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Sample records for two-dimensional imaging detector

  1. Two-dimensional microstrip detector for neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Oed, A [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    Because of their robust design, gas microstrip detectors, which were developed at ILL, can be assembled relatively quickly, provided the prefabricated components are available. At the beginning of 1996, orders were received for the construction of three two-dimensional neutron detectors. These detectors have been completed. The detectors are outlined below. (author). 2 refs.

  2. Two-dimensional position sensitive Si(Li) detector

    International Nuclear Information System (INIS)

    Walton, J.T.; Hubbard, G.S.; Haller, E.E.; Sommer, H.A.

    1978-11-01

    Circular, large-area two-dimensional Si(Li) position sensitive detectors have been fabricated. The detectors employ a thin lithium-diffused n + resisitive layer for one contact and a boron implanted p + resistive layer for the second contact. A position resolution of the order of 100 μm is indicated

  3. Resistive-strips micromegas detectors with two-dimensional readout

    Science.gov (United States)

    Byszewski, M.; Wotschack, J.

    2012-02-01

    Micromegas detectors show very good performance for charged particle tracking in high rate environments as for example at the LHC. It is shown that two coordinates can be extracted from a single gas gap in these detectors. Several micromegas chambers with spark protection by resistive strips and two-dimensional readout have been tested in the context of the R&D work for the ATLAS Muon System upgrade.

  4. A TWO-DIMENSIONAL POSITION SENSITIVE SI(LI) DETECTOR

    Energy Technology Data Exchange (ETDEWEB)

    Walton, Jack T.; Hubbard, G. Scott; Haller, Eugene E.; Sommer, Heinrich A.

    1978-11-01

    Circular, large-area two-dimensional Si(Li) position sensitive detectors have been fabricated. The detectors employ a thin lithium-diffused n{sup +} resistive layer for one contact and a boron implanted p{sup +} resistive layer for the second contact. A position resolution of the order of 100 {micro}m is indicated.

  5. Atomic resolution holography using advanced reconstruction techniques for two-dimensional detectors

    Energy Technology Data Exchange (ETDEWEB)

    Marko, M; Szakal, A; Cser, L [Neutron Spectroscopy Department, Research Institute for Solid State Physics and Optics, PO Box 49, H-1525 Budapest (Hungary); Krexner, G [Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna (Austria); Schefer, J, E-mail: marko@szfki.h [Laboratory for Neutron Scattering (LNS), Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

    2010-06-15

    Atomic resolution holography is based on two concepts. Either the emitter of the radiation used is embedded in the sample (internal source concept) or, on account of the optical reciprocity law, the detector forms part of the sample (internal detector concept). In many cases, holographic objects (atoms and nuclei) simultaneously adopt the roles of both source and detector. Thus, the recorded image contains a mixture of both inside source and inside detector holograms. When reconstructing one type of hologram, the presence of the other hologram causes serious distortions. In the present work, we propose a new method, the so-called double reconstruction (DR), which not only suppresses the mutual distortions but also exploits the information content of the measured hologram more effectively. This novel approach also decreases the level of distortion arising from diffraction and statistical noise. The efficiency of the DR technique is significantly enhanced by employing two-dimensional (2D) area detectors. The power of the method is illustrated here by applying it to a real measurement on a palladium-hydrogen sample.

  6. Small angle X-ray scattering experiments with three-dimensional imaging gas detectors

    International Nuclear Information System (INIS)

    La Monaca, A.; Iannuzzi, M.; Messi, R.

    1985-01-01

    Measurements of small angle X-ray scattering of lupolen - R, dry collagen and dry cornea are presented. The experiments have been performed with synchrotron radiation and a new three-dimensional imaging drif-chamber gas detector

  7. Polymer fiber detectors for photoacoustic imaging

    Science.gov (United States)

    Grün, Hubert; Berer, Thomas; Pühringer, Karoline; Nuster, Robert; Paltauf, Günther; Burgholzer, Peter

    2010-02-01

    Photoacoustic imaging is a novel imaging method for medical and biological applications, combining the advantages of Diffuse Optical Imaging (high contrast) and Ultrasonic Imaging (high spatial resolution). A short laser pulse hits the sample. The absorbed energy causes a thermoelastic expansion and thereby launches a broadband ultrasonic wave (photoacoustic signal). The distribution of absorbed energy density is reconstructed from measurements of the photoacoustic signals around the sample. For collecting photoacoustic signals either point like or extended, integrating detectors can be used. The latter integrate the pressure at least in one dimension, e.g. along a line. Thereby, the three dimensional imaging problem is reduced to a two dimensional problem. For a tomography device consisting of a scanning line detector and a rotating sample, fiber-based detectors made of polymer have been recently introduced. Fiber-based detectors are easy to use and possess a constant, high spatial resolution over their entire active length. Polymer fibers provide a better impedance matching and a better handling compared with glass fibers which were our first approach. First measurement results using polymer fiber detectors and some approaches for improving the performance are presented.

  8. Development of a two-dimensional imaging detector based on a neutron scintillator with wavelength-shifting fibers

    CERN Document Server

    Sakai, K; Oku, T; Morimoto, K; Shimizu, H M; Tokanai, F; Gorin, A; Manuilov, I V; Ryazantsev, A; Ino, T; Kuroda, K; Suzuki, J

    2002-01-01

    For evaluating neutron optical devices, a two-dimensional (2D) detector based on a neutron scintillator with wavelength-shifting fibers has been developed at RIKEN. We have investigated a ZnS(Ag)+LiF and a Li glass plate as neutron scintillators with the coding technique for realizing the large sensitive area of 50 x 50 mm sup 2. After fabricating the 2D detector, its performance was tested using cold neutrons at JAERI. As a result, a spatial resolution of propor to 1.0 mm was obtained. (orig.)

  9. Two-dimensional readout system for radiation detector

    International Nuclear Information System (INIS)

    Lee, L.Y.

    1975-01-01

    A two dimensional readout system has been provided for reading out locations of scintillations produced in a scintillation type radiation detector array wherein strips of scintillator material are arranged in a parallel planar array. Two sets of light guides are placed perpendicular to the scintillator strips, one on the top and one on the bottom to extend in alignment across the strips. Both the top and bottom guides are composed of a number of 90 0 triangular prisms with the lateral side forming the hypotenuse equal to twice the width of a scintillator strip. The prism system reflects light from a scintillation along one of the strips back and forth through adjacent strips to light pipes coupled to the outermost strips of the detector array which transmit light pulses to appropriate detectors to determine the scintillation along one axis. Other light pipes are connected to the end portions of the strips to transmit light from the individual strips to appropriate light detectors to indicate the particular strip activated, thereby determining the position of a scintillation along the other axis. The number of light guide pairs may be equal the number of the scintillation strips when equal spatial resolution for each of the two coordinates is desired. When the scintillator array detects an event which produces a scintillation along one of the strips, the emitted light travels along four different paths, two of which are along the strip, and two of which are through the light guide pair perpendicular to the strips until all four beams reach the outer edges of the array where they may be transmitted to light detectors by means of light pipes connected therebetween according to a binary code for direct digital readout. (U.S.)

  10. Development of a two-dimensional imaging system for clinical applications of intravenous coronary angiography using intense synchrotron radiation produced by a multipole wiggler

    International Nuclear Information System (INIS)

    Hyodo, K.; Ando, M.; Oku, Y.; Yamamoto, S.; Takeda, T.; Itai, Y.; Ohtsuka, S.; Sugishita, Y.; Tada, J.

    1998-01-01

    A two-dimensional clinical intravenous coronary angiography system, comprising a large-size View area produced by asymmetrical reflection from a silicon crystal using intense synchrotron radiation from a multipole wiggler and a two-dimensional detector with an image intensifier, has been completed. An advantage of the imaging system is that two-dimensional dynamic imaging of the cardiovascular system can be achieved due to its two-dimensional radiation field. This world-first two-dimensional system has been successfully adapted to clinical applications. Details of the imaging system are described in this paper

  11. Development of a two-dimensional imaging system for clinical applications of intravenous coronary angiography using intense synchrotron radiation produced by a multipole wiggler

    Energy Technology Data Exchange (ETDEWEB)

    Hyodo, K.; Ando, M. [High Energy Accelerator Research Organization, Inst. of Material Structure Sciences, Tsukuba (Japan); Oku, Y.; Yamamoto, S. [Graduated School for Advanced Sciences, Tsukuba (Japan); Takeda, T.; Itai, Y.; Ohtsuka, S.; Sugishita, Y. [The Univ. of Tsukuba, Inst. of Clinical Medicine, Tsukuba (Japan); Tada, J. [The Univ. of Tsukuba, Inst. of Basic Medical Sciences, Tsukuba (Japan)

    1998-05-01

    A two-dimensional clinical intravenous coronary angiography system, comprising a large-size View area produced by asymmetrical reflection from a silicon crystal using intense synchrotron radiation from a multipole wiggler and a two-dimensional detector with an image intensifier, has been completed. An advantage of the imaging system is that two-dimensional dynamic imaging of the cardiovascular system can be achieved due to its two-dimensional radiation field. This world-first two-dimensional system has been successfully adapted to clinical applications. Details of the imaging system are described in this paper. 18 refs.

  12. Comparison of morphological and conventional edge detectors in medical imaging applications

    Science.gov (United States)

    Kaabi, Lotfi; Loloyan, Mansur; Huang, H. K.

    1991-06-01

    Recently, mathematical morphology has been used to develop efficient image analysis tools. This paper compares the performance of morphological and conventional edge detectors applied to radiological images. Two morphological edge detectors including the dilation residue found by subtracting the original signal from its dilation by a small structuring element, and the blur-minimization edge detector which is defined as the minimum of erosion and dilation residues of the blurred image version, are compared with the linear Laplacian and Sobel and the non-linear Robert edge detectors. Various structuring elements were used in this study: regular 2-dimensional, and 3-dimensional. We utilized two criterions for edge detector's performance classification: edge point connectivity and the sensitivity to the noise. CT/MR and chest radiograph images have been used as test data. Comparison results show that the blur-minimization edge detector, with a rolling ball-like structuring element outperforms other standard linear and nonlinear edge detectors. It is less noise sensitive, and performs the most closed contours.

  13. Terahertz computed tomography in three-dimensional using a pyroelectric array detector

    Science.gov (United States)

    Li, Bin; Wang, Dayong; Zhou, Xun; Rong, Lu; Huang, Haochong; Wan, Min; Wang, Yunxin

    2017-05-01

    Terahertz frequency range spans from 0.1 to 10 THz. Terahertz radiation can penetrate nonpolar materials and nonmetallic materials, such as plastics, wood, and clothes. Then the feature makes the terahertz imaging have important research value. Terahertz computed tomography makes use of the penetrability of terahertz radiation and obtains three-dimensional object projection data. In the paper, continuous-wave terahertz computed tomography with a pyroelectric array detectoris presented. Compared with scanning terahertz computed tomography, a pyroelectric array detector can obtain a large number of projection data in a short time, as the acquisition mode of the array pyroelectric detector omit the projection process on the vertical and horizontal direction. With the two-dimensional cross-sectional images of the object are obtained by the filtered back projection algorithm. The two side distance of the straw wall account for 80 pixels, so it multiplied by the pixel size is equal to the diameter of the straw about 6.4 mm. Compared with the actual diameter of the straw, the relative error is 6%. In order to reconstruct the three-dimensional internal structure image of the straw, the y direction range from 70 to 150 are selected on the array pyroelectric detector and are reconstructed by the filtered back projection algorithm. As the pixel size is 80 μm, the height of three-dimensional internal structure image of the straw is 6.48 mm. The presented system can rapidly reconstruct the three-dimensional object by using a pyroelectric array detector and explores the feasibility of on non-destructive evaluation and security testing.

  14. Photoacoustic projection imaging using an all-optical detector array

    Science.gov (United States)

    Bauer-Marschallinger, J.; Felbermayer, K.; Berer, T.

    2018-02-01

    We present a prototype for all-optical photoacoustic projection imaging. By generating projection images, photoacoustic information of large volumes can be retrieved with less effort compared to common photoacoustic computed tomography where many detectors and/or multiple measurements are required. In our approach, an array of 60 integrating line detectors is used to acquire photoacoustic waves. The line detector array consists of fiber-optic MachZehnder interferometers, distributed on a cylindrical surface. From the measured variation of the optical path lengths of the interferometers, induced by photoacoustic waves, a photoacoustic projection image can be reconstructed. The resulting images represent the projection of the three-dimensional spatial light absorbance within the imaged object onto a two-dimensional plane, perpendicular to the line detector array. The fiber-optic detectors achieve a noise-equivalent pressure of 24 Pascal at a 10 MHz bandwidth. We present the operational principle, the structure of the array, and resulting images. The system can acquire high-resolution projection images of large volumes within a short period of time. Imaging large volumes at high frame rates facilitates monitoring of dynamic processes.

  15. Multiple-channel ultra-violet absorbance detector for two-dimensional chromatographic separations.

    Science.gov (United States)

    Lynch, Kyle B; Yang, Yu; Ren, Jiangtao; Liu, Shaorong

    2018-05-01

    In recent years, much research has gone into developing online comprehensive two-dimensional liquid chromatographic systems allowing for high peak capacities in comparable separation times to that of one-dimensional liquid chromatographic systems. However, the speed requirements in the second dimension (2nd-D) still remain one challenge for complex biological samples due to the current configuration of two column/two detector systems. Utilization of multiple 2nd-D columns can mitigate this challenge. To adapt this approach, we need a multiple channel detector. Here we develop a versatile multichannel ultraviolet (UV) light absorbance detector that is capable of simultaneously monitoring separations in 12 columns. The detector consists of a deuterium lighthouse, a flow cell assembly (a 13-channel flow cell fitted with a 13-photodiode-detection system), and a data acquisition and monitoring terminal. Through the use of a custom high optical quality furcated fiber to improve light transmission, precise machining of a flow cell to reduce background stray light through precision alignment, and sensitive electronic circuitry to reduce electronic noise through an active low pass filter, the background noise level is measured in the tens of µAU. We obtain a linear dynamic range of close to three orders of magnitude. Compared to a commercialized multichannel UV light absorbance detector like the Waters 2488 UV/Vis, our device provides an increase in channel detection while residing within the same noise region and linear range. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. High-Resolution Gamma-Ray Imaging Measurements Using Externally Segmented Germanium Detectors

    Science.gov (United States)

    Callas, J.; Mahoney, W.; Skelton, R.; Varnell, L.; Wheaton, W.

    1994-01-01

    Fully two-dimensional gamma-ray imaging with simultaneous high-resolution spectroscopy has been demonstrated using an externally segmented germanium sensor. The system employs a single high-purity coaxial detector with its outer electrode segmented into 5 distinct charge collection regions and a lead coded aperture with a uniformly redundant array (URA) pattern. A series of one-dimensional responses was collected around 511 keV while the system was rotated in steps through 180 degrees. A non-negative, linear least-squares algorithm was then employed to reconstruct a 2-dimensional image. Corrections for multiple scattering in the detector, and the finite distance of source and detector are made in the reconstruction process.

  17. Two-dimensional neutron scintillation detector with optimal gamma discrimination

    International Nuclear Information System (INIS)

    Kanyo, M.; Reinartz, R.; Schelten, J.; Mueller, K.D.

    1993-01-01

    The gamma sensitivity of a two-dimensional scintillation neutron detector based on position sensitive photomultipliers (Hamamatsu R2387 PM) has been minimized by a digital differential discrimination unit. Since the photomultiplier gain is position-dependent by ±25% a discrimination unit was developed where digital upper and lower discrimination levels are set due to the position-dependent photomultiplier gain obtained from calibration measurements. By this method narrow discriminator windows can be used to reduce the gamma background drastically without effecting the neutron sensitivity of the detector. The new discrimination method and its performance tested by neutron measurements will be described. Experimental results concerning spatial resolution and γ-sensitivity are presented

  18. A large area two-dimensional position sensitive multiwire proportional detector

    CERN Document Server

    Moura, M M D; Souza, F A; Alonso, E E; Fujii, R J; Meyknecht, A B; Added, N; Aissaoui, N; Cardenas, W H Z; Ferraretto, M D; Schnitter, U; Szanto, E M; Szanto de Toledo, A; Yamamura, M S; Carlin, N

    1999-01-01

    Large area two-dimensional position sensitive multiwire proportional detectors were developed to be used in the study of light heavy-ion nuclear reactions at the University of Sao Paulo Pelletron Laboratory. Each detector has a 20x20 cm sup 2 active area and consists of three grids (X-position, anode and Y-position) made of 25 mu m diameter gold plated tungsten wires. The position is determined through resistive divider chains. Results for position resolution, linearity and efficiency as a function of energy and position for different elements are reported.

  19. A prototype detector using the neutron image intensifier and multi-anode type photomultiplier tube for pulsed neutron imaging

    International Nuclear Information System (INIS)

    Ishikawa, Hirotaku; Sato, Hirotaka; Hara, Kaoru Y.; Kamiyama, Takashi

    2016-01-01

    We developed a neutron two-dimensional (2-D) detector for pulsed neutron imaging as a prototype detector, which was composed of a neutron image intensifier and a multi-anode type photomultiplier tube. A neutron transmission spectrum of α-Fe plate was measured by the prototype detector, and compared with the one measured by a typical neutron 2-D detector. The spectrum was in reasonable agreement with the one measured by the typical detector in the neutron wavelength region above 0.15 nm. In addition, a neutron transmission image of a cadmium indicator was obtained by the prototype detector. The usefulness of the prototype detector for pulsed neutron imaging was demonstrated. (author)

  20. High-resolution imaging gamma-ray spectroscopy with externally segmented germanium detectors

    Science.gov (United States)

    Callas, J. L.; Mahoney, W. A.; Varnell, L. S.; Wheaton, W. A.

    1993-01-01

    Externally segmented germanium detectors promise a breakthrough in gamma-ray imaging capabilities while retaining the superb energy resolution of germanium spectrometers. An angular resolution of 0.2 deg becomes practical by combining position-sensitive germanium detectors having a segment thickness of a few millimeters with a one-dimensional coded aperture located about a meter from the detectors. Correspondingly higher angular resolutions are possible with larger separations between the detectors and the coded aperture. Two-dimensional images can be obtained by rotating the instrument. Although the basic concept is similar to optical or X-ray coded-aperture imaging techniques, several complicating effects arise because of the penetrating nature of gamma rays. The complications include partial transmission through the coded aperture elements, Compton scattering in the germanium detectors, and high background count rates. Extensive electron-photon Monte Carlo modeling of a realistic detector/coded-aperture/collimator system has been performed. Results show that these complicating effects can be characterized and accounted for with no significant loss in instrument sensitivity.

  1. X-ray imaging device for one-dimensional and two-dimensional radioscopy

    International Nuclear Information System (INIS)

    1978-01-01

    The X-ray imaging device for the selectable one-dimensional or two-dimensional pictures of objects illuminated by X-rays, comprising an X-ray source, an X-ray screen, and an opto-electrical picture development device placed behind the screen, is characterized by an anamorphotic optical system, which is positioned with a one-dimensional illumination between the X-ray screen and the opto-electrical device and that a two-dimensional illumination will be developed, and that in view of the lens system which forms part of the opto-electrical device, there is placed an X-ray screen in a specified beam direction so that a magnified image may be formed by equalisation of the distance between the X-ray screen and the lens system. (G.C.)

  2. A novel silicon drift detector with two dimensional drift time measurement

    International Nuclear Information System (INIS)

    Hijzen, E.A.; Schooneveld, E.M.; Van Eijk, C.W.E.; Hollander, R.W.; Sarro, P.M.; Van den Bogaard, A.

    1994-01-01

    Until now silicon drift detectors with two dimensional position resolution made use of drift time measurement in one dimension only. The resolution in the other dimension was obtained by dividing the collecting anode into small pixels. In this paper we present a new type of drift detector that uses drift time measurements for both dimensions. The design consists of concentric quadrilateral closed strips with a small collecting anode in the centre. At first electrons will travel perpendicular to the strips until they reach a diagonal. Then they will proceed along this diagonal until they are collected at the centre. Position resolution in two dimensions can be obtained when both the time the electrons need to reach the diagonal and the time they need to reach the centre are measured. The latter is obtained from the collecting anode, the former from a diagonal strip present at the back side of the detector. Compared to common 2D drift detectors this detector offers the advantage of a small amount of readout electronics. It also has the advantage of having just one small collecting anode with a very low capacitance, resulting in low noise and therefore in a good energy resolution. ((orig.))

  3. A two-dimensional detector with delay line readout for slow neutron fields measurements

    International Nuclear Information System (INIS)

    Cheremukhina, G.A.; Chernenko, S.P.; Ivanov, A.B.

    1992-01-01

    This article presents the description of a two-dimensional detector of slow neutrons together with its readout and data acquisition electronics based on a PC/AT> The detector with a sensitive area of 260x140 mm 2 is based on a high pressure multiwire proportional chamber with delay line readout and gas filling of 3.0 atm. 3 He + propane. 25 refs.; 10 figs.; 2 tabs

  4. Laser bistatic two-dimensional scattering imaging simulation of lambert cone

    Science.gov (United States)

    Gong, Yanjun; Zhu, Chongyue; Wang, Mingjun; Gong, Lei

    2015-11-01

    This paper deals with the laser bistatic two-dimensional scattering imaging simulation of lambert cone. Two-dimensional imaging is called as planar imaging. It can reflect the shape of the target and material properties. Two-dimensional imaging has important significance for target recognition. The expression of bistatic laser scattering intensity of lambert cone is obtained based on laser radar eauqtion. The scattering intensity of a micro-element on the target could be obtained. The intensity is related to local angle of incidence, local angle of scattering and the infinitesimal area on the cone. According to the incident direction of laser, scattering direction and normal of infinitesimal area, the local incidence angle and scattering angle can be calculated. Through surface integration and the introduction of the rectangular function, we can get the intensity of imaging unit on the imaging surface, and then get Lambert cone bistatic laser two-dimensional scattering imaging simulation model. We analyze the effect of distinguishability, incident direction, observed direction and target size on the imaging. From the results, we can see that the scattering imaging simulation results of the lambert cone bistatic laser is correct.

  5. Analysis of Two-Dimensional Electrophoresis Gel Images

    DEFF Research Database (Denmark)

    Pedersen, Lars

    2002-01-01

    This thesis describes and proposes solutions to some of the currently most important problems in pattern recognition and image analysis of two-dimensional gel electrophoresis (2DGE) images. 2DGE is the leading technique to separate individual proteins in biological samples with many biological...

  6. Two-dimensional 220 MHz Fourier transform EPR imaging

    International Nuclear Information System (INIS)

    Placidi, Giuseppe; Brivati, John A.; Alecci, Marcello; Testa, Luca; Sotgiu, Antonello

    1998-01-01

    In the last decade radiofrequency continuous-wave EPR spectrometers have been developed to detect and localize free radicals in vivo. Only recently, pulsed radiofrequency EPR spectrometers have been described for imaging applications with small samples. In the present work, we show the first two-dimensional image obtained at 220 MHz on a large phantom (40 ml) that simulates typical conditions of in vivo EPR imaging. This pulsed EPR apparatus has the potential to make the time required for three-dimensional imaging compatible with the biological half-life of normally used paramagnetic probes. (author)

  7. Cardiac imaging using 256-detector row four-dimensional CT. Preliminary clinical report

    International Nuclear Information System (INIS)

    Kido, Teruhito; Kurata, Akira; Higashino, Hiroshi

    2007-01-01

    Along with the increase of detector rows on the z-axis and a faster gantry rotation speed, the spatial and temporal resolutions of the multislice computed tomography (CT) have been improved for noninvasive coronary artery imaging. We investigated the feasibility of the second specification prototype 256-detector row four-dimensional CT for assessing coronary artery and cardiac function. The subjects were five patients with coronary artery disease. Contrast medium (40-60 ml) was intravenously administered at the rate of 3-4 ml/s. The patient's whole heart was scanned for 1.5 s to cover at least one cardiac cycle during breathholding without electrocardiographic gating. Parameters used were 0.5 mm slice thickness, 0.5 s/rotation, 120 Kv, and 350 mA, with a half-scan reconstruction algorithm (temporal resolution 250 ms). Twenty-six transaxial datasets were reconstructed at intervals of 50 ms. The assessability of the coronary arteries in American Heart Association (AHA) segments 1, 2, 3, 5, 6, 7, 9, and 11 was visually evaluated, resulting in 29 of 32 (90.9%) segments being assessable. Functional assessment was also performed using animated movies without banding artifacts in all cases. The 256-detector row four-dimensional CT can assess the coronary artery and cardiac function using data during 1.5 s without banding artifacts. (author)

  8. Two-dimensional filtering of SPECT images using the Metz and Wiener filters

    International Nuclear Information System (INIS)

    King, M.A.; Schwinger, R.B.; Penney, B.C.; Doherty, P.W.

    1984-01-01

    Presently, single photon emission computed tomographic (SPECT) images are usually reconstructed by arbitrarily selecting a one-dimensional ''window'' function for use in reconstruction. A better method would be to automatically choose among a family of two-dimensional image restoration filters in such a way as to produce ''optimum'' image quality. Two-dimensional image processing techniques offer the advantages of a larger statistical sampling of the data for better noise reduction, and two-dimensional image deconvolution to correct for blurring during acquisition. An investigation of two such ''optimal'' digital image restoration techniques (the count-dependent Metz filter and the Wiener filter) was made. They were applied both as two-dimensional ''window'' functions for preprocessing SPECT images, and for filtering reconstructed images. Their performance was compared by measuring image contrast and per cent fractional standard deviation (% FSD) in multiple-acquisitions of the Jaszczak SPECT phantom at two different count levels. A statistically significant increase in image contrast and decrease in % FSD was observed with these techniques when compared to the results of reconstruction with a ramp filter. The adaptability of the techniques was manifested in a lesser % reduction in % FSD at the high count level coupled with a greater enhancement in image contrast. Using an array processor, processing time was 0.2 sec per image for the Metz filter and 3 sec for the Wiener filter. It is concluded that two-dimensional digital image restoration with these techniques can produce a significant increase in SPECT image quality

  9. Cerenkov ring imaging detector development at SLAC

    International Nuclear Information System (INIS)

    Williams, S.H.

    1984-06-01

    The imaging of Cerenkov light on to photosensitive detectors promises to be a powerful technique for identifying particles in colliding beam spectrometers. Toward this end two and three dimensional imaging photon detectors are being developed at SLAC. The present techniques involve photon conversion using easily ionized exotic chemicals like tetrakisdimethyl-amino-ethylene (TMAE) in a drift and amplifying gas mixture of methane and isobutane. Single photoelectrons from Cerenkov light are currently being drifted 20 cm and a new device under study will be used to study drifting up to 80 cm along a magnetic field. A short description of a large device currently being designed for the SLD spectrometer at the Stanford Linear Collider will be given

  10. A two-dimensional low energy gamma-ray position sensitive detector

    International Nuclear Information System (INIS)

    Charalambous, P.M.; Dean, A.J.; Drane, M.; Gil, A.; Stephen, J.B.; Young, N.G.S.; Barbareschi, L.; Perotti, F.; Villa, G.; Badiali, M.; La Padula, C.; Polcaro, F.; Ubertini, P.

    1984-01-01

    An array of 1-dimensional position sensitive detectors designed to operate over the photon energy range 0.2-10.0 MeV, so as to form an efficient 2-dimensional position sensitive detection plane is described. A series of experimental tests has been carried out to evaluate and confirm the computed capabilities. (orig.)

  11. The Cerenkov ring-imaging detector recent progress and future development

    CERN Document Server

    Ekelöf, T J C; Tocqueville, J; Ypsilantis, Thomas

    1981-01-01

    Results are reported on measurements of Cerenkov ring images using a multistage MWPC with an argon-TEA gas mixture. A specific detector response of N/sub 0/=56 cm/sup -1/ was obtained. It is shown that with some minor modifications to the detector, this value can be raised to N/sub 0/=90 cm/sup -1/. Using an argon-methane-TEA mixture in the MWPC, it is shown that efficient single-photoelectron detection can be achieved with proportional wire amplification without preamplification. A design of a new type of drift chamber (TPC) detector for two-dimensional measurement of the ring image is described. The use of the Cerenkov ring-imaging technique in high- energy physics experimentation is discussed, and in particular a full solid-angle detector for LEP is suggested. (10 refs).

  12. Performance of a thermal imager employing a hybrid pyroelectric detector array with MOSFET readout

    International Nuclear Information System (INIS)

    Watton, R.; Mansi, M.V.

    1988-01-01

    A thermal imager employing a two-dimensional hybrid array of pyroelectric detectors with MOSFET readout has been built. The design and theoretical performance of the detector are discussed, and the results of performance measurements are presented. 8 references

  13. Development of a two-dimensional ASIC for hard X-ray spectroscopy and imaging with a CdTe pixel detector

    International Nuclear Information System (INIS)

    Hiruta, Tatsuro; Tamura, K.; Ikeda, H.; Nakazawa, K.; Takasima, T.; Takahashi, T.

    2006-01-01

    We are developing a two-dimensional analog ASIC for the readout of pixel sensors based on silicon (Si) or cadmium telluride (CdTe) for spectroscopic imaging observations in the X-ray and gamma-ray regions. The aim for the ASIC is to obtain a low-noise performance better than 100 electrons (rms) with self-triggering capabilities. As the first step of prototyping, we have fabricated several ASICs. We obtained an energy resolution of 5.4 keV (FWHM) for 81 keV gamma-rays from 133 Ba with a one-dimensional ASIC connected to a CdTe diode and also verified a readout architecture via a two-dimensional ASIC with 144 pixel channels. Based on the results obtained and experience gained through prototype ASICs, we are developing a 4096-channel two-dimensional analog ASIC

  14. Timing characteristics of a two-dimensional multi-wire cathode strip detector for fission fragments

    International Nuclear Information System (INIS)

    Vind, R.P.; Joshi, B.N.; Jangale, R.V.; Inkar, A.L.; Prajapati, G.K.; John, B.V.; Biswas, D.C.

    2014-01-01

    In the recent past, a gas filled two-dimensional multi-wire cathode strip detector (MCSD) was developed for the detection of fission fragments (FFs). The position resolution was found to be about 1.0 and 1.5 mm in X and Y directions respectively. The detector has three electrode planes consisting of cathode strip (X-plane), anode wires and split-cathode wires (Y-plane). Each thin wire of the anode plane placed between the two cathode planes is essentially independent and behaves like a proportional counter. The construction of the detector in detail has been given in our earlier paper. The position information has been obtained by employing high impedance discrete delay line read out method for extracting position information in X and Y-directions. In this work, the timing characteristics of MCSD detector are reported to explore the possible use of this detector for the measurement of the mass of the fission fragments produced in heavy ion induced fission reactions

  15. High energy X-ray photon counting imaging using linear accelerator and silicon strip detectors

    International Nuclear Information System (INIS)

    Tian, Y.; Shimazoe, K.; Yan, X.; Ueda, O.; Ishikura, T.; Fujiwara, T.; Uesaka, M.; Ohno, M.; Tomita, H.; Yoshihara, Y.; Takahashi, H.

    2016-01-01

    A photon counting imaging detector system for high energy X-rays is developed for on-site non-destructive testing of thick objects. One-dimensional silicon strip (1 mm pitch) detectors are stacked to form a two-dimensional edge-on module. Each detector is connected to a 48-channel application specific integrated circuit (ASIC). The threshold-triggered events are recorded by a field programmable gate array based counter in each channel. The detector prototype is tested using 950 kV linear accelerator X-rays. The fast CR shaper (300 ns pulse width) of the ASIC makes it possible to deal with the high instant count rate during the 2 μs beam pulse. The preliminary imaging results of several metal and concrete samples are demonstrated.

  16. High energy X-ray photon counting imaging using linear accelerator and silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Y., E-mail: cycjty@sophie.q.t.u-tokyo.ac.jp [Department of Bioengineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Shimazoe, K.; Yan, X. [Department of Nuclear Engineering and Management, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Ueda, O.; Ishikura, T. [Fuji Electric Co., Ltd., Fuji, Hino, Tokyo 191-8502 (Japan); Fujiwara, T. [National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Uesaka, M.; Ohno, M. [Nuclear Professional School, the University of Tokyo, 2-22 Shirakata-shirane, Tokai, Ibaraki 319-1188 (Japan); Tomita, H. [Department of Quantum Engineering, Nagoya University, Furo, Chikusa, Nagoya 464-8603 (Japan); Yoshihara, Y. [Department of Nuclear Engineering and Management, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Takahashi, H. [Department of Bioengineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Nuclear Engineering and Management, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2016-09-11

    A photon counting imaging detector system for high energy X-rays is developed for on-site non-destructive testing of thick objects. One-dimensional silicon strip (1 mm pitch) detectors are stacked to form a two-dimensional edge-on module. Each detector is connected to a 48-channel application specific integrated circuit (ASIC). The threshold-triggered events are recorded by a field programmable gate array based counter in each channel. The detector prototype is tested using 950 kV linear accelerator X-rays. The fast CR shaper (300 ns pulse width) of the ASIC makes it possible to deal with the high instant count rate during the 2 μs beam pulse. The preliminary imaging results of several metal and concrete samples are demonstrated.

  17. Dynamic three-dimensional display of common congenital cardiac defects from reconstruction of two-dimensional echocardiographic images.

    Science.gov (United States)

    Hsieh, K S; Lin, C C; Liu, W S; Chen, F L

    1996-01-01

    Two-dimensional echocardiography had long been a standard diagnostic modality for congenital heart disease. Further attempts of three-dimensional reconstruction using two-dimensional echocardiographic images to visualize stereotypic structure of cardiac lesions have been successful only recently. So far only very few studies have been done to display three-dimensional anatomy of the heart through two-dimensional image acquisition because such complex procedures were involved. This study introduced a recently developed image acquisition and processing system for dynamic three-dimensional visualization of various congenital cardiac lesions. From December 1994 to April 1995, 35 cases were selected in the Echo Laboratory here from about 3000 Echo examinations completed. Each image was acquired on-line with specially designed high resolution image grazmber with EKG and respiratory gating technique. Off-line image processing using a window-architectured interactive software package includes construction of 2-D ehcocardiographic pixel to 3-D "voxel" with conversion of orthogonal to rotatory axial system, interpolation, extraction of region of interest, segmentation, shading and, finally, 3D rendering. Three-dimensional anatomy of various congenital cardiac defects was shown, including four cases with ventricular septal defects, two cases with atrial septal defects, and two cases with aortic stenosis. Dynamic reconstruction of a "beating heart" is recorded as vedio tape with video interface. The potential application of 3D display of the reconstruction from 2D echocardiographic images for the diagnosis of various congenital heart defects has been shown. The 3D display was able to improve the diagnostic ability of echocardiography, and clear-cut display of the various congenital cardiac defects and vavular stenosis could be demonstrated. Reinforcement of current techniques will expand future application of 3D display of conventional 2D images.

  18. Dosimetric characterization of a commercial two-dimensional array detector; Caracterizacao dosimetrica de um detector matricial bidimensional comercial

    Energy Technology Data Exchange (ETDEWEB)

    Gialluisi, Bruno L.; Santos, Gabriela R. dos; Sales, Camila P. de; Resende, Guilherme R.A.; Habitzreuter, Angela B.; Rodrigues, Laura N., E-mail: brunogialluisi@gmail.com [Universidade de Sao Paulo (HCFMRP/USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Servico de Radioterapia

    2013-04-15

    This paper investigates the dosimetric characteristics and performance of an array detector commercially available. The device is the I'mRT MatriXX® which is a two-dimensional detector array used in the verification of complex radiotherapy plans. It consists of 1,020 parallel plate ion chamber arranged in a 32x32 grid. Dose linearity was studied and its response was linear within the range of 5 to 1000 MU (R{sup 2} = 1). Dose rate dependence showed a maximum deviation of 0,62% comparatively with readings to 320 cGy/min. The detector stability was verified through repeated irradiations. Output factors matched well with measurements made with a Farmer chamber with an average deviation of 1,54%. The detector's effective point of measurement was determined and the inverse square law was also verified with a percentage deviation smaller than 3%. The results show that this detector can be used for quality control in IMRT thus reducing the time spent in the dosimetric verification of radiation fields. (author)

  19. Dosimetric characterization of a commercial two-dimensional array detector; Caracterizacao dosimetrica de um detector matricial bidimensional comercial

    Energy Technology Data Exchange (ETDEWEB)

    Gialluisi, Bruno L.; Santos, Gabriela R. dos; Sales, Camila P. de; Resende, Guilherme R.A.; Habitzreuter, Angela B.; Rodrigues, Laura N., E-mail: brunogialluisi@gmail.com [Universidade de Sao Paulo (HCFMRP/USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Servico de Radioterapia

    2013-04-15

    This paper investigates the dosimetric characteristics and performance of an array detector commercially available. The device is the I'mRT MatriXX® which is a two-dimensional detector array used in the verification of complex radiotherapy plans. It consists of 1,020 parallel plate ion chamber arranged in a 32x32 grid. Dose linearity was studied and its response was linear within the range of 5 to 1000 MU (R{sup 2} = 1). Dose rate dependence showed a maximum deviation of 0,62% comparatively with readings to 320 cGy/min. The detector stability was verified through repeated irradiations. Output factors matched well with measurements made with a Farmer chamber with an average deviation of 1,54%. The detector's effective point of measurement was determined and the inverse square law was also verified with a percentage deviation smaller than 3%. The results show that this detector can be used for quality control in IMRT thus reducing the time spent in the dosimetric verification of radiation fields. (author)

  20. High resolution X radiography imaging detector-micro gap chamber

    International Nuclear Information System (INIS)

    Long Huqiang; Wang Yun; Xu Dong; Xie Kuanzhong; Bian Jianjiang

    2007-01-01

    Micro gap chamber (MGC) is a new type of Two-Dimensional position sensitive detector having excellent properties on the space and time resolution, counting rate, 2D compact structure and the flexible of application. It will become a candidate of a new tracking detector for high energy physics experiment. The basic structure and properties of MGC as well as its main research subjects are presented in this paper. Furthermore, the feasibility and validity of utilizing diamond films as the MGC gap material were also discussed in detail. So, a potential radiography imaging detector is provided in order to realize X image and X ray diffraction experiment having very good spatial and time resolution in the 3rd Generation of Synchrotron Radiation Facility. (authors)

  1. Image Encryption Scheme Based on Balanced Two-Dimensional Cellular Automata

    Directory of Open Access Journals (Sweden)

    Xiaoyan Zhang

    2013-01-01

    Full Text Available Cellular automata (CA are simple models of computation which exhibit fascinatingly complex behavior. Due to the universality of CA model, it has been widely applied in traditional cryptography and image processing. The aim of this paper is to present a new image encryption scheme based on balanced two-dimensional cellular automata. In this scheme, a random image with the same size of the plain image to be encrypted is first generated by a pseudo-random number generator with a seed. Then, the random image is evoluted alternately with two balanced two-dimensional CA rules. At last, the cipher image is obtained by operating bitwise XOR on the final evolution image and the plain image. This proposed scheme possesses some advantages such as very large key space, high randomness, complex cryptographic structure, and pretty fast encryption/decryption speed. Simulation results obtained from some classical images at the USC-SIPI database demonstrate the strong performance of the proposed image encryption scheme.

  2. Study on two-dimensional distribution of X-ray image based on improved Elman algorithm

    International Nuclear Information System (INIS)

    Wang, Fang; Wang, Ming-Yuan; Tian, Feng-Shuo; Liu, Yu-Fang; Li, Lei; Zhao, Jing

    2015-01-01

    The principle of the X-ray detector which can simultaneously perform the measurement of the exposure rate and 2D (two-dimensional) distribution is described. A commercially available CMOS image sensor has been adopted as the key part to receive X-ray without any scintillators. The correlation between the pixel value (PV) and the absorbed exposure rate of X-ray is studied using the improved Elman neural network. Comparing the optimal adjustment process of the BP (Back Propagation) neural network and the improved Elman neural network, the neural network parameters are selected based on the fitting curve and the error curve. The experiments using the practical production data show that the proposed method achieves high accurate predictions to 10 −15 , which is consistent with the anticipated value. It is proven that it is possible to detect the exposure rate using the X-ray detector with the improved Elman algorithm for its advantages of fast converges and smooth error curve. - Highlights: • A method to measure the X-ray radiation with low cost and miniaturization. • A general CMOS image sensor is used to detect X-ray. • The system can measure exposure rate and 2D distribution simultaneously. • The Elman algorithm is adopted to improve the precision of the radiation detector

  3. Polycrystalline diamond detectors with three-dimensional electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Lagomarsino, S., E-mail: lagomarsino@fi.infn.it [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Bellini, M. [INO-CNR Firenze, Largo E. Fermi 6, 50125 Firenze (Italy); Brianzi, M. [INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Carzino, R. [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia, Genova, Via Morego 30, 16163 Genova (Italy); Cindro, V. [Joseph Stefan Institute, Jamova Cesta 39, 1000 Ljubljana (Slovenia); Corsi, C. [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); LENS Firenze, Via N. Carrara 1, 50019 Sesto Fiorentino (Italy); Morozzi, A.; Passeri, D. [INFN Perugia, Perugia (Italy); Università degli Studi di Perugia, Dipartimento di Ingegneria, via G. Duranti 93, 06125 Perugia (Italy); Sciortino, S. [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Servoli, L. [INFN Perugia, Perugia (Italy)

    2015-10-01

    The three-dimensional concept in diamond detectors has been applied, so far, to high quality single-crystal material, in order to test this technology in the best available conditions. However, its application to polycrystalline chemical vapor deposited diamond could be desirable for two reasons: first, the short inter-electrode distance of three-dimensional detectors should improve the intrinsically lower collection efficiency of polycrystalline diamond, and second, at high levels of radiation damage the performances of the poly-crystal material are not expected to be much lower than those of the single crystal one. We report on the fabrication and test of three-dimensional polycrystalline diamond detectors with several inter-electrode distances, and we demonstrate that their collection efficiency is equal or higher than that obtained with conventional planar detectors fabricated with the same material. - Highlights: • Pulsed laser fabrication of polycristalline diamond detectors with 3D electrodes. • Measurement of the charge collection efficiency (CCE) under beta irradiation. • Comparation between the CCE of 3D and conventional planar diamond sensors. • A rationale for the behavior of three-dimensional and planar sensors is given.

  4. Sparse Detector Imaging Sensor with Two-Class Silhouette Classification

    Directory of Open Access Journals (Sweden)

    David Russomanno

    2008-12-01

    Full Text Available This paper presents the design and test of a simple active near-infrared sparse detector imaging sensor. The prototype of the sensor is novel in that it can capture remarkable silhouettes or profiles of a wide-variety of moving objects, including humans, animals, and vehicles using a sparse detector array comprised of only sixteen sensing elements deployed in a vertical configuration. The prototype sensor was built to collect silhouettes for a variety of objects and to evaluate several algorithms for classifying the data obtained from the sensor into two classes: human versus non-human. Initial tests show that the classification of individually sensed objects into two classes can be achieved with accuracy greater than ninety-nine percent (99% with a subset of the sixteen detectors using a representative dataset consisting of 512 signatures. The prototype also includes a Webservice interface such that the sensor can be tasked in a network-centric environment. The sensor appears to be a low-cost alternative to traditional, high-resolution focal plane array imaging sensors for some applications. After a power optimization study, appropriate packaging, and testing with more extensive datasets, the sensor may be a good candidate for deployment in vast geographic regions for a myriad of intelligent electronic fence and persistent surveillance applications, including perimeter security scenarios.

  5. Development of one-energy group, two-dimensional, frequency dependent detector adjoint function based on the nodal method

    International Nuclear Information System (INIS)

    Khericha, Soli T.

    2000-01-01

    One-energy group, two-dimensional computer code was developed to calculate the response of a detector to a vibrating absorber in a reactor core. A concept of local/global components, based on the frequency dependent detector adjoint function, and a nodalization technique were utilized. The frequency dependent detector adjoint functions presented by complex equations were expanded into real and imaginary parts. In the nodalization technique, the flux is expanded into polynomials about the center point of each node. The phase angle and the magnitude of the one-energy group detector adjoint function were calculated for a detector located in the center of a 200x200 cm reactor using a two-dimensional nodalization technique, the computer code EXTERMINATOR, and the analytical solution. The purpose of this research was to investigate the applicability of a polynomial nodal model technique to the calculations of the real and the imaginary parts of the detector adjoint function for one-energy group two-dimensional polynomial nodal model technique. From the results as discussed earlier, it is concluded that the nodal model technique can be used to calculate the detector adjoint function and the phase angle. Using the computer code developed for nodal model technique, the magnitude of one energy group frequency dependent detector adjoint function and the phase angle were calculated for the detector located in the center of a 200x200 cm homogenous reactor. The real part of the detector adjoint function was compared with the results obtained from the EXTERMINATOR computer code as well as the analytical solution based on a double sine series expansion using the classical Green's Function solution. The values were found to be less than 1% greater at 20 cm away from the source region and about 3% greater closer to the source compared to the values obtained from the analytical solution and the EXTERMINATOR code. The currents at the node interface matched within 1% of the average

  6. Optimizing detector thickness in dual-shot dual-energy x-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Woon; Kam, Soohwa; Youn, Hanbean; Kim, Ho Kyung [Pusan National University, Busan (Korea, Republic of)

    2015-05-15

    As a result, there exist apparent limitations in the conventional two-dimensional (2D) radiography: One is that the contrast between the structure of interest and the background in a radiograph is much less than the intrinsic subject contrast (i.e. the difference between their attenuation coefficients; Another is that the superimposed anatomical structures in the 2D radiograph results in an anatomical background clutter that may decrease the conspicuity of subtle underlying features. These limitations in spatial and material discrimination are important motivations for the recent development of 3D (e.g. tomosynthesis) and dual energy imaging (DEI) systems. DEI technique uses a combination of two images obtained at two different energies in successive x-ray exposures by rapidly switching the kilovolage (kV) applied to the x-ray tube. Commercial DEI systems usually employ a 'single' of flat-panel detector (FPD) to obtain two different kV images. However, we have a doubt in the use of the same detector for acquiring two different projections for the low- and high-kV setups because it is typically known that there exists an optimal detector thickness regarding specific imaging tasks or energies used.

  7. Depth-enhanced three-dimensional-two-dimensional convertible display based on modified integral imaging.

    Science.gov (United States)

    Park, Jae-Hyeung; Kim, Hak-Rin; Kim, Yunhee; Kim, Joohwan; Hong, Jisoo; Lee, Sin-Doo; Lee, Byoungho

    2004-12-01

    A depth-enhanced three-dimensional-two-dimensional convertible display that uses a polymer-dispersed liquid crystal based on the principle of integral imaging is proposed. In the proposed method, a lens array is located behind a transmission-type display panel to form an array of point-light sources, and a polymer-dispersed liquid crystal is electrically controlled to pass or to scatter light coming from these point-light sources. Therefore, three-dimensional-two-dimensional conversion is accomplished electrically without any mechanical movement. Moreover, the nonimaging structure of the proposed method increases the expressible depth range considerably. We explain the method of operation and present experimental results.

  8. Comparison of one- and two-dimensional detectors on simulated and spin-stand readback waveforms

    International Nuclear Information System (INIS)

    Chan, Kheong Sann; Rachid, Elidrissi Moulay; Eason, Kwaku; Radhakrishnan, Rathnakumar; Teo, Kim Keng

    2012-01-01

    Shingled writing (SW) and two-dimensional magnetic recording (TDMR) are two complementary candidate technologies proposed to extend the life of magnetic recording. SW enables the writing of narrow tracks with a wider writer by shingling the tracks; each track partially overlaps the preceding track leaving only a fraction of that track on the medium. TDMR is the companion technology to SW that enables reading of narrower tracks with a wider reader. In this work we compare the performances of 1D and 2D detectors in the shingled writing environment, using both comprehensive channel models and spin-stand readback. - Research highlights: → Improvement to the GFP model to include variety of effects from micromagnetics. → 1D/2D detector performance evaluation over variations of GFP model. → 1D/2D detector performance evaluation over various levels of ISI/ITI. → First TDMR implementation attempt on the spin-stand.

  9. Three-dimensional reciprocal space x-ray coherent scattering tomography of two-dimensional object.

    Science.gov (United States)

    Zhu, Zheyuan; Pang, Shuo

    2018-04-01

    X-ray coherent scattering tomography is a powerful tool in discriminating biological tissues and bio-compatible materials. Conventional x-ray scattering tomography framework can only resolve isotropic scattering profile under the assumption that the material is amorphous or in powder form, which is not true especially for biological samples with orientation-dependent structure. Previous tomography schemes based on x-ray coherent scattering failed to preserve the scattering pattern from samples with preferred orientations, or required elaborated data acquisition scheme, which could limit its application in practical settings. Here, we demonstrate a simple imaging modality to preserve the anisotropic scattering signal in three-dimensional reciprocal (momentum transfer) space of a two-dimensional sample layer. By incorporating detector movement along the direction of x-ray beam, combined with a tomographic data acquisition scheme, we match the five dimensions of the measurements with the five dimensions (three in momentum transfer domain, and two in spatial domain) of the object. We employed a collimated pencil beam of a table-top copper-anode x-ray tube, along with a panel detector to investigate the feasibility of our method. We have demonstrated x-ray coherent scattering tomographic imaging at a spatial resolution ~2 mm and momentum transfer resolution 0.01 Å -1 for the rotation-invariant scattering direction. For any arbitrary, non-rotation-invariant direction, the same spatial and momentum transfer resolution can be achieved based on the spatial information from the rotation-invariant direction. The reconstructed scattering profile of each pixel from the experiment is consistent with the x-ray diffraction profile of each material. The three-dimensional scattering pattern recovered from the measurement reveals the partially ordered molecular structure of Teflon wrap in our sample. We extend the applicability of conventional x-ray coherent scattering tomography to

  10. Development of a large area, curved two-dimensional detector for single-crystal neutron diffraction studies

    International Nuclear Information System (INIS)

    Moon, Myung-Kook; Lee, Chang-Hee; Kim, Shin-Ae; Noda, Yukio

    2013-01-01

    A new type of two-dimensional curved position-sensitive neutron detector has been developed for a high-throughput single-crystal neutron diffractometer, which was designed to cover 110° horizontally and 56° vertically. The prototype curved detector covering 70° horizontally and 45° vertically was first developed to test the technical feasibility of the detector parameters, the internal anode and cathode structures for the curved shape, technical difficulties in the assembly procedure, and so on. Then, based on this experience, a full-scale curved detector with twice the active area of the prototype was fabricated with newly modified anode and cathode planes and optimized design parameters in terms of mechanical and electric properties. The detector was installed in a dedicated diffractometer at the ST3 beam port of the research reactor HANARO. In this paper, the fabrication and application of the prototype and a new larger-area curved position-sensitive neutron detector for single crystal diffraction is presented

  11. Development of a Two-Dimensional Tracker with Plasma Panel Detector

    CERN Document Server

    AUTHOR|(CDS)2233132

    Plasma panel sensors are micropattern gaseous radiation detectors which are based on the technology of plasma display panels. This thesis summarizes the research that had been done on commercially available plasma display panels that were converted to plasma panel sensor prototypes and describes the construction of a two-dimensional tracker consisting of four of those prototypes, with one-dimensional readout on each, used to detect tracks of cosmic muons. A large amount of 2-point as well as 3 and 4-point tracks were detected. Qualitative analyses as well as Pearson’s χ2 tests are performed on the track angular distribution and on a histogram of the linearity measure of 3-point tracks to reject the hypothesis that these tracks result from completely random panel hits. Some RF noise effects contributing to false positives are ruled out, while it is shown that other effects can be ruled out only with a high-intensity minimum ionizing particle source. A significant part of the tracker construction was the dev...

  12. DUNBID, the Delft University neutron backscattering imaging detector

    International Nuclear Information System (INIS)

    Bom, V.R.; Eijk, C.W.E. van; Ali, M.A.

    2005-01-01

    In the search for low-metallic land mines, the neutron backscattering technique may be applied if the soil is sufficiently dry. An advantage of this method is the speed of detection: the scanning speed may be made comparable to that of a metal detector. A two-dimensional position sensitive detector is tested to obtain an image of the back scattered thermal neutron radiation. Results of experiments using a radionuclide neutron source are presented. The on-mine to no-mine signal ratio can be improved by the application of a window on the neutron time-of-flight. Results using a pulsed neutron generator are also presented

  13. Detection of Point Sources on Two-Dimensional Images Based on Peaks

    Directory of Open Access Journals (Sweden)

    R. B. Barreiro

    2005-09-01

    Full Text Available This paper considers the detection of point sources in two-dimensional astronomical images. The detection scheme we propose is based on peak statistics. We discuss the example of the detection of far galaxies in cosmic microwave background experiments throughout the paper, although the method we present is totally general and can be used in many other fields of data analysis. We consider sources with a Gaussian profile—that is, a fair approximation of the profile of a point source convolved with the detector beam in microwave experiments—on a background modeled by a homogeneous and isotropic Gaussian random field characterized by a scale-free power spectrum. Point sources are enhanced with respect to the background by means of linear filters. After filtering, we identify local maxima and apply our detection scheme, a Neyman-Pearson detector that defines our region of acceptance based on the a priori pdf of the sources and the ratio of number densities. We study the different performances of some linear filters that have been used in this context in the literature: the Mexican hat wavelet, the matched filter, and the scale-adaptive filter. We consider as well an extension to two dimensions of the biparametric scale-adaptive filter (BSAF. The BSAF depends on two parameters which are determined by maximizing the number density of real detections while fixing the number density of spurious detections. For our detection criterion the BSAF outperforms the other filters in the interesting case of white noise.

  14. Two-dimensional imaging detectors for structural biology with X-ray lasers.

    Science.gov (United States)

    Denes, Peter

    2014-07-17

    Our ability to harness the advances in microelectronics over the past decade(s) for X-ray detection has resulted in significant improvements in the state of the art. Biology with X-ray free-electron lasers present daunting detector challenges: all of the photons arrive at the same time, and individual high peak power pulses must be read out shot-by-shot. Direct X-ray detection in silicon pixel detectors--monolithic or hybrid--are the standard for XFELs today. For structural biology, improvements are needed for today's 10-100 Hz XFELs, and further improvements are required for tomorrow's 10+ kHz XFELs. This article will discuss detector challenges, why they arise and ways to overcome them, along with the current state of the art. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  15. The pin pixel detector--X-ray imaging

    CERN Document Server

    Bateman, J E; Derbyshire, G E; Duxbury, D M; Marsh, A S; Simmons, J E; Stephenson, R

    2002-01-01

    The development and testing of a soft X-ray gas pixel detector, which uses connector pins for the anodes is reported. Based on a commercial 100 pin connector block, a prototype detector of aperture 25.4 mm centre dot 25.4 mm can be economically fabricated. The individual pin anodes all show the expected characteristics of small gas detectors capable of counting rates reaching 1 MHz per pin. A 2-dimensional resistive divide readout system has been developed to permit the imaging properties of the detector to be explored in advance of true pixel readout electronics.

  16. The pin pixel detector--neutron imaging

    CERN Document Server

    Bateman, J E; Derbyshire, G E; Duxbury, D M; Marsh, A S; Rhodes, N J; Schooneveld, E M; Simmons, J E; Stephenson, R

    2002-01-01

    The development and testing of a neutron gas pixel detector intended for application in neutron diffraction studies is reported. Using standard electrical connector pins as point anodes, the detector is based on a commercial 100 pin connector block. A prototype detector of aperture 25.4 mmx25.4 mm has been fabricated, giving a pixel size of 2.54 mm which matches well to the spatial resolution typically required in a neutron diffractometer. A 2-Dimensional resistive divide readout system has been adapted to permit the imaging properties of the detector to be explored in advance of true pixel readout electronics. The timing properties of the device match well to the requirements of the ISIS-pulsed neutron source.

  17. Image Making in Two Dimensional Art; Experiences with Straw and ...

    African Journals Online (AJOL)

    Image making in art is professionally referred to as bust in Sculpture andPortraiture in Painting. ... havebeen used to achieve these forms of art; like clay cement, marble, stone,different metals and, fibre glass in the three dimensional form; We also have Pencil, Charcoal Pastel and, Acrylic oil-paint in two dimensional form.

  18. Dynamic time-dependent analysis and static three-dimensional imaging procedures for computer-assisted CNS studies

    International Nuclear Information System (INIS)

    Budinger, T.F.; DeLand, F.H.; Duggan, H.E.; Bouz, J.J.; Hoop, B. Jr.; McLaughlin, W.T.; Weber, P.M.

    1975-01-01

    Two-dimensional computer image-processing techniques have not proved to be of importance in diagnostic nuclear medicine primarily because the radionuclide distribution represents a three-dimensional problem. More recent developments in three-dimensional reconstruction from multiple views or multiple detectors promise to overcome the major limitations in previous work with digital computers. These techniques are now in clinical use for static imaging; however, speed limitations have prevented application to dynamic imaging. The future development of these methods will require innovations in patient positioning and multiple-view devices for either single-gamma or positron annihilation detection

  19. Image Making in Two Dimensional Art; Experiences with Straw and ...

    African Journals Online (AJOL)

    Image making in art is professionally referred to as bust in Sculpture andPortraiture in Painting. It is an art form executed in three dimensional (3D)and two dimensional (2D) formats respectively. Uncountable materials havebeen used to achieve these forms of art; like clay cement, marble, stone,different metals and, fibre ...

  20. Discriminating image textures with the multiscale two-dimensional complexity-entropy causality plane

    International Nuclear Information System (INIS)

    Zunino, Luciano; Ribeiro, Haroldo V.

    2016-01-01

    The aim of this paper is to further explore the usefulness of the two-dimensional complexity-entropy causality plane as a texture image descriptor. A multiscale generalization is introduced in order to distinguish between different roughness features of images at small and large spatial scales. Numerically generated two-dimensional structures are initially considered for illustrating basic concepts in a controlled framework. Then, more realistic situations are studied. Obtained results allow us to confirm that intrinsic spatial correlations of images are successfully unveiled by implementing this multiscale symbolic information-theory approach. Consequently, we conclude that the proposed representation space is a versatile and practical tool for identifying, characterizing and discriminating image textures.

  1. Space imaging measurement system based on fixed lens and moving detector

    Science.gov (United States)

    Akiyama, Akira; Doshida, Minoru; Mutoh, Eiichiro; Kumagai, Hideo; Yamada, Hirofumi; Ishii, Hiromitsu

    2006-08-01

    We have developed the Space Imaging Measurement System based on the fixed lens and fast moving detector to the control of the autonomous ground vehicle. The space measurement is the most important task in the development of the autonomous ground vehicle. In this study we move the detector back and forth along the optical axis at the fast rate to measure the three-dimensional image data. This system is just appropriate to the autonomous ground vehicle because this system does not send out any optical energy to measure the distance and keep the safety. And we use the digital camera of the visible ray range. Therefore it gives us the cost reduction of the three-dimensional image data acquisition with respect to the imaging laser system. We can combine many pieces of the narrow space imaging measurement data to construct the wide range three-dimensional data. This gives us the improvement of the image recognition with respect to the object space. To develop the fast movement of the detector, we build the counter mass balance in the mechanical crank system of the Space Imaging Measurement System. And then we set up the duct to prevent the optical noise due to the ray not coming through lens. The object distance is derived from the focus distance which related to the best focused image data. The best focused image data is selected from the image of the maximum standard deviation in the standard deviations of series images.

  2. Imaging plate, a new type of x-ray area detector

    International Nuclear Information System (INIS)

    Kamiya, Nobuo; Amemiya, Yoshiyuki; Miyahara, Junji.

    1986-01-01

    In respective fields of X-ray crystallography, for the purpose of the efficient collection of reciprocal space information, two-dimensional X-ray detectors such as multiwire proportional chambers and X-ray television sets have been used together with conventional X-ray films. X-ray films are characterized by uniform sensitivity and high positional resolution over a wide area, but the sensitivity is low, and the range of action and the linearity of the sensitivity is problematic. They require the development process, accordingly lack promptitude. The MWPCs and X-ray television sets are superior in the sensitivity, its linearity, the range of action and promptitude, but interior in the uniformity and resolution to the films. Imaging plate is a new X-ray area detector developed by Fuji Photo Film Co., Ltd., for digital X-ray medical image diagnosis. This detector is superior in all the above mentioned performances, and it seems very useful also for X-ray crystallography. In this paper, the system composed of an imaging plate and its reader is described, and the basic performance as an X-ray area detector and the results of having recorded the diffraction images of protein crystals as the example of applying it to X-ray crystallography are reported. The imaging plate is that the crystalline fluorescent powder of BaFBr doped with Eu 2+ ions is applied on plastic films. (Kako, I.)

  3. Two-dimensional imaging of Debye-Scherrer ring for tri-axial stress analysis of industrial materials

    International Nuclear Information System (INIS)

    Sasaki, T; Maruyama, Y; Ohba, H; Ejiri, S

    2014-01-01

    In this study, an application of the two-dimensional imaging technology to the X ray tri-axial stress analysis was studied. An image plate (IP) was used to obtain a Debye-Scherre ring and the image data was analized for determining stress. A new principle for stress analysis which is suitable to two-dimensional imaging data was used. For the verification of this two-dimensional imaging type X-ray stress measurement method, an experiment was conducted using a ferritic steel sample which was processed with a surface grinder. Tri-axial stress analysis was conducted to evaluate the sample. The conventional method for X-ray tri-axial stress analysis proposed by Dölle and Hauk was used to evaluate residual stress in order to compare with the present method. As a result, it was confirmed that a sufficiently highly precise and high-speed stress measurement was enabled with the two-dimensional imaging technology compared with the conventional method

  4. The design and imaging characteristics of dynamic, solid-state, flat-panel x-ray image detectors for digital fluoroscopy and fluorography

    International Nuclear Information System (INIS)

    Cowen, A.R.; Davies, A.G.; Sivananthan, M.U.

