will allow for more precise treatment, further define the use of conventional radiotherapy, combined modality therapy or whole lung irradiation, and allow more accurate analysis of treatment results.

  11. 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.

  12. Osmotic blood-brain barrier modification: clinical documentation by enhanced CT scanning and/or radionuclide brain scanning

    SciTech Connect

    Neuwelt, E.A.; Specht, H.D.; Howieson, J.; Haines, J.E.; Bennett, M.J.; Hill, S.A.; Frenkel, E.P.

    1983-10-01

    Results of initial clinical trials of brain tumor chemotherapy after osmotic blood-brain barrier disruption are promising. In general, the procedure is well tolerated. The major complication has been seizures. In this report, data are presented which indicate that the etiology of these seizures is related to the use of contrast agent (meglumine iothalamate) to monitor barrier modification. A series of 19 patients underwent a total of 85 barrier modification procedures. Documentation of barrier disruption was monitored by contrast-enhanced computed tomographic (CT) scanning, radionuclide brain scanning, or a combination of both techniques. In 56 procedures (19 patients) monitored by enhanced CT, seizures occurred a total of 10 times in eight patients. Twenty-three barrier modification procedures (in nine of these 19 patients) documented by nuclear brain scans alone, however, resulted in only one focal motor seizure in each of two patients. In eight of the 19 patients who had seizures after barrier disruption and enhanced CT scan, four subsequently had repeat procedures monitored by radionuclide scan alone. In only one of these patients was further seizure activity noted; a single focal motor seizure was observed. Clearly, the radionuclide brain scan does not have the sensitivity and spatial resolution of enhanced CT, but at present it appears safer to monitor barrier modification by this method and to follow tumor growth between barrier modifications by enhanced CT. Four illustrative cases showing methods, problems, and promising results are presented.

  13. Automated lung volumetry from routine thoracic CT scans: how reliable is the result?

    PubMed

    Haas, Matthias; Hamm, Bernd; Niehues, Stefan M

    2014-05-01

    Today, lung volumes can be easily calculated from chest computed tomography (CT) scans. Modern postprocessing workstations allow automated volume measurement of data sets acquired. However, there are challenges in the use of lung volume as an indicator of pulmonary disease when it is obtained from routine CT. Intra-individual variation and methodologic aspects have to be considered. Our goal was to assess the reliability of volumetric measurements in routine CT lung scans. Forty adult cancer patients whose lungs were unaffected by the disease underwent routine chest CT scans in 3-month intervals, resulting in a total number of 302 chest CT scans. Lung volume was calculated by automatic volumetry software. On average of 7.2 CT scans were successfully evaluable per patient (range 2-15). Intra-individual changes were assessed. In the set of patients investigated, lung volume was approximately normally distributed, with a mean of 5283 cm(3) (standard deviation = 947 cm(3), skewness = -0.34, and curtosis = 0.16). Between different scans in one and the same patient the median intra-individual standard deviation in lung volume was 853 cm(3) (16% of the mean lung volume). Automatic lung segmentation of routine chest CT scans allows a technically stable estimation of lung volume. However, substantial intra-individual variations have to be considered. A median intra-individual deviation of 16% in lung volume between different routine scans was found. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  14. Immediate total-body CT scanning versus conventional imaging and selective CT scanning in patients with severe trauma (REACT-2): a randomised controlled trial.

    PubMed

    Sierink, Joanne C; Treskes, Kaij; Edwards, Michael J R; Beuker, Benn J A; den Hartog, Dennis; Hohmann, Joachim; Dijkgraaf, Marcel G W; Luitse, Jan S K; Beenen, Ludo F M; Hollmann, Markus W; Goslings, J Carel