    2008-01-01

    Dynamic, flat-panel, solid-state, x-ray image detectors for use in digital fluoroscopy and fluorography emerged at the turn of the millennium. This new generation of dynamic detectors utilize a thin layer of x-ray absorptive material superimposed upon an electronic active matrix array fabricated in a film of hydrogenated amorphous silicon (a-Si:H). Dynamic solid-state detectors come in two basic designs, the indirect-conversion (x-ray scintillator based) and the direct-conversion (x-ray photoconductor based). This review explains the underlying principles and enabling technologies associated with these detector designs, and evaluates their physical imaging characteristics, comparing their performance against the long established x-ray image intensifier television (TV) system. Solid-state detectors afford a number of physical imaging benefits compared with the latter. These include zero geometrical distortion and vignetting, immunity from blooming at exposure highlights and negligible contrast loss (due to internal scatter). They also exhibit a wider dynamic range and maintain higher spatial resolution when imaging over larger fields of view. The detective quantum efficiency of indirect-conversion, dynamic, solid-state detectors is superior to that of both x-ray image intensifier TV systems and direct-conversion detectors. Dynamic solid-state detectors are playing a burgeoning role in fluoroscopy-guided diagnosis and intervention, leading to the displacement of x-ray image intensifier TV-based systems. Future trends in dynamic, solid-state, digital fluoroscopy detectors are also briefly considered. These include the growth in associated three-dimensional (3D) visualization techniques and potential improvements in dynamic detector design

  5. Method and apparatus for enhanced sensitivity filmless medical x-ray imaging, including three-dimensional imaging

    Science.gov (United States)

    Parker, Sherwood

    1995-01-01

    A filmless X-ray imaging system includes at least one X-ray source, upper and lower collimators, and a solid-state detector array, and can provide three-dimensional imaging capability. The X-ray source plane is distance z.sub.1 above upper collimator plane, distance z.sub.2 above the lower collimator plane, and distance z.sub.3 above the plane of the detector array. The object to be X-rayed is located between the upper and lower collimator planes. The upper and lower collimators and the detector array are moved horizontally with scanning velocities v.sub.1, v.sub.2, v.sub.3 proportional to z.sub.1, z.sub.2 and z.sub.3, respectively. The pattern and size of openings in the collimators, and between detector positions is proportional such that similar triangles are always defined relative to the location of the X-ray source. X-rays that pass through openings in the upper collimator will always pass through corresponding and similar openings in the lower collimator, and thence to a corresponding detector in the underlying detector array. Substantially 100% of the X-rays irradiating the object (and neither absorbed nor scattered) pass through the lower collimator openings and are detected, which promotes enhanced sensitivity. A computer system coordinates repositioning of the collimators and detector array, and X-ray source locations. The computer system can store detector array output, and can associate a known X-ray source location with detector array output data, to provide three-dimensional imaging. Detector output may be viewed instantly, stored digitally, and/or transmitted electronically for image viewing at a remote site.

  6. Gas microstrip detectors for X-ray tomographic flow imaging

    CERN Document Server

    Key, M J; Luggar, R D; Kundu, A

    2003-01-01

    A investigation into the suitability of gas microstrip detector technology for a high-speed industrial X-ray tomography system is reported. X-ray energies in the region 20-30 keV are well suited to the application, which involves imaging two-dimensional slices through gas/liquid multiphase pipeline flows for quantitative component fraction measurement. Stable operation over a period representing several hundred individual tomographic scans at gas gains of 500 is demonstrated using a Penning gas mixture of krypton/propylene.

  7. Two-dimensional random arrays for real time volumetric imaging

    DEFF Research Database (Denmark)

    Davidsen, Richard E.; Jensen, Jørgen Arendt; Smith, Stephen W.

    1994-01-01

    real time volumetric imaging system, which employs a wide transmit beam and receive mode parallel processing to increase image frame rate. Depth-of-field comparisons were made from simulated on-axis and off-axis beamplots at ranges from 30 to 160 mm for both coaxial and offset transmit and receive......Two-dimensional arrays are necessary for a variety of ultrasonic imaging techniques, including elevation focusing, 2-D phase aberration correction, and real time volumetric imaging. In order to reduce system cost and complexity, sparse 2-D arrays have been considered with element geometries...... selected ad hoc, by algorithm, or by random process. Two random sparse array geometries and a sparse array with a Mills cross receive pattern were simulated and compared to a fully sampled aperture with the same overall dimensions. The sparse arrays were designed to the constraints of the Duke University...

  8. Two-dimensional DFA scaling analysis applied to encrypted images

    Science.gov (United States)

    Vargas-Olmos, C.; Murguía, J. S.; Ramírez-Torres, M. T.; Mejía Carlos, M.; Rosu, H. C.; González-Aguilar, H.

    2015-01-01

    The technique of detrended fluctuation analysis (DFA) has been widely used to unveil scaling properties of many different signals. In this paper, we determine scaling properties in the encrypted images by means of a two-dimensional DFA approach. To carry out the image encryption, we use an enhanced cryptosystem based on a rule-90 cellular automaton and we compare the results obtained with its unmodified version and the encryption system AES. The numerical results show that the encrypted images present a persistent behavior which is close to that of the 1/f-noise. These results point to the possibility that the DFA scaling exponent can be used to measure the quality of the encrypted image content.

  9. Calibration model of a dual gain flat panel detector for 2D and 3D x-ray imaging

    International Nuclear Information System (INIS)

    Schmidgunst, C.; Ritter, D.; Lang, E.

    2007-01-01

    The continuing research and further development in flat panel detector technology have led to its integration into more and more medical x-ray systems for two-dimensional (2D) and three-dimensional (3D) imaging, such as fixed or mobile C arms. Besides the obvious advantages of flat panel detectors, like the slim design and the resulting optimum accessibility to the patient, their success is primarily a product of the image quality that can be achieved. The benefits in the physical and performance-related features as opposed to conventional image intensifier systems (e.g., distortion-free reproduction of imaging information or almost linear signal response over a large dynamic range) can be fully exploited, however, only if the raw detector images are correctly calibrated and postprocessed. Previous procedures for processing raw data contain idealizations that, in the real world, lead to artifacts or losses in image quality. Thus, for example, temperature dependencies or changes in beam geometry, as can occur with mobile C arm systems, have not been taken into account up to this time. Additionally, adverse characteristics such as image lag or aging effects have to be compensated to attain the best possible image quality. In this article a procedure is presented that takes into account the important dependencies of the individual pixel sensitivity of flat panel detectors used in 2D or 3D imaging and simultaneously minimizes the work required for an extensive recalibration. It is suitable for conventional detectors with only one gain mode as well as for the detectors specially developed for 3D imaging with dual gain read-out technology

  10. A new method for information retrieval in two-dimensional grating-based X-ray phase contrast imaging

    International Nuclear Information System (INIS)

    Wang Zhi-Li; Gao Kun; Chen Jian; Ge Xin; Tian Yang-Chao; Wu Zi-Yu; Zhu Pei-Ping

    2012-01-01

    Grating-based X-ray phase contrast imaging has been demonstrated to be an extremely powerful phase-sensitive imaging technique. By using two-dimensional (2D) gratings, the observable contrast is extended to two refraction directions. Recently, we have developed a novel reverse-projection (RP) method, which is capable of retrieving the object information efficiently with one-dimensional (1D) grating-based phase contrast imaging. In this contribution, we present its extension to the 2D grating-based X-ray phase contrast imaging, named the two-dimensional reverse-projection (2D-RP) method, for information retrieval. The method takes into account the nonlinear contributions of two refraction directions and allows the retrieval of the absorption, the horizontal and the vertical refraction images. The obtained information can be used for the reconstruction of the three-dimensional phase gradient field, and for an improved phase map retrieval and reconstruction. Numerical experiments are carried out, and the results confirm the validity of the 2D-RP method

  11. A simple algorithm for estimation of source-to-detector distance in Compton imaging

    International Nuclear Information System (INIS)

    Rawool-Sullivan, Mohini W.; Sullivan, John P.; Tornga, Shawn R.; Brumby, Steven P.

    2008-01-01

    Compton imaging is used to predict the location of gamma-emitting radiation sources. The X and Y coordinates of the source can be obtained using a back-projected image and a two-dimensional peak-finding algorithm. The emphasis of this work is to estimate the source-to-detector distance (Z). The algorithm presented uses the solid angle subtended by the reconstructed image at various source-to-detector distances. This algorithm was validated using both measured data from the prototype Compton imager (PCI) constructed at the Los Alamos National Laboratory and simulated data of the same imager. Results show this method can be applied successfully to estimate Z, and it provides a way of determining Z without prior knowledge of the source location. This method is faster than the methods that employ maximum likelihood method because it is based on simple back projections of Compton scatter data

  12. Three-dimensional breast image reconstruction from a limited number of views

    Science.gov (United States)

    McCauley, Thomas G.; Stewart, Alexander X.; Stanton, Martin J.; Wu, Tao; Phillips, Walter C.

    2000-04-01

    Typically in three-dimensional (3D) computed tomography (CT) imaging, hundreds or thousands of x-ray projection images are recorded. The image-collection time and patient dose required rule out conventional CT as a tool for screening mammography. We have developed a CT method that overcomes these limitations by using (1) a novel image collection geometry, (2) new digital electronic x-ray detector technology, and (3) modern image reconstruction procedures. The method, which we call Computed Planar Mammography (CPM), is made possible by the full-field, low-noise, high-resolution CCD-based detector design that we have previously developed. With this method, we need to record only a limited number (10 - 50) of low-dose x- ray images of the breast. The resulting 3D full breast image has a resolution in two orientations equal to the full detector resolution (47 microns), and a lower, variable resolution (0.5 - 10 mm) in the third orientation. This 3D reconstructed image can then be viewed as a series of cross- sectional layers, or planes, each at the full detector resolution. Features due to overlapping tissue, which could not be differentiated in a conventional mammogram, are separated into layers at different depths. We demonstrate the features and capabilities of this method by presenting reconstructed images of phantoms and mastectomy specimens. Finally, we discuss outstanding issues related to the further development of this procedure, as well as considerations for its clinical implementation.

  13. Two-dimensional bismuth nanosheets as prospective photo-detector with tunable optoelectronic performance

    Science.gov (United States)

    Huang, Hao; Ren, Xiaohui; Li, Zhongjun; Wang, Huide; Huang, Zongyu; Qiao, Hui; Tang, Pinghua; Zhao, Jinlai; Liang, Weiyuan; Ge, Yanqi; Liu, Jie; Li, Jianqing; Qi, Xiang; Zhang, Han

    2018-06-01

    Two dimensional Bi nanosheets have been employed to fabricate electrodes for broadband photo-detection. A series of characterization techniques including scanning electron microscopy and high-resolution transmission electron microscopy have verified that Bi nanosheets with intact lamellar structure have been obtained after facile liquid phase exfoliation. In the meanwhile, UV–vis and Raman spectra are also carried out and the inherent optical and physical properties of Bi nanosheets are confirmed. Inherited from the topological characteristics of Bi bulk counterpart, the resultant Bi nanosheet-based photo-detector exhibits preferable photo-response activity as well as environmental robustness. We then evaluate the photo-electrochemical (PEC) performance of the photodetector in 1 M NaOH and 0.5 M Na2SO4 electrolytes, and demonstrated that the as-prepared Bi nanosheets may possess a great potential as PEC-type photo-detector. Additional PEC measurements show that the current density of Bi nanosheets can reach up to 830 nA cm‑2, while an enhanced responsivity (1.8 μA W‑1) had been achieved. We anticipate that this contribution can provide feasibility towards the construction of high-performance elemental Bi nanosheets-based optoelectronic devices in the future.

  14. Applications of 'edge-on' illuminated porous plate detectors for diagnostic X-ray imaging

    CERN Document Server

    Shikhaliev, P M

    2002-01-01

    Scanning X-ray imaging systems for non-invasive diagnostics have several advantages over conventional imaging systems using area detectors. They significantly reduce the detected scatter radiation, cover large areas and potentially provide high spatial resolution. Applications of one-dimensional gaseous detectors and 'edge-on' illuminated silicon strip detectors for scanning imaging systems are currently under intensive investigation. The purpose of this work is to investigate 'edge-on' illuminated Porous Plate (PP) detectors for applications in diagnostic X-ray imaging. MicroChannel Plate (MCP), which is a common type of PP, has previously been investigated as a detector in surface-on illumination mode for medical X-ray imaging. However, its detection efficiency was too low for medical imaging applications. In the present study, the PP are used in the 'edge-on' illumination mode. Furthermore, the structural parameters of different PP types are optimized to improve the detection efficiency in the diagnostic X...

  15. A position-sensitive scintillation detector for two-dimensional angular correlation of annihilation radiation using metal-package position-sensitive photomultiplier tubes

    International Nuclear Information System (INIS)

    Inoue, Koji; Nagai, Yasuyoshi; Saito, Haruo; Nagashima, Yasuyuki; Hyodo, Toshio; Muramatsu, Shinichi; Nagai, Shota

    1999-01-01

    We have constructed and tested a prototype of a new position sensitive γ-ray detector which consists of an array of 2.6x2.6x18 mm 3 BGO scintillator blocks, a light guide, and four metal-package position-sensitive photomultiplier tubes (R5900-00-C8) recently developed by Hamamatsu Photonics Co. Ltd. Scalability of the detector of this type makes it possible to construct a larger detector using many PS-PMTs, which will be useful for the two-dimensional angular correlation of annihilation radiation apparatus

  16. Novel gaseous detectors for medical imaging

    International Nuclear Information System (INIS)

    Danielsson, M.; Fonte, P.; Francke, T.; Iacobaeus, C.; Ostling, J.; Peskov, V.

    2004-01-01

    We have developed and successfully tested prototypes of two new types of gaseous detectors for medical imaging purposes. The first one is called the Electronic Portal Imaging Device (EPID). It is oriented on monitoring and the precise alignment of the therapeutic cancer treatment beam (pulsed gamma radiation) with respect to the patient's tumor position. The latest will be determined from an X-ray image of the patient obtained in the time intervals between the gamma pulses. The detector is based on a 'sandwich' of hole-type gaseous detectors (GEM and glass microcapillary plates) with metallic gamma and X-ray converters coated with CsI layers. The second detector is an X-ray image scanner oriented on mammography and other radiographic applications. It is based on specially developed by us high rate RPCs that are able to operate at rates of 10 5 Hz/mm 2 with a position resolution better than 50 μm at 1 atm. The quality of the images obtained with the latest version of this device were in most cases more superior than those obtained from commercially available detectors

  17. Image quality assessment using two-dimensional complex mel-cepstrum

    Science.gov (United States)

    Cakir, Serdar; Cetin, A. Enis

    2016-11-01

    Assessment of visual quality plays a crucial role in modeling, implementation, and optimization of image- and video-processing applications. The image quality assessment (IQA) techniques basically extract features from the images to generate objective scores. Feature-based IQA methods generally consist of two complementary phases: (1) feature extraction and (2) feature pooling. For feature extraction in the IQA framework, various algorithms have been used and recently, the two-dimensional (2-D) mel-cepstrum (2-DMC) feature extraction scheme has provided promising results in a feature-based IQA framework. However, the 2-DMC feature extraction scheme completely loses image-phase information that may contain high-frequency characteristics and important structural components of the image. In this work, "2-D complex mel-cepstrum" is proposed for feature extraction in an IQA framework. The method tries to integrate Fourier transform phase information into the 2-DMC, which was shown to be an efficient feature extraction scheme for assessment of image quality. Support vector regression is used for feature pooling that provides mapping between the proposed features and the subjective scores. Experimental results show that the proposed technique obtains promising results for the IQA problem by making use of the image-phase information.

  18. Two-dimensional fruit ripeness estimation using thermal imaging

    Science.gov (United States)

    Sumriddetchkajorn, Sarun; Intaravanne, Yuttana

    2013-06-01

    Some green fruits do not change their color from green to yellow when being ripe. As a result, ripeness estimation via color and fluorescent analytical approaches cannot be applied. In this article, we propose and show for the first time how a thermal imaging camera can be used to two-dimensionally classify fruits into different ripeness levels. Our key idea relies on the fact that the mature fruits have higher heat capacity than the immature ones and therefore the change in surface temperature overtime is slower. Our experimental proof of concept using a thermal imaging camera shows a promising result in non-destructively identifying three different ripeness levels of mangoes Mangifera indica L.

  19. Development of a 3-dimensional CT using an image intensifier

    International Nuclear Information System (INIS)

    Toyofuku, Fukai

    1992-01-01

    A prototype of three-dimensional CT (Fluoroscopic CT) has been developed using an image intensifier as a two-dimensional X-ray detector. A patient on a rotating table is projected onto an image intensifier by a cone beam of X-ray from the X-ray tube. A total of 390 projection images covering 180 degrees are acquired in a single scan (13 sec) and stored on a digital frame recorder (512 x 256 x 8-bit x 480). The transverse axial images are reconstructed by using the usual CT reconstruction algorithm, while longitudinal section images such as sagittal, coronal, oblique, and panoramic images are obtained by directly back-projecting the filtered projection image onto the sections. The radiation exposure was measured with an ionization chamber, and the exposure of the present fluoroscopic CT is about 10 to 20 times less than that of conventional X-ray CT. A similar monochromatic X-ray CT system has also been developed using synchrotron radiation. Large area parallel X-rays are obtained from a wiggler beam using a silicon crystal with [311] asymmetric reflection. By taking two images above and below iodine K-absorption edge (33.17 keV), iodine image is obtained. (author)

  20. Study on a two-dimensional scanning micro-mirror and its application in a MOEMS target detector.

    Science.gov (United States)

    Zhang, Chi; You, Zheng; Huang, Hu; Li, Guanhua

    2010-01-01

    A two-dimensional (2D) scanning micro-mirror for target detection and measurement has been developed. This new micro-mirror is used in a MOEMS target detector to replace the conventional scanning detector. The micro-mirror is fabricated by MEMS process and actuated by a piezoelectric actuator. To achieve large deflection angles, the micro-mirror is excited in the resonance modes. It has two degrees of freedom and changes the direction of the emitted laser beam for a regional 2D scanning. For the deflection angles measurement, piezoresistors are integrated in the micro-mirror and the deflection angles of each direction can be detected independently and precisely. Based on the scanning micro-mirror and the phase-shift ranging technology, a MOEMS target detector has been developed in a size of 90 mm × 35 mm × 50 mm. The experiment shows that the target can be detected in the scanning field and the relative range and orientation can be measured by the MOEMS target detector. For the target distance up to 3 m with a field of view about 20° × 20°, the measurement resolution is about 10.2 cm in range, 0.15° in the horizontal direction and 0.22° in the vertical direction for orientation.

  1. Radiography imaging by 64 and 128 micro-strips crystalline detectors at different X-ray energies

    International Nuclear Information System (INIS)

    Leyva, A.; Cabal, A.; Montano, L. M.; Fontaine, M.; Mora, R. de la; Padilla, F.

    2006-01-01

    This paper summarizes some results obtained in the evaluation of the performance of position sensitive detectors in track reconstruction in particle physics experiments. Crystalline silicon micro-strips detectors with 64 and 128 channels and 100 μm pitch were used to obtain radiographic digital images of different objects. The more relevant figures for spectrometry applications were measured and reported. Two-dimensional images were obtained by scanning the object with a collimated beam using different source-target-detector positioning and three sources of X-rays (8.04, 18.55 and 22.16 keV). The counts acquired by each strip correspond to a particular collimator position during the scan, thus serving to reconstruct the image of the exposed to X-ray object and to reveal its internal structure. The use of some techniques for image processing allow the further improvement of the radiography quality. The preliminary results obtained using in-house made and accreditation mammography phantoms allow to infer that such detectors can be successfully introduced in the digital mammography practice. (Author)

  2. Two-dimensional Tissue Image Reconstruction Based on Magnetic Field Data

    Directory of Open Access Journals (Sweden)

    J. Dedkova

    2012-09-01

    Full Text Available This paper introduces new possibilities within two-dimensional reconstruction of internal conductivity distribution. In addition to the electric field inside the given object, the injected current causes a magnetic field which can be measured either outside the object by means of a Hall probe or inside the object through magnetic resonance imaging. The Magnetic Resonance method, together with Electrical impedance tomography (MREIT, is well known as a bio-imaging modality providing cross-sectional conductivity images with a good spatial resolution from the measurements of internal magnetic flux density produced by externally injected currents. A new algorithm for the conductivity reconstruction, which utilizes the internal current information with respect to corresponding boundary conditions and the external magnetic field, was developed. A series of computer simulations has been conducted to assess the performance of the proposed algorithm within the process of estimating electrical conductivity changes in the lungs, heart, and brain tissues captured in two-dimensional piecewise homogeneous chest and head models. The reconstructed conductivity distribution using the proposed method is compared with that using a conventional method based on Electrical Impedance Tomography (EIT. The acquired experience is discussed and the direction of further research is proposed.

  3. A Robust Identification of the Protein Standard Bands in Two-Dimensional Electrophoresis Gel Images

    Directory of Open Access Journals (Sweden)

    Serackis Artūras

    2017-12-01

    Full Text Available The aim of the investigation presented in this paper was to develop a software-based assistant for the protein analysis workflow. The prior characterization of the unknown protein in two-dimensional electrophoresis gel images is performed according to the molecular weight and isoelectric point of each protein spot estimated from the gel image before further sequence analysis by mass spectrometry. The paper presents a method for automatic and robust identification of the protein standard band in a two-dimensional gel image. In addition, the method introduces the identification of the positions of the markers, prepared by using pre-selected proteins with known molecular mass. The robustness of the method was achieved by using special validation rules in the proposed original algorithms. In addition, a self-organizing map-based decision support algorithm is proposed, which takes Gabor coefficients as image features and searches for the differences in preselected vertical image bars. The experimental investigation proved the good performance of the new algorithms included into the proposed method. The detection of the protein standard markers works without modification of algorithm parameters on two-dimensional gel images obtained by using different staining and destaining procedures, which results in different average levels of intensity in the images.

  4. Two-dimensional x-ray diffraction

    CERN Document Server

    He, Bob B

    2009-01-01

    Written by one of the pioneers of 2D X-Ray Diffraction, this useful guide covers the fundamentals, experimental methods and applications of two-dimensional x-ray diffraction, including geometry convention, x-ray source and optics, two-dimensional detectors, diffraction data interpretation, and configurations for various applications, such as phase identification, texture, stress, microstructure analysis, crystallinity, thin film analysis and combinatorial screening. Experimental examples in materials research, pharmaceuticals, and forensics are also given. This presents a key resource to resea

  5. A method of image improvement in three-dimensional imaging

    International Nuclear Information System (INIS)

    Suto, Yasuzo; Huang, Tewen; Furuhata, Kentaro; Uchino, Masafumi.

    1988-01-01

    In general, image interpolation is required when the surface configurations of such structures as bones and organs are three-dimensionally constructed from the multi-sliced images obtained by CT. Image interpolation is a processing method whereby an artificial image is inserted between two adjacent slices to make spatial resolution equal to slice resolution in appearance. Such image interpolation makes it possible to increase the image quality of the constructed three-dimensional image. In our newly-developed algorithm, we have converted the presently and subsequently sliced images to distance images, and generated the interpolation images from these two distance images. As a result, compared with the previous method, three-dimensional images with better image quality have been constructed. (author)

  6. Development of a low-noise, two-dimensional amplifier array

    International Nuclear Information System (INIS)

    Kishishita, Tetsuichi; Ikeda, Hirokazu; Sakumura, Takuto; Tamura, Ken-ichi; Takahashi, Tadayuki

    2009-01-01

    This paper describes the recent development of a low-noise, two-dimensional analog front-end ASIC for hybrid pixel imaging detectors. Based on the Open-IP LSI project, the ASIC is designed to meet a low-noise requirement of better than 100e - (rms) with self-triggering capability. The ASIC is intended for the readout of pixel sensors utilizing silicon (Si) and cadmium telluride (CdTe) as detector materials for spectroscopic imaging observations in the X-ray and gamma-ray regions. The readout chip consists of a 4x4 matrix of identical 270μmx270μm pixel cells and was implemented with TSMC 0.35-μm CMOS technology. Each pixel cell contains a charge-sensitive amplifier, pole-zero cancellation circuit, shaper, comparator, and peak hold circuit. Preliminary testing of the ASIC achieved an 88e - (rms) equivalent noise charge and a 25e - /pF noise slope with power consumption of 150μW per pixel.

  7. Two and three dimensional imaging of compact toroid plasmas using fast photography

    International Nuclear Information System (INIS)

    Englert, S.E.; Bell, D.E.; Coffey, S.K.

    1992-01-01

    As is discussed in a companion paper, Degnan el al, fast photography is used as a visual diagnostic tool for high energy plasma research at the Phillips Laboratory. Both, two dimensional and three dimensional images, are gathered by using nanosecond and microsecond range fast photography techniques. A set of microchannel plate cameras and a fast framing camera are used to record images of a compact toroid plasma during formation and acceleration stages. These images are subsequently digitized and enhanced to bring out detailed information of interest. This spatial information is combined with other diagnostic results as well as theoretical models in order to build a more complete picture of the fundamental physics associated with high-energy plasmas

  8. Two-dimensional position sensitive neutron detector

    Indian Academy of Sciences (India)

    The detector is a 3He + Kr filled multiwire proportional counter with charge division position readout and has a sensitive area of 345 mm × 345 mm, pixel size 5 mm × 5 mm, active depth 25 mm and is designed for efficiency of 70% for 4 Å neutrons. The detector is tested with 0.5 bar 3He + 1.5 bar krypton gas mixture in active ...

  9. Study on a Two-Dimensional Scanning Micro-Mirror and Its Application in a MOEMS Target Detector

    Directory of Open Access Journals (Sweden)

    Hu Huang

    2010-07-01

    Full Text Available A two-dimensional (2D scanning micro-mirror for target detection and measurement has been developed. This new micro-mirror is used in a MOEMS target detector to replace the conventional scanning detector. The micro-mirror is fabricated by MEMS process and actuated by a piezoelectric actuator. To achieve large deflection angles, the micro-mirror is excited in the resonance modes. It has two degrees of freedom and changes the direction of the emitted laser beam for a regional 2D scanning. For the deflection angles measurement, piezoresistors are integrated in the micro-mirror and the deflection angles of each direction can be detected independently and precisely. Based on the scanning micro-mirror and the phase-shift ranging technology, a MOEMS target detector has been developed in a size of 90 mm × 35 mm × 50 mm. The experiment shows that the target can be detected in the scanning field and the relative range and orientation can be measured by the MOEMS target detector. For the target distance up to 3 m with a field of view about 20º × 20º, the measurement resolution is about 10.2 cm in range, 0.15º in the horizontal direction and 0.22º in the vertical direction for orientation.

  10. Three dimensional imaging of surface geometry in SEM

    International Nuclear Information System (INIS)

    Slowko, W.

    1997-01-01

    A great advantage of scanning electron microscopy (SEM) is its ability of the surface topography in the way as a human eye is accustomed to see lights and shadows on macroobjects. However, SEM's can hardly display vertical dimensions of the structures. One of possible solutions is reconstruction of the surface profiles by directional detection of secondary electrons and proper signal processing. However, the surface profile still gives two dimensional information and the method should be extended to obtain fully three dimensional imaging. The extension consists in a simultaneous reconstruction of the surface profiles in two perpendicular directions (x and y) and their superposition. The solution proposed is based on a quadrupole detector system and a computer or analogue system for signal processing. Quantitative data of the surface topography can be displayed in many manners in the system of two or three co-ordinates with use of pseudo-colour for the altitude coding. (author)

  11. Coplanar-grid CdZnTe detector with three-dimensional position sensitivity

    International Nuclear Information System (INIS)

    Luke, P.N.; Amman, M.; Lee, J.S.; Yaver, H.

    1998-06-01

    A 3-dimensional position-sensitive coplanar-grid detector design for use with compound semiconductors is described. This detector design maintains the advantage of a coplanar-grid detector in which good energy resolution can be obtained from materials with poor charge transport. Position readout in two dimensions is accomplished using proximity-sensing electrodes adjacent to the electron-collecting grid electrode of the detector. Additionally, depth information is obtained by taking the ratio of the amplitudes of the collecting grid signal and the cathode signal. Experimental results from a prototype CdZnTe detector are presented

  12. A novel disk-type X-ray area imaging detector using radiophotoluminescence in silver-activated phosphate glass

    International Nuclear Information System (INIS)

    Kurobori, Toshio; Nakamura, Shoichi

    2012-01-01

    We report a novel two- and three-dimensional (2-D, 3-D) imaging detector based on the radiophotoluminescence (RPL) phenomenon in silver-activated phosphate glass (PG:Ag) and evaluate its dosimetric characteristics. A compact disk-type PG:Ag detector with a diameter of 80 mm was rotated at a rate of 400 rpm to read out the accumulated dose information and then remove the images for reuse. After X-ray exposure, three RPL dosimeter processes, i.e., preheating, reading, and erasing, were carried out with only a UV laser at 375 nm by adjusting the stepwise output levels. The 3-D images and dose distributions were rapidly reconstructed with a high spatial resolution of 1 μm and a sensitivity of 1 mGy.

  13. Three-dimensional phase-contrast X-ray microtomography with scanning–imaging X-ray microscope optics

    International Nuclear Information System (INIS)

    Takeuchi, Akihisa; Uesugi, Kentaro; Suzuki, Yoshio

    2013-01-01

    A novel three-dimensional X-ray microtomographic micro-imaging system which enables simultaneous measurement of differential phase contrast and absorption contrast has been developed. The optical system consists of a scanning microscope with one-dimensional focusing device and an imaging microscope with one-dimensional objective. A three-dimensional (3D) X-ray tomographic micro-imaging system has been developed. The optical system is based on a scanning–imaging X-ray microscope (SIXM) optics, which is a hybrid system consisting of a scanning microscope optics with a one-dimensional (1D) focusing (line-focusing) device and an imaging microscope optics with a 1D objective. In the SIXM system, each 1D dataset of a two-dimensional (2D) image is recorded independently. An object is illuminated with a line-focused beam. Positional information of the region illuminated by the line-focused beam is recorded with the 1D imaging microscope optics as line-profile data. By scanning the object with the line focus, 2D image data are obtained. In the same manner as for a scanning microscope optics with a multi-pixel detector, imaging modes such as phase contrast and absorption contrast can be arbitrarily configured after the image data acquisition. By combining a tomographic scan method and the SIXM system, quantitative 3D imaging is performed. Results of a feasibility study of the SIXM for 3D imaging are shown

  14. A detector system for two-dimensional, position-sensitive detection of neutrons and gamma quanta

    International Nuclear Information System (INIS)

    Scholz, A.

    1988-08-01

    While the well-known Anger Camera utilizes a large number of photomultiplier tubes, which are arranged in a regular array behind a scintillation crystal, the new detector system makes use of electron optics to transfer the scintillation image of a large scintillation crystal (Li-6-glass) onto a small position detector. Because of this, only few photodetectors are required for position readout, associated with only a small number of amplifier chains and a very simple position reconstruction algorithm. The reduced complexity of the readout electronics ultimately leads to an improved maintainability and reliability of the detector system. A prototype of the new detector system was built and tested. After giving an overview on already known and realized detector configurations, the basic considerations, which led to the final detector design, will be explained. Different methods of detector readout and position determination are discussed. Measurement results which were obtained with the prototype detector system are presented and explained by means of simulation calculations. (orig./HP) [de

  15. CdZnTe detectors for gamma-ray Burst ArcSecond Imaging and Spectroscopy (BASIS)

    International Nuclear Information System (INIS)

    Stahle, C.M.; Palmer, D.; Bartlett, L.M.; Parsons, A.; Shi Zhiqing; Lisse, C.M.; Sappington, C.; Cao, N.; Shu, P.; Gehrels, N.; Teegarden, B.; Birsa, F.; Singh, S.; Odom, J.; Hanchak, C.; Tueller, J.; Barthelmy, S.; Krizmanic, J.; Barbier, L.

    1996-01-01

    A CdZnTe detector array is being developed for the proposed gamma-ray Burst ArcSecond Imaging and Spectroscopy (BASIS) spaceflight mission to accurately locate gamma-ray bursts, determine their distance scale, and measure the physical characteristics of the emission region. Two-dimensional strip detectors with 100 μm pitch have been fabricated and wire bonded to readout electronics to demonstrate the ability to localize 60 and 122 keV gamma-rays to less than 100 μm. Radiation damage studies on a CdZnTe detector exposed to MeV neutrons showed a small amount of activation but no detector performance degradation for fluences up to 10 10 neutrons/cm 2 . A 1 x 1 in. CdZnTe detector has also been flown on a balloon payload at 115 000 ft in order to measure the CdZnTe background rates. (orig.)

  16. Electronic noise in CT detectors: Impact on image noise and artifacts.

    Science.gov (United States)

    Duan, Xinhui; Wang, Jia; Leng, Shuai; Schmidt, Bernhard; Allmendinger, Thomas; Grant, Katharine; Flohr, Thomas; McCollough, Cynthia H

    2013-10-01

    The objective of our study was to evaluate in phantoms the differences in CT image noise and artifact level between two types of commercial CT detectors: one with distributed electronics (conventional) and one with integrated electronics intended to decrease system electronic noise. Cylindric water phantoms of 20, 30, and 40 cm in diameter were scanned using two CT scanners, one equipped with integrated detector electronics and one with distributed detector electronics. All other scanning parameters were identical. Scans were acquired at four tube potentials and 10 tube currents. Semianthropomorphic phantoms were scanned to mimic the shoulder and abdominal regions. Images of two patients were also selected to show the clinical values of the integrated detector. Reduction of image noise with the integrated detector depended on phantom size, tube potential, and tube current. Scans that had low detected signal had the greatest reductions in noise, up to 40% for a 30-cm phantom scanned using 80 kV. This noise reduction translated into up to 50% in dose reduction to achieve equivalent image noise. Streak artifacts through regions of high attenuation were reduced by up to 45% on scans obtained using the integrated detector. Patient images also showed superior image quality for the integrated detector. For the same applied radiation level, the use of integrated electronics in a CT detector showed a substantially reduced level of electronic noise, resulting in reductions in image noise and artifacts, compared with detectors having distributed electronics.

  17. A Review of Surface Deformation and Strain Measurement Using Two-Dimensional Digital Image Correlation

    Directory of Open Access Journals (Sweden)

    Khoo Sze-Wei

    2016-09-01

    Full Text Available Among the full-field optical measurement methods, the Digital Image Correlation (DIC is one of the techniques which has been given particular attention. Technically, the DIC technique refers to a non-contact strain measurement method that mathematically compares the grey intensity changes of the images captured at two different states: before and after deformation. The measurement can be performed by numerically calculating the displacement of speckles which are deposited on the top of object’s surface. In this paper, the Two-Dimensional Digital Image Correlation (2D-DIC is presented and its fundamental concepts are discussed. Next, the development of the 2D-DIC algorithms in the past 33 years is reviewed systematically. The improvement of 2DDIC algorithms is presented with respect to two distinct aspects: their computation efficiency and measurement accuracy. Furthermore, analysis of the 2D-DIC accuracy is included, followed by a review of the DIC applications for two-dimensional measurements.

  18. Assessment of array scintillation detector for follicle thyroid 2-d image acquisition using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Silva, Carlos Borges da; Braz, Delson

    2008-01-01

    Full text: This work presents an innovative study to find out the adequate scintillation inorganic detector array to be used coupled to a specific light photo sensor, a charge coupled device (CCD), through a fiber optic plate. The goal is to choose the type of detector that fits a 2-dimensional imaging acquisition of a cell thyroid tissue application with high resolution and detection efficiency in order to map a follicle image using gamma radiation emission. A point or volumetric source-detector simulation by using a MCNP4B general code, considering different source energies, detector materials and geometry including pixel sizes and reflector types was performed. In this study, simulations were performed for 7 x 7, 31 x 31 and 127 x 127 arrays using CsI(Tl), BGO, CdWO 4 , LSO, GOS and GSO scintillation detectors with pixel dimensions ranging from 1 x 1 cm 2 to 10 x 10 μm 2 and radiation thickness ranging from 1 mm to 10 mm. The effect of all these parameters was investigated to find the best source-detector system that results in an image with the best contrast details. The results showed that it is possible to design a specific imaging system that allows searching for in-vitro studies, specifically in radiobiology applied to endocrine physiology. A 2D image of two thyroid follicles simulated by using MCNP4B code is shown

  19. Three-dimensional cascaded system analysis of a 50 µm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis.

    Science.gov (United States)

    Zhao, C; Vassiljev, N; Konstantinidis, A C; Speller, R D; Kanicki, J

    2017-03-07

    High-resolution, low-noise x-ray detectors based on the complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology have been developed and proposed for digital breast tomosynthesis (DBT). In this study, we evaluated the three-dimensional (3D) imaging performance of a 50 µm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). The two-dimensional (2D) angle-dependent modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) were experimentally characterized and modeled using the cascaded system analysis at oblique incident angles up to 30°. The cascaded system model was extended to the 3D spatial frequency space in combination with the filtered back-projection (FBP) reconstruction method to calculate the 3D and in-plane MTF, NNPS and DQE parameters. The results demonstrate that the beam obliquity blurs the 2D MTF and DQE in the high spatial frequency range. However, this effect can be eliminated after FBP image reconstruction. In addition, impacts of the image acquisition geometry and detector parameters were evaluated using the 3D cascaded system analysis for DBT. The result shows that a wider projection angle range (e.g.  ±30°) improves the low spatial frequency (below 5 mm -1 ) performance of the CMOS APS detector. In addition, to maintain a high spatial resolution for DBT, a focal spot size of smaller than 0.3 mm should be used. Theoretical analysis suggests that a pixelated scintillator in combination with the 50 µm pixel pitch CMOS APS detector could further improve the 3D image resolution. Finally, the 3D imaging performance of the CMOS APS and an indirect amorphous silicon (a-Si:H) thin-film transistor (TFT) passive pixel sensor (PPS) detector was simulated and compared.

  20. New Approach for Segmentation and Quantification of Two-Dimensional Gel Electrophoresis Images

    DEFF Research Database (Denmark)

    Anjo, Antonio dos; Laurell Blom Møller, Anders; Ersbøll, Bjarne Kjær

    2011-01-01

    Motivation: Detection of protein spots in two-dimensional gel electrophoresis images (2-DE) is a very complex task and current approaches addressing this problem still suffer from significant shortcomings. When quantifying a spot, most of the current software applications include a lot of backgro...

  1. Musculoskeletal imaging with a prototype photon-counting detector.

    Science.gov (United States)

    Gruber, M; Homolka, P; Chmeissani, M; Uffmann, M; Pretterklieber, M; Kainberger, F

    2012-01-01

    To test a digital imaging X-ray device based on the direct capture of X-ray photons with pixel detectors, which are coupled with photon-counting readout electronics. The chip consists of a matrix of 256 × 256 pixels with a pixel pitch of 55 μm. A monolithic image of 11.2 cm × 7 cm was obtained by the consecutive displacement approach. Images of embalmed anatomical specimens of eight human hands were obtained at four different dose levels (skin dose 2.4, 6, 12, 25 μGy) with the new detector, as well as with a flat-panel detector. The overall rating scores for the evaluated anatomical regions ranged from 5.23 at the lowest dose level, 6.32 at approximately 6 μGy, 6.70 at 12 μGy, to 6.99 at the highest dose level with the photon-counting system. The corresponding rating scores for the flat-panel detector were 3.84, 5.39, 6.64, and 7.34. When images obtained at the same dose were compared, the new system outperformed the conventional DR system at the two lowest dose levels. At the higher dose levels, there were no significant differences between the two systems. The photon-counting detector has great potential to obtain musculoskeletal images of excellent quality at very low dose levels.

  2. Semi-automated analysis of three-dimensional track images

    International Nuclear Information System (INIS)

    Meesen, G.; Poffijn, A.

    2001-01-01

    In the past, three-dimensional (3-d) track images in solid state detectors were difficult to obtain. With the introduction of the confocal scanning laser microscope it is now possible to record 3-d track images in a non-destructive way. These 3-d track images can latter be used to measure typical track parameters. Preparing the detectors and recording the 3-d images however is only the first step. The second step in this process is enhancing the image quality by means of deconvolution techniques to obtain the maximum possible resolution. The third step is extracting the typical track parameters. This can be done on-screen by an experienced operator. For large sets of data however, this manual technique is not desirable. This paper will present some techniques to analyse 3-d track data in an automated way by means of image analysis routines. Advanced thresholding techniques guarantee stable results in different recording situations. By using pre-knowledge about the track shape, reliable object identification is obtained. In case of ambiguity, manual intervention is possible

  3. Generalized two-dimensional (2D) linear system analysis metrics (GMTF, GDQE) for digital radiography systems including the effect of focal spot, magnification, scatter, and detector characteristics.

    Science.gov (United States)

    Jain, Amit; Kuhls-Gilcrist, Andrew T; Gupta, Sandesh K; Bednarek, Daniel R; Rudin, Stephen

    2010-03-01

    The MTF, NNPS, and DQE are standard linear system metrics used to characterize intrinsic detector performance. To evaluate total system performance for actual clinical conditions, generalized linear system metrics (GMTF, GNNPS and GDQE) that include the effect of the focal spot distribution, scattered radiation, and geometric unsharpness are more meaningful and appropriate. In this study, a two-dimensional (2D) generalized linear system analysis was carried out for a standard flat panel detector (FPD) (194-micron pixel pitch and 600-micron thick CsI) and a newly-developed, high-resolution, micro-angiographic fluoroscope (MAF) (35-micron pixel pitch and 300-micron thick CsI). Realistic clinical parameters and x-ray spectra were used. The 2D detector MTFs were calculated using the new Noise Response method and slanted edge method and 2D focal spot distribution measurements were done using a pin-hole assembly. The scatter fraction, generated for a uniform head equivalent phantom, was measured and the scatter MTF was simulated with a theoretical model. Different magnifications and scatter fractions were used to estimate the 2D GMTF, GNNPS and GDQE for both detectors. Results show spatial non-isotropy for the 2D generalized metrics which provide a quantitative description of the performance of the complete imaging system for both detectors. This generalized analysis demonstrated that the MAF and FPD have similar capabilities at lower spatial frequencies, but that the MAF has superior performance over the FPD at higher frequencies even when considering focal spot blurring and scatter. This 2D generalized performance analysis is a valuable tool to evaluate total system capabilities and to enable optimized design for specific imaging tasks.

  4. Two- and three-dimensional CT analysis of ankle fractures

    International Nuclear Information System (INIS)

    Magid, D.; Fishman, E.K.; Ney, D.R.; Kuhlman, J.E.

    1988-01-01

    CT with coronal and sagittal reformatting (two-dimensional CT) and animated volumetric image rendering (three-dimensional CT) was used to assess ankle fractures. Partial volume limits transaxial CT in assessments of horizontally oriented structures. Two-dimensional CT, being orthogonal to the plafond, superior mortise, talar dome, and tibial epiphysis, often provides the most clinically useful images. Two-dimensional CT is most useful in characterizing potentially confusing fractures, such as Tillaux (anterior tubercle), triplane, osteochondral talar dome, or nondisplaced talar neck fractures, and it is the best study to confirm intraarticular fragments. Two-and three-dimensional CT best indicate the percentage of articular surface involvement and best demonstrate postoperative results or complications (hardware migration, residual step-off, delayed union, DJD, AVN, etc). Animated three-dimensional images are the preferred means of integrating the two-dimensional findings for surgical planning, as these images more closely simulate the clinical problem

  5. Four-dimensional image display for associated particle imaging

    International Nuclear Information System (INIS)

    Headley, G.; Beyerle, A.; Durkee, R.; Hurley, P.; Tunnell, L.

    1994-01-01

    Associated particle imaging (API) is a three-dimensional neutron gamma imaging technique which provides both spatial and spectral information about an unknown. A local area network consisting of a UNIX fileserver and multiple DOS workstations has been chosen to perform the data acquisition and display functions. The data are acquired with a CAMAC system, stored in list mode, and sorted on the fileserver for display on the DOS workstations. Three of the display PCs, interacting with the fileserver, provide coordinated views as the operator ''slices'' the image. The operator has a choice of: a one-dimensional shadowgram from any side, two-dimensional shadowgrams from any side; a three-dimensional view (either perspective projection or stereoscopic). A common color scheme is used to carry energy information into the spatial images. ((orig.))

  6. A high-spatial-resolution three-dimensional detector array for 30-200 keV X-rays based on structured scintillators

    DEFF Research Database (Denmark)

    Olsen, Ulrik Lund; Schmidt, Søren; Poulsen, Henning Friis

    2008-01-01

    A three-dimensional X-ray detector for imaging 30-200 keV photons is described. It comprises a set of semi-transparent structured scintillators, where each scintillator is a regular array of waveguides in silicon, and with pores filled with CsI. The performance of the detector is described...

  7. Positron annihilation imaging device using multiple offset rings of detectors

    International Nuclear Information System (INIS)

    Thompson, C.J.

    1981-01-01

    This patent application relates to a positron annihilation imaging device comprising two or more coaxial circular arrays of detectors (2,2'), with the detectors in one array angularly offset with respect to the detectors in the adjacent array to detect more than one tomographic image simultaneously through different cross-sections of a patient. (author)

  8. High resolution, position sensitive detector for energetic particle beams

    International Nuclear Information System (INIS)

    Marsh, E.P.; Strathman, M.D.; Reed, D.A.; Odom, R.W.; Morse, D.H.; Pontau, A.E.

    1993-01-01

    The performance and design of an imaging position sensitive, particle beam detector will be presented. The detector is minimally invasive, operates a wide dynamic range (>10 10 ), and exhibits high spatial resolution. The secondary electrons produced when a particle beam passes through a thin foil are imaged using stigmatic ion optics onto a two-dimensional imaging detector. Due to the low scattering cross section of the 6 nm carbon foil the detector is a minimal perturbation on the primary beam. A prototype detector with an image resolution of approximately 5 μm for a field of view of 1 mm has been reported. A higher resolution detector for imaging small beams (<50 μm) with an image resolution of better than 0.5 μm has since been developed and its design is presented. (orig.)

  9. Simulation study of two-energy X-ray fluorescence holograms reconstruction algorithm to remove twin images

    International Nuclear Information System (INIS)

    Xie Honglan; Hu Wen; Luo Hongxin; Deng Biao; Du Guohao; Xue Yanling; Chen Rongchang; Shi Shaomeng; Xiao Tiqiao

    2008-01-01

    Unlike traditional outside-source holography, X-ray fluorescence holography is carded out with fluorescent atoms in a sample as source light for holographic imaging. With the method, three-dimensional arrangement of atoms into crystals can be observed obviously. However, just like traditional outside-source holography, X-ray fluorescence holography suffers from the inherent twin-image problem, too. With a 27-Fe-atoms cubic lattice as model, we discuss in this paper influence of the photon energy of incident source in removing twin images in reconstructed atomic images by numerical simulation and reconstruction with two-energy X-ray fluorescence holography. The results indicate that incident X-rays of nearer energies have better effect of removing twin images. In the detector of X-ray holography, minimum difference of the two incident energies depends on energy resolution of the monochromator and detector, and for inside source X-ray holography, minimum difference of the two incident energies depends on difference of two neighboring fluorescent energies emitting from the element and energy resolution of detector. The spatial resolution of atomic images increases with the incident energies. This is important for experiments of X-ray fluorescence holography, which is being developed on Shanghai Synchrotron Radiation Facility. (authors)

  10. Two-dimensional shielding benchmarks for iron at YAYOI, (1)

    International Nuclear Information System (INIS)

    Oka, Yoshiaki; An, Shigehiro; Kasai, Shigeru; Miyasaka, Shun-ichi; Koyama, Kinji.

    The aim of this work is to assess the collapsed neutron and gamma multigroup cross sections for two dimensional discrete ordinate transport code. Two dimensional distributions of neutron flux and gamma ray dose through a 70cm thick and 94cm square iron shield were measured at the fast neutron source reactor ''YAYOI''. The iron shield was placed over the lead reflector in the vertical experimental column surrounded by heavy concrete wall. The detectors used in this experiment were threshold detectors In, Ni, Al, Mg, Fe and Zn, sandwitch resonance detectors Au, W and Co, activation foils Au for neutrons and thermoluminescence detectors for gamma ray dose. The experimental results were compared with the calculated ones by the discrete ordinate transport code ANISN and TWOTRAN. The region-wise, coupled neutron-gamma multigroup cross-sections (100n+20gamma, EURLIB structure) were generated from ENDF/B-IV library for neutrons and POPOP4 library for gamma-ray production cross-sections by using the code system RADHEAT. The effective microscopic neutron cross sections were obtained from the infinite dilution values applying ABBN type self-shielding factors. The gamma ray production multigroup cross-sections were calculated from these effective microscopic neutron cross-sections. For two-dimensional calculations the group constants were collapsed into 10 neutron groups and 3 gamma groups by using ANISN. (auth.)

  11. Rapid portal imaging with a high-efficiency, large field-of-view detector.

    Science.gov (United States)

    Mosleh-Shirazi, M A; Evans, P M; Swindell, W; Symonds-Tayler, J R; Webb, S; Partridge, M

    1998-12-01

    The design, construction, and performance evaluation of an electronic portal imaging device (EPID) are described. The EPID has the same imaging geometry as the current mirror-based systems except for the x-ray detection stage, where a two-dimensional (2D) array of 1 cm thick CsI(Tl) detector elements are utilized. The approximately 18% x-ray quantum efficiency of the scintillation detector and its 30 x 40 cm2 field-of-view at the isocenter are greater than other area-imaging EPIDs. The imaging issues addressed are theoretical and measured signal-to-noise ratio, linearity of the imaging chain, influence of frame-summing on image quality and image calibration. Portal images of test objects and a humanoid phantom are used to measure the performance of the system. An image quality similar to the current devices is achieved but with a lower dose. With approximately 1 cGy dose delivered by a 6 MV beam, a 2 mm diam structure of 1.3% contrast and an 18 mm diam object of 0.125% contrast can be resolved without using image-enhancement methods. A spatial resolution of about 2 mm at the isocenter is demonstrated. The capability of the system to perform fast sequential imaging, synchronized with the radiation pulses, makes it suitable for patient motion studies and verification of intensity-modulated beams as well as its application in cone-beam megavoltage computed tomography.

  12. Two-dimensional spectrophotometry of planetary nebulae by CCD imaging

    International Nuclear Information System (INIS)

    Jacoby, G.H.; Africano, J.L.; Quigley, R.J.; Western Washington Univ., Bellingham, WA)

    1987-01-01

    The spatial distribution of the electron temperature and density and the ionic abundances of O(+), O(2+), N(+), and S(+) have been derived from CCD images of the planetary nebulae NGC 40 and NGC 6826 taken in the important emission lines of forbidden O II, forbidden O III, H-beta, forbidden N II, and forbidden S II. The steps required in the derivation of the absolute fluxes, line, ratios, and ionic abundances are outlined and then discussed in greater detail. The results show that the CCD imaging technique for two-dimensional spectrophotometry can effectively compete with classical spectrophotometry, providing the added benefits of complete spatial coverage at seeing-disk spatial resolution. The multiplexing in the spatial dimension, however, results in a loss of spectral information, since only one emission line is observed at any one time. 37 references

  13. Two-Dimensional Spatial Imaging of Charge Transport in Germanium Crystals at Cryogenic Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Moffatt, Robert [Stanford Univ., CA (United States)

    2016-03-01

    In this dissertation, I describe a novel apparatus for studying the transport of charge in semiconductors at cryogenic temperatures. The motivation to conduct this experiment originated from an asymmetry observed between the behavior of electrons and holes in the germanium detector crystals used by the Cryogenic Dark Matter Search (CDMS). This asymmetry is a consequence of the anisotropic propagation of electrons in germanium at cryogenic temperatures. To better model our detectors, we incorporated this effect into our Monte Carlo simulations of charge transport. The purpose of the experiment described in this dissertation is to test those models in detail. Our measurements have allowed us to discover a shortcoming in our most recent Monte Carlo simulations of electrons in germanium. This discovery would not have been possible without the measurement of the full, two-dimensional charge distribution, which our experimental apparatus has allowed for the first time at cryogenic temperatures.

  14. High resolution, position sensitive detector for energetic particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, E P [Charles Evans and Associates, Redwood City, CA (United States); Strathman, M D [Charles Evans and Associates, Redwood City, CA (United States); Reed, D A [Charles Evans and Associates, Redwood City, CA (United States); Odom, R W [Charles Evans and Associates, Redwood City, CA (United States); Morse, D H [Sandia National Labs., Livermore, CA (United States); Pontau, A E [Sandia National Labs., Livermore, CA (United States)

    1993-05-01

    The performance and design of an imaging position sensitive, particle beam detector will be presented. The detector is minimally invasive, operates a wide dynamic range (>10[sup 10]), and exhibits high spatial resolution. The secondary electrons produced when a particle beam passes through a thin foil are imaged using stigmatic ion optics onto a two-dimensional imaging detector. Due to the low scattering cross section of the 6 nm carbon foil the detector is a minimal perturbation on the primary beam. A prototype detector with an image resolution of approximately 5 [mu]m for a field of view of 1 mm has been reported. A higher resolution detector for imaging small beams (<50 [mu]m) with an image resolution of better than 0.5 [mu]m has since been developed and its design is presented. (orig.)

  15. Two-dimensional pixel image lag simulation and optimization in a 4-T CMOS image sensor

    Energy Technology Data Exchange (ETDEWEB)

    Yu Junting; Li Binqiao; Yu Pingping; Xu Jiangtao [School of Electronics Information Engineering, Tianjin University, Tianjin 300072 (China); Mou Cun, E-mail: xujiangtao@tju.edu.c [Logistics Management Office, Hebei University of Technology, Tianjin 300130 (China)

    2010-09-15

    Pixel image lag in a 4-T CMOS image sensor is analyzed and simulated in a two-dimensional model. Strategies of reducing image lag are discussed from transfer gate channel threshold voltage doping adjustment, PPD N-type doping dose/implant tilt adjustment and transfer gate operation voltage adjustment for signal electron transfer. With the computer analysis tool ISE-TCAD, simulation results show that minimum image lag can be obtained at a pinned photodiode n-type doping dose of 7.0 x 10{sup 12} cm{sup -2}, an implant tilt of -2{sup 0}, a transfer gate channel doping dose of 3.0 x 10{sup 12} cm{sup -2} and an operation voltage of 3.4 V. The conclusions of this theoretical analysis can be a guideline for pixel design to improve the performance of 4-T CMOS image sensors. (semiconductor devices)

  16. Imaging detectors and electronics - A view of the future

    International Nuclear Information System (INIS)

    Spieler, Helmuth

    2004-01-01

    Imaging sensors and readout electronics have made tremendous strides in the past two decades. The application of modern semiconductor fabrication techniques and the introduction of customized monolithic integrated circuits have made large scale imaging systems routine in high energy physics. This technology is now finding its way into other areas, such as space missions, synchrotron light sources, and medical imaging. I review current developments and discuss the promise and limits of new technologies. Several detector systems are described as examples of future trends. The discussion emphasizes semiconductor detector systems, but I also include recent developments for large-scale superconducting detector arrays

  17. Integration of fringe projection and two-dimensional digital image correlation for three-dimensional displacements measurements

    Science.gov (United States)

    Felipe-Sesé, Luis; López-Alba, Elías; Siegmann, Philip; Díaz, Francisco A.

    2016-12-01

    A low-cost approach for three-dimensional (3-D) full-field displacement measurement is applied for the analysis of large displacements involved in two different mechanical events. The method is based on a combination of fringe projection and two-dimensional digital image correlation (DIC) techniques. The two techniques have been employed simultaneously using an RGB camera and a color encoding method; therefore, it is possible to measure in-plane and out-of-plane displacements at the same time with only one camera even at high speed rates. The potential of the proposed methodology has been employed for the analysis of large displacements during contact experiments in a soft material block. Displacement results have been successfully compared with those obtained using a 3D-DIC commercial system. Moreover, the analysis of displacements during an impact test on a metal plate was performed to emphasize the application of the methodology for dynamics events. Results show a good level of agreement, highlighting the potential of FP + 2D DIC as low-cost alternative for the analysis of large deformations problems.

  18. The Edge Detectors Suitable for Retinal OCT Image Segmentation

    Directory of Open Access Journals (Sweden)

    Su Luo

    2017-01-01

    Full Text Available Retinal layer thickness measurement offers important information for reliable diagnosis of retinal diseases and for the evaluation of disease development and medical treatment responses. This task critically depends on the accurate edge detection of the retinal layers in OCT images. Here, we intended to search for the most suitable edge detectors for the retinal OCT image segmentation task. The three most promising edge detection algorithms were identified in the related literature: Canny edge detector, the two-pass method, and the EdgeFlow technique. The quantitative evaluation results show that the two-pass method outperforms consistently the Canny detector and the EdgeFlow technique in delineating the retinal layer boundaries in the OCT images. In addition, the mean localization deviation metrics show that the two-pass method caused the smallest edge shifting problem. These findings suggest that the two-pass method is the best among the three algorithms for detecting retinal layer boundaries. The overall better performance of Canny and two-pass methods over EdgeFlow technique implies that the OCT images contain more intensity gradient information than texture changes along the retinal layer boundaries. The results will guide our future efforts in the quantitative analysis of retinal OCT images for the effective use of OCT technologies in the field of ophthalmology.

  19. Model independent search for new particles in two-dimensional mass space using events with missing energy, two jets and two leptons with the CMS detector

    CERN Document Server

    AUTHOR|(CDS)2080070; Hebbeker, Thomas

    2017-07-07

    The discovery of a new particle consistent with the standard model Higgs boson at the Large Hadron Collider in 2012 completed the standard model of particle physics (SM). Despite its remarkable success many questions remain unexplained. Numerous theoretical models, predicting the existence of new heavy particles, provide answers to these unresolved questions and are tested at high energy experiments such as the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC). In this thesis a model independent search method for new particles in two-dimensional mass space in events with missing transverse energy is presented using 19.7 $\\mbox{fb}^{-1}$ of proton-proton collision data recorded by the CMS detector at a centre of mass energy $\\sqrt{s}$ = 8 TeV at the LHC. The analysis searches for signatures of pair-produced new heavy particles $\\mbox{T}^\\prime$ which decay further into unknown heavy particles $\\mbox{W}^\\prime$ and SM quarks $q$ ($\\mbox{T}^\\prime\\overline{\\mbox{T}^\\prime} \\rightarrow {...

  20. Design and implementation of an array of micro-electrochemical detectors for two-dimensional liquid chromatography--proof of principle.

    Science.gov (United States)

    Abia, Jude A; Putnam, Joel; Mriziq, Khaled; Guiochon, Georges A

    2010-03-05

    Simultaneous two-dimensional liquid chromatography (2D-LC) is an implementation of two-dimensional liquid chromatography which has the potential to provide very fast, yet highly efficient separations. It is based on the use of time x space and space x space separation systems. The basic principle of this instrument has been validated long ago by the success of two-dimensional thin layer chromatography. The construction of a pressurized wide and flat column (100 mm x 100 mm x 1 mm) operated under an inlet pressure of up to 50 bar was described previously. However, to become a modern analytical method, simultaneous 2D-LC requires the development of detectors suitable for the monitoring of the composition of the eluent of this pressurized planar, wide column. An array of five equidistant micro-electrochemical sensors was built for this purpose and tested. Each sensor is a three-electrode system, with the working electrode being a 25 microm polished platinum micro-electrode. The auxiliary electrode is a thin platinum wire and the reference electrode an Ag/AgCl (3M sat. KCl) electrode. In this first implementation, proof of principle is demonstrated, but the final instrument will require a much larger array. 2010 Elsevier B.V. All rights reserved.

  1. Smile detectors correlation

    Science.gov (United States)

    Yuksel, Kivanc; Chang, Xin; Skarbek, Władysław

    2017-08-01

    The novel smile recognition algorithm is presented based on extraction of 68 facial salient points (fp68) using the ensemble of regression trees. The smile detector exploits the Support Vector Machine linear model. It is trained with few hundreds exemplar images by SVM algorithm working in 136 dimensional space. It is shown by the strict statistical data analysis that such geometric detector strongly depends on the geometry of mouth opening area, measured by triangulation of outer lip contour. To this goal two Bayesian detectors were developed and compared with SVM detector. The first uses the mouth area in 2D image, while the second refers to the mouth area in 3D animated face model. The 3D modeling is based on Candide-3 model and it is performed in real time along with three smile detectors and statistics estimators. The mouth area/Bayesian detectors exhibit high correlation with fp68/SVM detector in a range [0:8; 1:0], depending mainly on light conditions and individual features with advantage of 3D technique, especially in hard light conditions.

  2. A comparison of interest point and region detectors on structured, range and texture images

    DEFF Research Database (Denmark)

    Kazmi, Wajahat; Andersen, Hans Jørgen

    2015-01-01

    )) and corner based detectors (such as Hessian and Harris with both Affine/Laplace variants, SURF with determinant of Hessian based corners and SIFT with difference of Gaussians) acquired more than 90% mean average precision, whereas on range images, homogeneous region detector did not work well. TLR offered...... and textured images. It is also shown that in a bi-channel approach, combining surface and edge regions (MSER and TLR) boosts the overall performance. Among the descriptors, SIFT and SURF generally offer higher performance but low dimensional descriptors such as Steerable Filters follow closely....

  3. Two dimensional CCD [charged coupled device] arrays as parallel detectors in electron energy loss and x-ray wavelength dispersive spectroscopy

    International Nuclear Information System (INIS)

    Zaluzec, N.J.

    1988-08-01

    Parallel detection systems for spectroscopy have generally been based upon linear detector arrays. Replacing the linear arrays with two dimensional systems yields more complicated devices; however, there are corresponding benefits which can be realized for both x-ray and electron energy loss spectroscopy. The operational design of these systems, as well as preliminary results from the construction of such a device used for electron spectroscopy, are presented. 10 refs., 8 figs

  4. Visual grading analysis of digital neonatal chest phantom X-ray images: Impact of detector type, dose and image processing on image quality.

    Science.gov (United States)

    Smet, M H; Breysem, L; Mussen, E; Bosmans, H; Marshall, N W; Cockmartin, L

    2018-07-01

    To evaluate the impact of digital detector, dose level and post-processing on neonatal chest phantom X-ray image quality (IQ). A neonatal phantom was imaged using four different detectors: a CR powder phosphor (PIP), a CR needle phosphor (NIP) and two wireless CsI DR detectors (DXD and DRX). Five different dose levels were studied for each detector and two post-processing algorithms evaluated for each vendor. Three paediatric radiologists scored the images using European quality criteria plus additional questions on vascular lines, noise and disease simulation. Visual grading characteristics and ordinal regression statistics were used to evaluate the effect of detector type, post-processing and dose on VGA score (VGAS). No significant differences were found between the NIP, DXD and CRX detectors (p>0.05) whereas the PIP detector had significantly lower VGAS (pProcessing did not influence VGAS (p=0.819). Increasing dose resulted in significantly higher VGAS (plevels but not image post-processing changes. VGA showed a DAK/image value above which perceived IQ did not improve, potentially useful for commissioning. • A VGA study detects IQ differences between detectors and dose levels. • The NIP detector matched the VGAS of the CsI DR detectors. • VGA data are useful in setting initial detector air kerma level. • Differences in NNPS were consistent with changes in VGAS.

  5. The data acquisition system for the Leeds Infirmary MWPC X-ray imaging detector

    International Nuclear Information System (INIS)

    Quinton, S.; Gibbings, D.; Jones, D.; Norton, H.

    1979-10-01

    An electronic system is described which is designed to acquire and process data from a MWPC X-ray imaging detector. Two dimensional information from the chamber is obtained by using cathode plane delay-line readout. A single crate CAMAC assembly is used as the chamber-computer interface. The use of control source units for the delay line scalers and TV display driver functions together with an intermediate memory in the crate allows input data rates up to 1MHz and TV display facilities without constant computer refreshing. (author)

  6. A high-speed computerized tomography image reconstruction using direct two-dimensional Fourier transform method

    International Nuclear Information System (INIS)

    Niki, Noboru; Mizutani, Toshio; Takahashi, Yoshizo; Inouye, Tamon.

    1983-01-01

    The nescessity for developing real-time computerized tomography (CT) aiming at the dynamic observation of organs such as hearts has lately been advocated. It is necessary for its realization to reconstruct the images which are markedly faster than present CTs. Although various reconstructing methods have been proposed so far, the method practically employed at present is the filtered backprojection (FBP) method only, which can give high quality image reconstruction, but takes much computing time. In the past, the two-dimensional Fourier transform (TFT) method was regarded as unsuitable to practical use because the quality of images obtained was not good, in spite of the promising method for high speed reconstruction because of its less computing time. However, since it was revealed that the image quality by TFT method depended greatly on interpolation accuracy in two-dimensional Fourier space, the authors have developed a high-speed calculation algorithm that can obtain high quality images by pursuing the relationship between the image quality and the interpolation method. In this case, radial data sampling points in Fourier space are increased to β-th power of 2 times, and the linear or spline interpolation is used. Comparison of this method with the present FBP method resulted in the conclusion that the image quality is almost the same in practical image matrix, the computational time by TFT method becomes about 1/10 of FBP method, and the memory capacity also reduces by about 20 %. (Wakatsuki, Y.)

  7. Measurement of the presampled two-dimensional modulation transfer function of digital imaging systems

    International Nuclear Information System (INIS)

    Fetterly, Kenneth A.; Hangiandreou, Nicholas J.; Schueler, Beth A.; Ritenour, E. Russell

    2002-01-01

    The purpose of this work was to develop methods to measure the presampled two-dimensional modulation transfer function (2D MTF) of digital imaging systems. A custom x-ray 'point source' phantom was created by machining 256 holes with diameter 0.107 mm through a 0.5-mm-thick copper plate. The phantom was imaged several times, resulting in many images of individual x-ray 'spots'. The center of each spot (with respect to the pixel matrix) was determined to subpixel accuracy by fitting each spot to a 2D Gaussian function. The subpixel spot center locations were used to create a 5x oversampled system point spread function (PSF), which characterizes the optical and electrical properties of the system and is independent of the pixel sampling of the original image. The modulus of the Fourier transform of the PSF was calculated. Next, the Fourier function was normalized to the zero frequency value. Finally, the Fourier transform function was divided by the first-order Bessel function that defined the frequency content of the holes, resulting in the presampled 2D MTF. The presampled 2D MTF of a 0.1 mm pixel pitch computed radiography system and 0.2 mm pixel pitch flat panel digital imaging system that utilized a cesium iodide scintillator was measured. Comparison of the axial components of the 2D MTF to one-dimensional MTF measurements acquired using an edge device method demonstrated that the two methods produced consistent results

  8. A low noise ASIC for two dimensional neutron gas detector with performance of high spatial resolution (Contract research)

    International Nuclear Information System (INIS)

    Yamagishi, Hideshi; Toh, Kentaro; Nakamura, Tatsuya; Sakasai, Kaoru; Soyama, Kazuhiko

    2012-02-01

    An ASD-ASIC (Amplifier-Shaper-Discriminator ASIC) with fast response and low noise performances has been designed for two-dimensional position sensitive neutron gas detectors (InSPaD). The InSPaD is a 2D neutron detector system with 3 He gas and provides a high spatial resolution by making distinction between proton and triton particles generated in the gas chamber. The new ASD-ASIC is required to have very low noise, a wide dynamic range, good output linearity and high counting rate. The new ASD-ASIC has been designed by using CMOS and consisted of 64-channel ASDs, a 16-channel multiplexer with LVTTL drivers and sum amplifier system for summing all analog signals. The performances were evaluated by the Spice simulation. It was confirmed that the new ASD-ASIC had very low noise performance, wide dynamic range and fast signal processing functions. (author)

  9. Two-dimensional multifractal cross-correlation analysis

    International Nuclear Information System (INIS)

    Xi, Caiping; Zhang, Shuning; Xiong, Gang; Zhao, Huichang; Yang, Yonghong

    2017-01-01

    Highlights: • We study the mathematical models of 2D-MFXPF, 2D-MFXDFA and 2D-MFXDMA. • Present the definition of the two-dimensional N 2 -partitioned multiplicative cascading process. • Do the comparative analysis of 2D-MC by 2D-MFXPF, 2D-MFXDFA and 2D-MFXDMA. • Provide a reference on the choice and parameter settings of these methods in practice. - Abstract: There are a number of situations in which several signals are simultaneously recorded in complex systems, which exhibit long-term power-law cross-correlations. This paper presents two-dimensional multifractal cross-correlation analysis based on the partition function (2D-MFXPF), two-dimensional multifractal cross-correlation analysis based on the detrended fluctuation analysis (2D-MFXDFA) and two-dimensional multifractal cross-correlation analysis based on the detrended moving average analysis (2D-MFXDMA). We apply these methods to pairs of two-dimensional multiplicative cascades (2D-MC) to do a comparative study. Then, we apply the two-dimensional multifractal cross-correlation analysis based on the detrended fluctuation analysis (2D-MFXDFA) to real images and unveil intriguing multifractality in the cross correlations of the material structures. At last, we give the main conclusions and provide a valuable reference on how to choose the multifractal algorithms in the potential applications in the field of SAR image classification and detection.

  10. Volume scanning three-dimensional display with an inclined two-dimensional display and a mirror scanner

    Science.gov (United States)

    Miyazaki, Daisuke; Kawanishi, Tsuyoshi; Nishimura, Yasuhiro; Matsushita, Kenji

    2001-11-01

    A new three-dimensional display system based on a volume-scanning method is demonstrated. To form a three-dimensional real image, an inclined two-dimensional image is rapidly moved with a mirror scanner while the cross-section patterns of a three-dimensional object are displayed sequentially. A vector-scan CRT display unit is used to obtain a high-resolution image. An optical scanning system is constructed with concave mirrors and a galvanometer mirror. It is confirmed that three-dimensional images, formed by the experimental system, satisfy all the criteria for human stereoscopic vision.

  11. A Thermal Imaging Instrument with Uncooled Detectors

    Science.gov (United States)

    Joseph, A. T.; Barrentine, E. M.; Brown, A. D.

    2017-12-01

    In this work, we perform an instrument concept study for sustainable thermal imaging over land with uncooled detectors. The National Research Council's Committee on Implementation of a Sustained Land Imaging Program has identified the inclusion of a thermal imager as critical for both current and future land imaging missions. Such an imaging instrument operating in two bands located at approximately 11 and 12 microns (for example, in Landsat 8, and also Landsat 9 when launched) will provide essential information for furthering our hydrologic understanding at scales of human influence, and produce field-scale moisture information through accurate retrievals of evapotranspiration (ET). Landsat 9 is slated to recycle the TIRS-2 instrument launched with Landsat 8 that uses cooled quantum well infrared photodetectors (QWIPs), hence requiring expensive and massive cryocooler technology to achieve its required spectral and spatial accuracies. Our goal is to conceptualize and develop a thermal imaging instrument which leverages recent and imminent technology advances in uncooled detectors. Such detector technology will offer the benefit of greatly reduced instrument cost, mass, and power at the expense of some acceptable loss in detector sensitivity. It would also allow a thermal imaging instrument to be fielded on board a low-cost platform, e.g., a CubeSat. Sustained and enhanced land imaging is crucial for providing high-quality science data on change in land use, forest health, crop status, environment, and climate. Accurate satellite mapping of ET at the agricultural field scale (the finest spatial scale of the environmental processes of interest) requires high-quality thermal data to produce the corresponding accurate land surface temperature (LST) retrievals used to drive an ET model. Such an imaging instrument would provide important information on the following: 1) the relationship between land-use and land/water management practices and water use dynamics; 2) the

  12. Reconstruction 3-dimensional image from 2-dimensional image of status optical coherence tomography (OCT) for analysis of changes in retinal thickness

    Energy Technology Data Exchange (ETDEWEB)

    Arinilhaq,; Widita, Rena [Department of Physics, Nuclear Physics and Biophysics Research Group, Institut Teknologi Bandung (Indonesia)

    2014-09-30

    Optical Coherence Tomography is often used in medical image acquisition to diagnose that change due easy to use and low price. Unfortunately, this type of examination produces a two-dimensional retinal image of the point of acquisition. Therefore, this study developed a method that combines and reconstruct 2-dimensional retinal images into three-dimensional images to display volumetric macular accurately. The system is built with three main stages: data acquisition, data extraction and 3-dimensional reconstruction. At data acquisition step, Optical Coherence Tomography produced six *.jpg images of each patient were further extracted with MATLAB 2010a software into six one-dimensional arrays. The six arrays are combined into a 3-dimensional matrix using a kriging interpolation method with SURFER9 resulting 3-dimensional graphics of macula. Finally, system provides three-dimensional color graphs based on the data distribution normal macula. The reconstruction system which has been designed produces three-dimensional images with size of 481 × 481 × h (retinal thickness) pixels.

  13. Two-dimensional sonographic cine imaging improves confidence in the initial evaluation of the fetal heart.

    Science.gov (United States)

    Poole, Patricia Sims; Chung, Romy; Lacoursiere, Yvette; Palmieri, Carolina Rossi; Hull, Andrew; Engelkemier, Dawn; Rochelle, Michele; Trivedi, Neha; Pretorius, Dolores H

    2013-06-01

    Initial screening sonography of the fetal heart with static images is often inadequate, resulting in repeated imaging or failure to detect abnormalities. We hypothesized that the addition of short cine clips would reduce the need for repeated imaging. Two-dimensional (2D) static sonograms and short 2D cine clips of the 4-chamber view and left and right ventricular outflow tracts were obtained from 342 patients with gestational ages of greater than 16 weeks. A diagnostic radiologist and a perinatologist retrospectively reviewed the static and cine images independently and graded them as normal, abnormal, or suboptimal. A statistically significant increase in the number of structures called normal was seen when 2D cine clips were added to static imaging for both observers (P cine images versus 61.9% with static images alone, whereas the perinatologist recorded 68.1% as normal versus 58.8%, respectively. The radiologist called 77.8% of structures normal with cine images only versus 61.9% with static images only (P cine images alone (38.9%) versus static images alone (58.8%). The use of cine loops alone resulted in no significant increase in the ability to clear the heart as normal. The maternal body mass index was inversely associated with the ability to clear structures when 2D cine images were added to static images (P cine clips to standard 2D static imaging of the fetal heart significantly improves the number of structures cleared as normal. Two-dimensional cine clips are easily obtained, add little time to a study, and require minimal archival space.

  14. Intravascular imaging with a storage phosphor detector

    Energy Technology Data Exchange (ETDEWEB)

    Shikhaliev, Polad M; Petrek, Peter; Matthews, Kenneth L II; Fritz, Shannon G [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA (United States); Bujenovic, L Steven [PET Imaging Center, Our Lady of the Lake Medical Center, Baton Rouge, LA (United States); Xu Tong, E-mail: pshikhal@lsu.ed [Department of Physics, Carleton University, Ottawa (Canada)

    2010-05-21

    The aim of this study is to develop and test an intravascular positron imaging system based on a storage phosphor detector for imaging and detecting vulnerable plaques of human coronary arteries. The radiotracer F18-FDG accumulates in vulnerable plaques with inflammation of the overlying cap. The vulnerable plaques can, therefore, be imaged by recording positrons emitted from F18-FDG with a detector inserted into the artery. A prototype intravascular detector was constructed based on storage phosphor. The detector uses a flexible storage phosphor tube with 55 mm length, 2 mm diameter and 0.28 mm wall thickness. The intravascular detector is guided into the vessel using x-ray fluoroscopy and the accumulated x-ray signal must be erased prior to positron imaging. For this purpose, a light diffuser, 0.9 mm in diameter and 55 mm in length, was inserted into the detector tube. The light diffuser was connected to a laser source through a 2 m long optical fiber. The diffuser redirected the 0.38 W laser light to the inner surface of the phosphor detector to erase it. A heart phantom with 300 cm{sup 3} volume and three coronary arteries with 3.2 mm diameter and with several plaques was constructed. FDG solution with 0.5 {mu}Ci cm{sup -3} activity concentration was filled in the heart and coronary arteries. The detector was inserted in a coronary artery and the signal from the plaques and surrounding background activity was recorded for 2 min. Then the phosphor detector was extracted and read out using a storage phosphor reader. The light diffuser erased the signal resulting from fluoroscopic exposure to level below that encountered during positron imaging. Vulnerable plaques with area activities higher than 1.2 nCi mm{sup -2} were visualized by the detector. This activity is a factor of 10-20 lower than that expected in human vulnerable plaques. The detector was able to image the internal surface of the coronary vessels with 50 mm length and 360{sup 0} circumference. Spatial

  15. Use of semiconductor detector c-Si microstrip type in obtaining the digital radiographic imaging of phantoms and biological samples of mammary glands

    International Nuclear Information System (INIS)

    Leyva, A.; Cabal, A.; Pinera, I.; Abreu, Y.; Cruz, C. M.; Montano, L. M.; Diaz, C. C.; Fontaine, M.; Ortiz, C. M.; Padilla, F.; De la Mora, R.

    2009-01-01

    The present work synthesizes the experimental results obtained in the characterization of 64 micro strips crystalline silicon detector designed for experiments in high energies physics, with the objective of studying its possible application in advanced medical radiography, specifically in digital mammography and angiography. The research includes the acquisition of two-dimensional radiography of a mammography phantom using the scanning method, and its comparison with similar images simulated mathematically for different X rays sources. The paper also shows the experimental radiography of two biological samples taken from biopsies of mammas, where it is possible to identify the presence of possible pathological lesions. The results reached in this work point positively toward the effective possibility of satisfactorily introducing those advanced detectors in medical digital imaging applications. (Author)

  16. Detector Development for the European XFEL: Requirements and Status

    International Nuclear Information System (INIS)

    Koch, Andreas; Kuster, Markus; Sztuk-Dambietz, Jolanta; Turcato, Monica

    2013-01-01

    The variety of applications and especially the unique European XFEL time structure will require adequate instrumentation to be developed to exploit the full potential of the light source. Two-dimensional integrating X-ray detectors with ultra-fast read out up to 4.5 MHz for 1024 × 1024 pixel images are under development for a variety of imaging applications. The actual status of the European XFEL detector development projects is presented. Furthermore, an outlook will be given with respect to detector research and development, performance optimization, integration, and commissioning.

  17. Ghost imaging with a single detector

    International Nuclear Information System (INIS)

    Bromberg, Yaron; Katz, Ori; Silberberg, Yaron

    2009-01-01

    We experimentally demonstrate pseudothermal ghost imaging and ghost diffraction using only a single detector. We achieve this by replacing the high-resolution detector of the reference beam with a computation of the propagating field, following a recent proposal by Shapiro [Phys. Rev. A 78, 061802(R) (2008)]. Since only a single detector is used, this provides experimental evidence that pseudothermal ghost imaging does not rely on nonlocal quantum correlations. In addition, we show the depth-resolving capability of this ghost imaging technique.

  18. Image matrix processor for fast multi-dimensional computations

    Science.gov (United States)

    Roberson, George P.; Skeate, Michael F.

    1996-01-01

    An apparatus for multi-dimensional computation which comprises a computation engine, including a plurality of processing modules. The processing modules are configured in parallel and compute respective contributions to a computed multi-dimensional image of respective two dimensional data sets. A high-speed, parallel access storage system is provided which stores the multi-dimensional data sets, and a switching circuit routes the data among the processing modules in the computation engine and the storage system. A data acquisition port receives the two dimensional data sets representing projections through an image, for reconstruction algorithms such as encountered in computerized tomography. The processing modules include a programmable local host, by which they may be configured to execute a plurality of different types of multi-dimensional algorithms. The processing modules thus include an image manipulation processor, which includes a source cache, a target cache, a coefficient table, and control software for executing image transformation routines using data in the source cache and the coefficient table and loading resulting data in the target cache. The local host processor operates to load the source cache with a two dimensional data set, loads the coefficient table, and transfers resulting data out of the target cache to the storage system, or to another destination.

  19. Digital position sensitive discrimination for 2-dimensional scintillation detectors

    International Nuclear Information System (INIS)

    Engels, R.; Reinartz, R.; Reinhart, P.

    1996-01-01

    The energy sensitivity of a two-dimensional scintillation gamma detector based on position sensitive photomultipliers has been minimized by a digital differential discrimination unit. Since the photomultiplier gain is position-dependent by 50%, a discrimination unit has been developed where digital upper and lower discrimination levels are set due to the position-dependent photomultiplier gain obtained from calibration measurements. Depending on the spatial resolution there can be up to 65.536 position-sensitive discriminator levels defining energy windows. By this method, narrow discriminator windows can be used for reducing the low and high energy quanta without effecting the sensitivity of the detector. The new discrimination method, its performance and test measurements with gamma rays will be described. Furthermore experimental results are presented

  20. The effect of base image window level selection on the dimensional measurement accuracy of resultant three-dimensional image displays

    International Nuclear Information System (INIS)

    Kurmis, A.P.; Hearn, T.C.; Reynolds, K.J.

    2003-01-01

    Purpose: The aim of this study was to determine the effect of base image window level selection on direct linear measurement of knee structures displayed using new magnetic resonance (MR)-based three-dimensional reconstructed computer imaging techniques. Methods: A prospective comparative study was performed using a series of three-dimensional knee images, generated from conventional MR imaging (MRI) sections. Thirty distinct anatomical structural features were identified within the image series of which repeated measurements were compared at 10 different window grey scale levels. Results: Statistical analysis demonstrated an excellent raw correlation between measurements and suggested no significant difference between measurements made at each of the 10 window level settings (P>0.05). Conclusions: The findings of this study suggest that unlike conventional MR or CT applications, grey scale window level selection at the time of imaging does not significantly affect the visual quality of resultant three-dimensional reconstructed images and hence the accuracy of subsequent direct linear measurement. The diagnostic potential of clinical progression from routine two-dimensional to advanced three-dimensional reconstructed imaging techniques may therefore be less likely to be degraded by inappropriate MR technician image windowing during the capturing of image series

  1. Synchrotron 4-dimensional imaging of two-phase flow through porous media.

    Science.gov (United States)

    Kim, F H; Penumadu, D; Patel, P; Xiao, X; Garboczi, E J; Moylan, S P; Donmez, M A

    2016-01-01

    Near real-time visualization of complex two-phase flow in a porous medium was demonstrated with dynamic 4-dimensional (4D) (3D + time) imaging at the 2-BM beam line of the Advanced Photon Source (APS) at Argonne National Laboratory. Advancing fluid fronts through tortuous flow paths and their interactions with sand grains were clearly captured, and formations of air bubbles and capillary bridges were visualized. The intense X-ray photon flux of the synchrotron facility made 4D imaging possible, capturing the dynamic evolution of both solid and fluid phases. Computed Tomography (CT) scans were collected every 12 s with a pixel size of 3.25 µm. The experiment was carried out to improve understanding of the physics associated with two-phase flow. The results provide a source of validation data for numerical simulation codes such as Lattice-Boltzmann, which are used to model multi-phase flow through porous media.

  2. High-definition resolution three-dimensional imaging systems in laparoscopic radical prostatectomy: randomized comparative study with high-definition resolution two-dimensional systems.

    Science.gov (United States)

    Kinoshita, Hidefumi; Nakagawa, Ken; Usui, Yukio; Iwamura, Masatsugu; Ito, Akihiro; Miyajima, Akira; Hoshi, Akio; Arai, Yoichi; Baba, Shiro; Matsuda, Tadashi

    2015-08-01

    Three-dimensional (3D) imaging systems have been introduced worldwide for surgical instrumentation. A difficulty of laparoscopic surgery involves converting two-dimensional (2D) images into 3D images and depth perception rearrangement. 3D imaging may remove the need for depth perception rearrangement and therefore have clinical benefits. We conducted a multicenter, open-label, randomized trial to compare the surgical outcome of 3D-high-definition (HD) resolution and 2D-HD imaging in laparoscopic radical prostatectomy (LRP), in order to determine whether an LRP under HD resolution 3D imaging is superior to that under HD resolution 2D imaging in perioperative outcome, feasibility, and fatigue. One-hundred twenty-two patients were randomly assigned to a 2D or 3D group. The primary outcome was time to perform vesicourethral anastomosis (VUA), which is technically demanding and may include a number of technical difficulties considered in laparoscopic surgeries. VUA time was not significantly shorter in the 3D group (26.7 min, mean) compared with the 2D group (30.1 min, mean) (p = 0.11, Student's t test). However, experienced surgeons and 3D-HD imaging were independent predictors for shorter VUA times (p = 0.000, p = 0.014, multivariate logistic regression analysis). Total pneumoperitoneum time was not different. No conversion case from 3D to 2D or LRP to open RP was observed. Fatigue was evaluated by a simulation sickness questionnaire and critical flicker frequency. Results were not different between the two groups. Subjective feasibility and satisfaction scores were significantly higher in the 3D group. Using a 3D imaging system in LRP may have only limited advantages in decreasing operation times over 2D imaging systems. However, the 3D system increased surgical feasibility and decreased surgeons' effort levels without inducing significant fatigue.

  3. Three-dimensional cross point readout detector design for including depth information

    Science.gov (United States)

    Lee, Seung-Jae; Baek, Cheol-Ha

    2018-04-01

    We designed a depth-encoding positron emission tomography (PET) detector using a cross point readout method with wavelength-shifting (WLS) fibers. To evaluate the characteristics of the novel detector module and the PET system, we used the DETECT2000 to perform optical photon transport in the crystal array. The GATE was also used. The detector module is made up of four layers of scintillator arrays, the five layers of WLS fiber arrays, and two sensor arrays. The WLS fiber arrays in each layer cross each other to transport light to each sensor array. The two sensor arrays are coupled to the forward and left sides of the WLS fiber array, respectively. The identification of three-dimensional pixels was determined using a digital positioning algorithm. All pixels were well decoded, with the system resolution ranging from 2.11 mm to 2.29 mm at full width at half maximum (FWHM).

  4. Cherenkov Ring Imaging Detector front-end electronics

    International Nuclear Information System (INIS)

    Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Marshall, D.; Muller, D.; Nagamine, T.; Oxoby, G.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Suekane, F.; Toge, N.; Va'Vra, J.; Williams, S.; Wilson, R.J.; Whitaker, J.S.; Bean, A.; Caldwell, D.; Duboscq, J.; Huber, J.; Lu, A.; Mathys, L.; McHugh, S.; Morrison, R.; Witherell, M.; Yellin, S.; Coyle, P.; Coyne, D.; Spencer, E.; d'Oliveira, A.; Johnson, R.A.; Martinez, J.; Nussbaum, M.; Santha, A.K.S.; Shoup, A.; Stockdale, I.; Jacques, P.; Plano, R.; Stamer, P.; Abe, K.; Hasegawa, K.; Yuta, H.

    1990-10-01

    The SLD Cherenkov Ring Imaging Detector use a proportional wire detector for which a single channel hybrid has been developed. It consists of a preamplifier, gain selectable amplifier, load driver amplifier, power switching, and precision calibrator. For this hybrid, a bipolar, semicustom integrated circuit has been designed which includes video operational amplifiers for two of the gain stages. This approach allows maximization of the detector volume, allows DC coupling, and enables gain selection. System tests show good noise performance, calibration precision, system linearity, and signal shape uniformity over the full dynamic range. 10 refs., 8 figs

  5. Two-dimensional PCA-based human gait identification

    Science.gov (United States)

    Chen, Jinyan; Wu, Rongteng

    2012-11-01

    It is very necessary to recognize person through visual surveillance automatically for public security reason. Human gait based identification focus on recognizing human by his walking video automatically using computer vision and image processing approaches. As a potential biometric measure, human gait identification has attracted more and more researchers. Current human gait identification methods can be divided into two categories: model-based methods and motion-based methods. In this paper a two-Dimensional Principal Component Analysis and temporal-space analysis based human gait identification method is proposed. Using background estimation and image subtraction we can get a binary images sequence from the surveillance video. By comparing the difference of two adjacent images in the gait images sequence, we can get a difference binary images sequence. Every binary difference image indicates the body moving mode during a person walking. We use the following steps to extract the temporal-space features from the difference binary images sequence: Projecting one difference image to Y axis or X axis we can get two vectors. Project every difference image in the difference binary images sequence to Y axis or X axis difference binary images sequence we can get two matrixes. These two matrixes indicate the styles of one walking. Then Two-Dimensional Principal Component Analysis(2DPCA) is used to transform these two matrixes to two vectors while at the same time keep the maximum separability. Finally the similarity of two human gait images is calculated by the Euclidean distance of the two vectors. The performance of our methods is illustrated using the CASIA Gait Database.

  6. Three-dimensional imaging technology offers promise in medicine.

    Science.gov (United States)

    Karako, Kenji; Wu, Qiong; Gao, Jianjun

    2014-04-01

    Medical imaging plays an increasingly important role in the diagnosis and treatment of disease. Currently, medical equipment mainly has two-dimensional (2D) imaging systems. Although this conventional imaging largely satisfies clinical requirements, it cannot depict pathologic changes in 3 dimensions. The development of three-dimensional (3D) imaging technology has encouraged advances in medical imaging. Three-dimensional imaging technology offers doctors much more information on a pathology than 2D imaging, thus significantly improving diagnostic capability and the quality of treatment. Moreover, the combination of 3D imaging with augmented reality significantly improves surgical navigation process. The advantages of 3D imaging technology have made it an important component of technological progress in the field of medical imaging.

  7. Algorithm for automatic image dodging of unmanned aerial vehicle images using two-dimensional radiometric spatial attributes

    Science.gov (United States)

    Li, Wenzhuo; Sun, Kaimin; Li, Deren; Bai, Ting

    2016-07-01

    Unmanned aerial vehicle (UAV) remote sensing technology has come into wide use in recent years. The poor stability of the UAV platform, however, produces more inconsistencies in hue and illumination among UAV images than other more stable platforms. Image dodging is a process used to reduce these inconsistencies caused by different imaging conditions. We propose an algorithm for automatic image dodging of UAV images using two-dimensional radiometric spatial attributes. We use object-level image smoothing to smooth foreground objects in images and acquire an overall reference background image by relative radiometric correction. We apply the Contourlet transform to separate high- and low-frequency sections for every single image, and replace the low-frequency section with the low-frequency section extracted from the corresponding region in the overall reference background image. We apply the inverse Contourlet transform to reconstruct the final dodged images. In this process, a single image must be split into reasonable block sizes with overlaps due to large pixel size. Experimental mosaic results show that our proposed method reduces the uneven distribution of hue and illumination. Moreover, it effectively eliminates dark-bright interstrip effects caused by shadows and vignetting in UAV images while maximally protecting image texture information.

  8. Two-dimensional power Doppler-three-dimensional ultrasound imaging of a cesarean section dehiscence with utero-peritoneal fistula: a case report

    Directory of Open Access Journals (Sweden)

    Royo Pedro

    2009-01-01

    Full Text Available Abstract Introduction An imaging diagnosis after an iterative cesarean delivery is reviewed demonstrating a fine ultrasound-pathologic correlation. Case presentation A 33-year-old woman (G3, P3 presented referring intense dysmenorrhea and intermenstrual spotting since her third cesarean delivery, 1 year before. A cesarean section dehiscence with utero-peritoneal fistula was diagnosed by transvaginal ultrasound. Conclusion We can conclude that transvaginal two-dimensional power Doppler and three-dimensional ultrasound are highly accurate in detecting cesarean section dehiscence and uterine fistula.

  9. Three-dimensional imaging utilizing energy discrimination

    International Nuclear Information System (INIS)

    Gunter, D.L.; Hoffman, K.R.; Beck, R.N.

    1990-01-01

    An algorithm is proposed for three-dimensional image reconstruction in nuclear medicine which uses scattered radiation rather than multiple projected images to determine the source depth within the body. Images taken from numerous energy windows are combined to construct the source distribution in the body. The gamma-ray camera is not moved during the imaging process. Experiments with both Tc-99m and Ga-67 demonstrate that two channels of depth information can be extracted from the low energy images produced by scattered radiation. By combining this technique with standard SPECT reconstruction using multiple projections the authors anticipate much improved spatial resolution in the overall three-dimensional reconstruction

  10. Processing two-dimensional X-ray diffraction and small-angle scattering data in DAWN 2.

    Science.gov (United States)

    Filik, J; Ashton, A W; Chang, P C Y; Chater, P A; Day, S J; Drakopoulos, M; Gerring, M W; Hart, M L; Magdysyuk, O V; Michalik, S; Smith, A; Tang, C C; Terrill, N J; Wharmby, M T; Wilhelm, H

    2017-06-01

    A software package for the calibration and processing of powder X-ray diffraction and small-angle X-ray scattering data is presented. It provides a multitude of data processing and visualization tools as well as a command-line scripting interface for on-the-fly processing and the incorporation of complex data treatment tasks. Customizable processing chains permit the execution of many data processing steps to convert a single image or a batch of raw two-dimensional data into meaningful data and one-dimensional diffractograms. The processed data files contain the full data provenance of each process applied to the data. The calibration routines can run automatically even for high energies and also for large detector tilt angles. Some of the functionalities are highlighted by specific use cases.

  11. Characteristic performance evaluation of a photon counting Si strip detector for low dose spectral breast CT imaging

    Science.gov (United States)

    Cho, Hyo-Min; Barber, William C.; Ding, Huanjun; Iwanczyk, Jan S.; Molloi, Sabee

    2014-01-01

    Purpose: The possible clinical applications which can be performed using a newly developed detector depend on the detector's characteristic performance in a number of metrics including the dynamic range, resolution, uniformity, and stability. The authors have evaluated a prototype energy resolved fast photon counting x-ray detector based on a silicon (Si) strip sensor used in an edge-on geometry with an application specific integrated circuit to record the number of x-rays and their energies at high flux and fast frame rates. The investigated detector was integrated with a dedicated breast spectral computed tomography (CT) system to make use of the detector's high spatial and energy resolution and low noise performance under conditions suitable for clinical breast imaging. The aim of this article is to investigate the intrinsic characteristics of the detector, in terms of maximum output count rate, spatial and energy resolution, and noise performance of the imaging system. Methods: The maximum output count rate was obtained with a 50 W x-ray tube with a maximum continuous output of 50 kVp at 1.0 mA. A109Cd source, with a characteristic x-ray peak at 22 keV from Ag, was used to measure the energy resolution of the detector. The axial plane modulation transfer function (MTF) was measured using a 67 μm diameter tungsten wire. The two-dimensional (2D) noise power spectrum (NPS) was measured using flat field images and noise equivalent quanta (NEQ) were calculated using the MTF and NPS results. The image quality parameters were studied as a function of various radiation doses and reconstruction filters. The one-dimensional (1D) NPS was used to investigate the effect of electronic noise elimination by varying the minimum energy threshold. Results: A maximum output count rate of 100 million counts per second per square millimeter (cps/mm2) has been obtained (1 million cps per 100 × 100 μm pixel). The electrical noise floor was less than 4 keV. The energy resolution

  12. Superlattice electroabsorption radiation detector

    International Nuclear Information System (INIS)

    Cooke, B.J.

    1993-06-01

    This paper provides a preliminary investigation of a new class of superlattice electroabsorption radiation detectors that employ direct optical modulation for high-speed, two-dimensional (2-D), high-resolution imaging. Applications for the detector include nuclear radiation measurements, tactical guidance and detection (laser radar), inertial fusion plasma studies, and satellite-based sensors. Initial calculations discussed in this paper indicate that a 1.5-μm (GaAlAs) multi-quantum-well (MQW) Fabry-Perot detector can respond directly to radiation of energies 1 eV to 10 KeV, and indirectly (with scattering targets) up through gamma, with 2-D sample rates on the order of 20 ps

  13. Negative refraction imaging of solid acoustic waves by two-dimensional three-component phononic crystal

    International Nuclear Information System (INIS)

    Li Jing; Liu Zhengyou; Qiu Chunyin

    2008-01-01

    By using of the multiple scattering methods, we study the negative refraction imaging effect of solid acoustic waves by two-dimensional three-component phononic crystals composed of coated solid inclusions placed in solid matrix. We show that localized resonance mechanism brings on a group of flat single-mode bands in low-frequency region, which provides two equivalent frequency surfaces (EFS) close to circular. The two constant frequency surfaces correspond to two Bloch modes, a right-handed and a left-handed, whose leading mode are respectively transverse (T) and longitudinal (L) modes. The negative refraction behaviors of the two kinds of modes have been demonstrated by simulation of a Gaussian beam through a finite system. High-quality far-field imaging by a planar lens for transverse or longitudinal waves has been realized separately. This three-component phononic crystal may thus serve as a mode selector in negative refraction imaging of solid acoustic waves

  14. Prenatal diagnosis of sirenomelia by two-dimensional and three-dimensional skeletal imaging ultrasound.

    Science.gov (United States)

    Liu, Rong; Chen, Xin-lin; Yang, Xiao-hong; Ma, Hui-jing

    2015-12-01

    This study sought to evaluate the contribution of two-dimensional ultrasound (2D-US) and three-dimensional skeletal imaging ultrasound (3D-SUIS) in the prenatal diagnosis of sirenomelia. Between September 2010 and April 2014, a prospective study was conducted in a single referral center using 3D-SUIS performed after 2D-US in 10 cases of sirenomelia. Diagnostic accuracy and detailed findings were compared with postnatal three-dimensional helical computed tomography (3D-HCT), radiological findings and autopsy. Pregnancy was terminated in all 10 sirenomelia cases, including 9 singletons and 1 conjoined twin pregnancy, for a total of 5 males and 5 females. These cases of sirenomelia were determined by autopsy and/or chromosomal examination. Initial 2D-US showed that there were 10 cases of oligohydramnios, bilateral renal agenesis, bladder agenesis, single umbilical artery, fusion of the lower limbs and spinal abnormalities; 8 cases of dipus or monopus; 2 cases of apus; and 8 cases of cardiac abnormalities. Subsequent 3D-SUIS showed that there were 9 cases of scoliosis, 10 cases of sacrococcygeal vertebra dysplasia, 3 cases of hemivertebra, 1 case of vertebral fusion, 3 cases of spina bifida, and 5 cases of rib abnormalities. 3D-SUIS identified significantly more skeletal abnormalities than did 2D-US, and its accuracy was 79.5% (70/88) compared with 3D-HCT and radiography. 3D-SUIS seems to be a useful complementary method to 2D-US and may improve the accuracy of identifying prenatal skeletal abnormalities related to sirenomelia.

  15. RECONSTRUCTING THREE-DIMENSIONAL JET GEOMETRY FROM TWO-DIMENSIONAL IMAGES

    Science.gov (United States)

    Avachat, Sayali; Perlman, Eric S.; Li, Kunyang; Kosak, Katie

    2018-01-01

    Relativistic jets in AGN are one of the most interesting and complex structures in the Universe. Some of the jets can be spread over hundreds of kilo parsecs from the central engine and display various bends, knots and hotspots. Observations of the jets can prove helpful in understanding the emission and particle acceleration processes from sub-arcsec to kilo parsec scales and the role of magnetic field in it. The M87 jet has many bright knots as well as regions of small and large bends. We attempt to model the jet geometry using the observed 2 dimensional structure. The radio and optical images of the jet show evidence of presence of helical magnetic field throughout. Using the observed structure in the sky frame, our goal is to gain an insight into the intrinsic 3 dimensional geometry in the jets frame. The structure of the bends in jet's frame may be quite different than what we see in the sky frame. The knowledge of the intrinsic structure will be helpful in understanding the appearance of the magnetic field and hence polarization morphology. To achieve this, we are using numerical methods to solve the non-linear equations based on the jet geometry. We are using the Log Likelihood method and algorithm based on Markov Chain Monte Carlo (MCMC) simulations.

  16. Three-dimensional biomedical imaging

    International Nuclear Information System (INIS)

    Robb, R.A.

    1985-01-01

    Scientists in biomedical imaging provide researchers, physicians, and academicians with an understanding of the fundamental theories and practical applications of three-dimensional biomedical imaging methodologies. Succinct descriptions of each imaging modality are supported by numerous diagrams and illustrations which clarify important concepts and demonstrate system performance in a variety of applications. Comparison of the different functional attributes, relative advantages and limitations, complementary capabilities, and future directions of three-dimensional biomedical imaging modalities are given. Volume 1: Introductions to Three-Dimensional Biomedical Imaging Photoelectronic-Digital Imaging for Diagnostic Radiology. X-Ray Computed Tomography - Basic Principles. X-Ray Computed Tomography - Implementation and Applications. X-Ray Computed Tomography: Advanced Systems and Applications in Biomedical Research and Diagnosis. Volume II: Single Photon Emission Computed Tomography. Position Emission Tomography (PET). Computerized Ultrasound Tomography. Fundamentals of NMR Imaging. Display of Multi-Dimensional Biomedical Image Information. Summary and Prognostications

  17. Initial performance of the two-dimensional 1024-channel amplifier array

    International Nuclear Information System (INIS)

    Kishishita, Tetsuichi; Ikeda, Hirokazu; Tamura, Ken-ichi; Hiruta, Tatsuro; Nakazawa, Kazuhiro; Takashima, Takeshi; Takahashi, Tadayuki

    2007-01-01

    This paper describes the initial performance of a two-dimensional analog ASIC that has been developed to read out CdTe pixel detectors for the next-generation hard X-ray imager. The readout chip consists of a 32x32 matrix of identical 200μmx200μm pixel cells. Each readout cell contains a low noise charge-sensitive amplifier, three-stage pulse shaping amplifiers and a comparator circuit. Pulse processing circuits have been also designed to achieve lower power consumption for the space application. Analog outputs by injecting a test pulse have been obtained from 991 pixels out of 1024 pixels. The mean noise level is 297+/-29 electrons (rms) and power consumption is 110μW/pixel

  18. Workshops on radiation imaging detectors

    International Nuclear Information System (INIS)

    Sochinskii, N.V.; Sun, G.C.; Kostamo, P.; Silenas, A.; Saynatjoki, A.; Grant, J.; Owens, A.; Kozorezov, A.G.; Noschis, E.; Van Eijk, C.; Nagarkar, V.; Sekiya, H.; Pribat, D.; Campbell, M.; Lundgren, J.; Arques, M.; Gabrielli, A.; Padmore, H.; Maiorino, M.; Volpert, M.; Lebrun, F.; Van der Putten, S.; Pickford, A.; Barnsley, R.; Anton, M.E.G.; Mitschke, M.; Gros d'Aillon, E.; Frojdh, C.; Norlin, B.; Marchal, J.; Quattrocchi, M.; Stohr, U.; Bethke, K.; Bronnimann, C.H.; Pouvesle, J.M.; Hoheisel, M.; Clemens, J.C.; Gallin-Martel, M.L.; Bergamaschi, A.; Redondo-Fernandez, I.; Gal, O.; Kwiatowski, K.; Montesi, M.C.; Smith, K.

    2005-01-01

    This document gathers the transparencies that were presented at the international workshop on radiation imaging detectors. 9 sessions were organized: 1) materials for detectors and detector structure, 2) front end electronics, 3) interconnected technologies, 4) space, fusion applications, 5) the physics of detection, 6) industrial applications, 7) synchrotron radiation, 8) X-ray sources, and 9) medical and other applications

  19. Workshops on radiation imaging detectors

    Energy Technology Data Exchange (ETDEWEB)

    Sochinskii, N V; Sun, G C; Kostamo, P; Silenas, A; Saynatjoki, A; Grant, J; Owens, A; Kozorezov, A G; Noschis, E; Van Eijk, C; Nagarkar, V; Sekiya, H; Pribat, D; Campbell, M; Lundgren, J; Arques, M; Gabrielli, A; Padmore, H; Maiorino, M; Volpert, M; Lebrun, F; Van der Putten, S; Pickford, A; Barnsley, R; Anton, M E.G.; Mitschke, M; Gros d' Aillon, E; Frojdh, C; Norlin, B; Marchal, J; Quattrocchi, M; Stohr, U; Bethke, K; Bronnimann, C H; Pouvesle, J M; Hoheisel, M; Clemens, J C; Gallin-Martel, M L; Bergamaschi, A; Redondo-Fernandez, I; Gal, O; Kwiatowski, K; Montesi, M C; Smith, K

    2005-07-01

    This document gathers the transparencies that were presented at the international workshop on radiation imaging detectors. 9 sessions were organized: 1) materials for detectors and detector structure, 2) front end electronics, 3) interconnected technologies, 4) space, fusion applications, 5) the physics of detection, 6) industrial applications, 7) synchrotron radiation, 8) X-ray sources, and 9) medical and other applications.

  20. Research and Realization of Medical Image Fusion Based on Three-Dimensional Reconstruction

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new medical image fusion technique is presented. The method is based on three-dimensional reconstruction. After reconstruction, the three-dimensional volume data is normalized by three-dimensional coordinate conversion in the same way and intercepted through setting up cutting plane including anatomical structure, as a result two images in entire registration on space and geometry are obtained and the images are fused at last.Compared with traditional two-dimensional fusion technique, three-dimensional fusion technique can not only resolve the different problems existed in the two kinds of images, but also avoid the registration error of the two kinds of images when they have different scan and imaging parameter. The research proves this fusion technique is more exact and has no registration, so it is more adapt to arbitrary medical image fusion with different equipments.

  1. Three-dimensional imaging modalities in endodontics

    Science.gov (United States)

    Mao, Teresa

    2014-01-01

    Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome. PMID:25279337

  2. Three-dimensional imaging modalities in endodontics

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Teresa; Neelakantan, Prasanna [Dept. of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha University, Chennai (India)

    2014-09-15

    Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome.

  3. Three-dimensional imaging modalities in endodontics

    International Nuclear Information System (INIS)

    Mao, Teresa; Neelakantan, Prasanna

    2014-01-01

    Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome

  4. Two- and three-dimensional CT evaluation of sacral and pelvic anomalies

    International Nuclear Information System (INIS)

    Kuhlman, J.E.; Fishman, E.K.; Magid, D.

    1988-01-01

    Pelvic anomalies are difficult to evaluate with standard techniques. Detailed knowledge of the existing pelvic structures and musculature is essential for successful repair. The authors evaluated 12 patients with complex malformations of the pelvis using two- and three-dimensional imaging. The anomalies included bladder exstrophy (n = 4), cloacal exstrophy (n = 1), duplicated and absent sacrum (n = 3), myelomeningoceles (n = 2), and diastrophic dwarfism (n = 2). The two-dimensional images consisted of sequential coronal and sagittal reconstructions that could be reviewed dynamically on screen. Three-dimensional images were generated on the Pixar imaging computer with use of volumetric rendering. Two- and three-dimensional CT proved complementary in the evaluation of pelvic anomalies, providing optimal information from transaxial CT data

  5. New method for thickness determination and microscopic imaging of graphene-like two-dimensional materials

    International Nuclear Information System (INIS)

    Qin Xudong; Chen Yonghai; Liu Yu; Zhu Laipan; Li Yuan; Wu Qing; Huang Wei

    2016-01-01

    We employed the microscopic reflectance difference spectroscopy (micro-RDS) to determine the layer-number and microscopically image the surface topography of graphene and MoS 2 samples. The contrast image shows the efficiency and reliability of this new clipping technique. As a low-cost, quantifiable, no-contact and non-destructive method, it is not concerned with the characteristic signal of certain materials and can be applied to arbitrary substrates. Therefore it is a perfect candidate for characterizing the thickness of graphene-like two-dimensional materials. (paper)

  6. Pixel Detectors for Particle Physics and Imaging Applications

    CERN Document Server

    Wermes, N

    2003-01-01

    Semiconductor pixel detectors offer features for the detection of radiation which are interesting for particle physics detectors as well as for imaging e.g. in biomedical applications (radiography, autoradiography, protein crystallography) or in Xray astronomy. At the present time hybrid pixel detectors are technologically mastered to a large extent and large scale particle detectors are being built. Although the physical requirements are often quite different, imaging applications are emerging and interesting prototype results are available. Monolithic detectors, however, offer interesting features for both fields in future applications. The state of development of hybrid and monolithic pixel detectors, excluding CCDs, and their different suitability for particle detection and imaging, is reviewed.

  7. CFAR Edge Detector for Polarimetric SAR Images

    DEFF Research Database (Denmark)

    Schou, Jesper; Skriver, Henning; Nielsen, Allan Aasbjerg

    2003-01-01

    Finding the edges between different regions in an image is one of the fundamental steps of image analysis, and several edge detectors suitable for the special statistics of synthetic aperture radar (SAR) intensity images have previously been developed. In this paper, a new edge detector for polar...

  8. Solid-state, flat-panel, digital radiography detectors and their physical imaging characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Cowen, A.R. [LXi Research, Academic Unit of Medical Physics, University of Leeds, West Yorkshire (United Kingdom)], E-mail: a.r.cowen@leeds.ac.uk; Kengyelics, S.M.; Davies, A.G. [LXi Research, Academic Unit of Medical Physics, University of Leeds, West Yorkshire (United Kingdom)

    2008-05-15

    Solid-state, digital radiography (DR) detectors, designed specifically for standard projection radiography, emerged just before the turn of the millennium. This new generation of digital image detector comprises a thin layer of x-ray absorptive material combined with an electronic active matrix array fabricated in a thin film of hydrogenated amorphous silicon (a-Si:H). DR detectors can offer both efficient (low-dose) x-ray image acquisition plus on-line readout of the latent image as electronic data. To date, solid-state, flat-panel, DR detectors have come in two principal designs, the indirect-conversion (x-ray scintillator-based) and the direct-conversion (x-ray photoconductor-based) types. This review describes the underlying principles and enabling technologies exploited by these designs of detector, and evaluates their physical imaging characteristics, comparing performance both against each other and computed radiography (CR). In standard projection radiography indirect conversion DR detectors currently offer superior physical image quality and dose efficiency compared with direct conversion DR and modern point-scan CR. These conclusions have been confirmed in the findings of clinical evaluations of DR detectors. Future trends in solid-state DR detector technologies are also briefly considered. Salient innovations include WiFi-enabled, portable DR detectors, improvements in x-ray absorber layers and developments in alternative electronic media to a-Si:H.

  9. Design and development of the associated-particle three-dimensional imaging technique

    International Nuclear Information System (INIS)

    Ussery, L.E.; Hollas, C.L.

    1994-10-01

    The authors describe the development of the ''associated-particle'' imaging technique for producing low-resolution three-dimensional images of objects. Based on the t(d,n) 4 He reaction, the method requires access to only one side of the object being imaged and allows for the imaging of individual chemical elements in the material under observation. Studies were performed to (1) select the appropriate components of the system, including detectors, data-acquisition electronics, and neutron source, and (2) optimize experimental methods for collection and presentation of data. This report describes some of the development steps involved and provides a description of the complete final system that was developed

  10. A three-dimensional computer graphic imaging for neurosurgery

    International Nuclear Information System (INIS)

    Uchino, Masafumi; Onagi, Atsuo; Seiki, Yoshikatsu

    1987-01-01

    Information offered by conventional diagnostic tools for medical use, including X-ray films, CT, MRI, RI images and PET, are usually two-dimensional. However, the human body and pathological lesions are really extended in 3 dimensions. Interpreters have to reconstruct an imaginative, 3-dimensional configuration of lesions from 2-dimensional information on many films, according to their knowledge and experience. All this sometimes wastes a lot of time and gives rise to inconclusive discussion among interpreters. The advent and rapid progress of new computer graphic techniques, however, makes it possible to draw an apparent 3-dimensional image of a lesion on the basis of a 2-dimensional display; this is named a pseudo-3-dimensional image. After the region of interest of the CT-sliced image has been extracted by means of a semi-automatic contour extraction algorithm, multi-slice CT images are constructed by the voxel method. A 3-dimensional image is then generated by the use of the Z-buffer. Subsequently, transparent, semi-transparent, and color display are provided. This new method of display was used for CT-scan films of various intracerebral pathological lesions, including tumors, hematomas, and congenital anomalies: The benefits, prospects, and technical limits of this imaging technique for clinical use were discussed. (author)

  11. Three-dimensional optoacoustic tomography using a conventional ultrasound linear detector array: whole-body tomographic system for small animals.

    Science.gov (United States)

    Gateau, Jerome; Caballero, Miguel Angel Araque; Dima, Alexander; Ntziachristos, Vasilis

    2013-01-01

    Optoacoustic imaging relies on the detection of ultrasonic waves induced by laser pulse excitations to map optical absorption in biological tissue. A tomographic geometry employing a conventional ultrasound linear detector array for volumetric optoacoustic imaging is reported. The geometry is based on a translate-rotate scanning motion of the detector array, and capitalizes on the geometrical characteristics of the transducer assembly to provide a large solid angular detection aperture. A system for three-dimensional whole-body optoacoustic tomography of small animals is implemented. The detection geometry was tested using a 128-element linear array (5.0∕7.0 MHz, Acuson L7, Siemens), moved by steps with a rotation∕translation stage assembly. Translation and rotation range of 13.5 mm and 180°, respectively, were implemented. Optoacoustic emissions were induced in tissue-mimicking phantoms and ex vivo mice using a pulsed laser operating in the near-IR spectral range at 760 nm. Volumetric images were formed using a filtered backprojection algorithm. The resolution of the optoacoustic tomography system was measured to be better than 130 μm in-plane and 330 μm in elevation (full width half maximum), and to be homogenous along a 15 mm diameter cross section due to the translate-rotate scanning geometry. Whole-body volumetric optoacoustic images of mice were performed ex vivo, and imaged organs and blood vessels through the intact abdominal and head regions were correlated to the mouse anatomy. Overall, the feasibility of three-dimensional and high-resolution whole-body optoacoustic imaging of small animal using a conventional linear array was demonstrated. Furthermore, the scanning geometry may be used for other linear arrays and is therefore expected to be of great interest for optoacoustic tomography at macroscopic and mesoscopic scale. Specifically, conventional detector arrays with higher central frequencies may be investigated.

  12. Large area two dimensional position sensitive detectors

    International Nuclear Information System (INIS)

    Sann, H.; Olmi, A.; Lynen, U.; Stelzer, H.; Gobbi, A.; Bock, R.

    1979-02-01

    After an introduction, a position-sensitive ionization chamber, a parallel-plate detector, and a multiwire position-sensitive chamber are described. Then the data acquisition and analysis methods are considered. Furthermore, the experimental methods for a multi-parameter experiment are described. Finally, the measurement of gamma-ray and neutron multiplicities and sequential fission is considered, and the results are presented. (HSI) [de

  13. Quantitative estimation of brain atrophy and function with PET and MRI two-dimensional projection images

    International Nuclear Information System (INIS)

    Saito, Reiko; Uemura, Koji; Uchiyama, Akihiko; Toyama, Hinako; Ishii, Kenji; Senda, Michio

    2001-01-01

    The purpose of this paper is to estimate the extent of atrophy and the decline in brain function objectively and quantitatively. Two-dimensional (2D) projection images of three-dimensional (3D) transaxial images of positron emission tomography (PET) and magnetic resonance imaging (MRI) were made by means of the Mollweide method which keeps the area of the brain surface. A correlation image was generated between 2D projection images of MRI and cerebral blood flow (CBF) or 18 F-fluorodeoxyglucose (FDG) PET images and the sulcus was extracted from the correlation image clustered by K-means method. Furthermore, the extent of atrophy was evaluated from the extracted sulcus on 2D-projection MRI and the cerebral cortical function such as blood flow or glucose metabolic rate was assessed in the cortex excluding sulcus on 2D-projection PET image, and then the relationship between the cerebral atrophy and function was evaluated. This method was applied to the two groups, the young and the aged normal subjects, and the relationship between the age and the rate of atrophy or the cerebral blood flow was investigated. This method was also applied to FDG-PET and MRI studies in the normal controls and in patients with corticobasal degeneration. The mean rate of atrophy in the aged group was found to be higher than that in the young. The mean value and the variance of the cerebral blood flow for the young are greater than those of the aged. The sulci were similarly extracted using either CBF or FDG PET images. The purposed method using 2-D projection images of MRI and PET is clinically useful for quantitative assessment of atrophic change and functional disorder of cerebral cortex. (author)

  14. Advanced concepts in multi-dimensional radiation detection and imaging

    International Nuclear Information System (INIS)

    Vetter, Kai; Barnowski, Ross; Pavlovsky, Ryan; Haefner, Andy; Torii, Tatsuo; Shikaze, Yoshiaki; Sanada, Yukihisa

    2016-01-01

    Recent developments in the detector fabrication, signal readout, and data processing enable new concepts in radiation detection that are relevant for applications ranging from fundamental physics to medicine as well as nuclear security and safety. We present recent progress in multi-dimensional radiation detection and imaging in the Berkeley Applied Nuclear Physics program. It is based on the ability to reconstruct scenes in three dimensions and fuse it with gamma-ray image information. We are using the High-Efficiency Multimode Imager HEMI in its Compton imaging mode and combining it with contextual sensors such as the Microsoft Kinect or visual cameras. This new concept of volumetric imaging or scene data fusion provides unprecedented capabilities in radiation detection and imaging relevant for the detection and mapping of radiological and nuclear materials. This concept brings us one step closer to the seeing the world with gamma-ray eyes. (author)

  15. Two- and three-dimensional evaluation of the acetabulum in the pediatric patient

    International Nuclear Information System (INIS)

    Magid, D.; Fishman, E.K.; Sponseller, P.D.

    1987-01-01

    Complex anatomic structures such as the hip and acetabulum are best evaluated with the use of two- and three-dimensional reconstruction techniques and standard transaxial CT data. CT scans of children with various hip pathologies, including congenital hip dislocation, slipped capital femoral epiphyses, hip dysplasias, dwarfism, and acetabular fractures, were reviewed to determine the value of two- and three-dimensional imaging. The advantages of two-dimensional imaging techniques (sequential coronal/sagittal reconstruction) and three-dimensional valumetric imaging techniques (using real-time video display) are illustrated with specific examples

  16. X-ray detectors in medical imaging

    International Nuclear Information System (INIS)

    Spahn, Martin

    2013-01-01

    Healthcare systems are subject to continuous adaptation, following trends such as the change of demographic structures, the rise of life-style related and chronic diseases, and the need for efficient and outcome-oriented procedures. This also influences the design of new imaging systems as well as their components. The applications of X-ray imaging in the medical field are manifold and have led to dedicated modalities supporting specific imaging requirements, for example in computed tomography (CT), radiography, angiography, surgery or mammography, delivering projection or volumetric imaging data. Depending on the clinical needs, some X-ray systems enable diagnostic imaging while others support interventional procedures. X-ray detector design requirements for the different medical applications can vary strongly with respect to size and shape, spatial resolution, frame rates and X-ray flux, among others. Today, integrating X-ray detectors are in common use. They are predominantly based on scintillators (e.g. CsI or Gd 2 O 2 S) and arrays of photodiodes made from crystalline silicon (Si) or amorphous silicon (a-Si) or they employ semiconductors (e.g. Se) with active a-Si readout matrices. Ongoing and future developments of X-ray detectors will include optimization of current state-of-the-art integrating detectors in terms of performance and cost, will enable the usage of large size CMOS-based detectors, and may facilitate photon counting techniques with the potential to further enhance performance characteristics and foster the prospect of new clinical applications

  17. Two-dimensional restoration of single photon emission computed tomography images using the Kalman filter

    International Nuclear Information System (INIS)

    Boulfelfel, D.; Rangayyan, R.M.; Kuduvalli, G.R.; Hahn, L.J.; Kloiber, R.

    1994-01-01

    The discrete filtered backprojection (DFBP) algorithm used for the reconstruction of single photon emission computed tomography (SPECT) images affects image quality because of the operations of filtering and discretization. The discretization of the filtered backprojection process can cause the modulation transfer function (MTF) of the SPECT imaging system to be anisotropic and nonstationary, especially near the edges of the camera's field of view. The use of shift-invariant restoration techniques fails to restore large images because these techniques do not account for such variations in the MTF. This study presents the application of a two-dimensional (2-D) shift-variant Kalman filter for post-reconstruction restoration of SPECT slices. This filter was applied to SPECT images of a hollow cylinder phantom; a resolution phantom; and a large, truncated cone phantom containing two types of cold spots, a sphere, and a triangular prism. The images were acquired on an ADAC GENESYS camera. A comparison was performed between results obtained by the Kalman filter and those obtained by shift-invariant filters. Quantitative analysis of the restored images performed through measurement of root mean squared errors shows a considerable reduction in error of Kalman-filtered images over images restored using shift-invariant methods

  18. Mechanical design of the two dimensional beam emission spectroscopy diagnostics on mast

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, Istvan Gabor, E-mail: kiss.istvan.gabor@rmki.kfki.hu [Association EURATOM, KFKI-RMKI, P.O. Box 49, H-1525 Budapest (Hungary); Meszaros, Botond; Dunai, Daniel; Zoletnik, Sandor; Krizsanoczi, Tibor [Association EURATOM, KFKI-RMKI, P.O. Box 49, H-1525 Budapest (Hungary); Field, Anthony R.; Gaffka, Rob [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2011-10-15

    A two dimensional beam emission spectroscopy (BES) system optimized for density turbulence measurements has recently been installed on the MAST tokamak. This system observes the emission of a Deuterium heating beam using a rotatable mirror to view from the plasma centre to the outboard edge (0.7-1.5 m), although the optics is optimized for core region (1.2 m). The beam is imaged onto a 4x8 pixel Avalanche Photodiode (APD) array detector, enabling measurements with 1 MHz bandwidth at photon-flux level of few times 10{sup 11} photons/s. This article will present the mechanical design of MAST BES equipment with special emphasis on its in-vessel components.

  19. A new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array

    Science.gov (United States)

    Xia, Wenze; Ma, Yayun; Han, Shaokun; Wang, Yulin; Liu, Fei; Zhai, Yu

    2018-06-01

    One of the most important goals of research on three-dimensional nonscanning laser imaging systems is the improvement of the illumination system. In this paper, a new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array is proposed. This array is obtained using a fiber array connected to a laser array with each unit laser having independent control circuits. This system uses a point-to-point imaging process, which is realized using the exact corresponding optical relationship between the point-light-source array and a linear-mode avalanche photodiode array detector. The complete working process of this system is explained in detail, and the mathematical model of this system containing four equations is established. A simulated contrast experiment and two real contrast experiments which use the simplified setup without a laser array are performed. The final results demonstrate that unlike a conventional three-dimensional nonscanning laser imaging system, the proposed system meets all the requirements of an eligible illumination system. Finally, the imaging performance of this system is analyzed under defocusing situations, and analytical results show that the system has good defocusing robustness and can be easily adjusted in real applications.

  20. Multi-purpose two- and three-dimensional momentum imaging of charged particles for attosecond experiments at 1 kHz repetition rate

    Energy Technology Data Exchange (ETDEWEB)

    Månsson, Erik P., E-mail: erik.mansson@sljus.lu.se; Sorensen, Stacey L.; Gisselbrecht, Mathieu [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden); Arnold, Cord L.; Kroon, David; Guénot, Diego; Fordell, Thomas; Johnsson, Per; L’Huillier, Anne [Division of Atomic Physics, Lund University, Box 118, 221 00 Lund (Sweden); Lépine, Franck [Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, 10 rue Ada Byron, 69622 Villeurbanne cedex (France)

    2014-12-15

    We report on the versatile design and operation of a two-sided spectrometer for the imaging of charged-particle momenta in two dimensions (2D) and three dimensions (3D). The benefits of 3D detection are to discern particles of different mass and to study correlations between fragments from multi-ionization processes, while 2D detectors are more efficient for single-ionization applications. Combining these detector types in one instrument allows us to detect positive and negative particles simultaneously and to reduce acquisition times by using the 2D detector at a higher ionization rate when the third dimension is not required. The combined access to electronic and nuclear dynamics available when both sides are used together is important for studying photoreactions in samples of increasing complexity. The possibilities and limitations of 3D momentum imaging of electrons or ions in the same spectrometer geometry are investigated analytically and three different modes of operation demonstrated experimentally, with infrared or extreme ultraviolet light and an atomic/molecular beam.

  1. Photon Counting Energy Dispersive Detector Arrays for X-ray Imaging.

    Science.gov (United States)

    Iwanczyk, Jan S; Nygård, Einar; Meirav, Oded; Arenson, Jerry; Barber, William C; Hartsough, Neal E; Malakhov, Nail; Wessel, Jan C

    2009-01-01

    The development of an innovative detector technology for photon-counting in X-ray imaging is reported. This new generation of detectors, based on pixellated cadmium telluride (CdTe) and cadmium zinc telluride (CZT) detector arrays electrically connected to application specific integrated circuits (ASICs) for readout, will produce fast and highly efficient photon-counting and energy-dispersive X-ray imaging. There are a number of applications that can greatly benefit from these novel imagers including mammography, planar radiography, and computed tomography (CT). Systems based on this new detector technology can provide compositional analysis of tissue through spectroscopic X-ray imaging, significantly improve overall image quality, and may significantly reduce X-ray dose to the patient. A very high X-ray flux is utilized in many of these applications. For example, CT scanners can produce ~100 Mphotons/mm(2)/s in the unattenuated beam. High flux is required in order to collect sufficient photon statistics in the measurement of the transmitted flux (attenuated beam) during the very short time frame of a CT scan. This high count rate combined with a need for high detection efficiency requires the development of detector structures that can provide a response signal much faster than the transit time of carriers over the whole detector thickness. We have developed CdTe and CZT detector array structures which are 3 mm thick with 16×16 pixels and a 1 mm pixel pitch. These structures, in the two different implementations presented here, utilize either a small pixel effect or a drift phenomenon. An energy resolution of 4.75% at 122 keV has been obtained with a 30 ns peaking time using discrete electronics and a (57)Co source. An output rate of 6×10(6) counts per second per individual pixel has been obtained with our ASIC readout electronics and a clinical CT X-ray tube. Additionally, the first clinical CT images, taken with several of our prototype photon-counting and

  2. Quantitative SPECT brain imaging: Effects of attenuation and detector response

    International Nuclear Information System (INIS)

    Gilland, D.R.; Jaszczak, R.J.; Bowsher, J.E.; Turkington, T.G.; Liang, Z.; Greer, K.L.; Coleman, R.E.