    2016-08-13

    Published work suggests a survival benefit for patients with trauma who undergo total-body CT scanning during the initial trauma assessment; however, level 1 evidence is absent. We aimed to assess the effect of total-body CT scanning compared with the standard work-up on in-hospital mortality in patients with trauma. We undertook an international, multicentre, randomised controlled trial at four hospitals in the Netherlands and one in Switzerland. Patients aged 18 years or older with trauma with compromised vital parameters, clinical suspicion of life-threatening injuries, or severe injury were randomly assigned (1:1) by ALEA randomisation to immediate total-body CT scanning or to a standard work-up with conventional imaging supplemented with selective CT scanning. Neither doctors nor patients were masked to treatment allocation. The primary endpoint was in-hospital mortality, analysed in the intention-to-treat population and in subgroups of patients with polytrauma and those with traumatic brain injury. The χ(2) test was used to assess differences in mortality. This trial is registered with ClinicalTrials.gov, number NCT01523626. Between April 22, 2011, and Jan 1, 2014, 5475 patients were assessed for eligibility, 1403 of whom were randomly assigned: 702 to immediate total-body CT scanning and 701 to the standard work-up. 541 patients in the immediate total-body CT scanning group and 542 in the standard work-up group were included in the primary analysis. In-hospital mortality did not differ between groups (total-body CT 86 [16%] of 541 vs standard work-up 85 [16%] of 542; p=0.92). In-hospital mortality also did not differ between groups in subgroup analyses in patients with polytrauma (total-body CT 81 [22%] of 362 vs standard work-up 82 [25%] of 331; p=0.46) and traumatic brain injury (68 [38%] of 178 vs 66 [44%] of 151; p=0.31). Three serious adverse events were reported in patients in the total-body CT group (1%), one in the standard work-up group (<1%), and

  15. Use of CT scans and treatment planning software for validation of the dose component of food irradiation protocols

    NASA Astrophysics Data System (ADS)

    Borsa, Joseph; Chu, Rod; Sun, Jiansheng; Linton, Nick; Hunter, Craig

    2002-03-01

    The challenging problem of estimating the dose delivered to heterogeneous products by radiation modalities of limited penetration can be readily handled by using technologies developed for, and widely used in, radiation therapy applications. In particular, combining CT scanning with radiation treatment planning programs can simulate radiation processing with either photons or electrons, and can provide detailed, high resolution and accurate dose maps for any arbitrary product and package configuration. Such dose maps are an essential part of process validation. Comparison of the simulated dose distributions with measured dose maps verifies the soundness of this approach. The present communication presents results obtained with the simulation technique for a variety of common food items which are likely candidates for radiation processing.

  16. Course and variation of the intercostal artery by CT scan.

    PubMed

    Helm, Emma J; Rahman, Najib M; Talakoub, Omid; Fox, Danial L; Gleeson, Fergus V

    2013-03-01

    It is conventionally taught that the intercostal artery is shielded in the intercostal groove of the superior rib. The continuous course and variability of the intercostal artery, and factors that may influence them, have not been described in a large number of arteries in vivo. Maximal intensity projection reformats in the coronal plane were produced from CT scan pulmonary angiograms to identify the posterolateral course of the intercostal artery (seventh to 11th rib spaces). A novel semiautomated computer segmentation algorithm was used to measure distances between the lower border of the superior rib, the upper border of the inferior rib, and the position of the intercostal artery when exposed in the intercostal space. The position and variability of the artery were analyzed for association with clinical factors. Two hundred ninety-eight arteries from 47 patients were analyzed. The mean lateral distance from the spine over which the artery was exposed within the intercostal space was 39 mm, with wide variability (SD, 10 mm; 10th-90th centile, 28-51 mm). At 3 cm lateral distance from the spine, 17% of arteries were shielded by the superior rib, compared with 97% at 6 cm. Exposed artery length was not associated with age, sex, rib space, or side. The variability of arterial position was significantly associated with age (coefficient, 0.91; P < .001) and rib space number (coefficient, - 2.60; P < .001). The intercostal artery is exposed within the intercostal space in the first 6 cm lateral to the spine. The variability of its vertical position is greater in older patients and in more cephalad rib spaces.

  17. 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