    1993-01-01

    Two physical factors that substantially degrade quantitative accuracy in SPECT imaging of the brain are attenuation and detector response. In addition to the physical factors, random noise in the reconstructed image can greatly affect the quantitative measurement. The purpose of this work was to implement two reconstruction methods that compensate for attenuation and detector response, a 3D maximum likelihood-EM method (ML) and a filtered backprojection method (FB) with Metz filter and Chang attenuation compensation, and compare the methods in terms of quantitative accuracy and image noise. The methods were tested on simulated data of the 3D Hoffman brain phantom. The simulation incorporated attenuation and distance-dependent detector response. Bias and standard deviation of reconstructed voxel intensities were measured in the gray and white matter regions. The results with ML showed that in both the gray and white matter regions as the number of iterations increased, bias decreased and standard deviation increased. Similar results were observed with FB as the Metz filter power increased. In both regions, ML had smaller standard deviation than FB for a given bias. Reconstruction times for the ML method have been greatly reduced through efficient coding, limited source support, and by computing attenuation factors only along rays perpendicular to the detector

  3. Neutron beam imaging with GEM detectors

    International Nuclear Information System (INIS)

    Albani, G.; Cazzaniga, C.; Rebai, M.; Gorini, G.; Croci, G.; Muraro, A.; Cippo, E. Perelli; Tardocchi, M.; Cavenago, M.; Murtas, F.; Claps, G.; Pasqualotto, R.

    2015-01-01

    Neutron GEM-based detectors represent a new frontier of devices in neutron physics applications where a very high neutron flux must be measured such as future fusion experiments (e.g. ITER Neutral beam Injector) and spallation sources (e.g. the European Spallation source). This kind of detectors can be properly adapted to be used both as beam monitors but also as neutron diffraction detectors that could represent a valid alternative for the 3 He detectors replacement. Fast neutron GEM detectors (nGEM) feature a cathode composed by one layer of polyethylene and one of aluminium (neutron scattering on hydrogen generates protons that are detected in the gas) while thermal neutron GEM detectors (bGEM) are equipped with a borated aluminium cathode (charged particles are generated through the 10 B(n,α) 7 Li reaction). GEM detectors can be realized in large area (1 m 2 ) and their readout can be pixelated. Three different prototypes of nGEM and one prototype of bGEM detectors of different areas and equipped with different types of readout have been built and tested. All the detectors have been used to measure the fast and thermal neutron 2D beam image at the ISIS-VESUVIO beamline. The different kinds of readout patterns (different areas of the pixels) have been compared in similar conditions. All the detectors measured a width of the beam profile consitent with the expected one. The imaging property of each detector was then tested by inserting samples of different material and shape in the beam. All the samples were correctly reconstructed and the definition of the reconstruction depends on the type of readout anode. The fast neutron beam profile reconstruction was then compared to the one obtained by diamond detectors positioned on the same beamline while the thermal neutron one was compared to the imaged obtained by cadmium-coupled x-rays films. Also efficiency and the gamma background rejection have been determined. These prototypes represent the first step towards

  4. Neutron imaging plates

    International Nuclear Information System (INIS)

    Niimura, Nobuo

    1995-01-01

    Imaging plates have been used in the field of medical diagnosis since long ago, but their usefulness was verified as the two-dimensional detector for analyzing the X-ray crystalline structure of high bio molecules like protein, and they have contributed to the remarkable progress in this field. The great contribution is due to the excellent features, such as the detection efficiency of about 100%, the positional resolution smaller than 0.2 mm, the dynamic range of five digits, and the area of several hundreds mm square. The neutron imaging plates have not yet obtained the sufficient results. It was planned to construct the neutron diffractometer for biological matters, and to put imaging plate neutron detectors (IP-ND) to practical use as the detector. The research on the development of IP-NDs was carried out, and the IPp-NDs having the performance comparable with that for X-ray were able to be produced. Imaging plates are the integral type two-dimensional radiation detector using photostimulated luminescence matters, and their principle is explained. As to neutron imaging plates, the converter, neutron detection efficiency and the flight of secondary particles in photo-stimulated luminescence matters are described. As for the present state of development of neutron imaging plates, the IP-NDs made for trial, the dynamic range, the positional resolution, the detection efficiency and the kinds of converters, and the application of IP-NDs are reported. (K.I.)

  5. X-ray detectors based on image sensors

    International Nuclear Information System (INIS)

    Costa, A.P.R.

    1983-01-01

    X-ray detectors based on image sensors are described and a comparison is made between the advantages and the disadvantages of such a kind of detectors with the position sensitive detectors. (L.C.) [pt

  6. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy

    Science.gov (United States)

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-01

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  7. An algorithm for three-dimensional imaging in the positron camera

    International Nuclear Information System (INIS)

    Chen Kun; Ma Mei; Xu Rongfen; Shen Miaohe

    1986-01-01

    A mathematical algorithm of back-projection filtered for image reconstructions using two-dimensional signals detected from parallel multiwire proportional chambers is described. The approaches of pseudo three-dimensional and full three-dimensional image reconstructions are introduced, and the available point response functions are defined as well. The designing parameters and computation procedure of the full three-dimensional method is presented

  8. Reconstruction of absorption and scattering coefficients in two dimensional heterogeneous participating media

    International Nuclear Information System (INIS)

    Montero, Raul F. Carita; Roberty, Nilson C.; Silva Neto, Antonio J.; Universidade Federal, Rio de Janeiro, RJ

    2002-01-01

    In the present work it is presented the solution of the two dimensional inverse radiative transfer problem of scattering and absorption coefficients estimation, in heterogeneous media, using the source-detector methodology and a discrete ordinates method consistent with the source-detector system. The mathematical formulation of the direct and inverse problems is presented as well as test case results. (author)

  9. Efficient phase contrast imaging in STEM using a pixelated detector. Part 1: Experimental demonstration at atomic resolution

    Energy Technology Data Exchange (ETDEWEB)

    Pennycook, Timothy J., E-mail: tpennycook@gmail.com [EPSRC SuperSTEM Facility, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Lupini, Andrew R. [Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37830 (United States); Yang, Hao [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Murfitt, Matthew F. [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Jones, Lewys [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Nellist, Peter D. [EPSRC SuperSTEM Facility, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

    2015-04-15

    We demonstrate a method to achieve high efficiency phase contrast imaging in aberration corrected scanning transmission electron microscopy (STEM) with a pixelated detector. The pixelated detector is used to record the Ronchigram as a function of probe position which is then analyzed with ptychography. Ptychography has previously been used to provide super-resolution beyond the diffraction limit of the optics, alongside numerically correcting for spherical aberration. Here we rely on a hardware aberration corrector to eliminate aberrations, but use the pixelated detector data set to utilize the largest possible volume of Fourier space to create high efficiency phase contrast images. The use of ptychography to diagnose the effects of chromatic aberration is also demonstrated. Finally, the four dimensional dataset is used to compare different bright field detector configurations from the same scan for a sample of bilayer graphene. Our method of high efficiency ptychography produces the clearest images, while annular bright field produces almost no contrast for an in-focus aberration-corrected probe. - Highlights: • Ptychographic high efficiency phase contrast imaging is demonstrated in STEM. • We rely on a hardware aberration corrector to eliminate aberrations. • High efficiency is achieved by collecting all the relevant interference. • Use of a pixelated detector allows comparison of bright field modes post acquisition. • Ptychography provides the clearest images among the STEM bright field modes tested.

  10. Three-dimensional particle image velocimetry measurement technique

    International Nuclear Information System (INIS)

    Hassan, Y.A.; Seeley, C.H.; Henderson, J.A.; Schmidl, W.D.

    2004-01-01

    The experimental flow visualization tool, Particle Image Velocimetry (PIV), is being used to determine the velocity field in two-dimensional fluid flows. In the past few years, the technique has been improved to allow the capture of flow fields in three dimensions. This paper describes changes which were made to two existing two-dimensional tracking algorithms to enable them to track three-dimensional PIV data. Results of the tests performed on these three-dimensional routines with synthetic data are presented. Experimental data was also used to test the tracking algorithms. The test setup which was used to acquire the three-dimensional experimental data is described, along with the results from both of the tracking routines which were used to analyze the experimental data. (author)

  11. Holographic and time-resolving ability of pulse-pair two-dimensional velocity interferometry

    International Nuclear Information System (INIS)

    Erskine, David J.; Smith, R. F.; Celliers, P. M.; Collins, G. W.; Bolme, C. A.; Ali, S. J.

    2014-01-01

    Previous velocity interferometers used at research laboratories for shock physics experiments measured target motion at a point or many points on a line on the target. Recently, a two-dimensional (2d) version (2d-velocity interferometer system for any reflector) has been demonstrated using a pair of ultrashort (3 ps) pulses for illumination, separated by 268 ps. We have discovered new abilities for this instrument, by treating the complex output image as a hologram. For data taken in an out of focus configuration, we can Fourier process to bring narrow features such as cracks into sharp focus, which are otherwise completely blurred. This solves a practical problem when using high numerical aperture optics having narrow depth of field to observe moving surface features such as cracks. Furthermore, theory predicts that the target appearance (position and reflectivity) at two separate moments in time are recorded by the main and conjugate images of the same hologram, and are partially separable during analysis for narrow features. Hence, for the cracks we bring into refocus, we can make a two-frame movie with a subnanosecond frame period. Longer and shorter frame periods are possible with different interferometer delays. Since the megapixel optical detectors we use have superior spatial resolution over electronic beam based framing cameras, this technology could be of great use in studying microscopic three-dimensional-behavior of targets at ultrafast times scales. Demonstrations on shocked silicon are shown

  12. Holographic and time-resolving ability of pulse-pair two-dimensional velocity interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, David J., E-mail: erskine1@llnl.gov; Smith, R. F.; Celliers, P. M.; Collins, G. W. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Bolme, C. A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ali, S. J. [Department of Chemistry, University of California, Berkeley, California 94720 (United States)

    2014-06-15

    Previous velocity interferometers used at research laboratories for shock physics experiments measured target motion at a point or many points on a line on the target. Recently, a two-dimensional (2d) version (2d-velocity interferometer system for any reflector) has been demonstrated using a pair of ultrashort (3 ps) pulses for illumination, separated by 268 ps. We have discovered new abilities for this instrument, by treating the complex output image as a hologram. For data taken in an out of focus configuration, we can Fourier process to bring narrow features such as cracks into sharp focus, which are otherwise completely blurred. This solves a practical problem when using high numerical aperture optics having narrow depth of field to observe moving surface features such as cracks. Furthermore, theory predicts that the target appearance (position and reflectivity) at two separate moments in time are recorded by the main and conjugate images of the same hologram, and are partially separable during analysis for narrow features. Hence, for the cracks we bring into refocus, we can make a two-frame movie with a subnanosecond frame period. Longer and shorter frame periods are possible with different interferometer delays. Since the megapixel optical detectors we use have superior spatial resolution over electronic beam based framing cameras, this technology could be of great use in studying microscopic three-dimensional-behavior of targets at ultrafast times scales. Demonstrations on shocked silicon are shown.

  13. Two-and three-dimensional CT reconstruction

    International Nuclear Information System (INIS)

    Fishman, E.K.; Ney, D.R.; Magid, D.

    1990-01-01

    This paper determines the optimal imaging sequence for creating two- and three-dimensional (2D/3D) skeletal reconstructions from CT data. A cadaver femur, a bone phantom, and a surgically created fracture were scanned with varying protocols to determine the optimal protocol for creating 2D/3D images. The scanning protocols used varying section thickness (2, 4, and 8 mm) as well as scan spacing (2, 3, 4 and 8 mm). All images were reconstructed into 2D data sets with a bicubic interpolation and 3D datasets with volumetric rendering. The results were reviewed by two reviewers to determine the quality of images reconstruction

  14. Advancements of floating strip Micromegas detectors for medical imaging applications

    Energy Technology Data Exchange (ETDEWEB)

    Klitzner, Felix; Biebel, Otmar; Bortfeldt, Jonathan; Flierl, Bernhard [LS Schaile, LMU Muenchen (Germany); Magallanes, Lorena [LS Parodi, LMU Muenchen (Germany); Universitaetsklinikum Heidelberg (Germany); Parodi, Katia [LS Parodi, LMU Muenchen (Germany); Heidelberger Ionenstrahl Therapiezentrum (Germany); Voss, Bernd [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany)

    2016-07-01

    Floating strip Micromegas have proven to be high-rate capable tracking detectors with excellent spatial and temporal resolution for particle fluxes up to 7 MHz/cm{sup 2}. To further increase the high-rate capability a Ne:CF{sub 4} 86:14 vol.% gas mixture has been used as detector gas. We present results from measurements with a seven detector system consisting of six low material budget floating strip Micromegas, a GEM detector and a scintillator based particle range telescope. The gaseous and the scintillation detectors were read out with APV25 frontend boards, allowing for single strip readout with pulse height and timing information. A two-dimensional readout anode for floating strip Micromegas has been tested for the first time. The Micromegas detectors were operated with minimal additional drift field, which significantly improves the timing resolution and also the spatial resolution for inclined tracks. We discuss the detector performance in high-rate carbon and proton beams at the Heidelberg Ion Beam Therapy Center (HIT) and present radiographies of phantoms, acquired with the system.

  15. Evaluation of a novel helium ionization detector within the context of (low-)flow modulation comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Franchina, Flavio A; Maimone, Mariarosa; Sciarrone, Danilo; Purcaro, Giorgia; Tranchida, Peter Q; Mondello, Luigi

    2015-07-10

    The present research is focused on the use and evaluation of a novel helium ionization detector, defined as barrier discharge ionization detector (BID), within the context of (low-)flow modulation comprehensive two-dimensional gas chromatography (FM GC×GC). The performance of the BID device was compared to that of a flame ionization detector (FID), under similar FM GC×GC conditions. Following development and optimization of the FM GC×GC method, the BID was subjected to fine tuning in relation to acquisition frequency and discharge flow. Moreover, the BID performance was measured and compared to that of the FID, in terms of extra-column band broadening, sensitivity and dynamic range. The comparative study was carried out by using standard compounds belonging to different chemical classes, along with a sample of diesel fuel. Advantages and disadvantages of the BID system, also within the context of FM GC×GC, are critically discussed. In general, the BID system was characterized by a more limited dynamic range and increased sensitivity, compared to the FID. Additionally, BID and FID contribution to band broadening was found to be similar under the operational conditions applied. Particular attention was devoted to the behaviour of the FM GC×GC-BID system toward saturated and aromatic hydrocarbons, for a possible future use in the field of mineral-oil food contamination research. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Design and Construction of Detector and Data Acquisition Elements for Proton Computed Tomography

    International Nuclear Information System (INIS)

    Fermi Research Alliance; Northern Illinois University

    2015-01-01

    Proton computed tomography (pCT) offers an alternative to x-ray imaging with potential for three-dimensional imaging, reduced radiation exposure, and in-situ imaging. Northern Illinois University (NIU) is developing a second-generation proton computed tomography system with a goal of demonstrating the feasibility of three-dimensional imaging within clinically realistic imaging times. The second-generation pCT system is comprised of a tracking system, a calorimeter, data acquisition, a computing farm, and software algorithms. The proton beam encounters the upstream tracking detectors, the patient or phantom, the downstream tracking detectors, and a calorimeter. The schematic layout of the PCT system is shown. The data acquisition sends the proton scattering information to an offline computing farm. Major innovations of the second generation pCT project involve an increased data acquisition rate ( MHz range) and development of three-dimensional imaging algorithms. The Fermilab Particle Physics Division and Northern Illinois Center for Accelerator and Detector Development at Northern Illinois University worked together to design and construct the tracking detectors, calorimeter, readout electronics and detector mounting system.

  17. A gamma-ray tracking detector for molecular imaging

    International Nuclear Information System (INIS)

    Hall, C.J.; Lewis, R.A.; Helsby, W.I.; Nolan, P.; Boston, A.

    2003-01-01

    A design for a gamma-ray detector for molecular imaging is presented. The system is based on solid-state strip detector technology. The advantages of position sensitivity coupled with fine spectral resolution are exploited to produce a tracking detector for use with a variety of isotopes in nuclear medicine. Current design concepts employ both silicon and germanium layers to provide an energy range from 60 keV to >1 MeV. This allows a reference X-ray image to be collected simultaneously with the gamma-ray image providing accurate anatomical registration. The tracking ability of the gamma-ray detector allows ambiguities in the data set to be resolved which would otherwise cause events to be rejected in standard non-tracking system. Efficiency improvements that high solid angle coverage and the use of a higher proportion of events make time resolved imaging and multi-isotope work possible. A modular detector system, designed for viewing small animals has been accepted for funding

  18. Evaluation of XRI-UNO CdTe detector for nuclear medical imaging

    International Nuclear Information System (INIS)

    Jambi, L.K.; Lees, J.E.; Bugby, S.L.; Alqahtani, M.S.; Tipper, S.; Perkins, A.C.

    2015-01-01

    Over the last two decades advances in semiconductor detector technology have reached the point where they are sufficiently sensitive to become an alternative to scintillators for high energy gamma ray detection for application in fields such as medical imaging. This paper assessed the Cadmium-Telluride (CdTe) XRI-UNO semiconductor detector produced by X-RAY Imatek for photon energies of interest in nuclear imaging. The XRI-UNO detector was found to have an intrinsic spatial resolution of <0.5mm and a high incident count rate capability up to at least 1680cps. The system spatial resolution, uniformity and sensitivity characteristics are also reported

  19. Three dimensional image reconstruction in the Fourier domain

    International Nuclear Information System (INIS)

    Stearns, C.W.; Chesler, D.A.; Brownell, G.L.

    1987-01-01

    Filtered backprojection reconstruction algorithms are based upon the relationship between the Fourier transform of the imaged object and the Fourier transforms of its projections. A new reconstruction algorithm has been developed which performs the image assembly operation in Fourier space, rather than in image space by backprojection. This represents a significant decrease in the number of operations required to assemble the image. The new Fourier domain algorithm has resolution comparable to the filtered backprojection algorithm, and, after correction by a pointwise multiplication, demonstrates proper recovery throughout image space. Although originally intended for three-dimensional imaging applications, the Fourier domain algorithm can also be developed for two-dimensional imaging applications such as planar positron imaging systems

  20. Comparison of two three-dimensional cephalometric analysis computer software

    OpenAIRE

    Sawchuk, Dena; Alhadlaq, Adel; Alkhadra, Thamer; Carlyle, Terry D; Kusnoto, Budi; El-Bialy, Tarek

    2014-01-01

    Background: Three-dimensional cephalometric analyses are getting more attraction in orthodontics. The aim of this study was to compare two softwares to evaluate three-dimensional cephalometric analyses of orthodontic treatment outcomes. Materials and Methods: Twenty cone beam computed tomography images were obtained using i-CAT® imaging system from patient's records as part of their regular orthodontic records. The images were analyzed using InVivoDental5.0 (Anatomage Inc.) and 3DCeph™ (Unive...

  1. Position-sensitive detector system OBI for High Resolution X-Ray Powder Diffraction using on-site readable image plates

    International Nuclear Information System (INIS)

    Knapp, M.; Joco, V.; Baehtz, C.; Brecht, H.H.; Berghaeuser, A.; Ehrenberg, H.; Seggern, H. von; Fuess, H.

    2004-01-01

    A one-dimensional detector system has been developed using image plates. The detector is working in transmission mode or Debye-Scherrer geometry and is on-site readable which reduces the effort for calibration. It covers a wide angular range up to 110 deg. and shows narrow reflection half-widths depending on the capillary diameter. The acquisition time is in the range of minutes and the data quality allows for reliable Rietveld refinement of complicated structures, even in multi-phase samples. The detector opens a wide field of new applications in kinetics and temperature resolved measurements

  2. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy

    International Nuclear Information System (INIS)

    Kim, Joshua; Zhang, Tiezhi; Lu, Weiguo

    2014-01-01

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source–dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10–15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source–dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented. (paper)

  3. Recent developments in X-ray imaging detectors

    CERN Document Server

    Moy, J P

    2000-01-01

    The replacement of the radiographic film in medical imaging has been the driving force in X-ray imaging developments. It requires a approx 40 cm wide detector to cover all examinations, an equivalent noise level of 1-5 X-ray quanta per pixel, and spatial resolution in the range 100-150 mu m. The need for entirely electronic imaging equipments has fostered the development of many X-ray detectors, most of them based on an array of amorphous silicon pixels, which is the only technology capable to achieve such large areas. Essentially, two concepts have been implemented: - intermediate conversion of X-rays to light by a scintillator, detected by an array of light sensitive pixels, comprising a photodiode and a switching device, either a TFT or a diode. - conversion into electron-hole pairs in a photoconductor, collected by an array of electrodes and switches. In both cases, charge amplifiers read the generated charges line by line. Scintillator and photoconductor-based systems are now close to production. They ac...

  4. Diagnostic Accuracy of the Volume Rendering Images of Multi-Detector CT for the Detection of Lumbar Transverse Process Fractures

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yun Hak; Chun, Tong Jin [Dept. of Radiology, Eulji University Hospital, Daejeon (Korea, Republic of)

    2012-01-15

    To compare the accuracy of three-dimensional computed tomographic (3D CT) volume rendering techniques with axial images of multi-detector row computed tomography to identify lumbar transverse process (LTP) fractures in trauma patients. We retrospectively evaluated 42 patients with back pain as a result of blunt trauma between January and June of 2010. Two radiologists examined the 3D CT volume rendering images independently. The confirmation of a LTP fracture was based on the consensus of the axial images by the two radiologists. The results of 3D CT volume rendering images were compared with the axial images and the diagnostic powers (sensitivity, specificity, and accuracy) were calculated. Seven of the 42 patients had twenty five lumbar transverse process fractures. The diagnostic power of the 3D CT volume rendering technique is as accurate as axial images. Reader 1, sensitivity 96%, specificity 100%, accuracy 99.9%; and Reader 2 sensitivity 100%, specificity 99.8%, accuracy 99.8%. The accordance of the two radiologists was 99.8%. 3D CT volume rendering images can alternate axial images to detect lumbar transverse process fractures with good image quality.

  5. Needle path planning and steering in a three-dimensional non-static environment using two-dimensional ultrasound images

    Science.gov (United States)

    Vrooijink, Gustaaf J.; Abayazid, Momen; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak

    2015-01-01

    Needle insertion is commonly performed in minimally invasive medical procedures such as biopsy and radiation cancer treatment. During such procedures, accurate needle tip placement is critical for correct diagnosis or successful treatment. Accurate placement of the needle tip inside tissue is challenging, especially when the target moves and anatomical obstacles must be avoided. We develop a needle steering system capable of autonomously and accurately guiding a steerable needle using two-dimensional (2D) ultrasound images. The needle is steered to a moving target while avoiding moving obstacles in a three-dimensional (3D) non-static environment. Using a 2D ultrasound imaging device, our system accurately tracks the needle tip motion in 3D space in order to estimate the tip pose. The needle tip pose is used by a rapidly exploring random tree-based motion planner to compute a feasible needle path to the target. The motion planner is sufficiently fast such that replanning can be performed repeatedly in a closed-loop manner. This enables the system to correct for perturbations in needle motion, and movement in obstacle and target locations. Our needle steering experiments in a soft-tissue phantom achieves maximum targeting errors of 0.86 ± 0.35 mm (without obstacles) and 2.16 ± 0.88 mm (with a moving obstacle). PMID:26279600

  6. Scintillating-fiber imaging detector for 14-MeV neutrons

    International Nuclear Information System (INIS)

    Ress, D.; Lerche, R.A.; Ellis, R.J.; Heaton, G.W.; Nelson, M.B.; Mant, G.; Lehr, D.E.

    1994-01-01

    The authors have created a detector to image the neutrons emitted by imploded inertial-confinement fusion targets. The 14-MeV neutrons, which are produced by deuterium-tritium fusion events in the target, pass through an aperture to create an image on the detector. The neutron radiation is converted to blue light (430 nm) with a 20-cm-square array of plastic scintillating fibers. Each fiber is 10-cm long with a 1-mm-square cross section; approximately 35-thousand fibers make up the array. The resulting blue-light image is reduced and amplified by a sequence of fiber-optic tapers and image intensifiers, then acquired by a CCD camera. The fiber-optic readout system was tested optically for overall throughput the resolution. The authors plan to characterize the scintillator array reusing an ion-beam neutron source as well as DT-fusion neutrons emitted by inertial confinement targets. Characterization experiments will measure the light-production efficiency, spatial resolution, and neutron scattering within the detector. Several neutron images of laser-fusion targets have been obtained with the detector. Several neutron images of laser-fusion targets have been obtained with the detector. They describe the detector and their characterization methods, present characterization results, and give examples of the neutron images

  7. Radiation imaging with optically read out GEM-based detectors

    Science.gov (United States)

    Brunbauer, F. M.; Lupberger, M.; Oliveri, E.; Resnati, F.; Ropelewski, L.; Streli, C.; Thuiner, P.; van Stenis, M.

    2018-02-01

    Modern imaging sensors allow for high granularity optical readout of radiation detectors such as MicroPattern Gaseous Detectors (MPGDs). Taking advantage of the high signal amplification factors achievable by MPGD technologies such as Gaseous Electron Multipliers (GEMs), highly sensitive detectors can be realised and employing gas mixtures with strong scintillation yield in the visible wavelength regime, optical readout of such detectors can provide high-resolution event representations. Applications from X-ray imaging to fluoroscopy and tomography profit from the good spatial resolution of optical readout and the possibility to obtain images without the need for extensive reconstruction. Sensitivity to low-energy X-rays and energy resolution permit energy resolved imaging and material distinction in X-ray fluorescence measurements. Additionally, the low material budget of gaseous detectors and the possibility to couple scintillation light to imaging sensors via fibres or mirrors makes optically read out GEMs an ideal candidate for beam monitoring detectors in high energy physics as well as radiotherapy. We present applications and achievements of optically read out GEM-based detectors including high spatial resolution imaging and X-ray fluorescence measurements as an alternative readout approach for MPGDs. A detector concept for low intensity applications such as X-ray crystallography, which maximises detection efficiency with a thick conversion region but mitigates parallax-induced broadening is presented and beam monitoring capabilities of optical readout are explored. Augmenting high resolution 2D projections of particle tracks obtained with optical readout with timing information from fast photon detectors or transparent anodes for charge readout, 3D reconstruction of particle trajectories can be performed and permits the realisation of optically read out time projection chambers. Combining readily available high performance imaging sensors with compatible

  8. Ultrafast secondary emission x-ray imaging detectors

    International Nuclear Information System (INIS)

    Akkerman, A.; Gibrekhterman, A.; Majewski, S.

    1991-07-01

    Fast high accuracy, x-ray imaging at high photon flux can be achieved when coupling thin solid convertors to gaseous electron multipliers, operating at low gas pressures. Secondary electron emitted from the convertor foil are multiplied in several successive amplification elements. The obvious advantage of solid x-ray detectors, as compared to gaseous conversion, are the production of parallax-free images and the fast (subnanoseconds) response. These x-ray detectors have many potential applications in basic and applied research. Of particular interest is the possibility of an efficient and ultrafast high resolution imaging of transition radiation,with a reduced dE/dx background. We present experimental results on the operation of the secondary emission x-ray (SEX) detectors, their detection efficiency, localization and time resolution. The experimental work is accompanied by mathematical modelling and computer simulation of transition radiation detectors based on CsI transition radiation convertors. (author)

  9. PILATUS: a two-dimensional X-ray detector for macromolecular crystallography

    CERN Document Server

    Eikenberry, E F; Huelsen, G; Toyokawa, H; Horisberger, R P; Schmitt, B; Schulze-Briese, C; Tomizaki, T

    2003-01-01

    A large quantum-limited area X-ray detector for protein crystallography is under development at the Swiss Light Source. The final detector will be 2kx2k pixels covering 40x40 cm sup 2. A three-module prototype with 1120x157 pixels covering an active area of 24.3x3.4 cm sup 2 has been tested. X-rays above 6 keV with peak count rates exceeding 5x10 sup 5 X-ray/pixel/s could be detected in single photon counting mode. Statistics of module production and results of threshold trimming are presented. To demonstrate the potential of this new detector, protein crystal data were collected at beamline 6S of the SLS.

  10. Imaging off-plane shear waves with a two-dimensional phononic crystal lens

    International Nuclear Information System (INIS)

    Chiang Chenyu; Luan Pigang

    2010-01-01

    A two-dimensional flat phononic crystal (PC) lens for focusing off-plane shear waves is proposed. The lens consists of a triangular lattice hole-array, embedded in a solid matrix. The self-collimation effect is employed to guide the shear waves propagating through the lens along specific directions. The Dirichlet-to-Neumann maps (DtN) method is employed to calculate the band structure of the PC, which can avoid the problems of bad convergence and fake bands automatically in the void-solid PC structure. When the lens is illuminated by the off-plane shear waves emanating from a point source, a subwavelength image appears in the far-field zone. The imaging characteristics are investigated by calculating the displacement fields explicitly using the multiple scattering method, and the results are in good agreement with the ray-trace predictions. Our results may provide insights for designing new phononic devices.

  11. Two-Dimensional Extreme Learning Machine

    Directory of Open Access Journals (Sweden)

    Bo Jia

    2015-01-01

    (BP networks. However, like many other methods, ELM is originally proposed to handle vector pattern while nonvector patterns in real applications need to be explored, such as image data. We propose the two-dimensional extreme learning machine (2DELM based on the very natural idea to deal with matrix data directly. Unlike original ELM which handles vectors, 2DELM take the matrices as input features without vectorization. Empirical studies on several real image datasets show the efficiency and effectiveness of the algorithm.

  12. 18th International Workshop on Radiation Imaging Detectors

    CERN Document Server

    2016-01-01

    The International Workshops on Radiation Imaging Detectors are held yearly and provide an international forum for discussing current research and developments in the area of position sensitive detectors for radiation imaging, including semiconductor detectors, gas and scintillator-based detectors. Topics include processing and characterization of detector materials, hybridization and interconnect technologies, design of counting or integrating electronics, readout and data acquisition systems, and applications in various scientific and industrial fields. The workshop will have plenary sessions with invited and contributed papers presented orally and in poster sessions. The invited talks will be chosen to review recent advances in different areas covered in the workshop.

  13. Comparison of two three-dimensional cephalometric analysis computer software.

    Science.gov (United States)

    Sawchuk, Dena; Alhadlaq, Adel; Alkhadra, Thamer; Carlyle, Terry D; Kusnoto, Budi; El-Bialy, Tarek

    2014-10-01

    Three-dimensional cephalometric analyses are getting more attraction in orthodontics. The aim of this study was to compare two softwares to evaluate three-dimensional cephalometric analyses of orthodontic treatment outcomes. Twenty cone beam computed tomography images were obtained using i-CAT(®) imaging system from patient's records as part of their regular orthodontic records. The images were analyzed using InVivoDental5.0 (Anatomage Inc.) and 3DCeph™ (University of Illinois at Chicago, Chicago, IL, USA) software. Before and after orthodontic treatments data were analyzed using t-test. Reliability test using interclass correlation coefficient was stronger for InVivoDental5.0 (0.83-0.98) compared with 3DCeph™ (0.51-0.90). Paired t-test comparison of the two softwares shows no statistical significant difference in the measurements made in the two softwares. InVivoDental5.0 measurements are more reproducible and user friendly when compared to 3DCeph™. No statistical difference between the two softwares in linear or angular measurements. 3DCeph™ is more time-consuming in performing three-dimensional analysis compared with InVivoDental5.0.

  14. The noise analysis and optimum filtering techniques for a two-dimensional position sensitive orthogonal strip gamma ray detector employing resistive charge division

    International Nuclear Information System (INIS)

    Gerber, M.S.; Muller, D.W.

    1976-01-01

    The analysis of an orthogonal strip, two-dimensional position sensitive high purity germanium gamma ray detector is discussed. Position sensitivity is obtained by connecting each electrode strip on the detector to a resistor network. Charge, entering the network, divides in relation to the resistance between its entry point and the virtual earth points of the charge sensitive preamplifiers located at the end of each resistor network. The difference of the voltage pulses at the output of each preamplifier is proportional to the position at which the charge entered the resistor network and the sum of the pulse is proportional to the energy of the detected gamma ray. The analysis and spatial noise resolution is presented for this type of position sensitive detector. The results of the analysis show that the position resolution is proportional to the square root of the filter amplifier's output pulse time constant and that for energy measurement the resolution is maximized at the filter amplifier's noise corner time constant. The design of the electronic noise filtering system for the prototype gamma ray camera was based on the mathematical energy and spatial resolution equations. For the spatial channel a Gaussian trapezoidal filtering system was developed. Gaussian filtering was used for the energy channel. The detector noise model was verified by taking rms noise measurements of the filtered energy and spatial pulses from resistive readout charge dividing detectors. These measurements were within 10% of theory. (Auth.)

  15. Theoretical analysis of the effect of charge-sharing on the Detective Quantum Efficiency of single-photon counting segmented silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Marchal, J [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)], E-mail: julien.marchal@diamond.ac.uk

    2010-01-15

    A detector cascaded model is proposed to describe charge-sharing effect in single-photon counting segmented silicon detectors. Linear system theory is applied to this cascaded model in order to derive detector performance parameters such as large-area gain, presampling Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE) as a function of energy detection threshold. This theory is used to model one-dimensional detectors (i.e. strip detectors) where X-ray-generated charge can be shared between two sampling elements, but the concepts developed in this article can be generalized to two-dimensional arrays of detecting elements (i.e. pixels detectors). The zero-frequency DQE derived from this model is consistent with expressions reported in the literature using a different method. The ability of this model to simulate the effect of charge sharing on image quality in the spatial frequency domain is demonstrated by applying it to a hypothetical one-dimensional single-photon counting detector illuminated with a typical mammography spectrum.

  16. Application of Simulated Three Dimensional CT Image in Orthognathic Surgery

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Don; Park, Chang Seo [Dept. of Dental Radiology, College of Dentistry, Yensei University, Seoul (Korea, Republic of); Yoo, Sun Kook; Lee, Kyoung Sang [Dept. of Medical Engineering, College of Medicine, Yensei University, Seoul (Korea, Republic of)

    1998-08-15

    In orthodontics and orthognathic surgery, cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery, too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipment and because of its expenses and amount of exposure to radiation, limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram, pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms, and for validation of new method, in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery, computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of

  17. Application of Simulated Three Dimensional CT Image in Orthognathic Surgery

    International Nuclear Information System (INIS)

    Kim, Hyun Don; Park, Chang Seo; Yoo, Sun Kook; Lee, Kyoung Sang

    1998-01-01

    In orthodontics and orthognathic surgery, cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery, too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipment and because of its expenses and amount of exposure to radiation, limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram, pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms, and for validation of new method, in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery, computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of

  18. Recognition of Equations Using a Two-Dimensional Stochastic Context-Free Grammar

    Science.gov (United States)

    Chou, Philip A.

    1989-11-01

    We propose using two-dimensional stochastic context-free grammars for image recognition, in a manner analogous to using hidden Markov models for speech recognition. The value of the approach is demonstrated in a system that recognizes printed, noisy equations. The system uses a two-dimensional probabilistic version of the Cocke-Younger-Kasami parsing algorithm to find the most likely parse of the observed image, and then traverses the corresponding parse tree in accordance with translation formats associated with each production rule, to produce eqn I troff commands for the imaged equation. In addition, it uses two-dimensional versions of the Inside/Outside and Baum re-estimation algorithms for learning the parameters of the grammar from a training set of examples. Parsing the image of a simple noisy equation currently takes about one second of cpu time on an Alliant FX/80.

  19. The Use of Radiation Detectors in Medicine: Radiation Detectors for Morphological Imaging (1/3)

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    The development of radiation detectors in the field of nuclear and particle physics has had a terrific impact in medical imaging since this latter discipline took off in late ’70 with the invention of the CT scanners. The massive use in High Energy Physics of position sensitive gas detectors, of high Z and high density scintillators coupled to Photomultiplier (PMT) and Position Sensitive Photomultipliers (PSPMT), and of solid state detectors has triggered during the last 30 years a series of novel applications in Medical Imaging with ionizing radiation. The accelerated scientific progression in genetics and molecular biology has finally generated what it is now called Molecular Imaging. This field of research presents additional challenges not only in the technology of radiation detector, but more and more in the ASIC electronics, fast digital readout and parallel software. In this series of three lectures I will try to present how high energy physics and medical imaging development have both benefited by t...

  20. The Use of Radiation Detectors in Medicine: Radiation Detectors for Functional Imaging (2/3)

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    The development of radiation detectors in the field of nuclear and particle physics has had a terrific impact in medical imaging since this latter discipline took off in late ’70 with the invention of the CT scanners. The massive use in High Energy Physics of position sensitive gas detectors, of high Z and high density scintillators coupled to Photomultiplier (PMT) and Position Sensitive Photomultipliers (PSPMT), and of solid state detectors has triggered during the last 30 years a series of novel applications in Medical Imaging with ionizing radiation. The accelerated scientific progression in genetics and molecular biology has finally generated what it is now called Molecular Imaging. This field of research presents additional challenges not only in the technology of radiation detector, but more and more in the ASIC electronics, fast digital readout and parallel software. In this series of three lectures I will try to present how high energy physics and medical imaging development have both benefited by t...

  1. Development and characterisation of a visible light photon counting imaging detector system

    CERN Document Server

    Barnstedt, J

    2002-01-01

    We report on the development of a visible light photon counting imaging detector system. The detector concept is based on standard 25 mm diameter microchannel plate image intensifiers made by Proxitronic in Bensheim (Germany). Modifications applied to these image intensifiers are the use of three microchannel plates instead of two and a high resistance ceramics plate used instead of the standard phosphor output screen. A wedge and strip anode mounted directly behind the high resistance ceramics plate was used as a read out device. This wedge and strip anode picks up the image charge of electron clouds emerging from the microchannel plates. The charge pulses are fed into four charge amplifiers and subsequently into a digital position decoding electronics, achieving a position resolution of up to 1024x1024 pixels. Mounting the anode outside the detector tube is a new approach and has the great advantage of avoiding electrical feedthroughs from the anode so that the standard image intensifier fabrication process...

  2. A three-dimensional correlation method for registration of medical images in radiology

    Energy Technology Data Exchange (ETDEWEB)

    Georgiou, Michalakis; Sfakianakis, George N [Department of Radiology, University of Miami, Jackson Memorial Hospital, Miami, FL 33136 (United States); Nagel, Joachim H [Institute of Biomedical Engineering, University of Stuttgart, Stuttgart 70174 (Germany)

    1999-12-31

    The availability of methods to register multi-modality images in order to `fuse` them to correlate their information is increasingly becoming an important requirement for various diagnostic and therapeutic procedures. A variety of image registration methods have been developed but they remain limited to specific clinical applications. Assuming rigid body transformation, two images can be registered if their differences are calculated in terms of translation, rotation and scaling. This paper describes the development and testing of a new correlation based approach for three-dimensional image registration. First, the scaling factors introduced by the imaging devices are calculated and compensated for. Then, the two images become translation invariant by computing their three-dimensional Fourier magnitude spectra. Subsequently, spherical coordinate transformation is performed and then the three-dimensional rotation is computed using a novice approach referred to as {sup p}olar Shells{sup .} The method of polar shells maps the three angles of rotation into one rotation and two translations of a two-dimensional function and then proceeds to calculate them using appropriate transformations based on the Fourier invariance properties. A basic assumption in the method is that the three-dimensional rotation is constrained to one large and two relatively small angles. This assumption is generally satisfied in normal clinical settings. The new three-dimensional image registration method was tested with simulations using computer generated phantom data as well as actual clinical data. Performance analysis and accuracy evaluation of the method using computer simulations yielded errors in the sub-pixel range. (authors) 6 refs., 3 figs.

  3. A three-dimensional correlation method for registration of medical images in radiology

    International Nuclear Information System (INIS)

    Georgiou, Michalakis; Sfakianakis, George N.; Nagel, Joachim H.

    1998-01-01

    The availability of methods to register multi-modality images in order to 'fuse' them to correlate their information is increasingly becoming an important requirement for various diagnostic and therapeutic procedures. A variety of image registration methods have been developed but they remain limited to specific clinical applications. Assuming rigid body transformation, two images can be registered if their differences are calculated in terms of translation, rotation and scaling. This paper describes the development and testing of a new correlation based approach for three-dimensional image registration. First, the scaling factors introduced by the imaging devices are calculated and compensated for. Then, the two images become translation invariant by computing their three-dimensional Fourier magnitude spectra. Subsequently, spherical coordinate transformation is performed and then the three-dimensional rotation is computed using a novice approach referred to as p olar Shells . The method of polar shells maps the three angles of rotation into one rotation and two translations of a two-dimensional function and then proceeds to calculate them using appropriate transformations based on the Fourier invariance properties. A basic assumption in the method is that the three-dimensional rotation is constrained to one large and two relatively small angles. This assumption is generally satisfied in normal clinical settings. The new three-dimensional image registration method was tested with simulations using computer generated phantom data as well as actual clinical data. Performance analysis and accuracy evaluation of the method using computer simulations yielded errors in the sub-pixel range. (authors)

  4. The simulation of two-dimensional migration patterns - a novel approach

    International Nuclear Information System (INIS)

    Villar, Heldio Pereira

    1997-01-01

    A novel approach to the problem of simulation of two-dimensional migration of solutes in saturated soils is presented. In this approach, the two-dimensional advection-dispersion equation is solved by finite-differences in a stepwise fashion, by employing the one-dimensional solution first in the direction of flow and then perpendicularly, using the same time increment in both cases. As the results of this numerical model were to be verified against experimental results obtained by radioactive tracer experiments, an attenuation factor, to account for the contribution of the gamma rays emitted by the whole plume of tracer to the readings of the adopted radiation detectors, was introduced into the model. The comparison between experimental and simulated concentration contours showed good agreement, thus establishing the feasibility of the approach proposed herein. (author)

  5. Radiographic evaluation of the maxillary sinus prior to dental implant therapy: A comparison between two dimensional and three dimensional radiographic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tadinada, Aditya; Fung, Karen; Thacker, Sejal; Mahdian, Mina; Jadhaw, Aniket; Schincaglia, Gian Pietro [University of Connecticut School of Dental Medicine, Farmington (United States)

    2015-09-15

    This study was performed to evaluate the diagnostic efficacy of panoramic radiography and cone-beam computed tomography (CBCT) in detecting sinus pathology. This study was based on a retrospective evaluation of patients who had undergone both a panoramic radiograph and a CBCT exam. A total of 100 maxillary sinuses were evaluated. Four examiners with various levels of expertise evaluated the images using a five-point scoring system. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficacy of the two modalities. The image analysis was repeated twice, with at least two weeks between the evaluation sessions. Interobserver reliability was assessed using Cronbach's alpha, and intraobserver reliability was assessed using Cohen's kappa. Maxillary sinus pathology was detected in 72% of the patients. High interobserver and intraobserver reliability were observed for both imaging modalities and among the four examiners. Statistical analyses using ROC curves demonstrated that the CBCT images had a larger area under the curve (0.940) than the panoramic radiographs (0.579). Three-dimensional evaluation of the sinus with CBCT was significantly more reliable in detecting pathology than panoramic imaging.

  6. High-resolution non-destructive three-dimensional imaging of integrated circuits.

    Science.gov (United States)

    Holler, Mirko; Guizar-Sicairos, Manuel; Tsai, Esther H R; Dinapoli, Roberto; Müller, Elisabeth; Bunk, Oliver; Raabe, Jörg; Aeppli, Gabriel

    2017-03-15

    Modern nanoelectronics has advanced to a point at which it is impossible to image entire devices and their interconnections non-destructively because of their small feature sizes and the complex three-dimensional structures resulting from their integration on a chip. This metrology gap implies a lack of direct feedback between design and manufacturing processes, and hampers quality control during production, shipment and use. Here we demonstrate that X-ray ptychography-a high-resolution coherent diffractive imaging technique-can create three-dimensional images of integrated circuits of known and unknown designs with a lateral resolution in all directions down to 14.6 nanometres. We obtained detailed device geometries and corresponding elemental maps, and show how the devices are integrated with each other to form the chip. Our experiments represent a major advance in chip inspection and reverse engineering over the traditional destructive electron microscopy and ion milling techniques. Foreseeable developments in X-ray sources, optics and detectors, as well as adoption of an instrument geometry optimized for planar rather than cylindrical samples, could lead to a thousand-fold increase in efficiency, with concomitant reductions in scan times and voxel sizes.

  7. High-resolution non-destructive three-dimensional imaging of integrated circuits

    Science.gov (United States)

    Holler, Mirko; Guizar-Sicairos, Manuel; Tsai, Esther H. R.; Dinapoli, Roberto; Müller, Elisabeth; Bunk, Oliver; Raabe, Jörg; Aeppli, Gabriel

    2017-03-01

    Modern nanoelectronics has advanced to a point at which it is impossible to image entire devices and their interconnections non-destructively because of their small feature sizes and the complex three-dimensional structures resulting from their integration on a chip. This metrology gap implies a lack of direct feedback between design and manufacturing processes, and hampers quality control during production, shipment and use. Here we demonstrate that X-ray ptychography—a high-resolution coherent diffractive imaging technique—can create three-dimensional images of integrated circuits of known and unknown designs with a lateral resolution in all directions down to 14.6 nanometres. We obtained detailed device geometries and corresponding elemental maps, and show how the devices are integrated with each other to form the chip. Our experiments represent a major advance in chip inspection and reverse engineering over the traditional destructive electron microscopy and ion milling techniques. Foreseeable developments in X-ray sources, optics and detectors, as well as adoption of an instrument geometry optimized for planar rather than cylindrical samples, could lead to a thousand-fold increase in efficiency, with concomitant reductions in scan times and voxel sizes.

  8. Bio-medical X-ray imaging with spectroscopic pixel detectors

    CERN Document Server

    Butler, A P H; Tipples, R; Cook, N; Watts, R; Meyer, J; Bell, A J; Melzer, T R; Butler, P H

    2008-01-01

    The aim of this study is to review the clinical potential of spectroscopic X-ray detectors and to undertake a feasibility study using a novel detector in a clinical hospital setting. Detectors currently in development, such as Medipix-3, will have multiple energy thresholds allowing for routine use of spectroscopic bio-medical imaging. We have coined the term MARS (Medipix All Resolution System) for bio-medical images that provide spatial, temporal, and energy information. The full clinical significance of spectroscopic X-ray imaging is difficult to predict but insights can be gained by examining both image reconstruction artifacts and the current uses of dual-energy techniques. This paper reviews the known uses of energy information in vascular imaging and mammography, clinically important fields. It then presents initial results from using Medipix-2, to image human tissues within a clinical radiology department. Detectors currently in development, such as Medipix-3, will have multiple energy thresholds allo...

  9. Two-dimensional position sensitive silicon photodiode as a charged particle detector

    International Nuclear Information System (INIS)

    Kovacevic, K.; Zadro, M.

    1999-01-01

    A two-dimensional position sensitive silicon photodiode has been tested for measurement of position and energy of charged particles. Position nonlinearity and resolution, as well as energy resolution and ballistic deficit were measured for 5.486 MeV α-particles. The results obtained for different pulse shaping time constants are presented

  10. Tracking brachytherapy sources using emission imaging with one flat panel detector

    International Nuclear Information System (INIS)

    Song Haijun; Bowsher, James; Das, Shiva; Yin Fangfang

    2009-01-01

    This work proposes to use the radiation from brachytherapy sources to track their dwell positions in three-dimensional (3D) space. The prototype device uses a single flat panel detector and a BB tray. The BBs are arranged in a defined pattern. The shadow of the BBs on the flat panel is analyzed to derive the 3D coordinates of the illumination source, i.e., the dwell position of the brachytherapy source. A kilovoltage x-ray source located 3.3 m away was used to align the center BB with the center pixel on the flat panel detector. For a test plan of 11 dwell positions, with an Ir-192 high dose rate unit, one projection was taken for each dwell point, and locations of the BB shadows were manually identified on the projection images. The 3D coordinates for the 11 dwell positions were reconstructed based on two BBs. The distances between dwell points were compared with the expected values. The average difference was 0.07 cm with a standard deviation of 0.15 cm. With automated BB shadow recognition in the future, this technique possesses the potential of tracking the 3D trajectory and the dwell times of a brachytherapy source in real time, enabling real time source position verification.

  11. One-dimensional neutron imager for the Sandia Z facility.

    Science.gov (United States)

    Fittinghoff, David N; Bower, Dan E; Hollaway, James R; Jacoby, Barry A; Weiss, Paul B; Buckles, Robert A; Sammons, Timothy J; McPherson, Leroy A; Ruiz, Carlos L; Chandler, Gordon A; Torres, José A; Leeper, Ramon J; Cooper, Gary W; Nelson, Alan J

    2008-10-01

    A multiinstitution collaboration is developing a neutron imaging system for the Sandia Z facility. The initial system design is for slit aperture imaging system capable of obtaining a one-dimensional image of a 2.45 MeV source producing 5x10(12) neutrons with a resolution of 320 microm along the axial dimension of the plasma, but the design being developed can be modified for two-dimensional imaging and imaging of DT neutrons with other resolutions. This system will allow us to understand the spatial production of neutrons in the plasmas produced at the Z facility.

  12. Performance test of a micro-pattern stereo detector with two gas electron multipliers

    International Nuclear Information System (INIS)

    Barvich, T.; Bluem, P.; Erdmann, M.; Fahrer, M.; Kaercher, K.; Kuehn, F.; Moermann, D.; Mueller, Th.; Neuberger, D.; Roederer, F.; Simonis, H.J.; Skiba, A.; Thuemmel, W.H.; Weiler, Th.; Weseler, S.

    2002-01-01

    We report on the performance of a large micro-pattern detector with two gas electron multiplier foils and a two-layer readout structure at ground potential. The two readout layers each have a 406 μm pitch and cross at an effective angle of 6.7 deg. . This structure allows for two orthogonal coordinates to be determined. Using a muon beam at CERN together with a silicon tracking system, the position resolutions of the two coordinates are measured to be 50 μm and 1 mm respectively (1 standard deviation). The muon detection efficiency for the two-dimensional space points reaches 96%. The detector was found to be well operational over a wide range in the settings of the different electrical fields

  13. Positron emission tomography with additional γ-ray detectors for multiple-tracer imaging.

    Science.gov (United States)

    Fukuchi, Tomonori; Okauchi, Takashi; Shigeta, Mika; Yamamoto, Seiichi; Watanabe, Yasuyoshi; Enomoto, Shuichi

    2017-06-01

    Positron emission tomography (PET) is a useful imaging modality that quantifies the physiological distributions of radiolabeled tracers in vivo in humans and animals. However, this technique is unsuitable for multiple-tracer imaging because the annihilation photons used for PET imaging have a fixed energy regardless of the selection of the radionuclide tracer. This study developed a multi-isotope PET (MI-PET) system and evaluated its imaging performance. Our MI-PET system is composed of a PET system and additional γ-ray detectors. The PET system consists of pixelized gadolinium orthosilicate (GSO) scintillation detectors and has a ring geometry that is 95 mm in diameter with an axial field of view of 37.5 mm. The additional detectors are eight bismuth germanium oxide (BGO) scintillation detectors, each of which is 50 × 50 × 30 mm 3 , arranged into two rings mounted on each side of the PET ring with a 92-mm-inner diameter. This system can distinguish between different tracers using the additional γ-ray detectors to observe prompt γ-rays, which are emitted after positron emission and have an energy intrinsic to each radionuclide. Our system can simultaneously acquire double- (two annihilation photons) and triple- (two annihilation photons and a prompt γ-ray) coincidence events. The system's efficiency for detecting prompt de-excitation γ-rays was measured using a positron-γ emitter, 22 Na. Dual-radionuclide ( 18 F and 22 Na) imaging of a rod phantom and a mouse was performed to demonstrate the performance of the developed system. Our system's basic performance was evaluated by reconstructing two images, one containing both tracers and the other containing just the second tracer, from list-mode data sets that were categorized by the presence or absence of the prompt γ-ray. The maximum detection efficiency for 1275 keV γ-rays emitted from 22 Na was approximately 7% at the scanner's center, and the minimum detection efficiency was 5.1% at the edge of

  14. SU-F-T-576: Characterization of Two Dimensional Liquid Filled Detector Array(SRS 1000) in High Precision Cyberknife Robotic Radiosurgery System

    International Nuclear Information System (INIS)

    Muthukumaran, M; Manigandan, D; Murali, V; Chitra, S; Ganapathy, K; Vikraman, S

    2016-01-01

    Purpose: The aim of the study is to characterize a two dimensional liquid filled detector array SRS 1000 for routine QA in Cyberknife Robotic Radiosurgery system. Methods: SRS 1000 consists of 977 liquid filled ionization chambers and is designed to be used in small field SRS/SBRT techniques. The detector array has got two different spacial resolutions. Till field size of 5.5×5.5 cm the spacial resolution is 2.5mm (center to center) and after that till field size of 11 × 11 cm the spacial resolution is 5mm. The size of the detector is 2.3 × 2.3 0.5 mm with a volume of .003 cc. The CyberKnife Robotic Radiosurgery System is a frameless stereotactic radiosurgery system in which a LINAC is mounted on a robotic manipulator to deliver beams with a high sub millimeter accuracy. The SRS 1000’s MU linearity, stability, reproducibility in Cyberknife Robotic Radiosurgery system was measured and investigated. The output factors for fixed and IRIS collimators for all available collimators (5mm till 60 mm) was measured and compared with the measurement done with PTW pin-point ionization chamber. Results: The MU linearity was measured from 2 MU till 1000 MU for doserates in the range of 700cGy/min – 780 cGy/min and compared with the measurement done with pin point chamber The MU linearity was with in 3%. The detector arrays stability and reproducibility was excellent and was withinin 0.5% The measured output factors showed an agreement of better than 2% when compared with the measurements with pinpoint chamber for both fixed and IRIS collimators with all available field sizes. Conclusion: We have characterised PTW 1000 SRS as a precise and accurate measurement tool for routine QA of Cyberknife Robotic radiosurgery system.

  15. SU-F-T-576: Characterization of Two Dimensional Liquid Filled Detector Array(SRS 1000) in High Precision Cyberknife Robotic Radiosurgery System

    Energy Technology Data Exchange (ETDEWEB)

    Muthukumaran, M [Apollo Speciality Hospitals, Chennai, Tamil Nadu (India); Manigandan, D [Fortis Cancer Institute, Mohali, Punjab (India); Murali, V; Chitra, S; Ganapathy, K [Apollo Speciality Hospital, Chennai, Tamil Nadu (India); Vikraman, S [Jaypee Hospital – Radiation Onology, Noida, UTTAR PRADESH (India)

    2016-06-15

    Purpose: The aim of the study is to characterize a two dimensional liquid filled detector array SRS 1000 for routine QA in Cyberknife Robotic Radiosurgery system. Methods: SRS 1000 consists of 977 liquid filled ionization chambers and is designed to be used in small field SRS/SBRT techniques. The detector array has got two different spacial resolutions. Till field size of 5.5×5.5 cm the spacial resolution is 2.5mm (center to center) and after that till field size of 11 × 11 cm the spacial resolution is 5mm. The size of the detector is 2.3 × 2.3 0.5 mm with a volume of .003 cc. The CyberKnife Robotic Radiosurgery System is a frameless stereotactic radiosurgery system in which a LINAC is mounted on a robotic manipulator to deliver beams with a high sub millimeter accuracy. The SRS 1000’s MU linearity, stability, reproducibility in Cyberknife Robotic Radiosurgery system was measured and investigated. The output factors for fixed and IRIS collimators for all available collimators (5mm till 60 mm) was measured and compared with the measurement done with PTW pin-point ionization chamber. Results: The MU linearity was measured from 2 MU till 1000 MU for doserates in the range of 700cGy/min – 780 cGy/min and compared with the measurement done with pin point chamber The MU linearity was with in 3%. The detector arrays stability and reproducibility was excellent and was withinin 0.5% The measured output factors showed an agreement of better than 2% when compared with the measurements with pinpoint chamber for both fixed and IRIS collimators with all available field sizes. Conclusion: We have characterised PTW 1000 SRS as a precise and accurate measurement tool for routine QA of Cyberknife Robotic radiosurgery system.

  16. Application of position-sensitive detectors to positron imaging

    International Nuclear Information System (INIS)

    Yamashita, Takaji; Uchida, Hiroshi; Watanabe, Mitsuo; Omura, Tomohide

    1994-01-01

    Positron imaging including positron emission tomography (PET) is expected to be a promising tool for basic and clinical research, because it makes possible the study of regional chemistry within multiple organs of the body in living human beings and experimental animals. New schemes of high resolution block detectors have been developed to improve the performance of positron imaging systems, which employ small segments of bismuth germanate (BGO) arrays and position-sensitive photomultiplier tubes (PS-PMT). The coincidence detector resolution of less than 2.0 mm in full width at half maximum was achieved with the detectors, which is very close to the theoretical resolution limit in positron imaging. (author)

  17. Matching Two-dimensional Gel Electrophoresis' Spots

    DEFF Research Database (Denmark)

    Dos Anjos, António; AL-Tam, Faroq; Shahbazkia, Hamid Reza

    2012-01-01

    This paper describes an approach for matching Two-Dimensional Electrophoresis (2-DE) gels' spots, involving the use of image registration. The number of false positive matches produced by the proposed approach is small, when compared to academic and commercial state-of-the-art approaches. This ar...

  18. Management of a Two-rooted Maxillary Central Incisor Using Cone-beam Computed Tomography: Importance of Three-dimensional Imaging

    Directory of Open Access Journals (Sweden)

    Saurabh Kumar Gupta

    2015-09-01

    Full Text Available We report a rare case of a two-rooted maxillary central incisor, stressing the importance of three-dimensional imaging in treatment planning and conservative approach of management. Endodontic treatment of this central incisor was carried out with a successful outcome.

  19. Left ventricular thrombi: in vivo detection by indium-111 platelet imaging and two dimensional echocardiography

    International Nuclear Information System (INIS)

    Stratton, J.R.; Ritchie, J.L.; Hamilton, G.W.; Hammermeister, K.E.; Harker, L.A.

    1981-01-01

    Indium-111 platelet imaging, which can identify sites of active intravascular platelet deposition, and two dimensional echocardiography, which can identify intracardiac masses, can both be used to detect left ventricular thrombi noninvasively. We compared these techniques in 44 men at risk for thrombi from remote transmural myocardial infarction (31 patients) or cardiomyopathy (13 patients). All 44 patients underwent platelet imaging; 35 underwent echocardiography. On platelet imaging nine patients had thrombi and onehad a possible thrombus. Of these 10 studies, none were positive at 2 hours, 5 were positive at 24 hours and all were positive 48 or 72 hours after platelet labeling. Nine of these patients underwent echocardiography, and all had an intraventricular mass. The findings on platelet scanning were negative in six patients who had positive (four patients) or equivocally positive (two patients) findings on echocardiography. All patients with thrombi detected by either noninvasive method had transmural anterior myocardial infarction with ventricular aneurysm. Of the seven patients who underwent cardiac surgery or autopsy, three had thrombi. Platelet imaging failed to identify one thrombus in a patient in whom imaging was performed only at 24 hours after labeling. There were no false positive platelet images in this group. Five of these seven patients (two with throbi, three without) underwent echocardiography; in all cases the echocardiographic findings agreed with the pathologic findings. Both platelet imaging and echocardiography detect ventricular thrombi. Platelet imaging may detect only the most hematologically active thrombi. Both techniques may help define patients at risk of embolization and may be useful for in vivo assessment of antithrombotic drugs

  20. The HERMES dual-radiator ring imaging Cherenkov detector

    CERN Document Server

    Akopov, N; Bailey, K; Bernreuther, S; Bianchi, N; Capitani, G P; Carter, P; Cisbani, E; De Leo, R; De Sanctis, E; De Schepper, D; Dzhordzhadze, V; Filippone, B W; Frullani, S; Garibaldi, F; Hansen, J O; Hommez, B; Iodice, M; Jackson, H E; Jung, P; Kaiser, R; Kanesaka, J; Kowalczyk, R; Lagamba, L; Maas, A; Muccifora, V; Nappi, E; Negodaeva, K; Nowak, Wolf-Dieter; O'Connor, T; O'Neill, T G; Potterveld, D H; Ryckbosch, D; Sakemi, Y; Sato, F; Schwind, A; Shibata, T A; Suetsugu, K; Thomas, E; Tytgat, M; Urciuoli, G M; Van De Kerckhove, K; Van De Vyver, R; Yoneyama, S; Zhang, L F; Zohrabyan, H G

    2002-01-01

    The construction and use of a dual radiator Ring Imaging Cherenkov (RICH) detector is described. This instrument was developed for the HERMES experiment at DESY which emphasises measurements of semi-inclusive deep-inelastic scattering. It provides particle identification for pions, kaons, and protons in the momentum range from 2 to 15 GeV, which is essential to these studies. The instrument uses two radiators, C sub 4 F sub 1 sub 0 , a heavy fluorocarbon gas, and a wall of silica aerogel tiles. The use of aerogel in a RICH detector has only recently become possible with the development of clear, large, homogeneous and hydrophobic aerogel. A lightweight mirror was constructed using a newly perfected technique to make resin-coated carbon-fiber surfaces of optical quality. The photon detector consists of 1934 photomultiplier tubes (PMT) for each detector half, held in a soft steel matrix to provide shielding against the residual field of the main spectrometer magnet.

  1. Image feature detectors and descriptors foundations and applications

    CERN Document Server

    Hassaballah, Mahmoud

    2016-01-01

    This book provides readers with a selection of high-quality chapters that cover both theoretical concepts and practical applications of image feature detectors and descriptors. It serves as reference for researchers and practitioners by featuring survey chapters and research contributions on image feature detectors and descriptors. Additionally, it emphasizes several keywords in both theoretical and practical aspects of image feature extraction. The keywords include acceleration of feature detection and extraction, hardware implantations, image segmentation, evolutionary algorithm, ordinal measures, as well as visual speech recognition. .

  2. Detector correction in large container inspection systems

    CERN Document Server

    Kang Ke Jun; Chen Zhi Qiang

    2002-01-01

    In large container inspection systems, the image is constructed by parallel scanning with a one-dimensional detector array with a linac used as the X-ray source. The linear nonuniformity and nonlinearity of multiple detectors and the nonuniform intensity distribution of the X-ray sector beam result in horizontal striations in the scan image. This greatly impairs the image quality, so the image needs to be corrected. The correction parameters are determined experimentally by scaling the detector responses at multiple points with logarithm interpolation of the results. The horizontal striations are eliminated by modifying the original image data with the correction parameters. This method has proven to be effective and applicable in large container inspection systems

  3. Active terahertz imaging with Ne indicator lamp detector arrays

    Science.gov (United States)

    Kopeika, N. S.; Abramovich, A.; Yadid-Pecht, O.; Yitzhaky, Y.

    2009-08-01

    The advantages of terahertz (THz) imaging are well known. They penetrate well most non-conducting media and there are no known biological hazards, This makes such imaging systems important for homeland security, as they can be used to image concealed objects and often into rooms or buildings from the outside. There are also biomedical applications that are arising. Unfortunately, THz imaging is quite expensive, especially for real time systems, largely because of the price of the detector. Bolometers and pyroelectric detectors can each easily cost at least hundreds of dollars if not more, thus making focal plane arrays of them quite expensive. We have found that common miniature commercial neon indicator lamps costing typically about 30 cents each exhibit high sensitivity to THz radiation [1-3], with microsecond order rise times, thus making them excellent candidates for such focal plane arrays. NEP is on the order of 10-10 W/Hz1/2. Significant improvement of detection performance is expected when heterodyne detection is used Efforts are being made to develop focal plane array imagers using such devices at 300 GHz. Indeed, preliminary images using 4x4 arrays have already been obtained. An 8x8 VLSI board has been developed and is presently being tested. Since no similar imaging systems have been developed previously, there are many new problems to be solved with such a novel and unconventional imaging system. These devices act as square law detectors, with detected signal proportional to THz power. This allows them to act as mixers in heterodyne detection, thus allowing NEP to be reduced further by almost two orders of magnitude. Plans are to expand the arrays to larger sizes, and to employ super resolution techniques to improve image quality beyond that ordinarily obtainable at THz frequencies.

  4. Investigation of innovative radiation imaging method and system for radiological environments

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, H. [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of); Joung, J., E-mail: jinhun.joung@nucaremed.com [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of); Nucare, Inc., Incheon (Korea, Republic of); Kim, Y. [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of); Nucare, Inc., Incheon (Korea, Republic of); Lee, K. [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of)

    2017-03-01

    We have developed a novel imaging method that can be applied to most applications in the field of radiological environment imaging. It resolves either two-dimensional (2D) or three-dimensional (3D) distributions of radioactive sources in applications for homeland security, environmental monitoring, radiation contamination monitoring, baggage inspection, nuclear power plant monitoring, and more. The proposed imaging method uses a simple detector configured as a radiation-counting detector with spectroscopic capabilities. The detector module consists of two components: a flat field-of-view (FOV) collimator with a 30° FOV opening and a typical single-channel radiation detector made of a 2 in.×2 in. NaI(Tl) scintillator coupled to a 2 in photomultiplier tube (PMT). This simple detector module makes it possible to develop a cost-effective imaging system and provide design freedom in extending the system configuration to include one-dimensional (1D) or 2D detector-array shapes to meet the needs of various applications. One of most distinctive features of the new imaging method is that it uses only a pair of 2D projections to obtain a 3D reconstruction. The projections are measured by the proposed detector module at two positions orthogonal to one another; the measured projections are manipulated to enhance the resolution of the reconstructed 3D image. The imaging method comprises several steps performed consecutively: projection measurement, energy re-binning, projection separation, resolution and attenuation recovery, image reconstruction, and image consolidation and quantitative analysis. The resolution and attenuation recovery step provides the most distinctive and important processing by which the poor quality of projection data is enhanced. Such poor quality is mainly due to the use of a simple detector with a wide-opening flat FOV collimator. Simulation and experimental studies have been conducted to validate the proposed method. In this investigation, we

  5. The simulation of two-dimensional migration patterns - a novel approach

    Energy Technology Data Exchange (ETDEWEB)

    Villar, Heldio Pereira [Universidade de Pernambuco, Recife, PE (Brazil). Escola Politecnica]|[Centro Regional de Ciencias Nucleares, Recife, PE (Brazil)

    1997-12-31

    A novel approach to the problem of simulation of two-dimensional migration of solutes in saturated soils is presented. In this approach, the two-dimensional advection-dispersion equation is solved by finite-differences in a stepwise fashion, by employing the one-dimensional solution first in the direction of flow and then perpendicularly, using the same time increment in both cases. As the results of this numerical model were to be verified against experimental results obtained by radioactive tracer experiments, an attenuation factor, to account for the contribution of the gamma rays emitted by the whole plume of tracer to the readings of the adopted radiation detectors, was introduced into the model. The comparison between experimental and simulated concentration contours showed good agreement, thus establishing the feasibility of the approach proposed herein. (author) 6 refs., 6 figs.

  6. Gamma-ray detectors for breast imaging

    Science.gov (United States)

    Williams, Mark B.; Goode, Allen R.; Majewski, Stan; Steinbach, Daniela; Weisenberger, Andrew G.; Wojcik, Randolph F.; Farzanpay, Farzin

    1997-07-01

    Breast cancer is the most common cancer of American women and is the leading cause of cancer-related death among women aged 15 - 54; however recent years have shown that early detection using x-ray mammography can lead to a high probability of cure. However, because of mammography's low positive predictive value, surgical or core biopsy is typically required for diagnosis. In addition, the low radiographic contrast of many nonpalpable breast masses, particularly among women with radiographically dense breasts, results in an overall rate of 10% to 25% for missed tumors. Nuclear imaging of the breast using single gamma emitters (scintimammography) such as (superscript 99m)Tc, or positron emitters such as F-18- fluorodeoxyglucose (FDG) for positron emission tomography (PET), can provide information on functional or metabolic tumor activity that is complementary to the structural information of x-ray mammography, thereby potentially reducing the number of unnecessary biopsies and missed cancers. This paper summarizes recent data on the efficacy of scintimammography using conventional gamma cameras, and describes the development of dedicated detectors for gamma emission breast imaging. The detectors use new, high density crystal scintillators and large area position sensitive photomultiplier tubes (PSPMTs). Detector design, imaging requirements, and preliminary measured imaging performance are discussed.

  7. Direct observation of two dimensional trace gas distributions with an airborne Imaging DOAS instrument

    Directory of Open Access Journals (Sweden)

    K.-P. Heue

    2008-11-01

    Full Text Available In many investigations of tropospheric chemistry information about the two dimensional distribution of trace gases on a small scale (e.g. tens to hundreds of metres is highly desirable. An airborne instrument based on imaging Differential Optical Absorption Spectroscopy has been built to map the two dimensional distribution of a series of relevant trace gases including NO2, HCHO, C2H2O2, H2O, O4, SO2, and BrO on a scale of 100 m.

    Here we report on the first tests of the novel aircraft instrument over the industrialised South African Highveld, where large variations in NO2 column densities in the immediate vicinity of several sources e.g. power plants or steel works, were measured. The observed patterns in the trace gas distribution are interpreted with respect to flux estimates, and it is seen that the fine resolution of the measurements allows separate sources in close proximity to one another to be distinguished.

  8. Computed tomography and three-dimensional imaging

    International Nuclear Information System (INIS)

    Harris, L.D.; Ritman, E.L.; Robb, R.A.

    1987-01-01

    Presented here is a brief introduction to two-, three-, and four-dimensional computed tomography. More detailed descriptions of the mathematics of reconstruction and of CT scanner operation are presented elsewhere. The complementary tomographic imaging methods of single-photon-emission tomography (SPECT) positron-emission tomography (PET), nuclear magnetic resonance (NMR) imaging, ulltrasound sector scanning, and ulltrasound computer-assisted tomography [UCAT] are only named here. Each imaging modality ''probes'' the body with a different energy form, yielding unique and useful information about tomographic sections through the body

  9. Effects of temperature and irradiance on a benthic microalgal community: A combined two-dimensional oxygen and fluorescence imaging approach

    DEFF Research Database (Denmark)

    Hancke, Kasper; Sorrell, Brian Keith; Lund-Hansen, Lars Chresten

    2014-01-01

    The effects of temperature and light on both oxygen (O2) production and gross photosynthesis were resolved in a benthic microalgae community by combining two-dimensional (2D) imaging of O2 and variable chlorophyll a (Chl a) fluorescence. Images revealed a photosynthetically active community...... microbial community, at different temperatures. The present imaging approach demonstrates a great potential to study consequences of environmental effects on photosynthetic activity and O2 turnover in complex phototrophic benthic communities....

  10. Features of atomic images reconstructed from photoelectron, Auger electron, and internal detector electron holography using SPEA-MEM

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Tomohiro, E-mail: matusita@spring8.or.jp [Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198 (Japan); Matsui, Fumihiko [Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192 (Japan)

    2014-08-15

    Highlights: • We develop a 3D atomic image reconstruction algorithm for photoelectron, Auger electron, and internal detector holography. • We examine the shapes of the atomic images reconstructed by using a developed kernel function. • We examine refraction effect at surface, limitation effect of the hologram data, energy resolution effect, and angular resolution effect. • These discussions indicate the experimental requirements to obtain the clear 3D atomic image. - Abstract: Three-dimensional atomic images can be reconstructed from photoelectron, Auger electron, and internal detector electron holograms using a scattering pattern extraction algorithm using the maximum entropy method (SPEA-MEM) that utilizes an integral transform. An integral kernel function for the integral transform is the key to clear atomic image reconstruction. We composed the kernel function using a scattering pattern function and estimated its ability. Image distortion caused by multiple scattering was also evaluated. Four types of Auger electron wave functions were investigated, and the effect of these wave function types was estimated. In addition, we addressed refraction at the surface, the effects of data limitation, and energy and angular resolutions.

  11. Three-dimensional reconstruction of functional brain images

    International Nuclear Information System (INIS)

    Inoue, Masato; Shoji, Kazuhiko; Kojima, Hisayoshi; Hirano, Shigeru; Naito, Yasushi; Honjo, Iwao

    1999-01-01

    We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: routine images by SPM, three-dimensional static images, and three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface

  12. Three-dimensional reconstruction of functional brain images

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Masato; Shoji, Kazuhiko; Kojima, Hisayoshi; Hirano, Shigeru; Naito, Yasushi; Honjo, Iwao [Kyoto Univ. (Japan)

    1999-08-01

    We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: routine images by SPM, three-dimensional static images, and three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface

  13. First results with prototype ISIS devices for ILC vertex detector

    International Nuclear Information System (INIS)

    Damerell, C.; Zhang, Z.; Gao, R.; John John, Jaya; Li, Y.; Nomerotski, A.; Holland, A.; Seabroke, G.; Havranek, M.; Stefanov, K.; Kar-Roy, A.; Bell, R.; Burt, D.; Pool, P.

    2010-01-01

    The vertex detectors at the International Linear Collider (ILC) (there will be two of them, one for each of two general purpose detectors) will certainly be built with silicon pixel detectors, either monolithic or perhaps vertically integrated. However, beyond this general statement, there is a wide range of options supported by active R and D programmes all over the world. Pixel-based vertex detectors build on the experience at the SLAC large detector (SLD) operating at the SLAC linear collider (SLC), where a 307 Mpixel detector permitted the highest physics performance at LEP or SLC. For ILC, machine conditions demand much faster readout than at SLC, something like 20 time slices during the 1 ms bunch train. The approach of the image sensor with in-situ storage (ISIS) is unique in offering this capability while avoiding the undesirable requirement of 'pulsed power'. First results from a prototype device that approaches the pixel size of 20 μm square, needed for physics, are reported. The dimensional challenge is met by using a 0.18 μm imaging CMOS process, instead of a conventional CCD process.

  14. First results with prototype ISIS devices for ILC vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Damerell, C., E-mail: c.damerell@rl.ac.u [RAL, Oxon OX11 0QX (United Kingdom); Zhang, Z. [RAL, Oxon OX11 0QX (United Kingdom); Gao, R.; John John, Jaya; Li, Y.; Nomerotski, A. [Oxford U (United Kingdom); Holland, A.; Seabroke, G. [Centre for Electronic Imaging, Open U (United Kingdom); Havranek, M. [Czech Technical University in Prague (Czech Republic); Stefanov, K. [Sentec Ltd, Cambridge (United Kingdom); Kar-Roy, A. [Jazz Semiconductors, California (United States); Bell, R.; Burt, D.; Pool, P. [e2V Technologies, Chelmsford (United Kingdom)

    2010-12-11

    The vertex detectors at the International Linear Collider (ILC) (there will be two of them, one for each of two general purpose detectors) will certainly be built with silicon pixel detectors, either monolithic or perhaps vertically integrated. However, beyond this general statement, there is a wide range of options supported by active R and D programmes all over the world. Pixel-based vertex detectors build on the experience at the SLAC large detector (SLD) operating at the SLAC linear collider (SLC), where a 307 Mpixel detector permitted the highest physics performance at LEP or SLC. For ILC, machine conditions demand much faster readout than at SLC, something like 20 time slices during the 1 ms bunch train. The approach of the image sensor with in-situ storage (ISIS) is unique in offering this capability while avoiding the undesirable requirement of 'pulsed power'. First results from a prototype device that approaches the pixel size of 20 {mu}m square, needed for physics, are reported. The dimensional challenge is met by using a 0.18 {mu}m imaging CMOS process, instead of a conventional CCD process.

  15. Melanie II--a third-generation software package for analysis of two-dimensional electrophoresis images: II. Algorithms.

    Science.gov (United States)

    Appel, R D; Vargas, J R; Palagi, P M; Walther, D; Hochstrasser, D F

    1997-12-01

    After two generations of software systems for the analysis of two-dimensional electrophoresis (2-DE) images, a third generation of such software packages has recently emerged that combines state-of-the-art graphical user interfaces with comprehensive spot data analysis capabilities. A key characteristic common to most of these software packages is that many of their tools are implementations of algorithms that resulted from research areas such as image processing, vision, artificial intelligence or machine learning. This article presents the main algorithms implemented in the Melanie II 2-D PAGE software package. The applications of these algorithms, embodied as the feature of the program, are explained in an accompanying article (R. D. Appel et al.; Electrophoresis 1997, 18, 2724-2734).

  16. Directional detection of dark matter with two-dimensional targets

    Science.gov (United States)

    Hochberg, Yonit; Kahn, Yonatan; Lisanti, Mariangela; Tully, Christopher G.; Zurek, Kathryn M.

    2017-09-01

    We propose two-dimensional materials as targets for direct detection of dark matter. Using graphene as an example, we focus on the case where dark matter scattering deposits sufficient energy on a valence-band electron to eject it from the target. We show that the sensitivity of graphene to dark matter of MeV to GeV mass can be comparable, for similar exposure and background levels, to that of semiconductor targets such as silicon and germanium. Moreover, a two-dimensional target is an excellent directional detector, as the ejected electron retains information about the angular dependence of the incident dark matter particle. This proposal can be implemented by the PTOLEMY experiment, presenting for the first time an opportunity for directional detection of sub-GeV dark matter.

  17. Absorption imaging of a quasi-two-dimensional gas: a multiple scattering analysis

    International Nuclear Information System (INIS)

    Chomaz, L; Corman, L; Yefsah, T; Desbuquois, R; Dalibard, J

    2012-01-01

    Absorption imaging with quasi-resonant laser light is a commonly used technique for probing ultra-cold atomic gases in various geometries. In this paper, we investigate some non-trivial aspects of this method when applying the method to in situ diagnosis of a quasi-two-dimensional (2D) gas. Using Monte Carlo simulations we study the modification of the absorption cross-section of a photon when it undergoes multiple scattering in the gas. We determine the variations of the optical density with various parameters, such as the detuning of the light from the atomic resonance and the thickness of the gas. We compare our results to the known 3D result (the Beer-Lambert law) and outline the specific features of the 2D case. (paper)

  18. Optimal Design of Large Dimensional Adaptive Subspace Detectors

    KAUST Repository

    Ben Atitallah, Ismail; Kammoun, Abla; Alouini, Mohamed-Slim; Alnaffouri, Tareq Y.

    2016-01-01

    This paper addresses the design of Adaptive Subspace Matched Filter (ASMF) detectors in the presence of a mismatch in the steering vector. These detectors are coined as adaptive in reference to the step of utilizing an estimate of the clutter covariance matrix using training data of signalfree observations. To estimate the clutter covariance matrix, we employ regularized covariance estimators that, by construction, force the eigenvalues of the covariance estimates to be greater than a positive scalar . While this feature is likely to increase the bias of the covariance estimate, it presents the advantage of improving its conditioning, thus making the regularization suitable for handling high dimensional regimes. In this paper, we consider the setting of the regularization parameter and the threshold for ASMF detectors in both Gaussian and Compound Gaussian clutters. In order to allow for a proper selection of these parameters, it is essential to analyze the false alarm and detection probabilities. For tractability, such a task is carried out under the asymptotic regime in which the number of observations and their dimensions grow simultaneously large, thereby allowing us to leverage existing results from random matrix theory. Simulation results are provided in order to illustrate the relevance of the proposed design strategy and to compare the performances of the proposed ASMF detectors versus Adaptive normalized Matched Filter (ANMF) detectors under mismatch scenarios.

  19. Optimal Design of Large Dimensional Adaptive Subspace Detectors

    KAUST Repository

    Ben Atitallah, Ismail

    2016-05-27

    This paper addresses the design of Adaptive Subspace Matched Filter (ASMF) detectors in the presence of a mismatch in the steering vector. These detectors are coined as adaptive in reference to the step of utilizing an estimate of the clutter covariance matrix using training data of signalfree observations. To estimate the clutter covariance matrix, we employ regularized covariance estimators that, by construction, force the eigenvalues of the covariance estimates to be greater than a positive scalar . While this feature is likely to increase the bias of the covariance estimate, it presents the advantage of improving its conditioning, thus making the regularization suitable for handling high dimensional regimes. In this paper, we consider the setting of the regularization parameter and the threshold for ASMF detectors in both Gaussian and Compound Gaussian clutters. In order to allow for a proper selection of these parameters, it is essential to analyze the false alarm and detection probabilities. For tractability, such a task is carried out under the asymptotic regime in which the number of observations and their dimensions grow simultaneously large, thereby allowing us to leverage existing results from random matrix theory. Simulation results are provided in order to illustrate the relevance of the proposed design strategy and to compare the performances of the proposed ASMF detectors versus Adaptive normalized Matched Filter (ANMF) detectors under mismatch scenarios.

  20. The Omega Ring Imaging Cerenkov Detector readout system user's guide

    International Nuclear Information System (INIS)

    Hallewell, G.

    1984-11-01

    The manual describes the electronic readout system of the Ring Imaging Cerenkov Detector at the CERN Omega Spectrometer. The system is described in its configuration of September 1984 after the Rich readout system had been used in two Omega experiments. (U.K.)

  1. Efficient processing of two-dimensional arrays with C or C++

    Science.gov (United States)

    Donato, David I.

    2017-07-20

    Because fast and efficient serial processing of raster-graphic images and other two-dimensional arrays is a requirement in land-change modeling and other applications, the effects of 10 factors on the runtimes for processing two-dimensional arrays with C and C++ are evaluated in a comparative factorial study. This study’s factors include the choice among three C or C++ source-code techniques for array processing; the choice of Microsoft Windows 7 or a Linux operating system; the choice of 4-byte or 8-byte array elements and indexes; and the choice of 32-bit or 64-bit memory addressing. This study demonstrates how programmer choices can reduce runtimes by 75 percent or more, even after compiler optimizations. Ten points of practical advice for faster processing of two-dimensional arrays are offered to C and C++ programmers. Further study and the development of a C and C++ software test suite are recommended.Key words: array processing, C, C++, compiler, computational speed, land-change modeling, raster-graphic image, two-dimensional array, software efficiency

  2. Image formation in track-etch detectors: Pt. 4

    International Nuclear Information System (INIS)

    Ilic, Radomir; Najzer, Mitja

    1990-01-01

    The radiographic performance of solid state nuclear track detectors was analysed with respect to image quality. Image quality is expressed in terms of three image quality factors: contrast or gradient of the detector, image unsharpness and detail discernment. Equations for the image quality factors were derived from the radiographic transfer function, taking into account image inhomogeneity caused by statistical fluctuations of track density. To find optimal radiographic conditions for a given application, a single quantity called the figure of radiographic merit was defined. It is expressed as the weighted product of the image quality factors. It was found that optimum image quality of a balanced image, characterized by equal importance of all three image quality factors, is obtained at an exposure value (defined as the product of the average visible track area and track density) of unity. (author)

  3. Positron annihilation imaging device using multiple offset rings of detectors

    International Nuclear Information System (INIS)

    Thompson, C.J.

    1982-01-01

    A means is provided for recording more than one tomographic image simultaneously through different cross-sections of a patient, using positron emission tomography. Separate rings of detectors are used to construct every odd-numbered slice, and coincident events that occur between adjacent rings of detectors provide a center or even-numbered slice. Detector rings are offset with respect to one another by half the angular separation of the detectors, allowing an image to be reconstructed from the central slice without the necessity of physically rotating the detector array while accumulating data

  4. A multicrystal two dimensional BGO detector system for positron emission tomography

    International Nuclear Information System (INIS)

    Casey, M.E.; Nutt, R.

    1986-01-01

    This paper presents a discussion of a new multicrystal detector system as it is implemented in Positron Emission Tomography. The system consists of a 32 x 8 matrix of BGO crystals, a tuned light pipe, and four photomultipliers. The electronics that decodes the position consists of fast preamps, gated integrators, and level comparators. This detector represents a major development toward reducing the cost of PET

  5. Two-Photon Ghost Image and Interference-Diffraction

    Science.gov (United States)

    Shih, Y. H.; Sergienko, A. V.; Pittman, T. B.; Strekalov, D. V.; Klyshko, D. N.

    1996-01-01

    One of the most surprising consequences of quantum mechanics is entanglement of two or more distance particles. The two-particle entangled state was mathematically formulated by Schrodinger. Based on this unusual quantum behavior, EPR defined their 'physical reality' and then asked the question: 'Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?' One may not appreciate EPR's criterion of physical reality and insist that 'no elementary quantum phenomenon is a phenomenon until it is a recorded phenomenon'. Optical spontaneous parametric down conversion (SPDC) is the most effective mechanism to generate an EPR type entangled two-photon state. In SPDC, an optical beam, called the pump, is incident on a birefringent crystal. The pump is intense enough so that nonlinear effects lead to the conversion of pump photons into pairs of photons, historically called signal and idler. Technically, the SPDC is said to be type-1 or type-2, depending on whether the signal and idler beams have parallel or orthogonal polarization. The SPDC conversion efficiency is typically on the order of 10(exp -9) to 10(exp -11), depending on the SPDC nonlinear material. The signal and idler intensities are extremely low, only single photon detection devices can register them. The quantum entanglement nature of SPDC has been demonstrated in EPR-Bohm experiments and Bell's inequality measurements. The following two experiments were recently performed in our laboratory, which are more closely related to the original 1935 EPR gedankenezperiment. The first experiment is a two-photon optical imaging type experiment, which has been named 'ghost image' by the physics community. The signal and idler beams of SPDC are sent in different directions, so that the detection of the signal and idler photons can be performed by two distant photon counting detectors. An aperture object (mask) is placed in front of the signal photon detector and illuminated by the signal beam through a

  6. Three-dimensional imaging of hidden objects using positron emission backscatter

    International Nuclear Information System (INIS)

    Lee, Dongwon; Cowee, Misa; Fenimore, Ed; Galassi, Mark; Looker, Quinn; Mcneil, Wendy V.; Stonehill, Laura; Wallace, Mark

    2009-01-01

    Positron emission backscatter imaging is a technique for interrogation and three-dimensional (3-D) reconstruction of hidden objects when we only have access to the objects from one side. Using time-of-flight differences in detected direct and backscattered positron-emitted photons, we construct 3-D images of target objects. Recently at Los Alamos National Laboratory, a fully three-dimensional imaging system has been built and the experimental results are discussed in this paper. Quantitative analysis of images reconstructed in both two- and three-dimensions are also presented.

  7. First observation of Cherenkov ring images using hybrid photon detectors

    International Nuclear Information System (INIS)

    Albrecht, E.; Wilkinson, G.; Bibby, J.H.; Giles, R.; Harnew, N.; Smale, N.; Brook, N.H.; Halley, A.W.; O'Shea, V.; French, M.; Gibson, V.; Wotton, S.A.; Schomaker, R.

    1998-01-01

    A ring-imaging Cherenkov detector, equipped with hybrid photon detectors, has been operated in a charged-particle beam. Focussed ring images from various particle types were detected using silica aerogel, air and C 4 F 10 gas radiators. The detector, a prototype for the CERN LHC-B experiment, is described and first observations are reported. (orig.)

  8. First observation of Cherenkov ring images using hybrid photon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, E.; Wilkinson, G. [European Organization for Nuclear Research, Geneva (Switzerland). Div. Particle Physics Experiments; Barber, G.; Duane, A.; John, M.; Miller, D.G.; Websdale, D. [Imperial College of Science Technology and Medicine, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Bibby, J.H.; Giles, R.; Harnew, N.; Smale, N. [University of Oxford, Department of Nuclear Physics, Keble Road, Oxford OX1 3RH (United Kingdom); Brook, N.H.; Halley, A.W.; O`Shea, V. [University of Glasgow, Department of Physics, Glasgow G12 8QQ (United Kingdom); French, M. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Gibson, V.; Wotton, S.A. [University of Cambridge, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE (United Kingdom); Schomaker, R. [Delft Electronic Products BV, 9300 AB Roden (Netherlands)

    1998-07-11

    A ring-imaging Cherenkov detector, equipped with hybrid photon detectors, has been operated in a charged-particle beam. Focussed ring images from various particle types were detected using silica aerogel, air and C{sub 4}F{sub 10} gas radiators. The detector, a prototype for the CERN LHC-B experiment, is described and first observations are reported. (orig.)

  9. A pilot study of three dimensional color CT images of brain diseases to improve informed consent

    International Nuclear Information System (INIS)

    Tanizaki, Yoshio; Akiyama, Takenori; Hiraga, Kenji; Akaji, Kazunori

    2005-01-01

    We have described brain diseases to patients and their family using monochrome CT images. It is thought that patients have difficulties in giving their consent to our conventional explanation because their understanding of brain diseases is based on three dimensional and color images, however, standard CT images are two dimensional and gray scale images. We have been trying to use three dimensional color CT images to improve the typical patient's comprehension of brain diseases. We also try to simulate surgery using these images. Multi-slice CT accumulates precise isotropic voxel data within a half minute. These two dimensional and monochrome data are converted to three dimensional color CT images by 3D workstation. Three dimensional color CT images of each brain structures (e.g. scalp, skull, brain, ventricles and lesions) are created separately. Then, selected structures are fused together for different purposes. These images are able to rotate around any axis. Because the methods to generate three-dimensional color images have not established, we neurosurgeons must create these images. In particular, when an operation is required, the surgeon should create the images. In this paper, we demonstrate how three-dimensional color CT images can improve informed consent. (author)

  10. Electron imaging with Medipix2 hybrid pixel detector

    CERN Document Server

    McMullan, G; Chen, S; Henderson, R; Llopart, X; Summerfield, C; Tlustos, L; Faruqi, A R

    2007-01-01

    The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 μm×55 μm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 μm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach 85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach 35% of that expected for a perfect detector (4/π2). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/π). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected v...

  11. Determination of optimal parameters for three-dimensional reconstruction images of central airways using helical CT

    International Nuclear Information System (INIS)

    Hirose, Takahumi; Akata, Soichi; Matsuno, Naoto; Nagao, Takeshi; Abe, Kimihiko

    2002-01-01

    Three-dimensional (3D) image reconstruction of central airways using helical CT requires several user-defined parameters that exceed the requirements of conventional CT. The purpose of this study was to evaluate the optimal parameters for 3D images of central airways using helical CT. In our experimental study using a piglet immediately after sacrifice, 3D images of the central airway were evaluated with changes of 3D imaging parameters, such as detector collimation (1, 2, 3 and 6 mm), table speed (1, 2, 3 and 5 mm/sec), tube electric current (50, 100, 150, 200 and 250 mA), reconstruction interval (0.3, 0.5, 1, 2 and 3 mm), algorithm (mediastinum and lung) and interpolation method (180 deg and 360 deg). To minimize detector collimation, table speed, and reconstruction interval could provide the best 3D images of the central airway. Stair-step artifacts could also be reduced with a slow table speed. However, decreasing the collimation and table speed decreases not only the effective section thickness but also the scan coverage that can be achieved with a helical CT. For routine diagnosis, we conclude that optimal parameters for 3D images of the central airway are to minimize the table speed necessary to cover the volume of interest and to set detector collimation to 1/2 of the table speed. The reconstruction intervals should also be selected at up to 1/2 of the detector collimation, but with trade-offs of increased image processing time, data storage requirements, and physician time for image review. Regarding to tube electric current, 200 mA or more was necessary. Pixel noise increased with the algorithm for the lung. The 180 deg interpolation is better than 360 deg interpolation due to thin effective section thickness. (author)

  12. Image scanning microscopy using a SPAD detector array (Conference Presentation)

    Science.gov (United States)

    Castello, Marco; Tortarolo, Giorgio; Buttafava, Mauro; Tosi, Alberto; Sheppard, Colin J. R.; Diaspro, Alberto; Vicidomini, Giuseppe

    2017-02-01

    The use of an array of detectors can help overcoming the traditional limitation of confocal microscopy: the compromise between signal and theoretical resolution. Each element independently records a view of the sample and the final image can be reconstructed by pixel reassignment or by inverse filtering (e.g. deconvolution). In this work, we used a SPAD array of 25 detectors specifically designed for this goal and our scanning microscopy control system (Carma) to acquire the partial images and to perform online image processing. Further work will be devoted to optimize the image reconstruction step and to improve the fill-factor of the detector.

  13. Quantitative optical mapping of two-dimensional materials

    DEFF Research Database (Denmark)

    Jessen, Bjarke S.; Whelan, Patrick R.; Mackenzie, David M. A.

    2018-01-01

    The pace of two-dimensional materials (2DM) research has been greatly accelerated by the ability to identify exfoliated thicknesses down to a monolayer from their optical contrast. Since this process requires time-consuming and error-prone manual assignment to avoid false-positives from image...

  14. A proposal of Fourier-Bessel expansion with optimized ensembles of bases to analyse two dimensional image

    Science.gov (United States)

    Yamasaki, K.; Fujisawa, A.; Nagashima, Y.

    2017-09-01

    It is a critical issue to find the best set of fitting function bases in mode structural analysis of two dimensional images like plasma emission profiles. The paper proposes a method to optimize a set of the bases in the case of Fourier-Bessel function series, using their orthonormal property, for more efficient and precise analysis. The method is applied on a tomography image of plasma emission obtained with the Maximum-likelihood expectation maximization method in a linear cylindrical device. The result demonstrates the excellency of the method that realizes the smaller residual error and minimum Akaike information criterion using smaller number of fitting function bases.

  15. Quantitative analysis of fragrance in selectable one dimensional or two dimensional gas chromatography-mass spectrometry with simultaneous detection of multiple detectors in single injection.

    Science.gov (United States)

    Tan, Hui Peng; Wan, Tow Shi; Min, Christina Liew Shu; Osborne, Murray; Ng, Khim Hui

    2014-03-14

    A selectable one-dimensional ((1)D) or two-dimensional ((2)D) gas chromatography-mass spectrometry (GC-MS) system coupled with flame ionization detector (FID) and olfactory detection port (ODP) was employed in this study to analyze perfume oil and fragrance in shower gel. A split/splitless (SSL) injector and a programmable temperature vaporization (PTV) injector are connected via a 2-way splitter of capillary flow technology (CFT) in this selectable (1)D/(2)D GC-MS/FID/ODP system to facilitate liquid sample injections and thermal desorption (TD) for stir bar sorptive extraction (SBSE) technique, respectively. The dual-linked injectors set-up enable the use of two different injector ports (one at a time) in single sequence run without having to relocate the (1)D capillary column from one inlet to another. Target analytes were separated in (1)D GC-MS/FID/ODP and followed by further separation of co-elution mixture from (1)D in (2)D GC-MS/FID/ODP in single injection without any instrumental reconfiguration. A (1)D/(2)D quantitative analysis method was developed and validated for its repeatability - tR; calculated linear retention indices (LRI); response ratio in both MS and FID signal, limit of detection (LOD), limit of quantitation (LOQ), as well as linearity over a concentration range. The method was successfully applied in quantitative analysis of perfume solution at different concentration level (RSD≤0.01%, n=5) and shower gel spiked with perfume at different dosages (RSD≤0.04%, n=5) with good recovery (96-103% for SSL injection; 94-107% for stir bar sorptive extraction-thermal desorption (SBSE-TD). Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Image reconstruction methods in positron tomography

    International Nuclear Information System (INIS)

    Townsend, D.W.; Defrise, M.

    1993-01-01

    In the two decades since the introduction of the X-ray scanner into radiology, medical imaging techniques have become widely established as essential tools in the diagnosis of disease. As a consequence of recent technological and mathematical advances, the non-invasive, three-dimensional imaging of internal organs such as the brain and the heart is now possible, not only for anatomical investigations using X-ray but also for studies which explore the functional status of the body using positron-emitting radioisotopes. This report reviews the historical and physical basis of medical imaging techniques using positron-emitting radioisotopes. Mathematical methods which enable three-dimensional distributions of radioisotopes to be reconstructed from projection data (sinograms) acquired by detectors suitably positioned around the patient are discussed. The extension of conventional two-dimensional tomographic reconstruction algorithms to fully three-dimensional reconstruction is described in detail. (orig.)

  17. Si and gaas pixel detectors for medical imaging applications

    International Nuclear Information System (INIS)

    Bisogni, M. G.

    2001-01-01

    As the use of digital radiographic equipment in the morphological imaging field is becoming the more and more diffuse, the research of new and more performing devices from public institutions and industrial companies is in constant progress. Most of these devices are based on solid-state detectors as X-ray sensors. Semiconductor pixel detectors, originally developed in the high energy physics environment, have been then proposed as digital detector for medical imaging applications. In this paper a digital single photon counting device, based on silicon and GaAs pixel detector, is presented. The detector is a thin slab of semiconductor crystal where an array of 64 by 64 square pixels, 170- m side, has been built on one side. The data read-out is performed by a VLSI integrated circuit named Photon Counting Chip (PCC), developed within the MEDIPIX collaboration. Each chip cell geometrically matches the sensor pixel. It contains a charge preamplifier, a threshold comparator and a 15 bits pseudo-random counter and it is coupled to the detector by means of bump bonding. Most important advantages of such system, with respect to a traditional X-rays film/screen device, are the wider linear dynamic range (3x104) and the higher performance in terms of MTF and DQE. Besides the single photon counting architecture allows to detect image contrasts lower than 3%. Electronics read-out performance as well as imaging capabilities of the digital device will be presented. Images of mammographic phantoms acquired with a standard Mammographic tube will be compared with radiographs obtained with traditional film/screen systems

  18. Three-dimensional imaging of acetabular dysplasia: diagnostic value and impact on surgical type classification

    Energy Technology Data Exchange (ETDEWEB)

    Smet, Maria-Helena E-mail: marleen.smet@uz.kuleuven.ac.be; Marchal, Guy J.; Baert, Albert L.; Hoe, Lieven van; Cleynenbreugel, Johan van; Daniels, Hans; Molenaers, Guy; Moens, Pierre; Fabry, Guy

    2000-04-01

    Objective: To investigate the diagnostic value and the impact on surgical type classification of three-dimensional (3D) images for pre-surgical evaluation of dysplastic hips. Materials and methods: Three children with a different surgical type of hip dysplasia were investigated with helical computed tomography. For each patient, two-dimensional (2D) images, 3D, and a stereolithographic model of the dysplastic hip were generated. In two separate sessions, 40 medical observers independently analyzed the 2D images (session 1), the 2D and 3D images (session 2), and tried to identify the corresponding stereolithographic hip model. The influence of both image presentation (2D versus 3D images) and observer (degree of experience, radiologist versus orthopedic surgeon) were statistically analyzed. The SL model choice reflected the impact on surgical type classification. Results: Image presentation was a significant factor whereas the individual observer was not. Three-dimensional images scored significantly better than 2D images (P=0.0003). Three-dimensional imaging increased the correct surgical type classification by 35%. Conclusion: Three-dimensional images significantly improve the pre-surgical diagnostic assessment and surgical type classification of dysplastic hips.

  19. Three-dimensional imaging of acetabular dysplasia: diagnostic value and impact on surgical type classification

    International Nuclear Information System (INIS)

    Smet, Maria-Helena; Marchal, Guy J.; Baert, Albert L.; Hoe, Lieven van; Cleynenbreugel, Johan van; Daniels, Hans; Molenaers, Guy; Moens, Pierre; Fabry, Guy

    2000-01-01

    Objective: To investigate the diagnostic value and the impact on surgical type classification of three-dimensional (3D) images for pre-surgical evaluation of dysplastic hips. Materials and methods: Three children with a different surgical type of hip dysplasia were investigated with helical computed tomography. For each patient, two-dimensional (2D) images, 3D, and a stereolithographic model of the dysplastic hip were generated. In two separate sessions, 40 medical observers independently analyzed the 2D images (session 1), the 2D and 3D images (session 2), and tried to identify the corresponding stereolithographic hip model. The influence of both image presentation (2D versus 3D images) and observer (degree of experience, radiologist versus orthopedic surgeon) were statistically analyzed. The SL model choice reflected the impact on surgical type classification. Results: Image presentation was a significant factor whereas the individual observer was not. Three-dimensional images scored significantly better than 2D images (P=0.0003). Three-dimensional imaging increased the correct surgical type classification by 35%. Conclusion: Three-dimensional images significantly improve the pre-surgical diagnostic assessment and surgical type classification of dysplastic hips

  20. Ghost imaging with atoms

    Science.gov (United States)

    Khakimov, R. I.; Henson, B. M.; Shin, D. K.; Hodgman, S. S.; Dall, R. G.; Baldwin, K. G. H.; Truscott, A. G.

    2016-12-01

    Ghost imaging is a counter-intuitive phenomenon—first realized in quantum optics—that enables the image of a two-dimensional object (mask) to be reconstructed using the spatio-temporal properties of a beam of particles with which it never interacts. Typically, two beams of correlated photons are used: one passes through the mask to a single-pixel (bucket) detector while the spatial profile of the other is measured by a high-resolution (multi-pixel) detector. The second beam never interacts with the mask. Neither detector can reconstruct the mask independently, but temporal cross-correlation between the two beams can be used to recover a ‘ghost’ image. Here we report the realization of ghost imaging using massive particles instead of photons. In our experiment, the two beams are formed by correlated pairs of ultracold, metastable helium atoms, which originate from s-wave scattering of two colliding Bose-Einstein condensates. We use higher-order Kapitza-Dirac scattering to generate a large number of correlated atom pairs, enabling the creation of a clear ghost image with submillimetre resolution. Future extensions of our technique could lead to the realization of ghost interference, and enable tests of Einstein-Podolsky-Rosen entanglement and Bell’s inequalities with atoms.

  1. The Two-Dimensional Gabor Function Adapted to Natural Image Statistics: A Model of Simple-Cell Receptive Fields and Sparse Structure in Images.

    Science.gov (United States)

    Loxley, P N

    2017-10-01

    The two-dimensional Gabor function is adapted to natural image statistics, leading to a tractable probabilistic generative model that can be used to model simple cell receptive field profiles, or generate basis functions for sparse coding applications. Learning is found to be most pronounced in three Gabor function parameters representing the size and spatial frequency of the two-dimensional Gabor function and characterized by a nonuniform probability distribution with heavy tails. All three parameters are found to be strongly correlated, resulting in a basis of multiscale Gabor functions with similar aspect ratios and size-dependent spatial frequencies. A key finding is that the distribution of receptive-field sizes is scale invariant over a wide range of values, so there is no characteristic receptive field size selected by natural image statistics. The Gabor function aspect ratio is found to be approximately conserved by the learning rules and is therefore not well determined by natural image statistics. This allows for three distinct solutions: a basis of Gabor functions with sharp orientation resolution at the expense of spatial-frequency resolution, a basis of Gabor functions with sharp spatial-frequency resolution at the expense of orientation resolution, or a basis with unit aspect ratio. Arbitrary mixtures of all three cases are also possible. Two parameters controlling the shape of the marginal distributions in a probabilistic generative model fully account for all three solutions. The best-performing probabilistic generative model for sparse coding applications is found to be a gaussian copula with Pareto marginal probability density functions.

  2. Single-shot full strain tensor determination with microbeam X-ray Laue diffraction and a two-dimensional energy-dispersive detector.

    Science.gov (United States)

    Abboud, A; Kirchlechner, C; Keckes, J; Conka Nurdan, T; Send, S; Micha, J S; Ulrich, O; Hartmann, R; Strüder, L; Pietsch, U

    2017-06-01

    The full strain and stress tensor determination in a triaxially stressed single crystal using X-ray diffraction requires a series of lattice spacing measurements at different crystal orientations. This can be achieved using a tunable X-ray source. This article reports on a novel experimental procedure for single-shot full strain tensor determination using polychromatic synchrotron radiation with an energy range from 5 to 23 keV. Microbeam X-ray Laue diffraction patterns were collected from a copper micro-bending beam along the central axis (centroid of the cross section). Taking advantage of a two-dimensional energy-dispersive X-ray detector (pnCCD), the position and energy of the collected Laue spots were measured for multiple positions on the sample, allowing the measurement of variations in the local microstructure. At the same time, both the deviatoric and hydrostatic components of the elastic strain and stress tensors were calculated.

  3. Two-dimensional Fast ESPRIT Algorithm for Linear Array SAR Imaging

    Directory of Open Access Journals (Sweden)

    Zhao Yi-chao

    2015-10-01

    Full Text Available The linear array Synthetic Aperture Radar (SAR system is a popular research tool, because it can realize three-dimensional imaging. However, owning to limitations of the aircraft platform and actual conditions, resolution improvement is difficult in cross-track and along-track directions. In this study, a twodimensional fast Estimation of Signal Parameters by Rotational Invariance Technique (ESPRIT algorithm for linear array SAR imaging is proposed to overcome these limitations. This approach combines the Gerschgorin disks method and the ESPRIT algorithm to estimate the positions of scatterers in cross and along-rack directions. Moreover, the reflectivity of scatterers is obtained by a modified pairing method based on “region growing”, replacing the least-squares method. The simulation results demonstrate the applicability of the algorithm with high resolution, quick calculation, and good real-time response.

  4. An Investigation of Preschoolers' Misattributions of the Properties of Two-Dimensional Images: Understanding the Relationship between a Symbol and Its Referent

    Science.gov (United States)

    Claxton, Laura J.

    2011-01-01

    Previous studies have found that preschoolers are confused about the relationship between two-dimensional (2D) symbols and their referents. Preschoolers report that 2D images (e.g. televised images and photographs) share some of the characteristics of the objects they are representing. A novel Comparison Task was created to test what might account…

  5. The retrieval of two-dimensional distribution of the earth's surface aerodynamic roughness using SAR image and TM thermal infrared image

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Renhua; WANG; Jinfeng; ZHU; Caiying; SUN; Xiaomin

    2004-01-01

    After having analyzed the requirement on the aerodynamic earth's surface roughness in two-dimensional distribution in the research field of interaction between land surface and atmosphere, this paper presents a new way to calculate the aerodynamic roughness using the earth's surface geometric roughness retrieved from SAR (Synthetic Aperture Radar) and TM thermal infrared image data. On the one hand, the SPM (Small Perturbation Model) was used as a theoretical SAR backscattering model to describe the relationship between the SAR backscattering coefficient and the earth's surface geometric roughness and its dielectric constant retrieved from the physical model between the soil thermal inertia and the soil surface moisture with the simultaneous TM thermal infrared image data and the ground microclimate data. On the basis of the SAR image matching with the TM image, the non-volume scattering surface geometric information was obtained from the SPM model at the TM image pixel scale, and the ground pixel surface's equivalent geometric roughness-height standard RMS (Root Mean Square) was achieved from the geometric information by the transformation of the typical topographic factors. The vegetation (wheat, tree) height retrieved from spectrum model was also transferred into its equivalent geometric roughness. A completely two-dimensional distribution map of the equivalent geometric roughness over the experimental area was produced by the data mosaic technique. On the other hand, according to the atmospheric eddy currents theory, the aerodynamic surface roughness was iterated out with the atmosphere stability correction method using the wind and the temperature profiles data measured at several typical fields such as bare soil field and vegetation field. After having analyzed the effect of surface equivalent geometric roughness together with dynamic and thermodynamic factors on the aerodynamic surface roughness within the working area, this paper first establishes a scale

  6. The consequences of multiplexing and limited view angle in coded-aperture imaging

    International Nuclear Information System (INIS)

    Smith, W.E.; Barrett, H.H.; Paxman, R.G.

    1984-01-01

    Coded-aperture imaging (CAI) is a method for reconstructing distributions of radionuclide tracers that offers advantages over ECT and PET; namely, many views can be taken simultaneously without detector motion, and large numbers of photons are utilized since collimators are not required. However, because of this type of data acquisition, the coded image suffers from multiplexing; i.e., more than one object point may be mapped to each detector in the coded image. To investigate the dependence of the reconstruction on multiplexing, the authors reconstruct a simulated two-dimensional circular object from multiplexed one-dimensional coded-image data, then perform the reconstruction from un-multiplexed data. Each of these reconstructions are produced both from noise-free and noisy simulated data. To investigate the dependence on view angle, the authors reconstruct two simulated three-dimensional objects; a spherical phantom, and a series of point-like objects arranged nearly in a plane. Each of these reconstructions are from multiplexed two-dimensional coded-image data, first using two orthogonal views, and then a single viewing direction. The two-dimensional reconstructions demonstrate that, in the noise-free case, the multiplexing of the data does not seriously affect the reconstruction equality and that in the noisy-data case, the multiplexing helps, due to the fact that more photons are collected. Also, for point-like objects confined to a near-planar region of space, the authors show that restricted views can give satisfactory results, but that, for a large, three-dimensional object, a more complete viewing geometry is required

  7. Thresholding using two-dimensional histogram and watershed algorithm in the luggage inspection system

    International Nuclear Information System (INIS)

    Chen Jingyun; Cong Peng; Song Qi

    2006-01-01

    The authors present a new DR image segmentation method based on two-dimensional histogram and watershed algorithm. The authors use watershed algorithm to locate threshold on the vertical projection plane of two-dimensional histogram. This method is applied to the segmentation of DR images produced by luggage inspection system with DR-CT. The advantage of this method is also analyzed. (authors)

  8. Three-dimensional field map of the Fermilab D0 detector

    International Nuclear Information System (INIS)

    Ostiguy, J.; Yamada, R.

    1991-08-01

    The D0 detector is a general purpose hadron collider detector presently under construction at Fermilab and scheduled to be put in operation in the fall of 1991. The D0 muon detection system is composed of three major toroids referred to respectively as the Central Field (CF) toroid and the End Field (EF) toroids. The complete detector weighs in excess of 4000 metric tons and rests on a steel platform. The muon detection system was designed using standard 2D codes and flux maps inside were obtained for each of the toroids taken separately. Various magnetic field measurements were performed; discrepancies with the design calculations have been observed and attributed to three dimensional effects. In this paper, we compare the predictions of the 2D computations to 3D calculations for a fully assembled detector. We also estimate the electromagnetic forces between the toroids and discuss other 3D effects, in particular, the effect of the supporting platform. 4 refs., 3 figs

  9. The Convergence Acceleration of Two-Dimensional Fourier Interpolation

    Directory of Open Access Journals (Sweden)

    Anry Nersessian

    2008-07-01

    Full Text Available Hereby, the convergence acceleration of two-dimensional trigonometric interpolation for a smooth functions on a uniform mesh is considered. Together with theoretical estimates some numerical results are presented and discussed that reveal the potential of this method for application in image processing. Experiments show that suggested algorithm allows acceleration of conventional Fourier interpolation even for sparse meshes that can lead to an efficient image compression/decompression algorithms and also to applications in image zooming procedures.

  10. Analysis of two dimensional signals via curvelet transform

    Science.gov (United States)

    Lech, W.; Wójcik, W.; Kotyra, A.; Popiel, P.; Duk, M.

    2007-04-01

    This paper describes an application of curvelet transform analysis problem of interferometric images. Comparing to two-dimensional wavelet transform, curvelet transform has higher time-frequency resolution. This article includes numerical experiments, which were executed on random interferometric image. In the result of nonlinear approximations, curvelet transform obtains matrix with smaller number of coefficients than is guaranteed by wavelet transform. Additionally, denoising simulations show that curvelet could be a very good tool to remove noise from images.

  11. Multi-dimensional imaging

    CERN Document Server

    Javidi, Bahram; Andres, Pedro

    2014-01-01

    Provides a broad overview of advanced multidimensional imaging systems with contributions from leading researchers in the field Multi-dimensional Imaging takes the reader from the introductory concepts through to the latest applications of these techniques. Split into 3 parts covering 3D image capture, processing, visualization and display, using 1) a Multi-View Approach and 2.) a Holographic Approach, followed by a 3rd part addressing other 3D systems approaches, applications and signal processing for advanced 3D imaging. This book describes recent developments, as well as the prospects and

  12. Development of a hybrid MSGC detector for thermal neutron imaging with a MHz data acquisition and histogramming system

    CERN Document Server

    Gebauer, B; Richter, G; Levchanovsky, F V; Nikiforov, A

    2001-01-01

    For thermal neutron imaging at the next generation of high-flux pulsed neutron sources a large area and fourfold segmented, hybrid, low-pressure, two-dimensional position sensitive, microstrip gas chamber detector, fabricated in a multilayer technology on glass substrates, is presently being developed, which utilizes a thin composite sup 1 sup 5 sup 7 Gd/CsI neutron converter. The present article focusses on the readout scheme and the data acquisition (DAQ) system. For position encoding, interpolating and fast multihit delay line based electronics is applied with up to eightfold sub-segmentation per geometrical detector segment. All signals, i.e. position, time-of-flight and pulse-height signals, are fed into deadtime-less 8-channel multihit TDC chips with 120 ps LSB via constant fraction and time-over-threshold discriminators, respectively. The multihit capability is utilized to raise the count rate limit in combination with a sum check algorithm for disentangling pulses from different events. The first vers...

  13. Two-dimensional errors

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This chapter addresses the extension of previous work in one-dimensional (linear) error theory to two-dimensional error analysis. The topics of the chapter include the definition of two-dimensional error, the probability ellipse, the probability circle, elliptical (circular) error evaluation, the application to position accuracy, and the use of control systems (points) in measurements

  14. Quantitative imaging of turbulent and reacting flows

    Energy Technology Data Exchange (ETDEWEB)

    Paul, P.H. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    Quantitative digital imaging, using planar laser light scattering techniques is being developed for the analysis of turbulent and reacting flows. Quantitative image data, implying both a direct relation to flowfield variables as well as sufficient signal and spatial dynamic range, can be readily processed to yield two-dimensional distributions of flowfield scalars and in turn two-dimensional images of gradients and turbulence scales. Much of the development of imaging techniques to date has concentrated on understanding the requisite molecular spectroscopy and collision dynamics to be able to determine how flowfield variable information is encoded into the measured signal. From this standpoint the image is seen as a collection of single point measurements. The present effort aims at realizing necessary improvements in signal and spatial dynamic range, signal-to-noise ratio and spatial resolution in the imaging system as well as developing excitation/detection strategies which provide for a quantitative measure of particular flowfield scalars. The standard camera used for the study is an intensified CCD array operated in a conventional video format. The design of the system was based on detailed modeling of signal and image transfer properties of fast UV imaging lenses, image intensifiers and CCD detector arrays. While this system is suitable for direct scalar imaging, derived quantities (e.g. temperature or velocity images) require an exceptionally wide dynamic range imaging detector. To apply these diagnostics to reacting flows also requires a very fast shuttered camera. The authors have developed and successfully tested a new type of gated low-light level detector. This system relies on fast switching of proximity focused image-diode which is direct fiber-optic coupled to a cooled CCD array. Tests on this new detector show significant improvements in detection limit, dynamic range and spatial resolution as compared to microchannel plate intensified arrays.

  15. X-ray imaging with the PILATUS 100k detector

    DEFF Research Database (Denmark)

    Bech, Martin; Bunk, O.; David, C.

    2008-01-01

    We report on the application of the PILATUS 100K pixel detector for medical imaging. Experimental results are presented in the form of X-ray radiographs using standard X-ray absorption contrast and a recently developed phase contrast imaging method. The results obtained with the PILATUS detector...... are compared to results obtained with a conventional X-ray imaging system consisting of an X-ray scintillation screen, lens optics, and a charge coupled device. Finally, the results for both systems are discussed more quantitatively based on an image power spectrum analysis. Udgivelsesdato: April...

  16. Usefulness of three dimensional reconstructive images for thoracic trauma induced fractures

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Kyung Hun; Kim, Dong Hun; Kim, Young Sook; Byun, Joo Nam [Chosun University Hospital, Gwangju (Korea, Republic of)

    2006-09-15

    We wanted to evaluate the usefulness of three-dimensional reconstructive images using multidetector computed tomography (MDCT) for thoracic traumatic patients visiting emergency room. 76 patients with fractures of the 105 patients who visited our emergency room with complaints of thoracic trauma were analyzed retrospectively. All the patients had thoracic MDCT performed and the three-dimensional reconstructive images were taken. The fractures were confirmed by axial CT, the clinical information, whole body bone scanning and the multiplanar reformation images. Plain x-ray images were analyzed by the fractured sites in a blind comparison of two radiologists' readings, and then that finding was compared with the axial CT scans and the three-dimensional reconstructive images. The fracture sites were rib (n 68), sternum (n = 14), clavicle (n = 6), scapula (n = 3), spine (n = 5) and combined fractures (n = 14). Plain x-ray and axial CT scans had a correspondency of 0.555 for the rib fractures. Axial CT scans and the three-dimensional reconstructive images had a correspondency of .952. For sternal fractures, those values were 0.692 and 0.928, respectively. The axial CT scans and three-dimensional reconstructive images showed sensitivities of 94% and 91% for rib and other fractures, respectively, and 93% and 100% for sternal fracture, respectively. Three-dimensional reconstructive image had an especially high sensitivity for the diagnosis of sternal fracture. While evaluating thoracic trauma at the emergency room, the three-dimensional reconstructive image was useful to easily diagnose the extent of fracture and it was very sensitive for detecting sternal fracture.

  17. Usefulness of three dimensional reconstructive images for thoracic trauma induced fractures

    International Nuclear Information System (INIS)

    Koh, Kyung Hun; Kim, Dong Hun; Kim, Young Sook; Byun, Joo Nam

    2006-01-01

    We wanted to evaluate the usefulness of three-dimensional reconstructive images using multidetector computed tomography (MDCT) for thoracic traumatic patients visiting emergency room. 76 patients with fractures of the 105 patients who visited our emergency room with complaints of thoracic trauma were analyzed retrospectively. All the patients had thoracic MDCT performed and the three-dimensional reconstructive images were taken. The fractures were confirmed by axial CT, the clinical information, whole body bone scanning and the multiplanar reformation images. Plain x-ray images were analyzed by the fractured sites in a blind comparison of two radiologists' readings, and then that finding was compared with the axial CT scans and the three-dimensional reconstructive images. The fracture sites were rib (n 68), sternum (n = 14), clavicle (n = 6), scapula (n = 3), spine (n = 5) and combined fractures (n = 14). Plain x-ray and axial CT scans had a correspondency of 0.555 for the rib fractures. Axial CT scans and the three-dimensional reconstructive images had a correspondency of .952. For sternal fractures, those values were 0.692 and 0.928, respectively. The axial CT scans and three-dimensional reconstructive images showed sensitivities of 94% and 91% for rib and other fractures, respectively, and 93% and 100% for sternal fracture, respectively. Three-dimensional reconstructive image had an especially high sensitivity for the diagnosis of sternal fracture. While evaluating thoracic trauma at the emergency room, the three-dimensional reconstructive image was useful to easily diagnose the extent of fracture and it was very sensitive for detecting sternal fracture

  18. Two New Types of Detector for X- or Gamma-Ray Cameras

    International Nuclear Information System (INIS)

    Kellershohn, C.; Desgrez, A.; Lansiart, A.

    1964-01-01

    X- or γ-ray cameras consist essentially of a hole-type or grid-type lens system together with a detector. The authors propose two kinds of detector quite different from the Anger device, which so far has been the only one in practical use. The first consists of a self-triggering spark chamber. This chamber, about 20 cm in diam. and filled with a rare gas (argon or xenon), forms a cathode and two grids. The cathode and the second grid are subjected to a potential difference of several kilovolts, somewhat lower than the breakdown voltage. The first cathode-grid space serves as an electron source under the action of the low-energy X- or γ-ray photons. The cathode can also be plated with a metal of high Z, or a crystal scintillator connected to a photocathode can be used. After suitable amplification, the sudden burst of charges due to electron multiplication in the Townsend avalanche produces a well localized spark with a delay of a fraction of a microsecond. The image is obtained with the aid of a camera whose shutter is permanently open. The second type of detector consists of a Csl (Tl) crystal connected to the photocathode of a Thomson tube, 20 cm in diam. and with electrostatic focusing. The image on the secondary screen of this tube is transferred by an optical device to the photocathode of a tube with parallel electric and magnetic field (manufactured by the English Electric Valve Company) and serving as shutter. Some of the light entering the optical device is received by a photomultiplier, which controls the opening of the shutter tube through an amplitude selector. This arrangement makes it possible to distinguish between the light due to the signal and that due to the noise of the Thomson tube. The shutter tube is opened only by the former. Since the shutter tube remains open for only an extremely short time, the signal-noise ratio of this detector arrangement is high enough to give an image on the end screen of the shutter tube using a permanently open

  19. Impact of imaging quality of change pitch on coronary CTA with 64-detector row CT

    International Nuclear Information System (INIS)

    Li Xiang; Jin Chaolin; Zhang Shutong

    2009-01-01

    Objective: To investigate the impact of imaging quality of pitch on coronary CT angiography (CTA) with 64-detector row CT. Methods: 566 patients were divided into four groups according to heart rate (≤ 50, 51 ∼ 70, 71 ∼ 80 and ≥ 80 bpm). Three dimensional reconstructions were used such as volume rendering (VR), maximum intensity projection(MIP) and curved planar reformation (CPR). Each group was divided into control group and experimential group randomly, using normal pitch and revised pitch respectively, and the imaging quality and influencing factors were analyzed among the four groups. Results: There was significant difference in imaging quality among the four groups (P < 0.05). Each group had difference in imaging quality with normal pitch and revised pitch. Conclusions: The revised pitch helps to improve the imaging quality and meet the demand of diagnosis. (authors)

  20. Evaluation of congenital heart disease by three-dimensional MR imaging

    International Nuclear Information System (INIS)

    Vannier, M.W.; Gutierrez, F.R.; Canter, C.E.; Yoffie, R.L.; Hildebolt, C.F.

    1988-01-01

    In an evaluation of the detectability of intra-and extracardiac morphologic defects with electrocardiographically gated magnetic resonance (MR) imaging, 100 patients were studied, including ten without and 90 with abnormalities. The abnormalities included septal defects, tetrology of Fallot, pulmonary atresia, transposition of the great vessels, and others. The patients with abnormalities were studied angiographically and with echocardiographic analyses. Two radiologists with cardiac MR imaging experience evaluated the scans in a blinded fashion, and the results were analyzed by means of receiver operating characteristic analysis. The diagnostic value of routine two-dimensional cardiac MR imaging was compared with that of three-dimensional reconstruction imaging and with the results of cardiac catheterization and echocardiography. The reported sensitivity and specificity of echocardiography in the detection of congenital heart disease is comparable to that of MR imaging. The differences in diagnostic value between various modalities for the imaging of congenital heart disease may be determined from the results of the preliminary series

  1. Digital imaging system in mammography with X-ray of two different energies

    International Nuclear Information System (INIS)

    Swientek, K.; Dabrowski, W.; Grybos, P.; Wiacek, P.; Cabal Rodrigez, A. E.; Sanchez, C.C.; Gambaccini, M.; Gaitan, J.L.; Prino, F.; Ramello, L.

    2005-01-01

    The progress in nuclear medicine stimulates the higher quality of image processing at diminished radiation dose. In the presented apparatus system Si-microstrip detector with two-thresholds multichannel amplitude analyzer have been applied. Data acquisition system evaluates simultaneously images for two X-ray beams of different energies following the Bragg reflection of the primary beam from the mosaic crystal. The contrast cancellation technique has been tested using the simple mammography phantom. An efficacy of this method suitable for medical imaging could be significantly increased using an intensive X-ray source and sensitive detectors

  2. Review on the characteristics of radiation detectors for dosimetry and imaging

    International Nuclear Information System (INIS)

    Seco, Joao; Clasie, Ben; Partridge, Mike

    2014-01-01

    The enormous advances in the understanding of human anatomy, physiology and pathology in recent decades have led to ever-improving methods of disease prevention, diagnosis and treatment. Many of these achievements have been enabled, at least in part, by advances in ionizing radiation detectors. Radiology has been transformed by the implementation of multi-slice CT and digital x-ray imaging systems, with silver halide films now largely obsolete for many applications. Nuclear medicine has benefited from more sensitive, faster and higher-resolution detectors delivering ever-higher SPECT and PET image quality. PET/MR systems have been enabled by the development of gamma ray detectors that can operate in high magnetic fields. These huge advances in imaging have enabled equally impressive steps forward in radiotherapy delivery accuracy, with 4DCT, PET and MRI routinely used in treatment planning and online image guidance provided by cone-beam CT. The challenge of ensuring safe, accurate and precise delivery of highly complex radiation fields has also both driven and benefited from advances in radiation detectors. Detector systems have been developed for the measurement of electron, intensity-modulated and modulated arc x-ray, proton and ion beams, and around brachytherapy sources based on a very wide range of technologies. The types of measurement performed are equally wide, encompassing commissioning and quality assurance, reference dosimetry, in vivo dosimetry and personal and environmental monitoring. In this article, we briefly introduce the general physical characteristics and properties that are commonly used to describe the behaviour and performance of both discrete and imaging detectors. The physical principles of operation of calorimeters; ionization and charge detectors; semiconductor, luminescent, scintillating and chemical detectors; and radiochromic and radiographic films are then reviewed and their principle applications discussed. Finally, a general

  3. Laser sheet dropsizing based on two-dimensional Raman and Mie scattering.

    Science.gov (United States)

    Malarski, Anna; Schürer, Benedikt; Schmitz, Ingo; Zigan, Lars; Flügel, Alexandre; Leipertz, Alfred

    2009-04-01

    The imaging and quantification of droplet sizes in sprays is a challenging task for optical scientists and engineers. Laser sheet dropsizing (LSDS) combines the two-dimensional information of two different optical processes, one that is proportional to the droplet volume and one that depends on the droplet surface, e.g., Mie scattering. Besides Mie scattering, here we use two-dimensional Raman scattering as the volume-dependent measurement technique. Two different calibration strategies are presented and discussed. Two-dimensional droplet size distributions in a spray have been validated in comparison with the results of point-resolved phase Doppler anemometry (PDA) measurements.

  4. Laser sheet dropsizing based on two-dimensional Raman and Mie scattering

    International Nuclear Information System (INIS)

    Malarski, Anna; Schuerer, Benedikt; Schmitz, Ingo; Zigan, Lars; Fluegel, Alexandre; Leipertz, Alfred

    2009-01-01

    The imaging and quantification of droplet sizes in sprays is a challenging task for optical scientists and engineers. Laser sheet dropsizing (LSDS) combines the two-dimensional information of two different optical processes, one that is proportional to the droplet volume and one that depends on the droplet surface, e.g., Mie scattering. Besides Mie scattering, here we use two-dimensional Raman scattering as the volume-dependent measurement technique. Two different calibration strategies are presented and discussed. Two-dimensional droplet size distributions in a spray have been validated in comparison with the results of point-resolved phase Doppler anemometry (PDA) measurements

  5. CT Image Reconstruction in a Low Dimensional Manifold

    OpenAIRE

    Cong, Wenxiang; Wang, Ge; Yang, Qingsong; Hsieh, Jiang; Li, Jia; Lai, Rongjie

    2017-01-01

    Regularization methods are commonly used in X-ray CT image reconstruction. Different regularization methods reflect the characterization of different prior knowledge of images. In a recent work, a new regularization method called a low-dimensional manifold model (LDMM) is investigated to characterize the low-dimensional patch manifold structure of natural images, where the manifold dimensionality characterizes structural information of an image. In this paper, we propose a CT image reconstruc...

  6. Properties of the center of gravity as an algorithm for position measurements: Two-dimensional geometry

    CERN Document Server

    Landi, Gregorio

    2003-01-01

    The center of gravity as an algorithm for position measurements is analyzed for a two-dimensional geometry. Several mathematical consequences of discretization for various types of detector arrays are extracted. Arrays with rectangular, hexagonal, and triangular detectors are analytically studied, and tools are given to simulate their discretization properties. Special signal distributions free of discretized error are isolated. It is proved that some crosstalk spreads are able to eliminate the center of gravity discretization error for any signal distribution. Simulations, adapted to the CMS em-calorimeter and to a triangular detector array, are provided for energy and position reconstruction algorithms with a finite number of detectors.

  7. New method of three-dimensional reconstruction from two-dimensional MR data sets

    International Nuclear Information System (INIS)

    Wrazidlo, W.; Schneider, S.; Brambs, H.J.; Richter, G.M.; Kauffmann, G.W.; Geiger, B.; Fischer, C.

    1989-01-01

    In medical diagnosis and therapy, cross-sectional images are obtained by means of US, CT, or MR imaging. The authors propose a new solution to the problem of constructing a shape over a set of cross-sectional contours from two-dimensional (2D) MR data sets. The authors' method reduces the problem of constructing a shape over the cross sections to one of constructing a sequence of partial shapes, each of them connecting two cross sections lying on adjacent planes. The solution makes use of the Delaunay triangulation, which is isomorphic in that specific situation. The authors compute this Delaunay triangulation. Shape reconstruction is then achieved section by pruning Delaunay triangulations

  8. Restoration of three-dimensional MR images degraded by rotational movements

    International Nuclear Information System (INIS)

    Wood, M.L.

    1990-01-01

    This paper describes a method to restore three-dimensional (3D) magnetic resonance (MR) images that have been degraded by rotational movements, such as head nodding by a restless patient. The technique for acquiring the 3D MR images includes additional MR signals, which provide one-dimensional (1D) and two-dimensional (2D) projections of anatomy. The 1D projections detect gross movements, and the 2D projections resolve displacements in one plane. The 2D projections are transformed from Cartesian coordinates to polar coordinates to identify rotation. A spatial transformation to reverse the rotation is applied to the imaging data after they have been Fourier transformed to resolve structures in the plane of rotation, but before the Fourier transform for the third direction

  9. Imaging system

    International Nuclear Information System (INIS)

    Froggatt, R.J.

    1981-01-01

    The invention provides a two dimensional imaging system in which a pattern of radiation falling on the system is detected to give electrical signals for each of a plurality of strips across the pattern. The detection is repeated for different orientations of the strips and the whole processed by compensated back projection. For a shadow x-ray system a plurality of strip x-ray detectors are rotated on a turntable. For lower frequencies the pattern may be rotated with a Dove prism and the strips condensed to suit smaller detectors with a cylindrical lens. (author)

  10. A comparative study of three-dimensional reconstructive images of temporomandibular joint using computed tomogram

    International Nuclear Information System (INIS)

    Lim, Suk Young; Koh, Kwang Joon

    1993-01-01

    The purpose of this study was to clarify the spatial relationship of temporomandibular joint and to an aid in the diagnosis of temporomandibular disorder. For this study, three-dimensional images of normal temporomandibular joint were reconstructed by computer image analysis system and three-dimensional reconstructive program integrated in computed tomography. The obtained results were as follows : 1. Two-dimensional computed tomograms had the better resolution than three dimensional computed tomograms in the evaluation of bone structure and the disk of TMJ. 2. Direct sagittal computed tomograms and coronal computed tomograms had the better resolution in the evaluation of the disk of TMJ. 3. The positional relationship of the disk could be visualized, but the configuration of the disk could not be clearly visualized on three-dimensional reconstructive CT images. 4. Three-dimensional reconstructive CT images had the smoother margin than three-dimensional images reconstructed by computer image analysis system, but the images of the latter had the better perspective. 5. Three-dimensional reconstructive images had the better spatial relationship of the TMJ articulation, and the joint space were more clearly visualized on dissection images.

  11. NAMMA TWO-DIMENSIONAL STEREO PROBE AND CLOUD PARTICLE IMAGER V1

    Data.gov (United States)

    National Aeronautics and Space Administration — This Cloud Microphysics dataset consists of data from two probes used to measure the size, shape, and concentration of cloud particles; the two-dimensional stereo...

  12. Evaluation of In-Vacuum Imaging Plate Detector for X-Ray Diffraction Microscopy

    International Nuclear Information System (INIS)

    Nishino, Yoshinori; Takahashi, Yukio; Yamamoto, Masaki; Ishikawa, Tetsuya

    2007-01-01

    We performed evaluation tests of a newly developed in-vacuum imaging plate (IP) detector for x-ray diffraction microscopy. IP detectors have advantages over direct x-ray detection charge-coupled device (CCD) detectors, which have been commonly used in x-ray diffraction microscopy experiments, in the capabilities for a high photon count and for a wide area. The detector system contains two IPs to make measurement efficient by recording data with the one while reading or erasing the other. We compared speckled diffraction patterns of single particles taken with the IP and a direct x-ray detection CCD. The IP was inferior to the CCD in spatial resolution and in signal-to-noise ratio at a low photon count

  13. ONE-DIMENSIONAL AND TWO-DIMENSIONAL LEADERSHIP STYLES

    Directory of Open Access Journals (Sweden)

    Nikola Stefanović

    2007-06-01

    Full Text Available In order to motivate their group members to perform certain tasks, leaders use different leadership styles. These styles are based on leaders' backgrounds, knowledge, values, experiences, and expectations. The one-dimensional styles, used by many world leaders, are autocratic and democratic styles. These styles lie on the two opposite sides of the leadership spectrum. In order to precisely define the leadership styles on the spectrum between the autocratic leadership style and the democratic leadership style, leadership theory researchers use two dimensional matrices. The two-dimensional matrices define leadership styles on the basis of different parameters. By using these parameters, one can identify two-dimensional styles.

  14. A direct reflection OLVF debris detector based on dark-field imaging

    Science.gov (United States)

    Li, Bo; Xi, Yinhu; Feng, Song; Mao, Junhong; Xie, You-Bai

    2018-06-01

    To solve the problems of monitoring wear debris in black oil, a direct reflection online visual ferrograph (OLVF) debris detector is presented. In current OLVF detectors, a reflected light source is used. The emitted light is reflected by wear debris directly instead of passing through the lube oil. Therefore, the transparency of the lube oil ceases to matter. Two experiments were conducted to validate the wear debris imaging feasibility and effectiveness of the newly developed detector. The results show that the visual feature information of the wear debris can be reliably obtained from black oil by this detector, and it can also be used to track the fast-changing wear of tribopairs at different wear stages. To the best of our knowledge, to date there is no other report for solving this issue.

  15. Quantitative comparison and evaluation of two commercially available, two-dimensional electrophoresis image analysis software packages, Z3 and Melanie.

    Science.gov (United States)

    Raman, Babu; Cheung, Agnes; Marten, Mark R

    2002-07-01

    While a variety of software packages are available for analyzing two-dimensional electrophoresis (2-DE) gel images, no comparisons between these packages have been published, making it difficult for end users to determine which package would best meet their needs. The goal here was to develop a set of tests to quantitatively evaluate and then compare two software packages, Melanie 3.0 and Z3, in three of the fundamental steps involved in 2-DE image analysis: (i) spot detection, (ii) gel matching, and (iii) spot quantitation. To test spot detection capability, automatically detected protein spots were compared to manually counted, "real" protein spots. Spot matching efficiency was determined by comparing distorted (both geometrically and nongeometrically) gel images with undistorted original images, and quantitation tests were performed on artificial gels with spots of varying Gaussian volumes. In spot detection tests, Z3 performed better than Melanie 3.0 and required minimal user intervention to detect approximately 89% of the actual protein spots and relatively few extraneous spots. Results from gel matching tests depended on the type of image distortion used. For geometric distortions, Z3 performed better than Melanie 3.0, matching 99% of the spots, even for extreme distortions. For nongeometrical distortions, both Z3 and Melanie 3.0 required user intervention and performed comparably, matching 95% of the spots. In spot quantitation tests, both Z3 and Melanie 3.0 predicted spot volumes relatively well for spot ratios less than 1:6. For higher ratios, Melanie 3.0 did much better. In summary, results suggest Z3 requires less user intervention than Melanie 3.0, thus simplifying differential comparison of 2-DE gel images. Melanie 3.0, however, offers many more optional tools for image editing, spot detection, data reporting and statistical analysis than Z3. All image files used for these tests and updated information on the software are available on the internet

  16. Automatic analysis of quality of images from X-ray digital flat detectors

    International Nuclear Information System (INIS)

    Le Meur, Y.

    2009-04-01

    Since last decade, medical imaging has grown up with the development of new digital imaging techniques. In the field of X-ray radiography, new detectors replace progressively older techniques, based on film or x-ray intensifiers. These digital detectors offer a higher sensibility and reduced overall dimensions. This work has been prepared with Trixell, the world leading company in flat detectors for medical radiography. It deals with quality control on digital images stemming from these detectors. High quality standards of medical imaging impose a close analysis of the defects that can appear on the images. This work describes a complete process for quality analysis of such images. A particular focus is given on the detection task of the defects, thanks to methods well adapted to our context of spatially correlated defects in noise background. (author)

  17. Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging

    Directory of Open Access Journals (Sweden)

    Erwin Hack

    2016-02-01

    Full Text Available In terahertz (THz materials science, imaging by scanning prevails when low power THz sources are used. However, the application of array detectors operating with high power THz sources is increasingly reported. We compare the imaging properties of four different array detectors that are able to record THz radiation directly. Two micro-bolometer arrays are designed for infrared imaging in the 8–14 μm wavelength range, but are based on different absorber materials (i vanadium oxide; (ii amorphous silicon; (iii a micro-bolometer array optimized for recording THz radiation based on silicon nitride; and (iv a pyroelectric array detector for THz beam profile measurements. THz wavelengths of 96.5 μm, 118.8 μm, and 393.6 μm from a powerful far infrared laser were used to assess the technical performance in terms of signal to noise ratio, detector response and detectivity. The usefulness of the detectors for beam profiling and digital holography is assessed. Finally, the potential and limitation for real-time digital holography are discussed.

  18. Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging.

    Science.gov (United States)

    Hack, Erwin; Valzania, Lorenzo; Gäumann, Gregory; Shalaby, Mostafa; Hauri, Christoph P; Zolliker, Peter

    2016-02-06

    In terahertz (THz) materials science, imaging by scanning prevails when low power THz sources are used. However, the application of array detectors operating with high power THz sources is increasingly reported. We compare the imaging properties of four different array detectors that are able to record THz radiation directly. Two micro-bolometer arrays are designed for infrared imaging in the 8-14 μm wavelength range, but are based on different absorber materials (i) vanadium oxide; (ii) amorphous silicon; (iii) a micro-bolometer array optimized for recording THz radiation based on silicon nitride; and (iv) a pyroelectric array detector for THz beam profile measurements. THz wavelengths of 96.5 μm, 118.8 μm, and 393.6 μm from a powerful far infrared laser were used to assess the technical performance in terms of signal to noise ratio, detector response and detectivity. The usefulness of the detectors for beam profiling and digital holography is assessed. Finally, the potential and limitation for real-time digital holography are discussed.

  19. New detectors technology for radiology imaging

    International Nuclear Information System (INIS)

    Cuzin, M.; Peyret, O.

    1998-01-01

    We summarize the main parameters which describes the radiological image at first and the advantages of pixel detectors. All detectors converts X-rays in charges either with an intermediate step with light or directly in a semi-conductor media. That is true for tomography which is the first domain where digital processing have been taken in account and for radiology where flat panel are now proposed to radiologists. Nevertheless, luminescent stimulated screens are a good way to prepare users with digital radiography. As such technique is not valuable for dynamic acquisition, we describe systems which used standard luminescent screens with CCD cameras or with IIR. Some description and comparison of flat panel independent pixel detectors are given. (authors)

  20. Edge Detection from High Resolution Remote Sensing Images using Two-Dimensional log Gabor Filter in Frequency Domain

    International Nuclear Information System (INIS)

    Wang, K; Yu, T; Meng, Q Y; Wang, G K; Li, S P; Liu, S H

    2014-01-01

    Edges are vital features to describe the structural information of images, especially high spatial resolution remote sensing images. Edge features can be used to define the boundaries between different ground objects in high spatial resolution remote sensing images. Thus edge detection is important in the remote sensing image processing. Even though many different edge detection algorithms have been proposed, it is difficult to extract the edge features from high spatial resolution remote sensing image including complex ground objects. This paper introduces a novel method to detect edges from the high spatial resolution remote sensing image based on frequency domain. Firstly, the high spatial resolution remote sensing images are Fourier transformed to obtain the magnitude spectrum image (frequency image) by FFT. Then, the frequency spectrum is analyzed by using the radius and angle sampling. Finally, two-dimensional log Gabor filter with optimal parameters is designed according to the result of spectrum analysis. Finally, dot product between the result of Fourier transform and the log Gabor filter is inverse Fourier transformed to obtain the detections. The experimental result shows that the proposed algorithm can detect edge features from the high resolution remote sensing image commendably

  1. Imaging gaseous detectors and their applications

    CERN Document Server

    Nappi, Eugenio

    2013-01-01

    Covers the detector and imaging technology and their numerous applications in nuclear and high energy physics, astrophysics, medicine and radiation measurements Foreword from G. Charpak, awarded the Nobel Prize in Physics for this invention.

  2. A two-dimensional laser-wire scanner for electron accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, A. [Physics Department John Adams Institute for Accelerator Science at Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom)], E-mail: alessio.bosco@rhul.ac.uk; Price, M.T.; Blair, G.A.; Boogert, S.T.; Boorman, G.; Malton, S.; Driouichi, C. [Physics Department John Adams Institute for Accelerator Science at Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom); Kamps, T. [Berliner Elektronenspeicherring, Gesellschaft fur Synchrotronstrahlung, Albert Einstein-Str. 15, 12489 Berlin (Germany); Poirier, F.; Balewski, K.; Elsen, E.; Gharibyan, V.; Lewin, H.-C.; Schreiber, S.; Walker, N.; Wittenburg, K. [Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607 Hamburg (Germany)

    2008-07-21

    A two-dimensional laser-wire scanner capable of measuring the transverse charge profiles of an electron (or positron) bunch has been constructed at the PETRA accelerator in DESY. The development of the system is explained in this paper, along with descriptions of its photon detector and laser system. Results of transverse profile scans are presented for both horizontal and vertical directions. The measurement error is 1.3% from a multi-scan measurement in the vertical direction, where single scans can be performed in less than 50 s.

  3. Charge Division Readout of a Two-Dimensional Germanium Strip Detector

    National Research Council Canada - National Science Library

    Kroeger, R. A; Inderhees, S. E; Johnson, W. N; Kinzer, R. L; Kurfess, J. D; Gehrels, N

    1993-01-01

    .... The four data channels are stored as an event list for subsequent processing. We form a response map over the detector surface in order to locate the position of each interaction with the spatial resolution of the strip pitch, in our case 9 mm...

  4. Efficient High-Dimensional Entanglement Imaging with a Compressive-Sensing Double-Pixel Camera

    Directory of Open Access Journals (Sweden)

    Gregory A. Howland

    2013-02-01

    Full Text Available We implement a double-pixel compressive-sensing camera to efficiently characterize, at high resolution, the spatially entangled fields that are produced by spontaneous parametric down-conversion. This technique leverages sparsity in spatial correlations between entangled photons to improve acquisition times over raster scanning by a scaling factor up to n^{2}/log⁡(n for n-dimensional images. We image at resolutions up to 1024 dimensions per detector and demonstrate a channel capacity of 8.4 bits per photon. By comparing the entangled photons’ classical mutual information in conjugate bases, we violate an entropic Einstein-Podolsky-Rosen separability criterion for all measured resolutions. More broadly, our result indicates that compressive sensing can be especially effective for higher-order measurements on correlated systems.

  5. Electron imaging with Medipix2 hybrid pixel detector

    International Nuclear Information System (INIS)

    McMullan, G.; Cattermole, D.M.; Chen, S.; Henderson, R.; Llopart, X.; Summerfield, C.; Tlustos, L.; Faruqi, A.R.

    2007-01-01

    The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 μmx55 μm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 μm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach ∼85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach ∼35% of that expected for a perfect detector (4/π 2 ). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/π). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected values for the MTF and DQE as a function of the threshold energy. The good agreement between theory and experiment allows suggestions for further improvements to be made with confidence. The present detector is already very useful for experiments that require a high DQE at very low doses

  6. Electron imaging with Medipix2 hybrid pixel detector.

    Science.gov (United States)

    McMullan, G; Cattermole, D M; Chen, S; Henderson, R; Llopart, X; Summerfield, C; Tlustos, L; Faruqi, A R

    2007-01-01

    The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 microm x 55 microm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 microm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach approximately 85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach approximately 35% of that expected for a perfect detector (4/pi(2)). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/pi). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected values for the MTF and DQE as a function of the threshold energy. The good agreement between theory and experiment allows suggestions for further improvements to be made with confidence. The present detector is already very useful for experiments that require a high DQE at very low doses.

  7. The DELPHI Detector (DEtector with Lepton Photon and Hadron Identification)

    CERN Multimedia

    Crawley, B; Munich, K; Mckay, R; Matorras, F; Joram, C; Malychev, V; Behrmann, A; Van dam, P; Drees, J K; Stocchi, A; Adam, W; Booth, P; Bilenki, M; Rosenberg, E I; Morton, G; Rames, J; Hahn, S; Cosme, G; Ventura, L; Marco, J; Tortosa martinez, P; Monge silvestri, R; Moreno, S; Phillips, H; Alekseev, G; Boudinov, E; Martinez rivero, C; Gitarskiy, L; Davenport, M; De clercq, C; Firestone, A; Myagkov, A; Belous, K; Haider, S; Hamilton, K M; Lamsa, J; Rahmani, M H; Malek, A; Hughes, G J; Peralta, L; Carroll, L; Fuster verdu, J A; Cossutti, F; Gorn, L; Yi, J I; Bertrand, D; Myatt, G; Richard, F; Shapkin, M; Hahn, F; Ferrer soria, A; Reinhardt, R; Renton, P; Sekulin, R; Timmermans, J; Baillon, P

    2002-01-01

    % DELPHI The DELPHI Detector (Detector with Lepton Photon and Hadron Identification) \\\\ \\\\DELPHI is a general purpose detector for physics at LEP on and above the Z$^0$, offering three-dimensional information on curvature and energy deposition with fine spatial granularity as well as identification of leptons and hadrons over most of the solid angle. A superconducting coil provides a 1.2~T solenoidal field of high uniformity. Tracking relies on the silicon vertex detector, the inner detector, the Time Projection Chamber (TPC), the outer detector and forward drift chambers. Electromagnetic showers are measured in the barrel with high granularity by the High Density Projection Chamber (HPC) and in the endcaps by $ 1 ^0 $~x~$ 1 ^0 $ projective towers composed of lead glass as active material and phototriode read-out. Hadron identification is provided mainly by liquid and gas Ring Imaging Counters (RICH). The instrumented magnet yoke serves for hadron calorimetry and as filter for muons, which are identified in t...

  8. Design optimization of a breast imaging system based on silicon microstrip detectors

    International Nuclear Information System (INIS)

    Stres, S.; Mikuz, M.

    2000-01-01

    A mammographic imaging set-up using silicon microstrip detectors in edge-on geometry was simulated using the GEANT package. Deposited energy in tissue of various thicknesses was evaluated and shown to agree to within 10% with reference calculations. Optimal energies as well as spectra for mammography with silicon detectors were determined by maximizing the figure of merit of a realistic imaging set-up. The scattered to primary radiation ratio was studied for various detector geometries. It was found that fan-shaped detectors are needed to maintain the image quality for divergent photon beams. (author)

  9. Bolometric kinetic inductance detector technology for sub-millimeter radiometric imaging

    Science.gov (United States)

    Hassel, Juha; Timofeev, Andrey V.; Vesterinen, Visa; Sipola, Hannu; Helistö, Panu; Aikio, Mika; Mäyrä, Aki; Grönberg, Leif; Luukanen, Arttu

    2015-10-01

    Radiometric sub-millimeter imaging is a candidate technology especially in security screening applications utilizing the property of radiation in the band of 0.2 - 1.0 THz to penetrate through dielectric substances such as clothing. The challenge of the passive technology is the fact that the irradiance corresponding to the blackbody radiation is very weak in this spectral band: about two orders of magnitude below that of the infrared band. Therefore the role of the detector technology is of ultimate importance to achieve sufficient sensitivity. In this paper we present results related to our technology relying on superconducting kinetic inductance detectors operating in a thermal (bolometric) mode. The detector technology is motivated by the fact that it is naturally suitable for scalable multiplexed readout systems, and operates with relatively simple cryogenics. We will review the basic concepts of the detectors, and provide experimental figures of merit. Furthermore, we will discuss the issues related to the scale-up of our detector technology into large 2D focal plane arrays.

  10. State-of-the-art radiation detectors for medical imaging: Demands and trends

    International Nuclear Information System (INIS)

    Darambara, Dimitra G.

    2006-01-01

    Over the last half-century a variety of significant technical advances in several scientific fields has been pointing to an exploding growth in the field of medical imaging leading to a better interpretation of more specific anatomical, biochemical and molecular pathways. In particular, the development of novel imaging detectors and readout electronics has been critical to the advancement of medical imaging allowing the invention of breakthrough platforms for simultaneous acquisition of multi-modality images at molecular level. The present paper presents a review of the challenges, demands and constraints on radiation imaging detectors imposed by the nature of the modality and the physics of the imaging source. This is followed by a concise review and perspective on various types of state-of-the-art detector technologies that have been developed to meet these requirements. Trends, prospects and new concepts for future imaging detectors are also highlighted

  11. State-of-the-art radiation detectors for medical imaging: Demands and trends

    Energy Technology Data Exchange (ETDEWEB)

    Darambara, Dimitra G. [Joint Department of Physics, Royal Marsden Foundation Trust and Institute of Cancer Research, Fulham Road, London SW3 6JJ (United Kingdom)]. E-mail: dimitra.darambara@icr.ac.uk

    2006-12-20

    Over the last half-century a variety of significant technical advances in several scientific fields has been pointing to an exploding growth in the field of medical imaging leading to a better interpretation of more specific anatomical, biochemical and molecular pathways. In particular, the development of novel imaging detectors and readout electronics has been critical to the advancement of medical imaging allowing the invention of breakthrough platforms for simultaneous acquisition of multi-modality images at molecular level. The present paper presents a review of the challenges, demands and constraints on radiation imaging detectors imposed by the nature of the modality and the physics of the imaging source. This is followed by a concise review and perspective on various types of state-of-the-art detector technologies that have been developed to meet these requirements. Trends, prospects and new concepts for future imaging detectors are also highlighted.

  12. Reconstituted Three-Dimensional Interactive Imaging

    Science.gov (United States)

    Hamilton, Joseph; Foley, Theodore; Duncavage, Thomas; Mayes, Terrence

    2010-01-01

    A method combines two-dimensional images, enhancing the images as well as rendering a 3D, enhanced, interactive computer image or visual model. Any advanced compiler can be used in conjunction with any graphics library package for this method, which is intended to take digitized images and virtually stack them so that they can be interactively viewed as a set of slices. This innovation can take multiple image sources (film or digital) and create a "transparent" image with higher densities in the image being less transparent. The images are then stacked such that an apparent 3D object is created in virtual space for interactive review of the set of images. This innovation can be used with any application where 3D images are taken as slices of a larger object. These could include machines, materials for inspection, geological objects, or human scanning. Illuminous values were stacked into planes with different transparency levels of tissues. These transparency levels can use multiple energy levels, such as density of CT scans or radioactive density. A desktop computer with enough video memory to produce the image is capable of this work. The memory changes with the size and resolution of the desired images to be stacked and viewed.

  13. Bilocal current densities and mean trajectories in a Young interferometer with two Gaussian slits and two detectors

    Energy Technology Data Exchange (ETDEWEB)

    Withers, L. P., E-mail: lpwithers@mitre.org [School of Physics, Astronomy, and Computational Science, George Mason University, Fairfax, Virginia 22030-4444 (United States); Narducci, F. A., E-mail: francesco.narducci@navy.mil [Naval Air Systems Command, Patuxent River, Maryland 20670 (United States)

    2015-06-15

    The recent single-photon double-slit experiment of Steinberg et al., based on a weak measurement method proposed by Wiseman, showed that, by encoding the photon’s transverse momentum behind the slits into its polarization state, the momentum profile can subsequently be measured on average, from a difference of the separated fringe intensities for the two circular polarization components. They then integrated the measured average velocity field, to obtain the average trajectories of the photons enroute to the detector array. In this paper, we propose a modification of their experiment, to demonstrate that the average particle velocities and trajectories change when the mode of detection changes. The proposed experiment replaces a single detector by a pair of detectors with a given spacing between them. The pair of detectors is configured so that it is impossible to distinguish which detector received the particle. The pair of detectors is then analogous to the simple pair of slits, in that it is impossible to distinguish which slit the particle passed through. To establish the paradoxical outcome of the modified experiment, the theory and explicit three-dimensional formulas are developed for the bilocal probability and current densities, and for the average velocity field and trajectories as the particle wavefunction propagates in the volume of space behind the Gaussian slits. Examples of these predicted results are plotted. Implementation details of the proposed experiment are discussed.

  14. A tilted fiber-optic plate coupled CCD detector for high resolution neutron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jongyul; Cho, Gyuseong [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Kim, Jongyul; Hwy, Limchang; Kim, Taejoo; Lee, Kyehong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Seungwook [Pusan National Univ., Pusan (Korea, Republic of)

    2013-05-15

    One of these efforts is that a tilted scintillator geometry and lens coupled CCD detector for neutron imaging system were used to improve spatial resolution in one dimension. The increased spatial resolution in one dimension was applied to fuel cell study. However, a lens coupled CCD detector has lower sensitivity than a fiber-optic plate coupled CCD detector due to light loss. In this research, a tilted detector using fiber-optic plate coupled CCD detector was developed to improve resolution and sensitivity. In addition, a tilted detector can prevent an image sensor from direct radiation damage. Neutron imaging has been used for fuel cell study, lithium ion battery study, and many scientific applications. High quality neutron imaging is demanded for more detailed studies of applications, and spatial resolution should be considered to get high quality neutron imaging. Therefore, there were many efforts to improve spatial resolution.

  15. 16-slice multi-detector row CT coronary angiography: image quality and optimization of the image reconstruction window

    International Nuclear Information System (INIS)

    Kim, Yoo Kyung; Shim, Sung Shine; Lim, Soo Mee; Hwang, Ji Young; Kim, Yoon Kyung

    2005-01-01

    The purpose of this experiment is to investigate the image quality of CT coronary angiography using a 16-slice multi-detector row CT and to determine the optimal image reconstruction window. CT coronary angiography was obtained in 36 nonsymptomatic volunteers using a 16-slice multi-detector row CT (SOMATOM Sensation, Siemens Medical System). The mean heart rates were 70 beats per minute (bpm) or less in 18 persons and more than 70 bpm in 18 persons. Eleven data sets were obtained for each patient (reconstructed at 30%-80% of the cardiac cycle with an increment of 5%). Image quality of the eight coronary segments [left main coronary artery (LM), proximal and middle segments of left anterior descending artery (p-LAD, m-LAN) and left circumflex coronary artery (p-LCx, m-LCx) and proximal, middle and distal segments of right coronary artery (p-RCA, m-RCA, d-RCA)] was assessed. The optimal reconstruction windows in the cardiac cycle for the best image quality were 60-70% for the segments of the LM, LAD, and LC arteries in two groups (bpm 70) and 55-65% (bpm 70) for the segments of the RCA. On the best dataset for each coronary segment, the following diagnostic image quality was achieved in the two groups: LM: 100%, 83%; p-LAD: 100%, 88% m-LAD: 100%, 72%; p-LCx: 100%, 72%; m-LCx: 100%, 72%; p-RCA: 94%, 72%; m-RCA: 61%, 50%; d-RCA: 100%, 80%. The 16 slice multi-detector row CT scan provided visualization of the coronary arteries with high resolution. Especially in the group with a mean heart rate of 70 bpm or less, all the coronary segments except the RCA showed diagnostic image quality. Optimal image quality was achieved with a 60-70% trigger delay for all coronary arterial segments, but the best images of RCA were achieved in the earlier cardiac phase in the patients with a mean heart rate of more than 70 bpm

  16. Cherenkov detectors for spatial imaging applications using discrete-energy photons

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Paul B.; Erickson, Anna S., E-mail: erickson@gatech.edu [Georgia Institute of Technology, Nuclear and Radiological Engineering, G.W. Woodruff School of Mechanical Engineering, 770 State St., Atlanta, Georgia 30332 (United States)

    2016-08-14

    Cherenkov detectors can offer a significant advantage in spatial imaging applications when excellent timing response, low noise and cross talk, large area coverage, and the ability to operate in magnetic fields are required. We show that an array of Cherenkov detectors with crude energy resolution coupled with monochromatic photons resulting from a low-energy nuclear reaction can be used to produce a sharp image of material while providing large and inexpensive detector coverage. The analysis of the detector response to relative transmission of photons with various energies allows for reconstruction of material's effective atomic number further aiding in high-Z material identification.

  17. Three-dimensional CT and MR imaging in congenital dislocation of the hip: Technical considerations

    International Nuclear Information System (INIS)

    Lang, P.; Steiger, P.; Lindquist, T.; Skinner, S.; Moore, S.; Chafetz, N.I.; Genant, H.K.

    1987-01-01

    Two-dimensional (2D) software techniques were developed to generate diagnostic-quality three-dimensional (3D) MR studies in two patients with congenital dislocation of the hip. Comparable 3D CT studies were obtained in two other patients. Unsharp masks were divided into the original MR images to correct for local variations in signal intensity. Combinations of first- and second-echo images improved the object contrast. Pixels with insufficient homogeneity relative to their neighboring data were excluded. CT did not require 2D preprocessing. Three-dimensional CT and MR images demonstrated subluxation and dislocation. 3D MR, in contrast to CT, demonstrated the cartilaginous femoral head. The described 2D MR preprocessing provides diagnostic-quality 3D MR studies. It will be useful for generating 3D MR images of other anatomic structures

  18. Study of Three-Dimensional Image Brightness Loss in Stereoscopy

    Directory of Open Access Journals (Sweden)

    Hsing-Cheng Yu

    2015-10-01

    Full Text Available When viewing three-dimensional (3D images, whether in cinemas or on stereoscopic televisions, viewers experience the same problem of image brightness loss. This study aims to investigate image brightness loss in 3D displays, with the primary aim being to quantify the image brightness degradation in the 3D mode. A further aim is to determine the image brightness relationship to the corresponding two-dimensional (2D images in order to adjust the 3D-image brightness values. In addition, the photographic principle is used in this study to measure metering values by capturing 2D and 3D images on television screens. By analyzing these images with statistical product and service solutions (SPSS software, the image brightness values can be estimated using the statistical regression model, which can also indicate the impact of various environmental factors or hardware on the image brightness. In analysis of the experimental results, comparison of the image brightness between 2D and 3D images indicates 60.8% degradation in the 3D image brightness amplitude. The experimental values, from 52.4% to 69.2%, are within the 95% confidence interval

  19. Pixel detectors for x-ray imaging spectroscopy in space

    International Nuclear Information System (INIS)

    Treis, J; Andritschke, R; Hartmann, R; Herrmann, S; Holl, P; Lauf, T; Lechner, P; Lutz, G; Meidinger, N; Porro, M; Richter, R H; Schopper, F; Soltau, H; Strueder, L

    2009-01-01

    Pixelated semiconductor detectors for X-ray imaging spectroscopy are foreseen as key components of the payload of various future space missions exploring the x-ray sky. Located on the platform of the new Spectrum-Roentgen-Gamma satellite, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) instrument will perform an imaging all-sky survey up to an X-ray energy of 10 keV with unprecedented spectral and angular resolution. The instrument will consist of seven parallel oriented mirror modules each having its own pnCCD camera in the focus. The satellite born X-ray observatory SIMBOL-X will be the first mission to use formation-flying techniques to implement an X-ray telescope with an unprecedented focal length of around 20 m. The detector instrumentation consists of separate high- and low energy detectors, a monolithic 128 x 128 DEPFET macropixel array and a pixellated CdZTe detector respectively, making energy band between 0.5 to 80 keV accessible. A similar concept is proposed for the next generation X-ray observatory IXO. Finally, the MIXS (Mercury Imaging X-ray Spectrometer) instrument on the European Mercury exploration mission BepiColombo will use DEPFET macropixel arrays together with a small X-ray telescope to perform a spatially resolved planetary XRF analysis of Mercury's crust. Here, the mission concepts and their scientific targets are briefly discussed, and the resulting requirements on the detector devices together with the implementation strategies are shown.

  20. Pixel detectors for x-ray imaging spectroscopy in space

    Science.gov (United States)

    Treis, J.; Andritschke, R.; Hartmann, R.; Herrmann, S.; Holl, P.; Lauf, T.; Lechner, P.; Lutz, G.; Meidinger, N.; Porro, M.; Richter, R. H.; Schopper, F.; Soltau, H.; Strüder, L.

    2009-03-01

    Pixelated semiconductor detectors for X-ray imaging spectroscopy are foreseen as key components of the payload of various future space missions exploring the x-ray sky. Located on the platform of the new Spectrum-Roentgen-Gamma satellite, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) instrument will perform an imaging all-sky survey up to an X-ray energy of 10 keV with unprecedented spectral and angular resolution. The instrument will consist of seven parallel oriented mirror modules each having its own pnCCD camera in the focus. The satellite born X-ray observatory SIMBOL-X will be the first mission to use formation-flying techniques to implement an X-ray telescope with an unprecedented focal length of around 20 m. The detector instrumentation consists of separate high- and low energy detectors, a monolithic 128 × 128 DEPFET macropixel array and a pixellated CdZTe detector respectively, making energy band between 0.5 to 80 keV accessible. A similar concept is proposed for the next generation X-ray observatory IXO. Finally, the MIXS (Mercury Imaging X-ray Spectrometer) instrument on the European Mercury exploration mission BepiColombo will use DEPFET macropixel arrays together with a small X-ray telescope to perform a spatially resolved planetary XRF analysis of Mercury's crust. Here, the mission concepts and their scientific targets are briefly discussed, and the resulting requirements on the detector devices together with the implementation strategies are shown.

  1. Pixel detectors for x-ray imaging spectroscopy in space

    Energy Technology Data Exchange (ETDEWEB)

    Treis, J; Andritschke, R; Hartmann, R; Herrmann, S; Holl, P; Lauf, T; Lechner, P; Lutz, G; Meidinger, N; Porro, M; Richter, R H; Schopper, F; Soltau, H; Strueder, L [MPI Semiconductor Laboratory, Otto-Hahn-Ring 6, D-81739 Munich (Germany)], E-mail: jft@hll.mpg.de

    2009-03-15

    Pixelated semiconductor detectors for X-ray imaging spectroscopy are foreseen as key components of the payload of various future space missions exploring the x-ray sky. Located on the platform of the new Spectrum-Roentgen-Gamma satellite, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) instrument will perform an imaging all-sky survey up to an X-ray energy of 10 keV with unprecedented spectral and angular resolution. The instrument will consist of seven parallel oriented mirror modules each having its own pnCCD camera in the focus. The satellite born X-ray observatory SIMBOL-X will be the first mission to use formation-flying techniques to implement an X-ray telescope with an unprecedented focal length of around 20 m. The detector instrumentation consists of separate high- and low energy detectors, a monolithic 128 x 128 DEPFET macropixel array and a pixellated CdZTe detector respectively, making energy band between 0.5 to 80 keV accessible. A similar concept is proposed for the next generation X-ray observatory IXO. Finally, the MIXS (Mercury Imaging X-ray Spectrometer) instrument on the European Mercury exploration mission BepiColombo will use DEPFET macropixel arrays together with a small X-ray telescope to perform a spatially resolved planetary XRF analysis of Mercury's crust. Here, the mission concepts and their scientific targets are briefly discussed, and the resulting requirements on the detector devices together with the implementation strategies are shown.

  2. Large-area imaging micro-well detectors for high-energy astrophysics

    CERN Document Server

    Deines-Jones, P; Hunter, S D; Jahoda, K; Owens, S M

    2002-01-01

    Micro-well detectors are pixelized imaging sensors that can be inexpensively fabricated in very large arrays. Owing to their intrinsic gain and operation at room temperature, they can be instrumented at very low power, per unit area, making them valuable for a variety of space-flight applications where wide-angle X-ray imaging or large-area particle tracking is required. For example, micro-well detectors have been chosen as the focal plane imager for Lobster-ISS, a proposed soft X-ray all-sky monitor. We have fabricated detectors which image X-rays with 200 mu m FWHM resolution at 3 keV. In agreement with other groups using similar geometries, we find nominal proportional counter energy resolution (20% at 6 keV in P-10), and stable operation at gas gains up to 30,000.

  3. [Bone drilling simulation by three-dimensional imaging].

    Science.gov (United States)

    Suto, Y; Furuhata, K; Kojima, T; Kurokawa, T; Kobayashi, M

    1989-06-01

    The three-dimensional display technique has a wide range of medical applications. Pre-operative planning is one typical application: in orthopedic surgery, three-dimensional image processing has been used very successfully. We have employed this technique in pre-operative planning for orthopedic surgery, and have developed a simulation system for bone-drilling. Positive results were obtained by pre-operative rehearsal; when a region of interest is indicated by means of a mouse on the three-dimensional image displayed on the CRT, the corresponding region appears on the slice image which is displayed simultaneously. Consequently, the status of the bone-drilling is constantly monitored. In developing this system, we have placed emphasis on the quality of the reconstructed three-dimensional images, on fast processing, and on the easy operation of the surgical planning simulation.

  4. Preparation of wholemount mouse intestine for high-resolution three-dimensional imaging using two-photon microscopy.

    Science.gov (United States)

    Appleton, P L; Quyn, A J; Swift, S; Näthke, I

    2009-05-01

    Visualizing overall tissue architecture in three dimensions is fundamental for validating and integrating biochemical, cell biological and visual data from less complex systems such as cultured cells. Here, we describe a method to generate high-resolution three-dimensional image data of intact mouse gut tissue. Regions of highest interest lie between 50 and 200 mum within this tissue. The quality and usefulness of three-dimensional image data of tissue with such depth is limited owing to problems associated with scattered light, photobleaching and spherical aberration. Furthermore, the highest-quality oil-immersion lenses are designed to work at a maximum distance of image at high-resolution deep within tissue. We show that manipulating the refractive index of the mounting media and decreasing sample opacity greatly improves image quality such that the limiting factor for a standard, inverted multi-photon microscope is determined by the working distance of the objective as opposed to detectable fluorescence. This method negates the need for mechanical sectioning of tissue and enables the routine generation of high-quality, quantitative image data that can significantly advance our understanding of tissue architecture and physiology.

  5. Real-time imaging systems for superconducting nanowire single-photon detector arrays

    Energy Technology Data Exchange (ETDEWEB)

    Hofherr, Matthias

    2014-07-01

    Superconducting nanowire singe-photon detectors (SNSPD) are promising detectors in the field of applications, where single-photon resolution is required like in quantum optics, spectroscopy or astronomy. These cryogenic detectors gain from a broad spectrum in the optical and infrared range and deliver low dark counts and low jitter. This work provides a piece of deeper physical understanding of detector functionality in combination with highly engineered readout development. A detailed analysis focuses on the intrinsic detection mechanism of SNSPDs related to the detection in the infrared regime and the evolution of dark counts. With this fundamental knowledge, the next step is the development of a multi-pixel readout at cryogenic conditions. It is demonstrated, how two auspicious multi-pixel readout concepts can be realized, which enables statistical framing like in imaging applications using RSFQ electronics with fast framing rates and the readout of a detector array with continuous real-time single-photon resolution.

  6. Two-dimensional NMR spectrometry

    International Nuclear Information System (INIS)

    Farrar, T.C.

    1987-01-01

    This article is the second in a two-part series. In part one (ANALYTICAL CHEMISTRY, May 15) the authors discussed one-dimensional nuclear magnetic resonance (NMR) spectra and some relatively advanced nuclear spin gymnastics experiments that provide a capability for selective sensitivity enhancements. In this article and overview and some applications of two-dimensional NMR experiments are presented. These powerful experiments are important complements to the one-dimensional experiments. As in the more sophisticated one-dimensional experiments, the two-dimensional experiments involve three distinct time periods: a preparation period, t 0 ; an evolution period, t 1 ; and a detection period, t 2

  7. Two-dimensional profiling of Xanthomonas campestris pv. viticola ...

    African Journals Online (AJOL)

    However, the analysis of the 2D-PAGE gel images revealed a larger number of spots in the lysis method when compared to the others. Taking ... Keywords: Bacterial canker, Vitis vinifera, proteomics, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), two-dimensional gel electrophoresis (2D-PAGE).

  8. A gas microstrip detector for X-ray imaging with readout of the anode by resistive division

    CERN Document Server

    Bateman, J E; Lodge, A B; Stephenson, R; Mutikainen, R; Suni, I; Morse, J

    2002-01-01

    The results are presented of a development programme aimed at the validation of the key concepts and technologies for the construction of a two-dimensional X-ray detector based on gas microstrip detector technology using resistive division along the anode to achieve the second dimension. A prototype detector and its associated electronic readout system have been developed which demonstrate the capability of a spatial resolution (standard deviation) of approximately ((1)/(1000)) of the working aperture combined with readout rates of up to 400 kHz per anode. Test results and a description of the position sensing circuitry are given.

  9. Three-dimensional imaging using phase retrieval with two focus planes

    Science.gov (United States)

    Ilovitsh, Tali; Ilovitsh, Asaf; Weiss, Aryeh; Meir, Rinat; Zalevsky, Zeev

    2016-03-01

    This work presents a technique for a full 3D imaging of biological samples tagged with gold-nanoparticles (GNPs) using only two images, rather than many images per volume as is currently needed for 3D optical sectioning microscopy. The proposed approach is based on the Gerchberg-Saxton (GS) phase retrieval algorithm. The reconstructed field is free space propagated to all other focus planes using post processing, and the 2D z-stack is merged to create a 3D image of the sample with high fidelity. Because we propose to apply the phase retrieving on nano particles, the regular ambiguities typical to the Gerchberg-Saxton algorithm, are eliminated. In addition, since the method requires the capturing of two images only, it can be suitable for 3D live cell imaging. The proposed concept is presented and validated both on simulated data as well as experimentally.

  10. Transmission dosimetry with a liquid-filled electronic portal imaging device

    Energy Technology Data Exchange (ETDEWEB)

    Boellaard, R; Van Herk, M; Mijnheer, B J [Nederlands Kanker Inst. ` Antoni van Leeuwenhoekhuis` , Amsterdam (Netherlands)

    1995-12-01

    The aim of transmission dosimetry is to correlate transmission dose values with patient dose values. A liquid-filled electronic portal imaging device (EPID) has been developed. After determination of the dose response relationship, i.e. the relation between pixel value and dose rate, for clinical situations it was found that the EPID is applicable for two-dimensional dosimetry with an accuracy of about 1%. The aim of this study was to investigate transmission dose distributions at different phantom-detector distances to predict exit dose distributions from transmission dose images. An extensive set of transmission dose measurements below homogeneous phantoms were performed with the EPID. The influence of several parameters such as field size, phantom thickness, phantom-detector distance and phantom-source distance on the transmission dose and its distribution were investigated. The two-dimensional transmission dose images were separated into two components: a primary dose and a scattered dose distribution. It was found that the scattered dose is maximal at a phantom thickness of about 10 cm. The scattered dose distribution below a homogeneous phantom has a Gaussian shape. The width of the Gaussian is small at small phantom-detector distances and increases for larger phantom-detector distances. The dependence of the scattered dose distribution on the field size at various phantom-detector distances has been used to estimate the dose distribution at the exit site of the phantom. More work is underway to determine the exit dose distributions for clinical situations, including the presence of inhomogeneities.

  11. Transmission dosimetry with a liquid-filled electronic portal imaging device

    International Nuclear Information System (INIS)

    Boellaard, R.; Van Herk, M.; Mijnheer, B.J.

    1995-01-01

    The aim of transmission dosimetry is to correlate transmission dose values with patient dose values. A liquid-filled electronic portal imaging device (EPID) has been developed. After determination of the dose response relationship, i.e. the relation between pixel value and dose rate, for clinical situations it was found that the EPID is applicable for two-dimensional dosimetry with an accuracy of about 1%. The aim of this study was to investigate transmission dose distributions at different phantom-detector distances to predict exit dose distributions from transmission dose images. An extensive set of transmission dose measurements below homogeneous phantoms were performed with the EPID. The influence of several parameters such as field size, phantom thickness, phantom-detector distance and phantom-source distance on the transmission dose and its distribution were investigated. The two-dimensional transmission dose images were separated into two components: a primary dose and a scattered dose distribution. It was found that the scattered dose is maximal at a phantom thickness of about 10 cm. The scattered dose distribution below a homogeneous phantom has a Gaussian shape. The width of the Gaussian is small at small phantom-detector distances and increases for larger phantom-detector distances. The dependence of the scattered dose distribution on the field size at various phantom-detector distances has been used to estimate the dose distribution at the exit site of the phantom. More work is underway to determine the exit dose distributions for clinical situations, including the presence of inhomogeneities

  12. Multiparticle imaging velocimetry measurements in two-phase flow

    International Nuclear Information System (INIS)

    Hassan, Y.A.

    1998-01-01

    The experimental flow visualization tool, Particle Image Velocimetry (PIV), is being extended to determine the velocity fields in two and three-dimensional, two-phase fluid flows. In the past few years, the technique has attracted quite a lot of interest. PIV enables fluid velocities across a region of a flow to be measured at a single instant in time in global domain. This instantaneous velocity profile of a given flow field is determined by digitally recording particle (microspheres or bubbles) images within the flow over multiple successive video frames and then conducting flow pattern identification and analysis of the data. This paper presents instantaneous velocity measurements in various two and three- dimensional, two-phase flow situations. (author)

  13. Microsecond-scale X-ray imaging with Controlled-Drift Detectors

    International Nuclear Information System (INIS)

    Castoldi, A.; Galimberti, A.; Guazzoni, C.; Rehak, P.; Strueder, L.

    2006-01-01

    The Controlled-Drift Detector is a fully-depleted silicon detector that allows 2-D position sensing and energy spectroscopy of X-rays in the range 0.5-20keV with excellent time resolution (few tens of μs) and limited readout channels. In this paper we review the Controlled-Drift Detector operating principle and we present the X-ray imaging and spectroscopic capabilities of Controlled Drift Detectors in microsecond-scale experiments and the more relevant applications fields

  14. Experimental confirmation of a new semiconductor detector principle

    International Nuclear Information System (INIS)

    Kemmer, J.; Lutz, G.; Schuster, K.; Sterzik, M.; Strueder, L.; Prechtel, U.; Ziemann, T.

    1990-01-01

    A new detector-amplification principle proposed by Kemmer and Lutz in 1986 has been experimentally verified. Outstanding features of this device are the built-in amplification, the signal charge storage capability and the possibility of repeated non-destructive readout. The device was used for detection of X-rays from a 241 Am and from an 55 Fe source. Very low noise figures (σ=30 electrons corresponding to an energy resolution of FWHM=250 eV at 6 keV energy) have been obtained at room temperature. Various applications of the structure either as detector or as purely electronic element are possible. One of the most intriguing is the use as a pixel detector with random access non-destructive readout. This device may be operated at very low power, as only reading (of one single pixel at a time), not storing, consumes power. Further options of the device are fast clearing, gating and variation of the pixel size during readout. The latter property can be used to drastically increase the readout speed compared to more standard two dimensional devices as e.g. CCD detectors, as one may restrict the high density readout to regions of interest determined beforehand by a coarse scan of the whole detector. An alternative use of the device is as an analog or digital memory, or as a simple transistor by a coarse scan of the whole detector. An alternative use of the device is as an analog or digital memory, or as a simple transistor with drastically reduced parasitic capacitances. Possible further developments are the combination with a novel three dimensional analog storage device which may either be used as a detector with built-in storage of several charge images or as a three-dimensional analog memory. (orig.)

  15. DIRC, the internally reflecting ring imaging Cherenkov detector for BABAR

    International Nuclear Information System (INIS)

    Adam, I.; Aston, D.

    1997-11-01

    The DIRC is a new type of Cherenkov imaging device that will be used for the first time in the BABAR detector at the asymmetric B-factory, PEP-II. It is based on total internal reflection and uses long, rectangular bars made from synthetic fused silica as Cherenkov radiator and light guide. The principles of the DIRC ring imaging Cherenkov technique are explained and results from the prototype program are presented. Its choice for the BABAR detector particle identification system is motivated, followed by a discussion of the quartz radiator properties and the detector design

  16. Two-dimensional wavelet transform feature extraction for porous silicon chemical sensors.

    Science.gov (United States)

    Murguía, José S; Vergara, Alexander; Vargas-Olmos, Cecilia; Wong, Travis J; Fonollosa, Jordi; Huerta, Ramón

    2013-06-27

    Designing reliable, fast responding, highly sensitive, and low-power consuming chemo-sensory systems has long been a major goal in chemo-sensing. This goal, however, presents a difficult challenge because having a set of chemo-sensory detectors exhibiting all these aforementioned ideal conditions are still largely un-realizable to-date. This paper presents a unique perspective on capturing more in-depth insights into the physicochemical interactions of two distinct, selectively chemically modified porous silicon (pSi) film-based optical gas sensors by implementing an innovative, based on signal processing methodology, namely the two-dimensional discrete wavelet transform. Specifically, the method consists of using the two-dimensional discrete wavelet transform as a feature extraction method to capture the non-stationary behavior from the bi-dimensional pSi rugate sensor response. Utilizing a comprehensive set of measurements collected from each of the aforementioned optically based chemical sensors, we evaluate the significance of our approach on a complex, six-dimensional chemical analyte discrimination/quantification task problem. Due to the bi-dimensional aspects naturally governing the optical sensor response to chemical analytes, our findings provide evidence that the proposed feature extractor strategy may be a valuable tool to deepen our understanding of the performance of optically based chemical sensors as well as an important step toward attaining their implementation in more realistic chemo-sensing applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Automatic luminous reflections detector using global threshold with increased luminosity contrast in images

    Science.gov (United States)

    Silva, Ricardo Petri; Naozuka, Gustavo Taiji; Mastelini, Saulo Martiello; Felinto, Alan Salvany

    2018-01-01

    The incidence of luminous reflections (LR) in captured images can interfere with the color of the affected regions. These regions tend to oversaturate, becoming whitish and, consequently, losing the original color information of the scene. Decision processes that employ images acquired from digital cameras can be impaired by the LR incidence. Such applications include real-time video surgeries, facial, and ocular recognition. This work proposes an algorithm called contrast enhancement of potential LR regions, which is a preprocessing to increase the contrast of potential LR regions, in order to improve the performance of automatic LR detectors. In addition, three automatic detectors were compared with and without the employment of our preprocessing method. The first one is a technique already consolidated in the literature called the Chang-Tseng threshold. We propose two automatic detectors called adapted histogram peak and global threshold. We employed four performance metrics to evaluate the detectors, namely, accuracy, precision, exactitude, and root mean square error. The exactitude metric is developed by this work. Thus, a manually defined reference model was created. The global threshold detector combined with our preprocessing method presented the best results, with an average exactitude rate of 82.47%.

  18. Radiation therapy treatment planning: CT, MR imaging and three-dimensional planning

    International Nuclear Information System (INIS)

    Lichter, A.S.

    1987-01-01

    The accuracy and sophistication of radiation therapy treatment planning have increased rapidly in the last decade. Currently, CT-based treatment planning is standard throughout the country. Care must be taken when CT is used for treatment planning because of clear differences between diagnostic scans and scans intended for therapeutic management. The use of CT in radiation therapy planning is discussed and illustrated. MR imaging adds another dimension to treatment planning. The ability to use MR imaging directly in treatment planning involves an additional complex set of capabilities from a treatment planning system. The ability to unwarp the geometrically distorted MR image is a first step. Three-dimensional dose calculations are important to display the dose on sagittal and acoronal sections. The ability to integrate the MR and CT images into a unified radiographic image is critical. CT and MR images are two-dimensional representations of a three-dimensional problem. Through sophisticated computer graphics techniques, radiation therapists are now able to integrate a three-dimensional image of the patient into the treatment planning process. This allows the use of noncoplanar treatment plans and a detailed analysis of tumor and normal tissue anatomy; it is the first step toward a fully conformational treatment planning system. These concepts are illustrated and future research goals outlined

  19. [Clinical application of high-pitch excretory phase images during dual-source CT urography with stellar photon detector].

    Science.gov (United States)

    Sun, Hao; Xue, Hua-dan; Jin, Zheng-yu; Wang, Xuan; Chen, Yu; He, Yong-lan; Zhang, Da-ming; Zhu, Liang; Wang, Yun; Qi, Bing; Xu, Kai; Wang, Ming

    2014-10-01

    To retrospectively evaluate the clinical feasibility of high-pitch excretory phase images during dual-source CT urography with Stellar photon detector. Totally 100 patients received dual-source CT high-pitch urinary excretory phase scanning with Stellar photon detector [80 kV, ref.92 mAs, CARE Dose 4D and CARE kV, pitch of 3.0, filter back projection reconstruction algorithm (FBP)] (group A). Another 100 patients received dual-source CT high-pitch urinary excretory phase scanning with common detector(100 kV, ref.140 mAs, CARE Dose 4D, pitch of 3.0, FBP) (group B). Quantitative measurement of CT value of urinary segments (Hounsfield units), image noise (Hounsfield units), and effective radiation dose (millisievert) were compared using independent-samples t test between two groups. Urinary system subjective opacification scores were compared using Mann-Whitney U test between two groups. There was no significant difference in subjective opacification score of intrarenal collecting system and ureters between two groups (all P>0.05). The group A images yielded significantly higher CT values of all urinary segments (all P0.05). The effective radiation dose of group A (1.1 mSv) was significantly lower than that of group B (3.79 mSv) (Ppitch low-tube-voltage during excretory phase dual-source CT urography with Stellar photon detector is feasible, with acceptable image noise and lower radiation dose.

  20. Three-dimensional image reconstruction from stereo DSA

    International Nuclear Information System (INIS)

    Sakamoto, Kiyoshi; Kotoura, Noriko; Umehara, Takayoshi; Yamada, Eiji; Inaba, Tomohiro; Itou, Hiroshi

    1999-01-01

    The technique of interventional radiology has spread rapidly in recent years, and three-dimensional information from blood vessel images is being sought to enhance examinations. Stereo digital subtraction angiography (DSA) and rotational DSA were developed for that purpose. However, it is difficult with stereo DSA to observe the image pair during examination and to obtain positional information on blood vessels. Further, the exposure dose is increased in rotational DSA when many mask images need to be collected, and the patient is required to hold his or her breath for a long duration. We therefore devised a technique to construct three-dimensional blood vessel images by employing geometrical information extracted from stereo DSA images using the right and left images. We used a judgment method based on the correlation coefficient, although we had to extract an equal blood vessel from the right and left images to determine the three-dimensional coordinates of the blood vessel. The reconstructed three-dimensional blood vessels were projected from various angles, again by using a virtual focus, and new images were created. These image groups were displayed as rotational images by the animation display function incorporated in the DSA device. This system can observe blood vessel images of the same phase at a free angle, although the image quality is inferior to that of rotational DSA. In addition, because collection of the mask images is reduced, exposure dose can be decreased. Further, the system offers enhanced safety because no mechanical movement of the imaging system is involved. (author)

  1. The blind student’s interpretation of two-dimensional shapes in geometry

    Science.gov (United States)

    Andriyani; Budayasa, I. K.; Juniati, D.

    2018-01-01

    The blind student’s interpretation of two-dimensional shapes represents the blind student’s mental image of two-dimensional shapes that they can’t visualize directly, which is related to illustration of the characteristics and number of edges and angles. The objective of this research is to identify the blind student’s interpretation of two-dimensional shapes. This research was an exploratory study with qualitative approach. A subject of this research is a sixth-grade student who experiencing total blind from the fifth grade of elementary school. Researchers interviewed the subject about his interpretation of two-dimensional shapes according to his thinking.The findings of this study show the uniqueness of blind students, who have been totally blind since school age, in knowing and illustrating the characteristics of edges and angles of two-dimensional shapes by utilizing visual experiences that were previously obtained before the blind. The result can inspire teachers to design further learning for development of blind student geometry concepts.

  2. The effect of amorphous selenium detector thickness on dual-energy digital breast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yue-Houng, E-mail: yuehoung.hu@gmail.com; Zhao, Wei [Department of Radiology, State University of New York at Stony Brook, L-4 120 Health Sciences Center, Stony Brook, New York 11794-8460 (United States)

    2014-11-01

    -Se introduces additional image blur. The reduced MTF and DQE at high spatial frequencies lead to reduced two-dimensional d′. These losses in projection image resolution may subsequently result in a decrease in the 3D d′, but the degree of which is largely dependent on the DBT reconstruction algorithm. For a filtered backprojection (FBP) algorithm with spectral apodization and slice-thickness filters, which dominate the blur for reconstructed images at oblique angles, the effect of oblique entry of x-rays on 3D d′ is minimal. Thus, increasing d{sub Se} results in an improvement in d′ for both CE-DM and CE-DBT with typical FBP reconstruction parameters. Conclusions: Increased d{sub Se} improves CE breast imaging performance by increasing QDE of detectors at higher energies, e.g., 49 kVp. Although there is additional blur in the oblique angled projections of a DBT scan, the overall 3D d′ for DBT is not degraded because the dominant source blur at these angles results from the reconstruction filters of the employed FBP algorithm.

  3. SENSITIVITY OF STACKED IMAGING DETECTORS TO HARD X-RAY POLARIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Muleri, Fabio; Campana, Riccardo, E-mail: fabio.muleri@iaps.inaf.it [INAF-IAPS, Via del Fosso del Cavaliere 100, I-00133 Roma (Italy)

    2012-06-01

    The development of multi-layer optics which allow to focus photons up to 100 keV and more promises an enormous jump in sensitivity in the hard X-ray energy band. This technology is already planned to be exploited by future missions dedicated to spectroscopy and imaging at energies >10 keV, e.g., Astro-H and NuSTAR. Nevertheless, our understanding of the hard X-ray sky would greatly benefit from carrying out contemporaneous polarimetric measurements, because the study of hard spectral tails and of polarized emission are often two complementary diagnostics of the same non-thermal and acceleration processes. At energies above a few tens of keV, the preferred technique to detect polarization involves the determination of photon directions after a Compton scattering. Many authors have asserted that stacked detectors with imaging capabilities can be exploited for this purpose. If it is possible to discriminate those events which initially interact in the first detector by Compton scattering and are subsequently absorbed by the second layer, then the direction of scattering is singled out from the hit pixels in the two detectors. In this paper, we give the first detailed discussion of the sensitivity of such a generic design to the X-ray polarization. The efficiency and the modulation factor are calculated analytically from the geometry of the instruments and then compared with the performance as derived by means of Geant4 Monte Carlo simulations.

  4. A gas pixel detector for X-ray imaging

    International Nuclear Information System (INIS)

    Bateman, J.E.; Connolly, J.F.

    1991-11-01

    A simple, robust form of gas pixel detector is discussed which is based on the use of electronic connector pins as the gain elements. With a rate capability of >10 5 counts/s per pin, an X-ray imaging detector system capable of counting at global rates of the order of 10 10 counts/s is foreseen. (author)

  5. Study of three-dimensional image display by systemic CT

    International Nuclear Information System (INIS)

    Fujioka, Tadao; Ebihara, Yoshiyuki; Unei, Hiroshi; Hayashi, Masao; Shinohe, Tooru; Wada, Yuji; Sakai, Takatsugu; Kashima, Kenji; Fujita, Yoshihiro

    1989-01-01

    A head phantom for CT was scanned at 2 mm intervals from the cervix to the vertex in an attempt to obtain a three-dimensional image display of bones and facial epidermis from an ordinary axial image. Clinically, three-dimensional images were formed at eye sockets and hip joints. With the three-dimensional image using the head phantom, the entire head could be displayed at any angle. Clinically, images were obtained that could not be attained by ordinary CT scanning, such as broken bones in eye sockets and stereoscopic structure at the bottom of a cranium. The three-dimensional image display is considered to be useful in clinical diagnosis. (author)

  6. Development of compact DOI-measurable PET detectors for simultaneous PET/MR Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Yiping; Sun, Xishan [University of Texas MD Anderson Cancer Center (United States); Lou, Kai [Rice University (United States)

    2015-05-18

    It is critically needed yet challenging to develop compact PET detectors with high sensitivity and uniform, high imaging resolution for improving the performance of simultaneous PET/MR imaging, particularly for an integrated/inserted small-bore system. Using the latest “edge-less” SiPM arrays for DOI measurement using the design of dual-ended-scintillator readout, we developed several compact PET detectors suited for PET/MR imaging. Each detector consists of one LYSO array with each end coupled to a SiPM array. Multiple detectors can be seamlessly tiled together along all sides to form a large detector panel. Detectors with 1.5x1.5 and 2.0x2.0 mm crystals at 20 or 30 mm lengths were studied. Readout of individual SiPM or capacitor-based signal multiplexing was used to transfer 3D interaction position-coded analog signals through flexible-print-circuit cables to dedicated ASIC frontend electronics to output digital timing pulses that encode interaction information. These digital pulses can be transferred to, through standard LVDS cables, and decoded by a FPGA-based data acquisition positioned outside the MRI scanner for coincidence event selection. Initial detector performance measurement shows excellent crystal identification even with 30 mm long crystals, ~18% and 2.8 ns energy and timing resolutions, and around 2-3 mm DOI resolution. A large size detector panel can be scaled up with these modular detectors and different PET systems can be flexibly configured with the scalable readout electronics and data acquisition, providing an important design advantage for different system and application requirements. It is expected that standard shielding of detectors, electronics and signal transfer lines can be applied for simultaneous PET/MR imaging applications, with desired DOI measurement capability to enhance the PET performance and image quality.

  7. Development of compact DOI-measurable PET detectors for simultaneous PET/MR Imaging

    International Nuclear Information System (INIS)

    Shao, Yiping; Sun, Xishan; Lou, Kai

    2015-01-01

    It is critically needed yet challenging to develop compact PET detectors with high sensitivity and uniform, high imaging resolution for improving the performance of simultaneous PET/MR imaging, particularly for an integrated/inserted small-bore system. Using the latest “edge-less” SiPM arrays for DOI measurement using the design of dual-ended-scintillator readout, we developed several compact PET detectors suited for PET/MR imaging. Each detector consists of one LYSO array with each end coupled to a SiPM array. Multiple detectors can be seamlessly tiled together along all sides to form a large detector panel. Detectors with 1.5x1.5 and 2.0x2.0 mm crystals at 20 or 30 mm lengths were studied. Readout of individual SiPM or capacitor-based signal multiplexing was used to transfer 3D interaction position-coded analog signals through flexible-print-circuit cables to dedicated ASIC frontend electronics to output digital timing pulses that encode interaction information. These digital pulses can be transferred to, through standard LVDS cables, and decoded by a FPGA-based data acquisition positioned outside the MRI scanner for coincidence event selection. Initial detector performance measurement shows excellent crystal identification even with 30 mm long crystals, ~18% and 2.8 ns energy and timing resolutions, and around 2-3 mm DOI resolution. A large size detector panel can be scaled up with these modular detectors and different PET systems can be flexibly configured with the scalable readout electronics and data acquisition, providing an important design advantage for different system and application requirements. It is expected that standard shielding of detectors, electronics and signal transfer lines can be applied for simultaneous PET/MR imaging applications, with desired DOI measurement capability to enhance the PET performance and image quality.

  8. Atomic structure of a metal-supported two-dimensional germania film

    Science.gov (United States)

    Lewandowski, Adrián Leandro; Schlexer, Philomena; Büchner, Christin; Davis, Earl M.; Burrall, Hannah; Burson, Kristen M.; Schneider, Wolf-Dieter; Heyde, Markus; Pacchioni, Gianfranco; Freund, Hans-Joachim

    2018-03-01

    The growth and microscopic characterization of two-dimensional germania films is presented. Germanium oxide monolayer films were grown on Ru(0001) by physical vapor deposition and subsequent annealing in oxygen. We obtain a comprehensive image of the germania film structure by combining intensity-voltage low-energy electron diffraction (I/V-LEED) and ab initio density functional theory (DFT) analysis with atomic-resolution scanning tunneling microscopy (STM) imaging. For benchmarking purposes, the bare Ru(0001) substrate and the (2 ×2 )3 O covered Ru(0001) were analyzed with I/V-LEED with respect to previous reports. STM topographic images of the germania film reveal a hexagonal network where the oxygen and germanium atom positions appear in different imaging contrasts. For quantitative LEED, the best agreement has been achieved with DFT structures where the germanium atoms are located preferentially on the top and fcc hollow sites of the Ru(0001) substrate. Moreover, in these atomically flat germania films, local site geometries, i.e., tetrahedral building blocks, ring structures, and domain boundaries, have been identified, indicating possible pathways towards two-dimensional amorphous networks.

  9. Status of the digital pixel array detector for protein crystallography

    CERN Document Server

    Datte, P; Beuville, E; Endres, N; Druillole, F; Luo, L; Millaud, J E; Xuong, N H

    1999-01-01

    A two-dimensional photon counting digital pixel array detector is being designed for static and time resolved protein crystallography. The room temperature detector will significantly enhance monochromatic and polychromatic protein crystallographic through-put data rates by more than three orders of magnitude. The detector has an almost infinite photon counting dynamic range and exhibits superior spatial resolution when compared to present crystallographic phosphor imaging plates or phosphor coupled CCD detectors. The detector is a high resistivity N-type Si with a pixel pitch of 150x150 mu m, and a thickness of 300 mu m, and is bump bonded to an application specific integrated circuit. The event driven readout of the detector is based on the column architecture and allows an independent pixel hit rate above 1 million photons/s/pixel. The device provides energy discrimination and sparse data readout which yields minimal dead-time. This type of architecture allows a continuous (frameless) data acquisition, a f...

  10. Simulation of image detectors in radiology for determination of scatter-to-primary ratios using Monte Carlo radiation transport code MCNP/MCNPX.

    Science.gov (United States)

    Smans, Kristien; Zoetelief, Johannes; Verbrugge, Beatrijs; Haeck, Wim; Struelens, Lara; Vanhavere, Filip; Bosmans, Hilde

    2010-05-01

    The purpose of this study was to compare and validate three methods to simulate radiographic image detectors with the Monte Carlo software MCNP/MCNPX in a time efficient way. The first detector model was the standard semideterministic radiography tally, which has been used in previous image simulation studies. Next to the radiography tally two alternative stochastic detector models were developed: A perfect energy integrating detector and a detector based on the energy absorbed in the detector material. Validation of three image detector models was performed by comparing calculated scatter-to-primary ratios (SPRs) with the published and experimentally acquired SPR values. For mammographic applications, SPRs computed with the radiography tally were up to 44% larger than the published results, while the SPRs computed with the perfect energy integrating detectors and the blur-free absorbed energy detector model were, on the average, 0.3% (ranging from -3% to 3%) and 0.4% (ranging from -5% to 5%) lower, respectively. For general radiography applications, the radiography tally overestimated the measured SPR by as much as 46%. The SPRs calculated with the perfect energy integrating detectors were, on the average, 4.7% (ranging from -5.3% to -4%) lower than the measured SPRs, whereas for the blur-free absorbed energy detector model, the calculated SPRs were, on the average, 1.3% (ranging from -0.1% to 2.4%) larger than the measured SPRs. For mammographic applications, both the perfect energy integrating detector model and the blur-free energy absorbing detector model can be used to simulate image detectors, whereas for conventional x-ray imaging using higher energies, the blur-free energy absorbing detector model is the most appropriate image detector model. The radiography tally overestimates the scattered part and should therefore not be used to simulate radiographic image detectors.

  11. Development of a Gamma-Ray Detector for Z-Selective Radiographic Imaging

    International Nuclear Information System (INIS)

    Brandis, Michal

    2013-11-01

    Dual-Discrete Energy Gamma-Radiography (DDEGR) is a method for Special Nuclear Materials (SNM) detection. DDEGR utilizes 15.11 and 4.43 MeV gamma-rays produced in the 11B(d,n)12C reaction, in contrast to the conventional use of continuous Bremsstrahlung radiation. The clean and well separated gamma-rays result in high contrast sensitivity, enabling detection of small quantities of SNM. The most important aspects of a DDEGR system were discussed, simulated, measured and demonstrated. An experimental measurement of gamma-ray yields from the 11B(d,n)12C reaction showed that the yields from deuterons with 3{12 MeV energy are 2{201010 N/sr/mC 4.4 MeV gamma- rays and 2{5109 N/sr/mC 15.1 MeV gamma-rays. The measured neutron yields show that the neutron energies extend to 15-23 MeV for the same deuteron energy range. A simplied inspection system was simulated with GEANT4, showing that the ect of scattering on the signal measured in the detector is acceptable. Considering the reaction gamma yields, 1.8 mA deuteron current is required for separation of high-Z materials from medium- and low-Z materials and a 4.5 mA current is required for the additional capability of separating benign high-Z materials from SNM. The main part of the work was development of a detector suitable for a DDEGR system | Time Resolved Event Counting Optical Radiation (TRECOR) detector. TRECOR detector is a novel spectroscopic imaging detector for gamma-rays within the MeV energy range that uses an event counting image intensier with gamma-rays for the rst time. Neutrons that accompany the gamma radiation enable to implement, in parallel, Fast Neutron Resonance Radiography (FNRR), a method for explosives detection. A second generation detector, TRECOR-II, is capable of detecting gamma-rays and neutrons in parallel, separating them to create particle-specic images and energy-specic images for each particle, thus enabling simultaneous implementation of the two detection methods. A full DDEGR laboratory

  12. The forward ring imaging Cherenkov detector of DELPHI

    International Nuclear Information System (INIS)

    Adam, W.; Albrecht, E.; Ambec, I.; Augustinus, A.; Barnoux, C.; Bostjancic, B.; Botner, O.; Budziak, A.P.; Caloba, L.P.; Carecchio, P.; Cavalli, P.; Ceelie, L.; Cereseto, R.; Cerutti, G.; Dahl-Jensen, E.; Dam, P.; Damgaard, G.; Koning, N. de; De la Vega, A.S.; Dimitriou, N.; Dulinski, W.; Eek, L.O.; Ekeloef, T.; Erikson, J.; Florek, A.; Florek, B.; Fontanelli, F.; Fontenille, A.; Galuszka, K.; Garcia, J.; Gracco, V.; Hallgren, A.; Hao, W.; Henkes, T.; Isenhower, D.; Johansson, H.; Karvelas, E.; Kindblom, P.; Koene, B.; Korporaal, A.; Kostarakis, P.; Lenzen, G.; Lindqvist, L.E.; Lorenz, P.; Loukas, D.; Lund-Jensen, B.; Maltezos, A.; Markou, A.; Mattsson, L.; Medbo, J.; Michalowski, J.; Montano, F.; Nielsen, B.S.; Ostler, J.M.; Pakonski, K.; Perdikis, C.; Polok, G.; Robohm, A.; Sajot, G.; Sannino, M.; Saragas, E.; Schyns, E.; Squarcia, S.; Stavropoulos, G.; Stodulski, M.; Stopa, Z.; Thadome, J.; Theodosiou, G.E.; Traspedini, L.; Turala, M.; Ullaland, O.; Waerm, A.; Werner, J.; Xyroutsikos, S.; Zavrtanik, M.; Zevgolatakos, E.

    1994-01-01

    The Forward Ring Imaging Cherenkov detector of the DELPHI experiment at LEP provides hadron identification at polar angles 15 6 F 14 and a volume of gaseous C 4 F 10 , in combination provide coverage of momenta up to 40 GeV/c. A single array of photosensitive Time Projection Chambers registers the impact points of ultraviolet photons from both radiators. The design of the detector and of its readout system is described. First results obtained with a partly installed detector are reported. (orig.)

  13. Preliminary results from a novel CVD diamond detector system for molecular imaging applications

    International Nuclear Information System (INIS)

    Mahon, A.R.

    1996-01-01

    A novel biomolecular imaging system incorporating a Chemical Vapour Deposition diamond detector is in development. The synthetic diamond is used as a UV detector to image nucleic acids in electrophoresis gels. The microstrip diamond detector currently has a spatial resolution of 30 μm. Preliminary results are presented which include: QE measurements of diamond detectors, detector time response, detector UV response and current detection limits of biomolecules in gel. The potential applications of the technology, and its significant advantages in speed and sensitivity over the current systems are discussed

  14. Low energy electron microscopy imaging using Medipix2 detector

    International Nuclear Information System (INIS)

    Sikharulidze, I.; Gastel, R. van; Schramm, S.; Abrahams, J.P.; Poelsema, B.; Tromp, R.M.; Molen, S.J. van der

    2011-01-01

    Low Energy Electron Microscopy (LEEM) and Photo-Emission Electron Microscopy (PEEM) predominantly use a combination of microchannel plate (MCP), phosphor screen and optical camera to record images formed by 10-20 keV electrons. We have tested the performance of a LEEM/PEEM instrument with a Medipix2 hybrid pixel detector using an Ir(1 1 1) sample with graphene flakes grown on its surface. We find that Medipix2 offers a number of advantages over the MCP. The adjustable threshold settings allow Medipix2 to operate as a noiseless detector, offering an improved signal-to-noise ratio for the same amount of signal compared to the MCP. At the same magnification Medipix2 images exhibit superior resolution and can handle significantly higher electron current densities than an MCP, offering the prospect of substantially higher frame rates in LEEM imaging. These factors make Medipix2 an excellent candidate to become the detector of choice for LEEM/PEEM applications.

  15. Low energy electron microscopy imaging using Medipix2 detector

    Energy Technology Data Exchange (ETDEWEB)

    Sikharulidze, I., E-mail: irakli@chem.leidenuniv.nl [Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300RA Leiden (Netherlands); Gastel, R. van [MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands); Schramm, S. [Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300RA Leiden (Netherlands); Abrahams, J.P. [Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300RA Leiden (Netherlands); Poelsema, B. [MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands); Tromp, R.M. [Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300RA Leiden (Netherlands); IBM Research Division, T. J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598 (United States); Molen, S.J. van der [Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300RA Leiden (Netherlands)

    2011-05-15

    Low Energy Electron Microscopy (LEEM) and Photo-Emission Electron Microscopy (PEEM) predominantly use a combination of microchannel plate (MCP), phosphor screen and optical camera to record images formed by 10-20 keV electrons. We have tested the performance of a LEEM/PEEM instrument with a Medipix2 hybrid pixel detector using an Ir(1 1 1) sample with graphene flakes grown on its surface. We find that Medipix2 offers a number of advantages over the MCP. The adjustable threshold settings allow Medipix2 to operate as a noiseless detector, offering an improved signal-to-noise ratio for the same amount of signal compared to the MCP. At the same magnification Medipix2 images exhibit superior resolution and can handle significantly higher electron current densities than an MCP, offering the prospect of substantially higher frame rates in LEEM imaging. These factors make Medipix2 an excellent candidate to become the detector of choice for LEEM/PEEM applications.

  16. A Thermal Imaging Instrument with Uncooled Detectors

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposed work, we will perform an instrument concept study for sustainable thermal imaging over land with uncooled detectors. We will define the science and...

  17. New detector concepts

    International Nuclear Information System (INIS)

    Kemmer, J.; Lutz, G.

    1986-07-01

    On the basis of the semiconductor drift chamber many new detectors are proposed, which enable the determination of energy, energy loss, position and penetration depth of radiation. A novel integrated transistor-detector configuration allows non destructive repeated readout and amplification of the signal. The concept may be used for the construction of one or two-dimensional PIXEL arrays. (orig.)

  18. Photon-counting hexagonal pixel array CdTe detector: Spatial resolution characteristics for image-guided interventional applications.

    Science.gov (United States)

    Vedantham, Srinivasan; Shrestha, Suman; Karellas, Andrew; Shi, Linxi; Gounis, Matthew J; Bellazzini, Ronaldo; Spandre, Gloria; Brez, Alessandro; Minuti, Massimo

    2016-05-01

    High-resolution, photon-counting, energy-resolved detector with fast-framing capability can facilitate simultaneous acquisition of precontrast and postcontrast images for subtraction angiography without pixel registration artifacts and can facilitate high-resolution real-time imaging during image-guided interventions. Hence, this study was conducted to determine the spatial resolution characteristics of a hexagonal pixel array photon-counting cadmium telluride (CdTe) detector. A 650 μm thick CdTe Schottky photon-counting detector capable of concurrently acquiring up to two energy-windowed images was operated in a single energy-window mode to include photons of 10 keV or higher. The detector had hexagonal pixels with apothem of 30 μm resulting in pixel pitch of 60 and 51.96 μm along the two orthogonal directions. The detector was characterized at IEC-RQA5 spectral conditions. Linear response of the detector was determined over the air kerma rate relevant to image-guided interventional procedures ranging from 1.3 nGy/frame to 91.4 μGy/frame. Presampled modulation transfer was determined using a tungsten edge test device. The edge-spread function and the finely sampled line spread function accounted for hexagonal sampling, from which the presampled modulation transfer function (MTF) was determined. Since detectors with hexagonal pixels require resampling to square pixels for distortion-free display, the optimal square pixel size was determined by minimizing the root-mean-squared-error of the aperture functions for the square and hexagonal pixels up to the Nyquist limit. At Nyquist frequencies of 8.33 and 9.62 cycles/mm along the apothem and orthogonal to the apothem directions, the modulation factors were 0.397 and 0.228, respectively. For the corresponding axis, the limiting resolution defined as 10% MTF occurred at 13.3 and 12 cycles/mm, respectively. Evaluation of the aperture functions yielded an optimal square pixel size of 54 μm. After resampling to 54

  19. Detector design issues for compact nuclear emission cameras dedicated to breast imaging

    International Nuclear Information System (INIS)

    Levin, Craig S.

    2003-01-01

    Certain gamma ray and positron emitting radiotracers have shown great promise for use in the detection, diagnosis and staging of breast cancer. Unfortunately, standard nuclear emission cameras (SPECT, PET) found in the clinic are not practical for breast imaging of these emissions due to inadequate spatial and energy resolutions and sensitivity, large and awkward size, and relatively high cost per study. High spatial and energy resolutions and sensitivity are needed for good lesion detectability. Due to these limitations of standard cameras, there has been recent research into the development of small, compact nuclear emission imagers dedicated for close-proximity breast imaging. The small detector head size means a variety of exotic detectors or collimators may be implemented to improve spatial and energy resolution and sensitivity performances at a reasonable cost. In this paper, we will present some of the compact gamma ray and annihilation photon imaging detector designs that have been proposed and/or developed for dedicated breast imaging. We will review the physics and discuss the advantages and disadvantages of various detector configurations. Finally we will estimate the fundamental spatial resolution potential available with close-proximity nuclear emission imaging and discuss how one may approach those limits through proper detector design

  20. Two-dimensional position-sensitive detectors for small-angle neutron scattering

    International Nuclear Information System (INIS)

    McElhaney, S.A.; Vandermolen, R.I.

    1990-05-01

    In this paper, various detectors available for small angle neutron scattering (SANS) are discussed, along with some current developments being actively pursued. A section has been included to outline the various methodologies of position encoding/decoding with discussions on trends and limitations. Computer software/hardware vary greatly from institute and experiment and only a general discussion is given to this area. 85 refs., 33 figs

  1. Development of an X-ray imaging system with SOI pixel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Ryutaro, E-mail: ryunishi@post.kek.jp [School of High Energy Accelerator Science, SOKENDAI (The Graduate University for Advanced Studies), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Arai, Yasuo; Miyoshi, Toshinobu [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK-IPNS), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Hirano, Keiichi; Kishimoto, Shunji; Hashimoto, Ryo [Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK-IMSS), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan)

    2016-09-21

    An X-ray imaging system employing pixel sensors in silicon-on-insulator technology is currently under development. The system consists of an SOI pixel detector (INTPIX4) and a DAQ system based on a multi-purpose readout board (SEABAS2). To correct a bottleneck in the total throughput of the DAQ of the first prototype, parallel processing of the data taking and storing processes and a FIFO buffer were implemented for the new DAQ release. Due to these upgrades, the DAQ throughput was improved from 6 Hz (41 Mbps) to 90 Hz (613 Mbps). The first X-ray imaging system with the new DAQ software release was tested using 33.3 keV and 9.5 keV mono X-rays for three-dimensional computerized tomography. The results of these tests are presented. - Highlights: • The X-ray imaging system employing the SOI pixel sensor is currently under development. • The DAQ of the first prototype has the bottleneck in the total throughput. • The new DAQ release solve the bottleneck by parallel processing and FIFO buffer. • The new DAQ release was tested using 33.3 keV and 9.5 keV mono X-rays.

  2. Three-dimensional versus two-dimensional vision in laparoscopy

    DEFF Research Database (Denmark)

    Sørensen, Stine D; Savran, Mona Meral; Konge, Lars

    2016-01-01

    were cohort size and characteristics, skill trained or operation performed, instrument used, outcome measures, and conclusions. Two independent authors performed the search and data extraction. RESULTS: Three hundred and forty articles were screened for eligibility, and 31 RCTs were included...... through a two-dimensional (2D) projection on a monitor, which results in loss of depth perception. To counter this problem, 3D imaging for laparoscopy was developed. A systematic review of the literature was performed to assess the effect of 3D laparoscopy. METHODS: A systematic search of the literature...... in the review. Three trials were carried out in a clinical setting, and 28 trials used a simulated setting. Time was used as an outcome measure in all of the trials, and number of errors was used in 19 out of 31 trials. Twenty-two out of 31 trials (71 %) showed a reduction in performance time, and 12 out of 19...

  3. Three-dimensional imaging and scanning: Current and future applications for pathology

    Directory of Open Access Journals (Sweden)

    Navid Farahani

    2017-01-01

    Full Text Available Imaging is vital for the assessment of physiologic and phenotypic details. In the past, biomedical imaging was heavily reliant on analog, low-throughput methods, which would produce two-dimensional images. However, newer, digital, and high-throughput three-dimensional (3D imaging methods, which rely on computer vision and computer graphics, are transforming the way biomedical professionals practice. 3D imaging has been useful in diagnostic, prognostic, and therapeutic decision-making for the medical and biomedical professions. Herein, we summarize current imaging methods that enable optimal 3D histopathologic reconstruction: Scanning, 3D scanning, and whole slide imaging. Briefly mentioned are emerging platforms, which combine robotics, sectioning, and imaging in their pursuit to digitize and automate the entire microscopy workflow. Finally, both current and emerging 3D imaging methods are discussed in relation to current and future applications within the context of pathology.

  4. Morphology of bipolar planetary nebulae. I. Two-dimensional spectrophotometry

    International Nuclear Information System (INIS)

    Pascoli, G.

    1990-01-01

    Two-dimensional spectrophotometric observations of bipolar planetary nebulae were performed by using a CCD detector mounted at the Cassegrain focus of either 1.54 m Danish Telescope or 2.2 m German Telescope at La Silla (ESO) in Chile. Emission lines have been selected with the help of narrow band-pass interference filters (Δλ∼ 10 - 20 A). Isophotal maps in various lines Hα, [NII] λ 6584, [OIII] λ 5007 and [SII] λλ 6717-6731 are presented. Particular attention has been given to scrutinize the symmetries inside a few bipolar planetary nebulae, in order to subsequently investigate their space structure

  5. Simultaneous Scanning Electron Microscope Imaging of Topographical and Chemical Contrast Using In-Lens, In-Column, and Everhart-Thornley Detector Systems.

    Science.gov (United States)

    Zhang, Xinming; Cen, Xi; Ravichandran, Rijuta; Hughes, Lauren A; van Benthem, Klaus

    2016-06-01

    The scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart-Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron-specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart-Thornley detector.

  6. Three-Dimensional Neutral Transport Simulations of Gas Puff Imaging Experiments

    International Nuclear Information System (INIS)

    Stotler, D.P.; DIppolito, D.A.; LeBlanc, B.; Maqueda, R.J.; Myra, J.R.; Sabbagh, S.A.; Zweben, S.J.

    2003-01-01

    Gas Puff Imaging (GPI) experiments are designed to isolate the structure of plasma turbulence in the plane perpendicular to the magnetic field. Three-dimensional aspects of this diagnostic technique as used on the National Spherical Torus eXperiment (NSTX) are examined via Monte Carlo neutral transport simulations. The radial width of the simulated GPI images are in rough agreement with observations. However, the simulated emission clouds are angled approximately 15 degrees with respect to the experimental images. The simulations indicate that the finite extent of the gas puff along the viewing direction does not significantly degrade the radial resolution of the diagnostic. These simulations also yield effective neutral density data that can be used in an approximate attempt to infer two-dimensional electron density and temperature profiles from the experimental images

  7. Haptic two-dimensional shape identification in children, adolescents, and young adults

    NARCIS (Netherlands)

    Overvliet, Krista E.; Krampe, Ralf Th

    2018-01-01

    We investigated the influence of image mediation (the process that translates tactile information into a visual image) on the development of haptic two-dimensional (2D) shape identification in 78 participants from five different age groups: preschoolers (4–5 years), first graders (6–7 years), fifth

  8. A Ring Imaging Cerenkov detector for the CERN OMEGA spectrometer

    International Nuclear Information System (INIS)

    Apsimon, R.J.; Cowell, J.; Flower, P.S.

    1984-12-01

    A large acceptance Ring Imaging Cerenkov detector has been constructed for use at the CERN Omega Spectrometer. The design of the detector is discussed, with attention paid to its principal components, and preliminary results are given which show that the detector is capable of identifying pions and protons at 100 GeV/c. (author)

  9. Imaging performance of a Timepix detector based on semi-insulating GaAs

    Science.gov (United States)

    Zaťko, B.; Zápražný, Z.; Jakůbek, J.; Šagátová, A.; Boháček, P.; Sekáčová, M.; Korytár, D.; Nečas, V.; Žemlička, J.; Mora, Y.; Pichotka, M.

    2018-01-01

    This work focused on a Timepix chip [1] coupled with a bulk semi-insulating GaAs sensor. The sensor consisted of a matrix of 256 × 256 pixels with a pitch of 55 μm bump-bonded to a Timepix ASIC. The sensor was processed on a 350 μm-thick SI GaAs wafer. We carried out detector adjustment to optimize its performance. This included threshold equalization with setting up parameters of the Timepix chip, such as Ikrum, Pream, Vfbk, and so on. The energy calibration of the GaAs Timepix detector was realized using a 241Am radioisotope in two Timepix detector modes: time-over-threshold and threshold scan. An energy resolution of 4.4 keV in FWHM (Full Width at Half Maximum) was observed for 59.5 keV γ-photons using threshold scan mode. The X-ray imaging quality of the GaAs Timepix detector was tested using various samples irradiated by an X-ray source with a focal spot size smaller than 8 μm and accelerating voltage up to 80 kV. A 700 μm × 700 μm gold testing object (X-500-200-16Au with Siemens star) fabricated with high precision was used for the spatial resolution testing at different values of X-ray image magnification (up to 45). The measured spatial resolution of our X-ray imaging system was about 4 μm.

  10. Accelerating image reconstruction in three-dimensional optoacoustic tomography on graphics processing units.

    Science.gov (United States)

    Wang, Kun; Huang, Chao; Kao, Yu-Jiun; Chou, Cheng-Ying; Oraevsky, Alexander A; Anastasio, Mark A

    2013-02-01

    Optoacoustic tomography (OAT) is inherently a three-dimensional (3D) inverse problem. However, most studies of OAT image reconstruction still employ two-dimensional imaging models. One important reason is because 3D image reconstruction is computationally burdensome. The aim of this work is to accelerate existing image reconstruction algorithms for 3D OAT by use of parallel programming techniques. Parallelization strategies are proposed to accelerate a filtered backprojection (FBP) algorithm and two different pairs of projection/backprojection operations that correspond to two different numerical imaging models. The algorithms are designed to fully exploit the parallel computing power of graphics processing units (GPUs). In order to evaluate the parallelization strategies for the projection/backprojection pairs, an iterative image reconstruction algorithm is implemented. Computer simulation and experimental studies are conducted to investigate the computational efficiency and numerical accuracy of the developed algorithms. The GPU implementations improve the computational efficiency by factors of 1000, 125, and 250 for the FBP algorithm and the two pairs of projection/backprojection operators, respectively. Accurate images are reconstructed by use of the FBP and iterative image reconstruction algorithms from both computer-simulated and experimental data. Parallelization strategies for 3D OAT image reconstruction are proposed for the first time. These GPU-based implementations significantly reduce the computational time for 3D image reconstruction, complementing our earlier work on 3D OAT iterative image reconstruction.

  11. Use of a highly sensitive two-dimensional luminescence imaging system to monitor endogenous bioluminescence in plant leaves

    Directory of Open Access Journals (Sweden)

    Flor-Henry Michel

    2004-11-01

    Full Text Available Abstract Background All living organisms emit spontaneous low-level bioluminescence, which can be increased in response to stress. Methods for imaging this ultra-weak luminescence have previously been limited by the sensitivity of the detection systems used. Results We developed a novel configuration of a cooled charge-coupled device (CCD for 2-dimensional imaging of light emission from biological material. In this study, we imaged photon emission from plant leaves. The equipment allowed short integration times for image acquisition, providing high resolution spatial and temporal information on bioluminescence. We were able to carry out time course imaging of both delayed chlorophyll fluorescence from whole leaves, and of low level wound-induced luminescence that we showed to be localised to sites of tissue damage. We found that wound-induced luminescence was chlorophyll-dependent and was enhanced at higher temperatures. Conclusions The data gathered on plant bioluminescence illustrate that the equipment described here represents an improvement in 2-dimensional luminescence imaging technology. Using this system, we identify chlorophyll as the origin of wound-induced luminescence from leaves.

  12. Compton scatter in germanium and its effect on imaging with gamma-ray position-sensitive detectors

    International Nuclear Information System (INIS)

    Sherman, I.S.; Strauss, M.G.; Brenner, R.

    1978-01-01

    The spatial spread due to Compton scatter in Ge was measured to study the reduction in image contrast and signal-to-noise ratio (S/N) resulting from erroneous readout in Ge position-sensitive detectors. The step response revealing this spread was obtained by scanning with a 122 keV γ-ray beam across a boundary of two sectors of a slotted coaxial Ge(Li) detector that is 40 mm diameter by 22 mm long. The derived line-spread function at 140 keV (/sup 99m/Tc) exhibits much shorter but thicker tails than those due to scatter in tissue as observed with a NaI detector through 5.5 cm of scattering material. Convolutions of rectangular profiles of voids with the Ge(Li) line-spread function show marked deterioration in contrast for voids less than 10 mm across, which in turn results in even greater deterioration of the S/N. As a result, the contrast for voids in Ge images is only 20 to 30 percent higher than that in NaI and the S/N is only comparable for equal detector areas. The degradation in image contrast due to scatter in Ge detectors can be greatly reduced by either using thin detectors (approximately 5 mm), where scatter virtually does not exist, or by using thicker detectors and rejecting scatter electronically. To reduce the effects of scatter on the S/N as well as on contrast, the erroneous position readouts must actually be corrected. A more realizable approach to achieving the ultimate potential of Ge detectors may be a scanning array of discrete detectors (not position sensitive) in which readout is not affected by scatter

  13. Fetal cardiac stroke volume determination by four-dimensional ultrasound with spatio-temporal image correlation compared with two-dimensional and Doppler ultrasonography.

    Science.gov (United States)

    Rizzo, Giuseppe; Capponi, Alessandra; Cavicchioni, Ottavia; Vendola, Marianne; Arduini, Domenico

    2007-12-01

    To assess the agreement of stroke volume (SV) measured with two-dimensional (2D) ultrasonography with Doppler capability (vs) four-dimensional (4D) with spatiotemporal image correlation (STIC) in normal and growth restricted fetuses. 2D Doppler and 4D STIC were used to measure SV of 40 normal fetuses at 20 to 22 and 28 to 32 weeks, and 16 growth-restricted fetuses at 26 to 34 weeks of gestation. Intraclass correlation was used to evaluate the agreement between left and right SV obtained by the two techniques, and proportionate Bland-Altman plots constructed. The time necessary to obtain SV was analyzed. The intraclass correlation coefficient between 2D Doppler and 4D STIC measurements for the left ventricle were 0.977 and 0.980 for the right ventricle. The proportionate limits of agreement between the two methods were 18.7 to 23.9% for the left ventricle and - 20.9 to 21.7% for the right ventricle. The time necessary to measure SV was significantly shorter with 4D STIC (3.1 (vs) 7.9 min p < 0.0001) than with 2D Doppler. There is a good agreement between SV measured either by 2D Doppler or by 4D STIC. The 4D STIC represents a simple and rapid technique to estimate fetal SV and promises to become the method of choice. Copyright (c) 2007 John Wiley & Sons, Ltd.

  14. High-dynamic-range coherent diffractive imaging: ptychography using the mixed-mode pixel array detector

    Energy Technology Data Exchange (ETDEWEB)

    Giewekemeyer, Klaus, E-mail: klaus.giewekemeyer@xfel.eu [European XFEL GmbH, Hamburg (Germany); Philipp, Hugh T. [Cornell University, Ithaca, NY (United States); Wilke, Robin N. [Georg-August-Universität Göttingen, Göttingen (Germany); Aquila, Andrew [European XFEL GmbH, Hamburg (Germany); Osterhoff, Markus [Georg-August-Universität Göttingen, Göttingen (Germany); Tate, Mark W.; Shanks, Katherine S. [Cornell University, Ithaca, NY (United States); Zozulya, Alexey V. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Salditt, Tim [Georg-August-Universität Göttingen, Göttingen (Germany); Gruner, Sol M. [Cornell University, Ithaca, NY (United States); Cornell University, Ithaca, NY (United States); Kavli Institute of Cornell for Nanoscience, Ithaca, NY (United States); Mancuso, Adrian P. [European XFEL GmbH, Hamburg (Germany)

    2014-08-07

    The advantages of a novel wide dynamic range hard X-ray detector are demonstrated for (ptychographic) coherent X-ray diffractive imaging. Coherent (X-ray) diffractive imaging (CDI) is an increasingly popular form of X-ray microscopy, mainly due to its potential to produce high-resolution images and the lack of an objective lens between the sample and its corresponding imaging detector. One challenge, however, is that very high dynamic range diffraction data must be collected to produce both quantitative and high-resolution images. In this work, hard X-ray ptychographic coherent diffractive imaging has been performed at the P10 beamline of the PETRA III synchrotron to demonstrate the potential of a very wide dynamic range imaging X-ray detector (the Mixed-Mode Pixel Array Detector, or MM-PAD). The detector is capable of single photon detection, detecting fluxes exceeding 1 × 10{sup 8} 8-keV photons pixel{sup −1} s{sup −1}, and framing at 1 kHz. A ptychographic reconstruction was performed using a peak focal intensity on the order of 1 × 10{sup 10} photons µm{sup −2} s{sup −1} within an area of approximately 325 nm × 603 nm. This was done without need of a beam stop and with a very modest attenuation, while ‘still’ images of the empty beam far-field intensity were recorded without any attenuation. The treatment of the detector frames and CDI methodology for reconstruction of non-sensitive detector regions, partially also extending the active detector area, are described.

  15. Two-dimensional analysis of motion artifacts, including flow effects

    International Nuclear Information System (INIS)

    Litt, A.M.; Brody, A.S.; Spangler, R.A.; Scott, P.D.

    1990-01-01

    The effects of motion on magnetic resonance images have been theoretically analyzed for the case of a point-like object in simple harmonic motion and for other one-dimensional trajectories. The authors of this paper extend this analysis to a generalized two-dimensional magnetization with an arbitrary motion trajectory. The authors provide specific solutions for the clinically relevant cases of the cross-sections of cylindrical objects in the body, such as the aorta, which has a roughly one-dimensional, simple harmonic motion during respiration. By extending the solution to include inhomogeneous magnetizations, the authors present a model which allows the effects of motion artifacts and flow artifacts to be analyzed simultaneously

  16. Two-dimensional and 3-D images of thick tissue using time-constrained times-of-flight and absorbance spectrophotometry

    Science.gov (United States)

    Benaron, David A.; Lennox, M.; Stevenson, David K.

    1992-05-01

    Reconstructing deep-tissue images in real time using spectrophotometric data from optically diffusing thick tissues has been problematic. Continuous wave applications (e.g., pulse oximetry, regional cerebral saturation) ignore both the multiple paths traveled by the photons through the tissue and the effects of scattering, allowing scalar measurements but only under limited conditions; interferometry works poorly in thick, highly-scattering media; frequency- modulated approaches may not allow full deconvolution of scattering and absorbance; and pulsed-light techniques allow for preservation of information regarding the multiple paths taken by light through the tissue, but reconstruction is both computation intensive and limited by the relative surface area available for detection of photons. We have developed a picosecond times-of-flight and absorbance (TOFA) optical system, time-constrained to measure only photons with a narrow range of path lengths and arriving within a narrow angel of the emitter-detector axis. The delay until arrival of the earliest arriving photons is a function of both the scattering and absorbance of the tissues in a direct line between the emitter and detector, reducing the influence of surrounding tissues. Measurement using a variety of emitter and detector locations produces spatial information which can be analyzed in a standard 2-D grid, or subject to computer reconstruction to produce tomographic images representing 3-D structure. Using such a technique, we have been able to demonstrate the principles of tc-TOFA, detect and localize diffusive and/or absorptive objects suspended in highly scattering media (such as blood admixed with yeast), and perform simple 3-D reconstructions using phantom objects. We are now attempting to obtain images in vivo. Potential future applications include use as a research tool, and as a continuous, noninvasive, nondestructive monitor in diagnostic imaging, fetal monitoring, neurologic and cardiac

  17. Applying dual-laser spot positions measurement technology on a two-dimensional tracking measurement system

    International Nuclear Information System (INIS)

    Lee, Hau-Wei; Chen, Chieh-Li

    2009-01-01

    This paper presents a two-dimensional tracking measurement system with a tracking module, which consists of two stepping motors, two laser diodes and a four separated active areas segmented position sensitive detector (PSD). The PSD was placed on a two-dimensional moving stage and used as a tracking target. The two laser diodes in the tracking module were directly rotated to keep the laser spots on the origin of the PSD. The two-dimensional position of the target PSD on the moving stage is determined from the distance between the two motors and the tracking angles of the two laser diodes, which are rotated by the two stepping motors, respectively. In order to separate the four positional values of the two laser spots on one PSD, the laser diodes were modulated by two distinct frequencies. Multiple-laser spot position measurement technology was used to separate the four positional values of the two laser spots on the PSD. The experimental results show that the steady-state voltage shift rate is about 0.2% and dynamic cross-talk rate is smaller than 2% when the two laser spots are projected on one PSD at the same time. The measurement errors of the x and y axial positions of the two-dimensional tracking system were less than 1% in the measuring range of 20 mm. The results demonstrate that multiple-laser spot position measurement technology can be employed in a two-dimensional tracking measurement system

  18. Advanced Photon Counting Imaging Detectors with 100ps Timing for Astronomical and Space Sensing Applications

    Science.gov (United States)

    Siegmund, O.; Vallerga, J.; Welsh, B.; Rabin, M.; Bloch, J.

    In recent years EAG has implemented a variety of high-resolution, large format, photon-counting MCP detectors in space instrumentation for satellite FUSE, GALEX, IMAGE, SOHO, HST-COS, rocket, and shuttle payloads. Our scheme of choice has been delay line readouts encoding photon event position centroids, by determination of the difference in arrival time of the event charge at the two ends of a distributed resistive-capacitive (RC) delay line. Our most commonly used delay line configuration is the cross delay line (XDL). In its simplest form the delay-line encoding electronics consists of a fast amplifier for each end of the delay line, followed by time-to-digital converters (TDC's). We have achieved resolutions of Pulsar with a telescope as small as 1m. Although microchannel plate delay line detectors meet many of the imaging and timing demands of various applications, they have limitations. The relatively high gain (107) reduces lifetime and local counting rate, and the fixed delay (10's of ns) makes multiple simultaneous event recording problematic. To overcome these limitations we have begun development of cross strip readout anodes for microchannel plate detectors. The cross strip (XS) anode is a coarse (~0.5 mm) multi-layer metal and ceramic pattern of crossed fingers on an alumina substrate. The charge cloud is matched to the anode period so that it is collected on several neighboring fingers to ensure an accurate event charge centroid can be determined. Each finger of the anode is connected to a low noise charge sensitive amplifier and followed by subsequent A/D conversion of individual strip charge values and a hardware centroid determination of better than 1/100 of a strip are possible. Recently we have commissioned a full 32 x 32 mm XS open face laboratory detector and demonstrated excellent resolution (Los Alamos National Laboratory, NASA and NSF we are developing high rate (>107 Hz) XS encoding electronics that will encode temporally simultaneous

  19. Beam alignment based on two-dimensional power spectral density of a near-field image.

    Science.gov (United States)

    Wang, Shenzhen; Yuan, Qiang; Zeng, Fa; Zhang, Xin; Zhao, Junpu; Li, Kehong; Zhang, Xiaolu; Xue, Qiao; Yang, Ying; Dai, Wanjun; Zhou, Wei; Wang, Yuanchen; Zheng, Kuixing; Su, Jingqin; Hu, Dongxia; Zhu, Qihua

    2017-10-30

    Beam alignment is crucial to high-power laser facilities and is used to adjust the laser beams quickly and accurately to meet stringent requirements of pointing and centering. In this paper, a novel alignment method is presented, which employs data processing of the two-dimensional power spectral density (2D-PSD) for a near-field image and resolves the beam pointing error relative to the spatial filter pinhole directly. Combining this with a near-field fiducial mark, the operation of beam alignment is achieved. It is experimentally demonstrated that this scheme realizes a far-field alignment precision of approximately 3% of the pinhole size. This scheme adopts only one near-field camera to construct the alignment system, which provides a simple, efficient, and low-cost way to align lasers.

  20. Two-dimensional polarimeter with a charge-coupled-device image sensor and a piezoelastic modulator.

    Science.gov (United States)

    Povel, H P; Keller, C U; Yadigaroglu, I A

    1994-07-01

    We present the first measurements and scientific observations of the solar photosphere obtained with a new two-dimensional polarimeter based on piezoelastic modulators and synchronous demodulation in a CCD imager. This instrument, which is developed for precision solar-vector polarimetry, contains a specially masked CCD that has every second row covered with an opaque mask. During exposure the charges are shifted back and forth between covered and light-sensitive rows synchronized with the modulation. In this way Stokes I and one of the other Stokes parameters can be recorded. Since the charge shifting is performed at frequencies well above the seeing frequencies and both polarization states are measured with the same pixel, highly sensitive and accurate polarimetry is achieved. We have tested the instrument in laboratory conditions as well as at three solar telescopes.

  1. Autoradiography Imaging in Targeted Alpha Therapy with Timepix Detector

    Directory of Open Access Journals (Sweden)

    Ruqaya AL Darwish

    2015-01-01

    Full Text Available There is a lack of data related to activity uptake and particle track distribution in targeted alpha therapy. These data are required to estimate the absorbed dose on a cellular level as alpha particles have a limited range and traverse only a few cells. Tracking of individual alpha particles is possible using the Timepix semiconductor radiation detector. We investigated the feasibility of imaging alpha particle emissions in tumour sections from mice treated with Thorium-227 (using APOMAB, with and without prior chemotherapy and Timepix detector. Additionally, the sensitivity of the Timepix detector to monitor variations in tumour uptake based on the necrotic tissue volume was also studied. Compartmental analysis model was used, based on the obtained imaging data, to assess the Th-227 uptake. Results show that alpha particle, photon, electron, and muon tracks were detected and resolved by Timepix detector. The current study demonstrated that individual alpha particle emissions, resulting from targeted alpha therapy, can be visualised and quantified using Timepix detector. Furthermore, the variations in the uptake based on the tumour necrotic volume have been observed with four times higher uptake for tumours pretreated with chemotherapy than for those without chemotherapy.

  2. Compton imaging with a highly-segmented, position-sensitive HPGe detector

    Energy Technology Data Exchange (ETDEWEB)

    Steinbach, T.; Hirsch, R.; Reiter, P.; Birkenbach, B.; Bruyneel, B.; Eberth, J.; Hess, H.; Lewandowski, L. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Gernhaeuser, R.; Maier, L.; Schlarb, M.; Weiler, B.; Winkel, M. [Technische Universitaet Muenchen, Physik Department, Garching (Germany)

    2017-02-15

    A Compton camera based on a highly-segmented high-purity germanium (HPGe) detector and a double-sided silicon-strip detector (DSSD) was developed, tested, and put into operation; the origin of γ radiation was determined successfully. The Compton camera is operated in two different modes. Coincidences from Compton-scattered γ-ray events between DSSD and HPGe detector allow for best angular resolution; while the high-efficiency mode takes advantage of the position sensitivity of the highly-segmented HPGe detector. In this mode the setup is sensitive to the whole 4π solid angle. The interaction-point positions in the 36-fold segmented large-volume HPGe detector are determined by pulse-shape analysis (PSA) of all HPGe detector signals. Imaging algorithms were developed for each mode and successfully implemented. The angular resolution sensitively depends on parameters such as geometry, selected multiplicity and interaction-point distances. Best results were obtained taking into account the crosstalk properties, the time alignment of the signals and the distance metric for the PSA for both operation modes. An angular resolution between 13.8 {sup circle} and 19.1 {sup circle}, depending on the minimal interaction-point distance for the high-efficiency mode at an energy of 1275 keV, was achieved. In the coincidence mode, an increased angular resolution of 4.6 {sup circle} was determined for the same γ-ray energy. (orig.)

  3. EUV high resolution imager on-board solar orbiter: optical design and detector performances

    Science.gov (United States)

    Halain, J. P.; Mazzoli, A.; Rochus, P.; Renotte, E.; Stockman, Y.; Berghmans, D.; BenMoussa, A.; Auchère, F.

    2017-11-01

    The EUV high resolution imager (HRI) channel of the Extreme Ultraviolet Imager (EUI) on-board Solar Orbiter will observe the solar atmospheric layers at 17.4 nm wavelength with a 200 km resolution. The HRI channel is based on a compact two mirrors off-axis design. The spectral selection is obtained by a multilayer coating deposited on the mirrors and by redundant Aluminum filters rejecting the visible and infrared light. The detector is a 2k x 2k array back-thinned silicon CMOS-APS with 10 μm pixel pitch, sensitive in the EUV wavelength range. Due to the instrument compactness and the constraints on the optical design, the channel performance is very sensitive to the manufacturing, alignments and settling errors. A trade-off between two optical layouts was therefore performed to select the final optical design and to improve the mirror mounts. The effect of diffraction by the filter mesh support and by the mirror diffusion has been included in the overall error budget. Manufacturing of mirror and mounts has started and will result in thermo-mechanical validation on the EUI instrument structural and thermal model (STM). Because of the limited channel entrance aperture and consequently the low input flux, the channel performance also relies on the detector EUV sensitivity, readout noise and dynamic range. Based on the characterization of a CMOS-APS back-side detector prototype, showing promising results, the EUI detector has been specified and is under development. These detectors will undergo a qualification program before being tested and integrated on the EUI instrument.

  4. Silicon drift detectors, present and future prospects

    Science.gov (United States)

    Takahashi, J.; Bellwied, R.; Beuttenmuller, R.; Caines, H.; Chen, W.; Dyke, H.; Hoffmann, G. W.; Humanic, T.; Kotov, I.; Kuczewski, P.; Leonhardt, W.; Li, Z.; Lynn, D.; Minor, R.; Munhoz, M.; Ott, G.; Pandey, S. U.; Schambach, J.; Soja, R.; Sugarbaker, E.; Willson, R. M.

    2001-04-01

    Silicon drift detectors provide unambiguous two-dimensional position information for charged particle detection with a single detector layer. A large area silicon drift detector was developed for the inner tracking detector of the STAR experiment at RHIC. In this paper, we discuss the lessons learned and the future prospects of this technology.

  5. Nuclear imaging system

    International Nuclear Information System (INIS)

    Barrett, H.H.; Horrigan, F.A.

    1975-01-01

    This invention relates to a nuclear imaging system for mapping the source of high energy nuclear particles from a living organ which has selectively absorbed a radioactive compound by spatially coding the energy from the source in a Fresnel pattern on a detector and decoding the detector output to prouce an image of the source. The coding is produced by a Fresnel zone plate interposed between the nuclear energy source and the detector whose position is adjustable with respect to the detector to focus the slices of the nuclear source on the detector. By adjusting the zone plate to a plurality of positions, data from a plurality of cross-sectional slices are produced from which a three-dimensional image of the nuclear source may be obtained. (Patent Office Record)

  6. Energy dispersive detector for white beam synchrotron x-ray fluorescence imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Matthew D., E-mail: Matt.Wilson@stfc.ac.uk; Seller, Paul; Veale, Matthew C. [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Campus,UK (United Kingdom); Connolley, Thomas [Diamond Light Source, I12 Beamline, Harwell Campus, Didcot, Oxfordshire (United Kingdom); Dolbnya, Igor P.; Malandain, Andrew; Sawhney, Kawal [Diamond Light Source, B16 Beamline, Harwell Campus, Didcot, Oxfordshire (United Kingdom); Grant, Patrick S.; Liotti, Enzo; Lui, Andrew [Department of Materials, University of Oxford Parks Road, Oxford (United Kingdom)

    2016-07-27

    A novel, “single-shot” fluorescence imaging technique has been demonstrated on the B16 beamline at the Diamond Light Source synchrotron using the HEXITEC energy dispersive imaging detector. A custom made furnace with 200µm thick metal alloy samples was positioned in a white X-ray beam with a hole made in the furnace walls to allow the transmitted beam to be imaged with a conventional X-ray imaging camera consisting of a 500 µm thick single crystal LYSO scintillator, mirror and lens coupled to an AVT Manta G125B CCD sensor. The samples were positioned 45° to the incident beam to enable simultaneous transmission and fluorescence imaging. The HEXITEC detector was positioned at 90° to the sample with a 50 µm pinhole 13 cm from the sample and the detector positioned 2.3m from pinhole. The geometric magnification provided a field of view of 1.1×1.1mm{sup 2} with one of the 80×80 pixels imaging an area equivalent to 13µm{sup 2}. Al-Cu alloys doped with Zr, Ag and Mo were imaged in transmission and fluorescence mode. The fluorescence images showed that the dopant metals could be simultaneously imaged with sufficient counts on all 80x80 pixels within 60 s, with the X-ray flux limiting the fluorescence imaging rate. This technique demonstrated that it is possible to simultaneously image and identify multiple elements on a spatial resolution scale ~10µm or higher without the time consuming need to scan monochromatic energies or raster scan a focused beam of X-rays. Moving to high flux beamlines and using an array of detectors could improve the imaging speed of the technique with element specific imaging estimated to be on a 1 s timescale.

  7. Energy dispersive detector for white beam synchrotron x-ray fluorescence imaging

    International Nuclear Information System (INIS)

    Wilson, Matthew D.; Seller, Paul; Veale, Matthew C.; Connolley, Thomas; Dolbnya, Igor P.; Malandain, Andrew; Sawhney, Kawal; Grant, Patrick S.; Liotti, Enzo; Lui, Andrew

    2016-01-01

    A novel, “single-shot” fluorescence imaging technique has been demonstrated on the B16 beamline at the Diamond Light Source synchrotron using the HEXITEC energy dispersive imaging detector. A custom made furnace with 200µm thick metal alloy samples was positioned in a white X-ray beam with a hole made in the furnace walls to allow the transmitted beam to be imaged with a conventional X-ray imaging camera consisting of a 500 µm thick single crystal LYSO scintillator, mirror and lens coupled to an AVT Manta G125B CCD sensor. The samples were positioned 45° to the incident beam to enable simultaneous transmission and fluorescence imaging. The HEXITEC detector was positioned at 90° to the sample with a 50 µm pinhole 13 cm from the sample and the detector positioned 2.3m from pinhole. The geometric magnification provided a field of view of 1.1×1.1mm"2 with one of the 80×80 pixels imaging an area equivalent to 13µm"2. Al-Cu alloys doped with Zr, Ag and Mo were imaged in transmission and fluorescence mode. The fluorescence images showed that the dopant metals could be simultaneously imaged with sufficient counts on all 80x80 pixels within 60 s, with the X-ray flux limiting the fluorescence imaging rate. This technique demonstrated that it is possible to simultaneously image and identify multiple elements on a spatial resolution scale ~10µm or higher without the time consuming need to scan monochromatic energies or raster scan a focused beam of X-rays. Moving to high flux beamlines and using an array of detectors could improve the imaging speed of the technique with element specific imaging estimated to be on a 1 s timescale.

  8. The Usefulness of Three-Dimensional Angiography with a Flat Panel Detector of Direct Conversion Type in a Transcatheter Arterial Chemoembolization Procedure for Hepatocellular Carcinoma: Initial Experience

    International Nuclear Information System (INIS)

    Kakeda, Shingo; Korogi, Yukunori; Hatakeyama, Yoshihisa; Ohnari, Norihiro; Oda, Nobuhiro; Nishino, Kazuyoshi; Miyamoto, Wataru

    2008-01-01

    The purpose of this study was to assess the usefulness of a three-dimensional (3D) angiography system using a flat panel detector of direct conversion type in treatments with subsegmental transcatheter arterial chemoembolization (TACE) for hepatocellular carcinomas (HCCs). Thirty-six consecutive patients who underwent hepatic angiography were prospectively examined. First, two radiologists evaluated the degree of visualization of the peripheral branches of the hepatic arteries on 3D digital subtraction angiography (DSA). Then the radiologists evaluated the visualization of tumor staining and feeding arteries in 25 patients (30 HCCs) who underwent subsegmental TACE. The two radiologists who performed the TACE assessed whether the additional information provided by 3D DSA was useful for treatments. In 34 (94.4%) of 36 patients, the subsegmental branches of the hepatic arteries were sufficiently visualized. The feeding arteries of HCCs were sufficiently visualized in 28 (93%) of 30 HCCs, whereas tumor stains were sufficiently visualized in 18 (60%). Maximum intensity projection images were significantly superior to volume recording images for visualization of the tumor staining and feeding arteries of HCCs. In 27 (90%) of 30 HCCs, 3D DSA provided additional useful information for subsegmental TACE. The high-quality 3D DSA with flat panel detector angiography system provided a precise vascular road map, which was useful for performing subsegmental TACE .of HCCs

  9. LISe pixel detector for neutron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, Elan; Hamm, Daniel [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States); Wiggins, Brenden [Technology Development, Y-12 National Security Complex, Oak Ridge, TN (United States); Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (United States); Milburn, Rob [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States); Burger, Arnold [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (United States); Department of Life and Physical Sciences, Fisk University, Nashville, TN (United States); Bilheux, Hassina [Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Santodonato, Louis [Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Chvala, Ondrej [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States); Stowe, Ashley [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States); Technology Development, Y-12 National Security Complex, Oak Ridge, TN (United States); Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (United States); Lukosi, Eric, E-mail: elukosi@utk.edu [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States)

    2016-10-11

    Semiconducting lithium indium diselenide, {sup 6}LiInSe{sub 2} or LISe, has promising characteristics for neutron detection applications. The 95% isotopic enrichment of {sup 6}Li results in a highly efficient thermal neutron-sensitive material. In this study, we report on a proof-of-principle investigation of a semiconducting LISe pixel detector to demonstrate its potential as an efficient neutron imager. The LISe pixel detector had a 4×4 of pixels with a 550 µm pitch on a 5×5×0.56 mm{sup 3} LISe substrate. An experimentally verified spatial resolution of 300 µm was observed utilizing a super-sampling technique.

  10. Comparison of radiation dose estimates, image noise, and scan duration in pediatric body imaging for volumetric and helical modes on 320-detector CT and helical mode on 64-detector CT

    International Nuclear Information System (INIS)

    Johnston, Jennifer H.; Podberesky, Daniel J.; Larson, David B.; Alsip, Christopher; Yoshizumi, Terry T.; Angel, Erin; Barelli, Alessandra; Toncheva, Greta; Egelhoff, John C.; Anderson-Evans, Colin; Nguyen, Giao B.; Frush, Donald P.; Salisbury, Shelia R.

    2013-01-01

    Advanced multidetector CT systems facilitate volumetric image acquisition, which offers theoretic dose savings over helical acquisition with shorter scan times. Compare effective dose (ED), scan duration and image noise using 320- and 64-detector CT scanners in various acquisition modes for clinical chest, abdomen and pelvis protocols. ED and scan durations were determined for 64-detector helical, 160-detector helical and volume modes under chest, abdomen and pelvis protocols on 320-detector CT with adaptive collimation and 64-detector helical mode on 64-detector CT without adaptive collimation in a phantom representing a 5-year-old child. Noise was measured as standard deviation of Hounsfield units. Compared to 64-detector helical CT, all acquisition modes on 320-detector CT resulted in lower ED and scan durations. Dose savings were greater for chest (27-46%) than abdomen/pelvis (18-28%) and chest/abdomen/pelvis imaging (8-14%). Noise was similar across scanning modes, although some protocols on 320-detector CT produced slightly higher noise. Dose savings can be achieved for chest, abdomen/pelvis and chest/abdomen/pelvis examinations on 320-detector CT compared to helical acquisition on 64-detector CT, with shorter scan durations. Although noise differences between some modes reached statistical significance, this is of doubtful diagnostic significance and will be studied further in a clinical setting. (orig.)

  11. Two-dimensional maximum entropy image restoration

    International Nuclear Information System (INIS)

    Brolley, J.E.; Lazarus, R.B.; Suydam, B.R.; Trussell, H.J.

    1977-07-01

    An optical check problem was constructed to test P LOG P maximum entropy restoration of an extremely distorted image. Useful recovery of the original image was obtained. Comparison with maximum a posteriori restoration is made. 7 figures

  12. Three-dimensional Imaging, Visualization, and Display

    CERN Document Server

    Javidi, Bahram; Son, Jung-Young

    2009-01-01

    Three-Dimensional Imaging, Visualization, and Display describes recent developments, as well as the prospects and challenges facing 3D imaging, visualization, and display systems and devices. With the rapid advances in electronics, hardware, and software, 3D imaging techniques can now be implemented with commercially available components and can be used for many applications. This volume discusses the state-of-the-art in 3D display and visualization technologies, including binocular, multi-view, holographic, and image reproduction and capture techniques. It also covers 3D optical systems, 3D display instruments, 3D imaging applications, and details several attractive methods for producing 3D moving pictures. This book integrates the background material with new advances and applications in the field, and the available online supplement will include full color videos of 3D display systems. Three-Dimensional Imaging, Visualization, and Display is suitable for electrical engineers, computer scientists, optical e...

  13. A High Resolution Monolithic Crystal, DOI, MR Compatible, PET Detector. Final-Report

    International Nuclear Information System (INIS)

    Miyaoka, Robert S.

    2012-01-01

    The principle objective of this proposal is to develop a positron emission tomography (PET) detector with depth-of-interaction (DOI) positioning capability that will achieve state of the art spatial resolution and sensitivity performance for small animal PET imaging. When arranged in a ring or box detector geometry, the proposed detector module will support 15% absolute detection efficiency. The detector will also be compatible with operation in a MR scanner to support simultaneous multi-modality imaging. The detector design will utilize a thick, monolithic crystal scintillator readout by a two-dimensional array of silicon photomultiplier (SiPM) devices using a novel sensor on the entrance surface (SES) design. Our hypothesis is that our single-ended readout SES design will provide an effective DOI positioning performance equivalent to more expensive dual-ended readout techniques and at a significantly lower cost. Our monolithic crystal design will also lead to a significantly lower cost system. It is our goal to design a detector with state of the art performance but at a price point that is affordable so the technology can be disseminated to many laboratories. A second hypothesis is that using SiPM arrays, the detector will be able to operate in a MR scanner without any degradation in performance to support simultaneous PET/MR imaging. Having a co-registered MR image will assist in radiotracer localization and may also be used for partial volume corrections to improve radiotracer uptake quantitation. The far reaching goal of this research is to develop technology for medical research that will lead to improvements in human health care.

  14. CT liver volumetry using three-dimensional image data in living donor liver transplantation: Effects of slice thickness on volume calculation

    Science.gov (United States)

    Hori, Masatoshi; Suzuki, Kenji; Epstein, Mark L.; Baron, Richard L.

    2011-01-01

    The purpose was to evaluate a relationship between slice thickness and calculated volume on CT liver volumetry by comparing the results for images with various slice thicknesses including three-dimensional images. Twenty adult potential liver donors (12 men, 8 women; mean age, 39 years; range, 24–64) underwent CT with a 64-section multi-detector row CT scanner after intra-venous injection of contrast material. Four image sets with slice thicknesses of 0.625 mm, 2.5 mm, 5 mm, and 10 mm were used. First, a program developed in our laboratory for automated liver extraction was applied to CT images, and the liver boundary was obtained automatically. Then, an abdominal radiologist reviewed all images on which automatically extracted boundaries were superimposed, and edited the boundary on each slice to enhance the accuracy. Liver volumes were determined by counting of the voxels within the liver boundary. Mean whole liver volumes estimated with CT were 1322.5 cm3 on 0.625-mm, 1313.3 cm3 on 2.5-mm, 1310.3 cm3 on 5-mm, and 1268.2 cm3 on 10-mm images. Volumes calculated for three-dimensional (0.625-mm-thick) images were significantly larger than those for thicker images (Pvolumetry. If not, three-dimensional images could be essential. PMID:21850689

  15. A possible role for silicon microstrip detectors in nuclear medicine Compton imaging of positron emitters

    CERN Document Server

    Scannavini, M G; Royle, G J; Cullum, I; Raymond, M; Hall, G; Iles, G

    2002-01-01

    Collimation of gamma-rays based on Compton scatter could provide in principle high resolution and high sensitivity, thus becoming an advantageous method for the imaging of radioisotopes of clinical interest. A small laboratory prototype of a Compton camera is being constructed in order to initiate studies aimed at assessing the feasibility of Compton imaging of positron emitters. The design of the camera is based on the use of a silicon collimator consisting of a stack of double-sided, AC-coupled microstrip detectors (area 6x6 cm sup 2 , 500 mu m thickness, 128 channels/side). Two APV6 chips are employed for signal readout on opposite planes of each detector. This work presents the first results on the noise performance of the silicon strip detectors. Measurements of the electrical characteristics of the detector are also reported. On the basis of the measured noise, an angular resolution of approximately 5 deg. is predicted for the Compton collimator.

  16. Ultra-thin infrared metamaterial detector for multicolor imaging applications.

    Science.gov (United States)

    Montoya, John A; Tian, Zhao-Bing; Krishna, Sanjay; Padilla, Willie J

    2017-09-18

    The next generation of infrared imaging systems requires control of fundamental electromagnetic processes - absorption, polarization, spectral bandwidth - at the pixel level to acquire desirable information about the environment with low system latency. Metamaterial absorbers have sparked interest in the infrared imaging community for their ability to enhance absorption of incoming radiation with color, polarization and/or phase information. However, most metamaterial-based sensors fail to focus incoming radiation into the active region of a ultra-thin detecting element, thus achieving poor detection metrics. Here our multifunctional metamaterial absorber is directly integrated with a novel mid-wave infrared (MWIR) and long-wave infrared (LWIR) detector with an ultra-thin (~λ/15) InAs/GaSb Type-II superlattice (T2SL) interband cascade detector. The deep sub-wavelength metamaterial detector architecture proposed and demonstrated here, thus significantly improves the detection quantum efficiency (QE) and absorption of incoming radiation in a regime typically dominated by Fabry-Perot etalons. Our work evinces the ability of multifunctional metamaterials to realize efficient wavelength selective detection across the infrared spectrum for enhanced multispectral infrared imaging applications.

  17. Remote Ultra-low Light Imaging (RULLI) For Space Situational Awareness (SSA): Modeling And Simulation Results For Passive And Active SSA

    International Nuclear Information System (INIS)

    Thompson, David C.; Shirey, Robert L.; Roggemann, Michael C; Gudimetla, Rao

    2008-01-01

    Remote Ultra-Low Light Imaging detectors are photon limited detectors developed at Los Alamos National Laboratories. RULLI detectors provide a very high degree of temporal resolution for the arrival times of detected photoevents, but saturate at a photo-detection rate of about 10 6 photo-events per second. Rather than recording a conventional image, such as output by a charged coupled device (CCD) camera, the RULLI detector outputs a data stream consisting of the two-dimensional location, and time of arrival of each detected photo-electron. Hence, there is no need to select a specific exposure time to accumulate photo-events prior to the data collection with a RULLI detector this quantity can be optimized in post processing. RULLI detectors have lower peak quantum efficiency (from as low as 5% to perhaps as much as 40% with modern photocathode technology) than back-illuminated CCD's (80% or higher). As a result of these factors, and the associated analyses of signal and noise, we have found that RULLI detectors can play two key new roles in SSA: passive imaging of exceedingly dim objects, and three-dimensional imaging of objects illuminated with an appropriate pulsed laser. In this paper we describe the RULLI detection model, compare it to a conventional CCD detection model, and present analytic and simulation results to show the limits of performance of RULLI detectors used for SSA applications at AMOS field site

  18. Development of an automated extraction method for liver tumors in three dimensional multiphase multislice CT images

    International Nuclear Information System (INIS)

    Nakagawa, Junya; Shimizu, Akinobu; Kobatake, Hidefumi

    2004-01-01

    This paper proposes a tumor detection method using four phase three dimensional (3D) CT images of livers, i.e. non-contrast, early, portal, and late phase images. The method extracts liver regions from the four phase images and enhances tumors in the livers using a 3D adaptive convergence index filter. Then it detects local maximum points and extracts tumor candidates by a region growing method. Subsequently several features of the candidates are measured and each candidate is classified into true tumor or normal tissue based on Mahalanobis distances. Above processes except liver region extraction are applied to four phase images, independently and four resultant images are integrated into one. We applied the proposed method to 3D abdominal CT images of ten patients obtained with multi-detector row CT scanner and confirmed that tumor detection rate was 100% without false positives, which was quite promising results. (author)

  19. A two-dimensional Dirac fermion microscope

    DEFF Research Database (Denmark)

    Bøggild, Peter; Caridad, Jose; Stampfer, Christoph

    2017-01-01

    D electron guns, deflectors, tunable lenses and various detectors. The simulations show how simple objects can be imaged with well-controlled and collimated in-plane beams consisting of relativistic charge carriers. Finally, we discuss the potential of such microscopes for investigating edges...

  20. Photon-counting hexagonal pixel array CdTe detector: Spatial resolution characteristics for image-guided interventional applications

    Energy Technology Data Exchange (ETDEWEB)

    Vedantham, Srinivasan; Shrestha, Suman; Karellas, Andrew, E-mail: andrew.karellas@umassmed.edu; Shi, Linxi; Gounis, Matthew J. [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States); Bellazzini, Ronaldo; Spandre, Gloria; Brez, Alessandro; Minuti, Massimo [Istituto Nazionale di Fisica Nucleare (INFN), Pisa 56127, Italy and Pixirad Imaging Counters s.r.l., L. Pontecorvo 3, Pisa 56127 (Italy)

    2016-05-15

    Purpose: High-resolution, photon-counting, energy-resolved detector with fast-framing capability can facilitate simultaneous acquisition of precontrast and postcontrast images for subtraction angiography without pixel registration artifacts and can facilitate high-resolution real-time imaging during image-guided interventions. Hence, this study was conducted to determine the spatial resolution characteristics of a hexagonal pixel array photon-counting cadmium telluride (CdTe) detector. Methods: A 650 μm thick CdTe Schottky photon-counting detector capable of concurrently acquiring up to two energy-windowed images was operated in a single energy-window mode to include photons of 10 keV or higher. The detector had hexagonal pixels with apothem of 30 μm resulting in pixel pitch of 60 and 51.96 μm along the two orthogonal directions. The detector was characterized at IEC-RQA5 spectral conditions. Linear response of the detector was determined over the air kerma rate relevant to image-guided interventional procedures ranging from 1.3 nGy/frame to 91.4 μGy/frame. Presampled modulation transfer was determined using a tungsten edge test device. The edge-spread function and the finely sampled line spread function accounted for hexagonal sampling, from which the presampled modulation transfer function (MTF) was determined. Since detectors with hexagonal pixels require resampling to square pixels for distortion-free display, the optimal square pixel size was determined by minimizing the root-mean-squared-error of the aperture functions for the square and hexagonal pixels up to the Nyquist limit. Results: At Nyquist frequencies of 8.33 and 9.62 cycles/mm along the apothem and orthogonal to the apothem directions, the modulation factors were 0.397 and 0.228, respectively. For the corresponding axis, the limiting resolution defined as 10% MTF occurred at 13.3 and 12 cycles/mm, respectively. Evaluation of the aperture functions yielded an optimal square pixel size of 54

  1. Raman characterization of high temperature materials using an imaging detector

    International Nuclear Information System (INIS)

    Rosenblatt, G.M.; Veirs, D.K.

    1989-03-01

    The characterization of materials by Raman spectroscopy has been advanced by recent technological developments in light detectors. Imaging photomultiplier-tube detectors are now available that impart position information in two dimensions while retaining photon-counting sensitivity, effectively greatly reducing noise. The combination of sensitivity and reduced noise allows smaller amounts of material to be analyzed. The ability to observe small amount of material when coupled with position information makes possible Raman characterization in which many spatial elements are analyzed simultaneously. Raman spectroscopy making use of these capabilities has been used, for instance, to analyze the phases present in carbon films and fibers and to map phase-transformed zones accompanying crack propagation in toughened zirconia ceramics. 16 refs., 6 figs., 2 tabs

  2. Transmission characteristics of a two dimensional antiscatter grid prototype for CBCT.

    Science.gov (United States)

    Altunbas, Cem; Kavanagh, Brian; Alexeev, Timur; Miften, Moyed

    2017-08-01

    High fraction of scattered radiation in cone-beam CT (CBCT) imaging degrades CT number accuracy and visualization of low contrast objects. To suppress scatter in CBCT projections, we developed a focused, two-dimensional antiscatter grid (2DASG) prototype. In this work, we report on the primary and scatter transmission characteristics of the 2DASG prototype aimed for linac mounted, offset detector geometry CBCT systems in radiation therapy, and compared its performance to a conventional one-dimensional ASG (1DASG). The 2DASG is an array of through-holes separated by 0.1 mm septa that was fabricated from tungsten using additive manufacturing techniques. Through-holes' focusing geometry was designed for offset detector CBCT in Varian TrueBeam system. Two types of ASGs were evaluated: (a) a conventional 1DASG with a grid ratio of 10, (b) the 2DASG prototype with a grid ratio of 8.2. To assess the scatter suppression performance of both ASGs, Scatter-to-primary ratio (SPR) and scatter transmission fraction (Ts) were measured using the beam stop method. Scatter and primary intensities were modulated by varying the phantom thickness between 10 and 40 cm. Additionally, the effect of air gap and bow tie (BT) filter on SPR and Ts were evaluated. Average primary transmission fraction (T P ) and pixel specific primary transmission were also measured for both ASGs. To assess the effect of transmission characteristics on projection image signal-to-noise ratio (SNR), SNR improvement factor was calculated. Improvement in contrast to noise ratio (CNR) was demonstrated using a low contrast object. In comparison to 1DASG, 2DASG reduced SPRs by a factor of 3 to 6 across the range of phantom setups investigated. Ts values for 1D and 2DASGs were in the range of 21 to 29%, and 5 to 14% respectively. 2DASG continued to provide lower SPR and Ts at increased air gap and with BT filter. Tp of 1D and 2DASGs were 70.6% and 84.7% respectively. Due to the septal shadow of the 2DASG, its pixel

  3. An information-theoretical approach to image resolution applied to neutron imaging detectors based upon individual discriminator signals

    International Nuclear Information System (INIS)

    Clergeau, Jean-Francois; Ferraton, Matthieu; Guerard, Bruno; Khaplanov, Anton; Piscitelli, Francesco; Platz, Martin; Rigal, Jean-Marie; Van Esch, Patrick; Daulle, Thibault

    2013-06-01

    1D or 2D neutron imaging detectors with individual wire or strip readout using discriminators have the advantage of being able to treat several neutron impacts partially overlapping in time, hence reducing global dead time. A single neutron impact usually gives rise to several discriminator signals. In this paper, we introduce an information-theoretical definition of image resolution. Two point-like spots of neutron impacts with a given distance between them act as a source of information (each neutron hit belongs to one spot or the other), and the detector plus signal treatment is regarded as an imperfect communication channel that transmits this information. The maximal mutual information obtained from this channel as a function of the distance between the spots allows to define a calibration-independent measure of resolution. We then apply this measure to quantify the power of resolution of different algorithms treating these individual discriminator signals which can be implemented in firmware. The method is then applied to different detectors existing at the ILL. Center-of-gravity methods usually improve the resolution over best-wire algorithms which are the standard way of treating these signals. (authors)

  4. An information-theoretical approach to image resolution applied to neutron imaging detectors based upon individual discriminator signals

    Energy Technology Data Exchange (ETDEWEB)

    Clergeau, Jean-Francois; Ferraton, Matthieu; Guerard, Bruno; Khaplanov, Anton; Piscitelli, Francesco; Platz, Martin; Rigal, Jean-Marie; Van Esch, Patrick [Institut Laue Langevin, Neutron Detector Service, Grenoble (France); Daulle, Thibault [PHELMA Grenoble - INP Grenoble (France)

    2013-06-15

    1D or 2D neutron imaging detectors with individual wire or strip readout using discriminators have the advantage of being able to treat several neutron impacts partially overlapping in time, hence reducing global dead time. A single neutron impact usually gives rise to several discriminator signals. In this paper, we introduce an information-theoretical definition of image resolution. Two point-like spots of neutron impacts with a given distance between them act as a source of information (each neutron hit belongs to one spot or the other), and the detector plus signal treatment is regarded as an imperfect communication channel that transmits this information. The maximal mutual information obtained from this channel as a function of the distance between the spots allows to define a calibration-independent measure of resolution. We then apply this measure to quantify the power of resolution of different algorithms treating these individual discriminator signals which can be implemented in firmware. The method is then applied to different detectors existing at the ILL. Center-of-gravity methods usually improve the resolution over best-wire algorithms which are the standard way of treating these signals. (authors)

  5. Reducing image noise in computed tomography (CT) colonography: effect of an integrated circuit CT detector.

    Science.gov (United States)

    Liu, Yu; Leng, Shuai; Michalak, Gregory J; Vrieze, Thomas J; Duan, Xinhui; Qu, Mingliang; Shiung, Maria M; McCollough, Cynthia H; Fletcher, Joel G

    2014-01-01

    To investigate whether the integrated circuit (IC) detector results in reduced noise in computed tomography (CT) colonography (CTC). Three hundred sixty-six consecutive patients underwent clinically indicated CTC using the same CT scanner system, except for a difference in CT detectors (IC or conventional). Image noise, patient size, and scanner radiation output (volume CT dose index) were quantitatively compared between patient cohorts using each detector system, with separate comparisons for the abdomen and pelvis. For the abdomen and pelvis, despite significantly larger patient sizes in the IC detector cohort (both P 0.18). Based on the observed image noise reduction, radiation dose could alternatively be reduced by approximately 20% to result in similar levels of image noise. Computed tomography colonography images acquired using the IC detector had significantly lower noise than images acquired using the conventional detector. This noise reduction can permit further radiation dose reduction in CTC.

  6. Development of Scanning-Imaging X-Ray Microscope for Quantitative Three-Dimensional Phase Contrast Microimaging

    International Nuclear Information System (INIS)

    Takeuchi, Akihisa; Suzuki, Yoshio; Uesugi, Kentaro

    2013-01-01

    A novel x-ray microscope system has been developed for the purpose of quantitative and sensitive three-dimensional (3D) phase-contrast x-ray microimaging. The optical system is a hybrid that consists of a scanning microscope optics with a one-dimensional (1D) focusing (line-focusing) device and an imaging microscope optics with a 1D objective. These two optics are orthogonally arranged regarding their common optical axis. Each is used for forming each dimension of two-dimensional (2D) image. The same data acquisition process as that of the scanning microscope system enables quantitative and sensitive x-ray imaging such as phase contrast and absorption contrast. Because a 2D image is measured with only 1D translation scan, much shorter measurement time than that of conventional scanning optics has been realized. By combining a computed tomography (CT) technique, some 3D CT application examples are demonstrated

  7. Feature Detector and Descriptor for Medical Images

    Science.gov (United States)

    Sargent, Dusty; Chen, Chao-I.; Tsai, Chang-Ming; Wang, Yuan-Fang; Koppel, Daniel

    2009-02-01

    The ability to detect and match features across multiple views of a scene is a crucial first step in many computer vision algorithms for dynamic scene analysis. State-of-the-art methods such as SIFT and SURF perform successfully when applied to typical images taken by a digital camera or camcorder. However, these methods often fail to generate an acceptable number of features when applied to medical images, because such images usually contain large homogeneous regions with little color and intensity variation. As a result, tasks like image registration and 3D structure recovery become difficult or impossible in the medical domain. This paper presents a scale, rotation and color/illumination invariant feature detector and descriptor for medical applications. The method incorporates elements of SIFT and SURF while optimizing their performance on medical data. Based on experiments with various types of medical images, we combined, adjusted, and built on methods and parameter settings employed in both algorithms. An approximate Hessian based detector is used to locate scale invariant keypoints and a dominant orientation is assigned to each keypoint using a gradient orientation histogram, providing rotation invariance. Finally, keypoints are described with an orientation-normalized distribution of gradient responses at the assigned scale, and the feature vector is normalized for contrast invariance. Experiments show that the algorithm detects and matches far more features than SIFT and SURF on medical images, with similar error levels.

  8. Amorphous selenium based detectors for medical imaging applications

    Science.gov (United States)

    Mandal, Krishna C.; Kang, Sung H.; Choi, Michael; Jellison, Gerald E., Jr.

    2006-08-01

    We have developed and characterized large volume amorphous (a-) selenium (Se) stabilized alloys for room temperature medical imaging devices and high-energy physics detectors. The synthesis and preparation of well-defined and high quality a-Se (B, As, Cl) alloy materials have been conducted using a specially designed alloying reactor at EIC and installed in an argon atmosphere glove box. The alloy composition has been precisely controlled and optimized to ensure good device performance. The synthesis of large volume boron (B) doped (natural and isotopic 10B) a-Se (As, Cl) alloys has been carried out by thoroughly mixing vacuum distilled and zone-refined (ZR) Se with previously synthesized Se-As master alloys, Se-Cl master alloys and B. The synthesized a-Se (B, As, Cl) alloys have been characterized by x-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infra-red spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectroscopy (ICP-MS), and detector testing. The a- Se alloys have shown high promise for x-ray detectors with its high dark resistivity (10 10-10 13 Ωcm), good charge transport properties, and cost-effective large area scalability. Details of various steps about detector fabrication and testing of these imaging devices are also presented.

  9. The Mathematical Foundations of 3D Compton Scatter Emission Imaging

    Directory of Open Access Journals (Sweden)

    T. T. Truong

    2007-01-01

    Full Text Available The mathematical principles of tomographic imaging using detected (unscattered X- or gamma-rays are based on the two-dimensional Radon transform and many of its variants. In this paper, we show that two new generalizations, called conical Radon transforms, are related to three-dimensional imaging processes based on detected Compton scattered radiation. The first class of conical Radon transform has been introduced recently to support imaging principles of collimated detector systems. The second class is new and is closely related to the Compton camera imaging principles and invertible under special conditions. As they are poised to play a major role in future designs of biomedical imaging systems, we present an account of their most important properties which may be relevant for active researchers in the field.

  10. Two dimensional nonlinear spectral estimation techniques for breast cancer localization

    International Nuclear Information System (INIS)

    Stathaki, P.T.; Constantinides, A.G.

    1994-01-01

    In this paper the problem of image texture analysis in the presence of noise is examined from a higher-order statistical perspective. The approach taken involves the use of two dimensional second order Volterra filters where the filter weights are derived from third order cumulants of the two dimensional signal. The specific application contained in this contribution is in mammography, an area in which it is difficult to discern the appropriate features. The paper describes the fundamental issues of the various components of the approach. The results of the entire texture modelling, classification and segmentation scheme contained in this paper are very encouraging

  11. Real-Time Two-Dimensional Magnetic Particle Imaging for Electromagnetic Navigation in Targeted Drug Delivery

    Science.gov (United States)

    Le, Tuan-Anh; Zhang, Xingming; Hoshiar, Ali Kafash; Yoon, Jungwon

    2017-01-01

    Magnetic nanoparticles (MNPs) are effective drug carriers. By using electromagnetic actuated systems, MNPs can be controlled noninvasively in a vascular network for targeted drug delivery (TDD). Although drugs can reach their target location through capturing schemes of MNPs by permanent magnets, drugs delivered to non-target regions can affect healthy tissues and cause undesirable side effects. Real-time monitoring of MNPs can improve the targeting efficiency of TDD systems. In this paper, a two-dimensional (2D) real-time monitoring scheme has been developed for an MNP guidance system. Resovist particles 45 to 65 nm in diameter (5 nm core) can be monitored in real-time (update rate = 2 Hz) in 2D. The proposed 2D monitoring system allows dynamic tracking of MNPs during TDD and renders magnetic particle imaging-based navigation more feasible. PMID:28880220

  12. Development and Characterization of Two-Dimensional Gratings for Single-Shot X-ray Phase-Contrast Imaging

    Directory of Open Access Journals (Sweden)

    Margarita Zakharova

    2018-03-01

    Full Text Available Single-shot grating-based phase-contrast imaging techniques offer additional contrast modalities based on the refraction and scattering of X-rays in a robust and versatile configuration. The utilization of a single optical element is possible in such methods, allowing the shortening of the acquisition time and increasing flux efficiency. One of the ways to upgrade single-shot imaging techniques is to utilize customized optical components, such as two-dimensional (2D X-ray gratings. In this contribution, we present the achievements in the development of 2D gratings with UV lithography and gold electroplating. Absorption gratings represented by periodic free-standing gold pillars with lateral structure sizes from 5 µm to 25 µm and heights from 5 µm to 28 µm have shown a high degree of periodicity and defect-free patterns. Grating performance was tested in a radiographic setup using a self-developed quality assessment algorithm based on the intensity distribution histograms. The algorithm allows the final user to estimate the suitability of a specific grating to be used in a particular setup.

  13. Two-dimensional and three-dimensional ultrasonography for pregnancy diagnosis and antenatal fetal development in Beetal goats

    Directory of Open Access Journals (Sweden)

    Kailash Kumar

    2015-07-01

    Full Text Available Aim: The objective of this study was to compare two-dimensional (2D and three-dimensional (3D study of the pregnant uterus and antenatal development of the fetus. Materials and Methods: 2D and 3D ultrasound were performed from day 20 to 120 of gestation, twice in week from day 20 to 60 and once in week from day 60 to 120 of gestation on six goats. The ultrasonographic images were obtained using Toshiba, Nemio-XG (Japan 3D ultrasound machine. Results: On the 20th day of gestation, earliest diagnosis of pregnancy was done. First 3D ultrasonographic image of the conceptus, through transabdominal approach, was obtained on day 24. On 39th day, clear pictures of conceptus, amniotic membrane, and umbilicus were seen. On 76th day of gestation, internal organs of fetus viz heart, kidney, liver, urinary bladder, and stomach were seen both in 2D and 3D images. 3D imaging showed better details of uterine structures and internal organs of the fetus. Conclusions: Comparing 3D images with 2D images, it is concluded that 2D was better in visualizing fluid while 3D images were better to view details of attachment of fetus with endometrium.

  14. Advances in Gamma-Ray Imaging with Intensified Quantum-Imaging Detectors

    Science.gov (United States)

    Han, Ling

    Nuclear medicine, an important branch of modern medical imaging, is an essential tool for both diagnosis and treatment of disease. As the fundamental element of nuclear medicine imaging, the gamma camera is able to detect gamma-ray photons emitted by radiotracers injected into a patient and form an image of the radiotracer distribution, reflecting biological functions of organs or tissues. Recently, an intensified CCD/CMOS-based quantum detector, called iQID, was developed in the Center for Gamma-Ray Imaging. Originally designed as a novel type of gamma camera, iQID demonstrated ultra-high spatial resolution (advancing this conceptually-proven gamma-ray imaging technology to make it ready for both preclinical and clinical applications. To start with, a Monte Carlo simulation of the key light-intensification device, i.e. the image intensifier, was developed, which revealed the dominating factor(s) that limit energy resolution performance of the iQID cameras. For preclinical imaging applications, a previously-developed iQID-based single-photon-emission computed-tomography (SPECT) system, called FastSPECT III, was fully advanced in terms of data acquisition software, system sensitivity and effective FOV by developing and adopting a new photon-counting algorithm, thicker columnar scintillation detectors, and system calibration method. Originally designed for mouse brain imaging, the system is now able to provide full-body mouse imaging with sub-350-micron spatial resolution. To further advance the iQID technology to include clinical imaging applications, a novel large-area iQID gamma camera, called LA-iQID, was developed from concept to prototype. Sub-mm system resolution in an effective FOV of 188 mm x 188 mm has been achieved. The camera architecture, system components, design and integration, data acquisition, camera calibration, and performance evaluation are presented in this work. Mounted on a castered counter-weighted clinical cart, the camera also features

  15. The iQID camera: An ionizing-radiation quantum imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Brian W., E-mail: brian.miller@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); College of Optical Sciences, The University of Arizona, Tucson, AZ 85719 (United States); Gregory, Stephanie J.; Fuller, Erin S. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Barrett, Harrison H.; Bradford Barber, H.; Furenlid, Lars R. [Center for Gamma-Ray Imaging, The University of Arizona, Tucson, AZ 85719 (United States); College of Optical Sciences, The University of Arizona, Tucson, AZ 85719 (United States)

    2014-12-11

    We have developed and tested a novel, ionizing-radiation Quantum Imaging Detector (iQID). This scintillation-based detector was originally developed as a high-resolution gamma-ray imager, called BazookaSPECT, for use in single-photon emission computed tomography (SPECT). Recently, we have investigated the detector's response and imaging potential with other forms of ionizing radiation including alpha, neutron, beta, and fission fragment particles. The confirmed response to this broad range of ionizing radiation has prompted its new title. The principle operation of the iQID camera involves coupling a scintillator to an image intensifier. The scintillation light generated by particle interactions is optically amplified by the intensifier and then re-imaged onto a CCD/CMOS camera sensor. The intensifier provides sufficient optical gain that practically any CCD/CMOS camera can be used to image ionizing radiation. The spatial location and energy of individual particles are estimated on an event-by-event basis in real time using image analysis algorithms on high-performance graphics processing hardware. Distinguishing features of the iQID camera include portability, large active areas, excellent detection efficiency for charged particles, and high spatial resolution (tens of microns). Although modest, iQID has energy resolution that is sufficient to discriminate between particles. Additionally, spatial features of individual events can be used for particle discrimination. An important iQID imaging application that has recently been developed is real-time, single-particle digital autoradiography. We present the latest results and discuss potential applications.

  16. Continuous Dimensionality Characterization of Image Structures

    DEFF Research Database (Denmark)

    Felsberg, Michael; Kalkan, Sinan; Krüger, Norbert

    2009-01-01

    gradient field. By making use of a cone structure and barycentric co-ordinates, we can associate three confidences to the three different ideal cases of intrinsic dimensions corresponding to homogeneous image patches, edge-like structures and junctions. The main novelty of our approach......Intrinsic dimensionality is a concept introduced by statistics and later used in image processing to measure the dimensionality of a data set. In this paper, we introduce a continuous representation of the intrinsic dimension of an image patch in terms of its local spectrum or, equivalently, its...... is the representation of confidences as prior probabilities which can be used within a probabilistic framework. To show the potential of our continuous representation, we highlight applications in various contexts such as image structure classification, feature detection and localisation, visual scene statistics...

  17. CMOS detectors: lessons learned during the STC stereo channel preflight calibration

    Science.gov (United States)

    Simioni, E.; De Sio, A.; Da Deppo, V.; Naletto, G.; Cremonese, G.

    2017-09-01

    The Stereo Camera (STC), mounted on-board the BepiColombo spacecraft, will acquire in push frame stereo mode the entire surface of Mercury. STC will provide the images for the global three-dimensional reconstruction of the surface of the innermost planet of the Solar System. The launch of BepiColombo is foreseen in 2018. STC has an innovative optical system configuration, which allows good optical performances with a mass and volume reduction of a factor two with respect to classical stereo camera approach. In such a telescope, two different optical paths inclined of +/-20°, with respect to the nadir direction, are merged together in a unique off axis path and focused on a single detector. The focal plane is equipped with a 2k x 2k hybrid Si-PIN detector, based on CMOS technology, combining low read-out noise, high radiation hardness, compactness, lack of parasitic light, capability of snapshot image acquisition and short exposure times (less than 1 ms) and small pixel size (10 μm). During the preflight calibration campaign of STC, some detector spurious effects have been noticed. Analyzing the images taken during the calibration phase, two different signals affecting the background level have been measured. These signals can reduce the detector dynamics down to a factor of 1/4th and they are not due to dark current, stray light or similar effects. In this work we will describe all the features of these unwilled effects, and the calibration procedures we developed to analyze them.

  18. The two sides of silicon detectors

    International Nuclear Information System (INIS)

    Devine, S.R.

    2001-10-01

    Results are presented on in situ irradiation of silicon detector's at cryogenic temperature. The results show that irradiation at cryogenic temperatures does not detrimentally effect a silicon detectors performance when compared to its irradiation at room temperature. Operation of silicon devices at cryogenic temperatures offers the advantage of reducing radiation-induced leakage current to levels of a few pA, while at 130K the Lazarus Effect plays an important role i.e. minimum voltage required for full depletion. Performing voltage scans on a 'standard' silicon pad detector pre- and post annealing, the charge collection efficiency was found to be 60% at 200V and 95% at 200V respectively. Time dependence measurements are presented, showing that for a dose of 6.5x10 14 p/cm 2 (450GeV protons) the time dependence of the charge collection efficiency is negligible. However, for higher doses, 1.2x10 15 p/cm 2 , the charge collection efficiency drops from an initial measured value of 67% to a stable value of 58% over a period of 15 minutes for reversed biased diodes. An analysis of the 'double junction' effect is also presented. A comparison between the Transient Current Technique and an X-ray technique is presented. The double junction has been observed in p + /n/n + silicon detectors after irradiation beyond 'type inversion', corresponding to a fluence equivalent to ∼3x10 13 cm -2 1MeV neutrons, producing p + /p/n + and essentially two p-n junctions within one device. With increasing bias voltage, as the electric field is extending into the detector bulk from opposite sides of the silicon detector, there are two distinct depletion regions that collect charge signal independently. Summing the signal charge from the two regions, one is able to reconstruct the initial energy of the incident particle. From Transient Current measurements it is apparent that E-field manipulation is possible by excess carrier injection, enabling a high enough E-field to extend across the

  19. Simulation of scintillating fiber gamma ray detectors for medical imaging

    International Nuclear Information System (INIS)

    Chaney, R.C.; Fenyves, E.J.; Antich, P.P.

    1990-01-01

    This paper reports on plastic scintillating fibers which have been shown to be effective for high spatial and time resolution of gamma rays. They may be expected to significantly improve the resolution of current medical imaging systems such as PET and SPECT. Monte Carlo simulation of imaging systems using these detectors, provides a means to optimize their performance in this application, as well as demonstrate their resolution and efficiency. Monte Carlo results are presented for PET and SPECT systems constructed using these detectors

  20. X-ray imaging bilinear staggered GaAs detectors

    Energy Technology Data Exchange (ETDEWEB)

    Achmadullin, R.A.; Dvoryankin, V.F. E-mail: vfd217@ire216.msk.su; Dvoryankina, G.G.; Dikaev, Y.M.Yu.M.; Krikunov, A.I.; Kudryashov, A.A.; Panova, T.M.; Petrov, A.G.; Telegin, A.A

    2004-09-21

    The multichannel bilinear X-ray detector based on epitaxial GaAs structures is developed to obtain a digital X-ray image. Each detector operates in photovoltaic mode without reverse bias that enables almost complete elimination of detector noise arising due to leakage currents. The sensitivity range of the epitaxial GaAs photovoltaic X-ray detector covers the effective energies from 8 to 120 keV. A maximum response of the detector operating in the short-circuit mode was observed at an energy of 35 keV and amounted to 30 {mu}A min/(Gy cm{sup 2}). The multichannel detector was made of 1024 pixels with pitch of 0.8 mm. The spatial resolution of double staggered sensor row is twice as high as the resolution of that of single sensor row with the same pitch. Measured spatial resolution is 1.2 line-pairs/mm, contrast sensitivity not worse 1% and dynamic range defined as the ratio of maximum detectable X-ray signal to electronic noise level more than 2000 are received.

  1. X-ray imaging bilinear staggered GaAs detectors

    International Nuclear Information System (INIS)

    Achmadullin, R.A.; Dvoryankin, V.F.; Dvoryankina, G.G.; Dikaev, Y.M.Yu.M.; Krikunov, A.I.; Kudryashov, A.A.; Panova, T.M.; Petrov, A.G.; Telegin, A.A.

    2004-01-01

    The multichannel bilinear X-ray detector based on epitaxial GaAs structures is developed to obtain a digital X-ray image. Each detector operates in photovoltaic mode without reverse bias that enables almost complete elimination of detector noise arising due to leakage currents. The sensitivity range of the epitaxial GaAs photovoltaic X-ray detector covers the effective energies from 8 to 120 keV. A maximum response of the detector operating in the short-circuit mode was observed at an energy of 35 keV and amounted to 30 μA min/(Gy cm 2 ). The multichannel detector was made of 1024 pixels with pitch of 0.8 mm. The spatial resolution of double staggered sensor row is twice as high as the resolution of that of single sensor row with the same pitch. Measured spatial resolution is 1.2 line-pairs/mm, contrast sensitivity not worse 1% and dynamic range defined as the ratio of maximum detectable X-ray signal to electronic noise level more than 2000 are received

  2. THGEM based photon detector for Cherenkov imaging applications

    CERN Document Server

    Alexeev, M; Bradamante, F; Bressan, A; Chiosso, M; Ciliberti, P; Croci, G; Colantoni, M L; Dalla Torre, S; Duarte Pinto, S; Denisov, O; Diaz, V; Ferrero, A; Finger, M; Finger, M Jr; Fischer, H; Giacomini, G; Giorgi, M; Gobbo, B; Heinsius, F H; Herrmann, F; Jahodova, V; Königsmann, K; Lauser, L; Levorato, S; Maggiora, A; Martin, A; Menon, G; Nerling, F; Panzieri, D; Pesaro, G; Polak, J; Rocco, E; Ropelewski, L; Sauli, F; Sbrizzai, G; Schiavon, P; Schill, C; Schopferer, S; Slunecka, M; Sozzi, F; Steiger, L; Sulc, M; Takekawa, S; Tessarotto, F; Wollny, H

    2010-01-01

    We are developing a single photon detector for Cherenkov imaging counters. This detector is based on the use of THGEM electron multipliers in a multilayer design. The major goals of our project are ion feedback suppression down to a few per cent, large gain, fast response, insensitivity to magnetic fields, and a large detector size. We report about the project status and perspectives. In particular, we present a systematic study of the THGEM response as a function of geometrical parameters, production techniques and the gas mixture composition. The first figures obtained from measuring the response of a CsI coated THGEM to single photons are presented.

  3. A new design of the gaseous imaging detector: Micro Pixel Chamber

    CERN Document Server

    Ochi, A; Koishi, S; Tanimori, T; Nagae, T; Nakamura, M

    2001-01-01

    The novel gaseous detector 'Micro Pixel Chamber (Micro PIC)' has been developed for X-ray, gamma-ray and charged particle imaging. This detector consists of double sided printing circuit board (PCB). The stable operation of Micro PIC is realized by thick substrate and wide anode strips. One of the most outstanding feature is the process of production and the cost. The base technology of producing Micro PIC is same as producing PCB, then detector with large detection area (more than 10 cmx10 cm) can be made by present technology. Our first tests were performed using a 3 cmx3 cm detection area with a readout of 0.4 mm pitch. The gas gain and stability were measured in these tests. The gas gain of 10 sup 4 was obtained using argon ethane (8:2) gas mixture. Also, there was no discharge between anodes and cathodes in the gain of 10 sup 3 during two days of continuous operation. Although some discharges occurred in the higher gain (approximately 10 sup 4), no critical damage on the detector was found.

  4. Correlation between the physical performances measured from detectors and the diagnostic image quality in digital mammography

    International Nuclear Information System (INIS)

    Perez-Ponce, H.

    2009-05-01

    In digital mammography two approaches exist to estimate image quality. In the first approach, human observer assesses the lesion detection in mammograms. Unfortunately, such quality assessment is subject to interobserver variability, and requires a large amount of time and human resources. In the second approach, objective and human-independent parameters relating to image spatial resolution and noise (MTF and NPS) are used to evaluate digital detector performance; even if these parameters are objective, they are not directly related to lesion detection. A method leading to image quality assessment which is both human independent, and directly related to lesion detection is very important for the optimal use of mammographic units. This Ph.D thesis presents the steps towards such a method: the computation of realistic virtual images using an 'X ray source/digital detector' model taking into account the physical parameters of the detector (spatial resolution and noise measurements) measured under clinical conditions. From results obtained in this work, we have contributed to establish the link between the physical characteristics of detectors and the clinical quality of the image for usual exposition conditions. Furthermore, we suggest the use of our model for the creation of virtual images, in order to rapidly determine the optimal conditions in mammography, which usually is a long and tedious experimental process. This is an essential aspect to be taken into account for radioprotection of patients, especially in the context of organized mass screening of breast cancer. (author)

  5. Objective image characterization of a spectral CT scanner with dual-layer detector

    Science.gov (United States)

    Ozguner, Orhan; Dhanantwari, Amar; Halliburton, Sandra; Wen, Gezheng; Utrup, Steven; Jordan, David

    2018-01-01

    This work evaluated the performance of a detector-based spectral CT system by obtaining objective reference data, evaluating attenuation response of iodine and accuracy of iodine quantification, and comparing conventional CT and virtual monoenergetic images in three common phantoms. Scanning was performed using the hospital’s clinical adult body protocol. Modulation transfer function (MTF) was calculated for a tungsten wire and visual line pair targets were evaluated. Image noise power spectrum (NPS) and pixel standard deviation were calculated. MTF for monoenergetic images agreed with conventional images within 0.05 lp cm-1. NPS curves indicated that noise texture of 70 keV monoenergetic images is similar to conventional images. Standard deviation measurements showed monoenergetic images have lower noise except at 40 keV. Mean CT number and CNR agreed with conventional images at 75 keV. Measured iodine concentration agreed with true concentration within 6% for inserts at the center of the phantom. Performance of monoenergetic images at detector based spectral CT is the same as, or better than, that of conventional images. Spectral acquisition and reconstruction with a detector based platform represents the physical behaviour of iodine as expected and accurately quantifies the material concentration.

  6. Three-dimensional ultrasound strain imaging of skeletal muscles

    NARCIS (Netherlands)

    Gijsbertse, Kaj; Sprengers, Andre M.; Nillesen, Maartje; Hansen, Hendrik H.G.; Verdonschot, Nico; De Korte, Chris L.

    2015-01-01

    Muscle contraction is characterized by large deformation and translation, which requires a multi-dimensional imaging modality to reveal its behavior. Previous work on ultrasound strain imaging of the muscle contraction was limited to 2D and bi-plane techniques. In this study, a three-dimensional

  7. Fast method for geometric calibration of detectors and matching testing between two detectors

    International Nuclear Information System (INIS)

    Pechenova, O.Yu.

    2002-01-01

    A fast method of geometric calibration of detectors has been proposed. The main idea of this method is to determine offsets by fitting the real data distribution by analytic functions which describe the motion of one detector relative to the other one. This method can be applicable to offsets determination for one detector relative to the other detector or for one part of the detector relative to its other part. The detectors should be placed perpendicular to the beam axis. The form of analytic functions depends on the geometry of the experiment and direction of the coordinate axes. The analytic functions have been obtained using the rotation matrices. This method can be applied to the matching testing between two detectors

  8. Comparison of Electron Imaging Modes for Dimensional Measurements in the Scanning Electron Microscope.

    Science.gov (United States)

    Postek, Michael T; Vladár, András E; Villarrubia, John S; Muto, Atsushi

    2016-08-01

    Dimensional measurements from secondary electron (SE) images were compared with those from backscattered electron (BSE) and low-loss electron (LLE) images. With the commonly used 50% threshold criterion, the lines consistently appeared larger in the SE images. As the images were acquired simultaneously by an instrument with the capability to operate detectors for both signals at the same time, the differences cannot be explained by the assumption that contamination or drift between images affected the SE, BSE, or LLE images differently. Simulations with JMONSEL, an electron microscope simulator, indicate that the nanometer-scale differences observed on this sample can be explained by the different convolution effects of a beam with finite size on signals with different symmetry (the SE signal's characteristic peak versus the BSE or LLE signal's characteristic step). This effect is too small to explain the >100 nm discrepancies that were observed in earlier work on different samples. Additional modeling indicates that those discrepancies can be explained by the much larger sidewall angles of the earlier samples, coupled with the different response of SE versus BSE/LLE profiles to such wall angles.

  9. An X-ray imager based on silicon microstrip detector and coded mask

    International Nuclear Information System (INIS)

    Del Monte, E.; Costa, E.; Di Persio, G.; Donnarumma, I.; Evangelista, Y.; Feroci, M.; Frutti, M.; Lapshov, I.; Lazzarotto, F.; Mastropietro, M.; Morelli, E.; Pacciani, L.; Porrovecchio, G.; Rapisarda, M.; Rubini, A.; Soffitta, P.; Tavani, M.; Argan, A.

    2007-01-01

    SuperAGILE is the X-ray monitor of AGILE, a satellite mission for gamma-ray astronomy, and it is the first X-ray imaging instrument based on the technology of the silicon microstrip detectors combined with a coded aperture imaging technique. The SuperAGILE detection plane is composed of four 1-D silicon microstrip detector modules, mechanically coupled to tungsten coded mask units. The detector strips are separately and individually connected to the input analogue channels of the front-end electronics, composed of low-noise and low-power consumption VLSI ASIC chips. SuperAGILE can produce 1-D images with 6 arcmin angular resolution and ∼2-3 arcmin localisation capability, for intense sources, in a field of view composed of two orthogonal areas of 107 deg. x 68 deg. The time resolution is 2 μs, the overall dead time is ∼5 μs and the electronic noise is ∼7.5 keV full-width at half-maximum. The resulting instrument is very compact (40x40x14 cm 3 ), light (10 kg) and has low power consumption (12 W). AGILE is a mission of the Agenzia Spaziale Italiana and its launch is planned in 2007 in a low equatorial Earth orbit. In this contribution we present SuperAGILE and discuss its performance and scientific objectives

  10. Image Encryption Technology Based on Fractional Two-Dimensional Triangle Function Combination Discrete Chaotic Map Coupled with Menezes-Vanstone Elliptic Curve Cryptosystem

    Directory of Open Access Journals (Sweden)

    Zeyu Liu

    2018-01-01

    Full Text Available A new fractional two-dimensional triangle function combination discrete chaotic map (2D-TFCDM with the discrete fractional difference is proposed. We observe the bifurcation behaviors and draw the bifurcation diagrams, the largest Lyapunov exponent plot, and the phase portraits of the proposed map, respectively. On the application side, we apply the proposed discrete fractional map into image encryption with the secret keys ciphered by Menezes-Vanstone Elliptic Curve Cryptosystem (MVECC. Finally, the image encryption algorithm is analysed in four main aspects that indicate the proposed algorithm is better than others.

  11. Analysis of two-dimensional microdischarge distribution in dielectric-barrier discharges

    International Nuclear Information System (INIS)

    Chirokov, A; Gutsol, A; Fridman, A; Sieber, K D; Grace, J M; Robinson, K S

    2004-01-01

    The two-dimensional spatial distribution of microdischarges in atmospheric pressure dielectric-barrier discharges (DBDs) in air was studied. Experimental images of DBDs (Lichtenberg figures) were obtained using photostimulable phosphors. The storage phosphor imaging method takes advantage of the linear response of the phosphor for characterization of microdischarge intensity and position. A microdischarge interaction model in DBDs is proposed and a Monte Carlo simulation of microdischarge interactions in the discharge is presented. Comparison of modelled and experimental images indicates interactions and short-range structuring of microdischarge channels

  12. Bayesian image processing in two and three dimensions

    International Nuclear Information System (INIS)

    Hart, H.; Liang, Z.

    1986-01-01

    Tomographic image processing customarily analyzes data acquired over a series of projective orientations. If, however, the point source function (the matrix R) of the system is strongly depth dependent, tomographic information is also obtainable from a series of parallel planar images corresponding to different ''focal'' depths. Bayesian image processing (BIP) was carried out for two and three dimensional spatially uncorrelated discrete amplitude a priori source distributions

  13. Two wide-angle imaging neutral-atom spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    McComas, D.J.

    1997-12-31

    The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission provides a new capability for stereoscopically imaging the magnetosphere. By imaging the charge exchange neutral atoms over a broad energy range (1 < E , {approximately} 100 keV) using two identical instruments on two widely-spaced high-altitude, high-inclination spacecraft, TWINS will enable the 3-dimensional visualization and the resolution of large scale structures and dynamics within the magnetosphere for the first time. These observations will provide a leap ahead in the understanding of the global aspects of the terrestrial magnetosphere and directly address a number of critical issues in the ``Sun-Earth Connections`` science theme of the NASA Office of Space Science.

  14. Two wide-angle imaging neutral-atom spectrometers

    International Nuclear Information System (INIS)

    McComas, D.J.

    1997-01-01

    The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission provides a new capability for stereoscopically imaging the magnetosphere. By imaging the charge exchange neutral atoms over a broad energy range (1 < E , ∼ 100 keV) using two identical instruments on two widely-spaced high-altitude, high-inclination spacecraft, TWINS will enable the 3-dimensional visualization and the resolution of large scale structures and dynamics within the magnetosphere for the first time. These observations will provide a leap ahead in the understanding of the global aspects of the terrestrial magnetosphere and directly address a number of critical issues in the ''Sun-Earth Connections'' science theme of the NASA Office of Space Science

  15. A web service system supporting three-dimensional post-processing of medical images based on WADO protocol.

    Science.gov (United States)

    He, Longjun; Xu, Lang; Ming, Xing; Liu, Qian

    2015-02-01

    Three-dimensional post-processing operations on the volume data generated by a series of CT or MR images had important significance on image reading and diagnosis. As a part of the DIOCM standard, WADO service defined how to access DICOM objects on the Web, but it didn't involve three-dimensional post-processing operations on the series images. This paper analyzed the technical features of three-dimensional post-processing operations on the volume data, and then designed and implemented a web service system for three-dimensional post-processing operations of medical images based on the WADO protocol. In order to improve the scalability of the proposed system, the business tasks and calculation operations were separated into two modules. As results, it was proved that the proposed system could support three-dimensional post-processing service of medical images for multiple clients at the same moment, which met the demand of accessing three-dimensional post-processing operations on the volume data on the web.

  16. Three-dimensional true FISP for high-resolution imaging of the whole brain

    International Nuclear Information System (INIS)

    Schmitz, B.; Hagen, T.; Reith, W.

    2003-01-01

    While high-resolution T1-weighted sequences, such as three-dimensional magnetization-prepared rapid gradient-echo imaging, are widely available, there is a lack of an equivalent fast high-resolution sequence providing T2 contrast. Using fast high-performance gradient systems we show the feasibility of three-dimensional true fast imaging with steady-state precession (FISP) to fill this gap. We applied a three-dimensional true-FISP protocol with voxel sizes down to 0.5 x 0.5 x 0.5 mm and acquisition times of approximately 8 min on a 1.5-T Sonata (Siemens, Erlangen, Germany) magnetic resonance scanner. The sequence was included into routine brain imaging protocols for patients with cerebrospinal-fluid-related intracranial pathology. Images from 20 patients and 20 healthy volunteers were evaluated by two neuroradiologists with respect to diagnostic image quality and artifacts. All true-FISP scans showed excellent imaging quality free of artifacts in patients and volunteers. They were valuable for the assessment of anatomical and pathologic aspects of the included patients. High-resolution true-FISP imaging is a valuable adjunct for the exploration and neuronavigation of intracranial pathologies especially if cerebrospinal fluid is involved. (orig.)

  17. Sci-Sat AM(1): Imaging-08: Small animal APD PET detector with submillimetric resolution for molecular imaging.

    Science.gov (United States)

    Bérard, P; Bergeron, M; Pepin, C M; Cadorette, J; Tétrault, M-A; Viscogliosi, N; Fontaine, R; Dautet, H; Davies, M; Lecomte, R

    2008-07-01

    Visualization and quantification of biological processes in mice, the preferred animal model in most preclinical studies, require the best possible spatial resolution in positron emission tomography (PET). A new 64-channel avalanche photodiode (APD) detector module was developed to achieve submillimeter spatial resolution for this purpose. The module consists of dual 4 × 8 APD arrays mounted in a custom ceramic holder. Individual APD pixels having an active area of 1.1 × 1.1 mm2 at a 1.2 mm pitch can be fitted to an 8 × 8 LYSO scintillator block designed to accommodate one-to-one coupling. An analog test board with four 16-channel preamplifier ASICs was designed to be interfaced with the existing LabPET digital processing electronics. At a standard APD operating bias, a mean energy resolution of 27.5 ± 0.6% was typically obtained at 511 keV with a relative standard deviation of 13.8% in signal amplitude for the 64 individual pixels. Crosstalk between pixels was found to be well below the typical lower energy threshold used for PET imaging applications. With two modules in coincidence, a global timing resolution of 5.0 ns FWHM was measured. Finally, an intrinsic spatial resolution of 0.8 mm FWHM was measured by sweeping a 22Na point source between two detector arrays. The proposed detector module demonstrates promising characteristics for dedicated mouse PET imaging at submillimiter resolution. © 2008 American Association of Physicists in Medicine.

  18. Six-dimensional real and reciprocal space small-angle X-ray scattering tomography.

    Science.gov (United States)

    Schaff, Florian; Bech, Martin; Zaslansky, Paul; Jud, Christoph; Liebi, Marianne; Guizar-Sicairos, Manuel; Pfeiffer, Franz

    2015-11-19

    When used in combination with raster scanning, small-angle X-ray scattering (SAXS) has proven to be a valuable imaging technique of the nanoscale, for example of bone, teeth and brain matter. Although two-dimensional projection imaging has been used to characterize various materials successfully, its three-dimensional extension, SAXS computed tomography, poses substantial challenges, which have yet to be overcome. Previous work using SAXS computed tomography was unable to preserve oriented SAXS signals during reconstruction. Here we present a solution to this problem and obtain a complete SAXS computed tomography, which preserves oriented scattering information. By introducing virtual tomography axes, we take advantage of the two-dimensional SAXS information recorded on an area detector and use it to reconstruct the full three-dimensional scattering distribution in reciprocal space for each voxel of the three-dimensional object in real space. The presented method could be of interest for a combined six-dimensional real and reciprocal space characterization of mesoscopic materials with hierarchically structured features with length scales ranging from a few nanometres to a few millimetres--for example, biomaterials such as bone or teeth, or functional materials such as fuel-cell or battery components.

  19. X-ray Imaging Using a Hybrid Photon Counting GaAs Pixel Detector

    CERN Document Server

    Schwarz, C; Göppert, R; Heijne, Erik H M; Ludwig, J; Meddeler, G; Mikulec, B; Pernigotti, E; Rogalla, M; Runge, K; Smith, K M; Snoeys, W; Söldner-Rembold, S; Watt, J

    1999-01-01

    The performance of hybrid GaAs pixel detectors as X-ray imaging sensors were investigated at room temperature. These hybrids consist of 300 mu-m thick GaAs pixel detectors, flip-chip bonded to a CMOS Single Photon Counting Chip (PCC). This chip consists of a matrix of 64 x 64 identical square pixels (170 mu-m x 170 mu-m) and covers a total area of 1.2 cm**2. The electronics in each cell comprises a preamplifier, a discriminator with a 3-bit threshold adjust and a 15-bit counter. The detector is realized by an array of Schottky diodes processed on semi-insulating LEC-GaAs bulk material. An IV-charcteristic and a detector bias voltage scan showed that the detector can be operated with voltages around 200 V. Images of various objects were taken by using a standard X-ray tube for dental diagnostics. The signal to noise ratio (SNR) was also determined. The applications of these imaging systems range from medical applications like digital mammography or dental X-ray diagnostics to non destructive material testing (...

  20. Mid-term follow-up of patients with transposition of the great arteries after atrial inversion operation using two- and three-dimensional magnetic resonance imaging

    International Nuclear Information System (INIS)

    Fogel, Mark A.; Weinberg, Paul M.; Hubbard, Anne

    2002-01-01

    Background: Older patients with transposition of the great arteries who have undergone an atrial inversion procedure (ATRIAL-INV) are difficult to image by echocardiography. The surgical baffles are spatially complex. Objective: To test the hypothesis that two- and three-dimensional MRI can elucidate the spatially complex anatomy in this patient population. Materials and methods; Twelve patients with ATRIAL-INV, ages 16±4.5 years, underwent routine T1-weighted spin-echo axial imaging to obtain a full cardiac volumetric data set. Postprocessing created three-dimensional shaded surface displays and allowed for multiplanar reconstruction. Routine transthoracic echocardiography was available on all patients. Results: Three-dimensional reconstruction enabled complete spatial conceptualization of the venous pathways, and allowed for precise localization of a narrowed region in the upper limb of the systemic venous pathway found in two patients. This was subsequently confirmed on angiography. Routine MRI was able to image the full extent of the venous pathways in all 12 patients. Routine transthoracic echocardiography was able to visualize proximal portions of the venous pathways in eight (67%), the distal upper limb in five (42%), and the distal lower limb in four (33%) patients, and it was able to visualize the outflow tracts in all patients. Conclusion: Three-dimensional reconstruction adds important spatial information, which can be especially important in stenotic regions. Routine MRI is superior to transthoracic echocardiography in delineation of the systemic and pulmonary venous pathway anatomy of ATRIAL-INV patients at mid-term follow-up. Although transesophageal echocardiography is an option, it is more invasive. (orig.)

  1. Uterine cervical carcinoma: a comparison of two- and three-dimensional T2-weighted turbo spin-echo MR imaging at 3.0 T for image quality and local-regional staging

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Y.R. [The Catholic University of Korea, Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, 222, Banpo-daero, Seocho-gu, Seoul (Korea, Republic of); The Catholic University of Korea, Department of Radiology, Incheon St. Mary' s Hospital, College of Medicine, Bupyeong 6-dong, Bupyeong-gu, Incheon (Korea, Republic of); Rha, S.E.; Choi, B.G.; Oh, S.N.; Park, M.Y.; Byun, J.Y. [The Catholic University of Korea, Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, 222, Banpo-daero, Seocho-gu, Seoul (Korea, Republic of)

    2013-04-15

    To compare three-dimensional (3D) T2-weighted turbo spin-echo (TSE) with multiplanar two-dimensional (2D) T2-weighted TSE for the evaluation of invasive cervical carcinoma. Seventy-five patients with cervical carcinoma underwent MRI of the pelvis at 3.0 T, using both 5-mm-thick multiplanar 2D (total acquisition time = 12 min 25 s) and 1-mm-thick coronal 3D T2-weighted TSE sequences (7 min 20 s). Quantitative analysis of signal-to-noise ratio (SNR) and qualitative analysis of image quality were performed. Local-regional staging was performed in 45 patients who underwent radical hysterectomy. The estimated SNR of cervical carcinoma and the relative tumour contrast were significantly higher on 3D imaging (P < 0.0001). Tumour conspicuity was better with the 3D sequence, but the sharpness of tumour margin was better with the 2D sequence. No significant difference in overall image quality was noted between the two sequences (P = 0.38). There were no significant differences in terms of the diagnostic accuracy, sensitivity, and specificity of parametrial invasion, vaginal invasion, and lymph node metastases. Multiplanar reconstruction 3D T2-weighted imaging is largely equivalent to 2D T2-weighted imaging for overall image quality and staging accuracy of cervical carcinoma with a shorter MR data acquisition, but has limitations with regard to the sharpness of the tumour margin. circle 3D T2-weighted MR sequence is equivalent to 2D for cervical carcinoma staging. (orig.)

  2. Tests of innovative photon detectors and integrated electronics for the large-area CLAS12 ring-imaging Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Contalbrigo, M., E-mail: contalbrigo@fe.infn.it

    2015-07-01

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab. Its aim is to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and a densely packed and highly segmented photon detector. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). Extensive tests have been performed on Hamamatsu H8500 and novel flat multi-anode photomultipliers under development and on various types of silicon photomultipliers. A large scale prototype based on 28 H8500 MA-PMTs has been realized and tested with few GeV/c hadron beams at the T9 test-beam facility of CERN. In addition a small prototype was used to study the response of customized SiPM matrices within a temperature interval ranging from 25 down to −25 °C. The preliminary results of the individual photon detector tests and of the prototype performance at the test-beams are here reported.

  3. Suitability of helical multislice acquisition technique for routine unenhanced brain CT: an image quality study using a 16-row detector configuration

    Energy Technology Data Exchange (ETDEWEB)

    Hernalsteen, Danielle; Cosnard, Guy; Grandin, Cecile; Duprez, Thierry [Universite Catholique de Louvain, Cliniques Universitaires Saint-Luc, Department of Radiology and Medical Imaging, Brussels (Belgium); Robert, Annie [Public Health School, Universite Catholique de Louvain, Department of Epidemiologics and Medical Statistics, Brussels (Belgium); Vlassenbroek, Alain [CT Clinical Science, Philips Medical Systems, Cleveland, OH (United States)

    2007-04-15

    Subjective and objective image quality (IQ) criteria, radiation doses, and acquisition times were compared using incremental monoslice, incremental multislice, and helical multislice acquisition techniques for routine unenhanced brain computed tomography (CT). Twenty-four patients were examined by two techniques in the same imaging session using a 16-row CT system equipped with 0.75-width detectors. Contiguous ''native'' 3-mm-thick slices were reconstructed for all acquisitions from four detectors for each slice (4 x 0.75 mm), with one channel available per detector. Two protocols were tailored to compare: (1) one-slice vs four-slice incremental images; (2) incremental vs helical four-slice images. Two trained observers independently scored 12 subjective items of IQ. Preference for the technique was assessed by one-tailed t test and the interobserver variation by two-tailed t test. The two observers gave very close IQ scores for the three techniques without significant interobserver variations. Measured IQ parameters failed to reveal any difference between techniques, and an approximate half radiation dose reduction was obtained by using the full 16-row configuration. Acquisition times were cumulatively shortened by using the multislice and the helical modality. (orig.)

  4. Suitability of helical multislice acquisition technique for routine unenhanced brain CT: an image quality study using a 16-row detector configuration

    International Nuclear Information System (INIS)

    Hernalsteen, Danielle; Cosnard, Guy; Grandin, Cecile; Duprez, Thierry; Robert, Annie; Vlassenbroek, Alain

    2007-01-01

    Subjective and objective image quality (IQ) criteria, radiation doses, and acquisition times were compared using incremental monoslice, incremental multislice, and helical multislice acquisition techniques for routine unenhanced brain computed tomography (CT). Twenty-four patients were examined by two techniques in the same imaging session using a 16-row CT system equipped with 0.75-width detectors. Contiguous ''native'' 3-mm-thick slices were reconstructed for all acquisitions from four detectors for each slice (4 x 0.75 mm), with one channel available per detector. Two protocols were tailored to compare: (1) one-slice vs four-slice incremental images; (2) incremental vs helical four-slice images. Two trained observers independently scored 12 subjective items of IQ. Preference for the technique was assessed by one-tailed t test and the interobserver variation by two-tailed t test. The two observers gave very close IQ scores for the three techniques without significant interobserver variations. Measured IQ parameters failed to reveal any difference between techniques, and an approximate half radiation dose reduction was obtained by using the full 16-row configuration. Acquisition times were cumulatively shortened by using the multislice and the helical modality. (orig.)

  5. Three dimensional imaging in cardiac nuclear medicine

    International Nuclear Information System (INIS)

    Torizuka, Kanji; Ishii, Yasushi; Yonekura, Yoshiharu; Yamamoto, Kazutaka; Tamaki, Takeyoshi

    1981-01-01

    Methods to obtain three dimensional images of the heart were reviewed. Gated three dimensional display reconstructed from images using bidirectional collimator, was a useful method to detect akinesis of the heart wall. Tomographic observation of the heart can be carried out by a pinhole collimator to image ischemia with high sensitivity. However the focusing plane must be carefully selected to prevent false positives. In the case of emission CT (ECT), utilization of positron emitters gave a quantitative image without correction, whereas single photon ECT needed the correction due to the absorption of γ-ray. Though the reliability of the images by ECT was high, the time required for data acquisition was much longer than that by a 7 pinhole or bidirectional collimator. (Nakanishi, T.)

  6. Development of CRID [Cerenkov Ring Imaging Detector] single electron wire detector

    International Nuclear Information System (INIS)

    Aston, D.; Bean, A.; Bienz, T.

    1989-02-01

    We describe the R and D effort to define the design parameters, method of construction and experimental results from the single electron wire detectors. These detectors will be used for particle identification using the Cerenkov Ring Imaging techniques in the SLD experiment at SLAC. We present measurements of pulse heights for several gases as a function of gas gain, charge division performance on a single electron signal using both 7 μm and 33 μm diameter carbon wires, photon feedback in TMAE laden gas, average pulse shape, and its comparison with the predicted shape and cross-talk. In addition, we present results of wire aging tests, and other tests associated with construction of this unusual type of wire chamber. 12 refs., 9 figs

  7. Two-dimensional tracking of a motile micro-organism allowing high-resolution observation with various imaging techniques

    International Nuclear Information System (INIS)

    Oku, H.; Ogawa, N.; Ishikawa, M.; Hashimoto, K.

    2005-01-01

    In this article, a micro-organism tracking system using a high-speed vision system is reported. This system two dimensionally tracks a freely swimming micro-organism within the field of an optical microscope by moving a chamber of target micro-organisms based on high-speed visual feedback. The system we developed could track a paramecium using various imaging techniques, including bright-field illumination, dark-field illumination, and differential interference contrast, at magnifications of 5 times and 20 times. A maximum tracking duration of 300 s was demonstrated. Also, the system could track an object with a velocity of up to 35 000 μm/s (175 diameters/s), which is significantly faster than swimming micro-organisms

  8. High gain multigap avalanche detectors for Cerenkov ring imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, R.S.; Lavender, W.M.; Leith, D.W.G.S.; Williams, S.H.

    1980-10-01

    We report on a continuing study of multigap parallel plate avalanche chambers, primarily as photoelectron detectors for use with Cerenkov ring imaging counters. By suitable control of the fields in successive gaps and by introducing screens to reduce photon feedback to the cathode the gain many be increased considerably. We have obtained gains in excess of 6 x 10/sup 7/ for photoelectrons with a good pulse height spectrum and expect to increase this further. We discuss the use of resistive anodes to give avalanche positions in two dimensions by charge division.

  9. An electronic image processing device featuring continuously selectable two-dimensional bipolar filter functions and real-time operation

    International Nuclear Information System (INIS)

    Charleston, B.D.; Beckman, F.H.; Franco, M.J.; Charleston, D.B.

    1981-01-01

    A versatile electronic-analogue image processing system has been developed for use in improving the quality of various types of images with emphasis on those encountered in experimental and diagnostic medicine. The operational principle utilizes spatial filtering which selectively controls the contrast of an image according to the spatial frequency content of relevant and non-relevant features of the image. Noise can be reduced or eliminated by selectively lowering the contrast of information in the high spatial frequency range. Edge sharpness can be enhanced by accentuating the upper midrange spatial frequencies. Both methods of spatial frequency control may be adjusted continuously in the same image to obtain maximum visibility of the features of interest. A precision video camera is used to view medical diagnostic images, either prints, transparencies or CRT displays. The output of the camera provides the analogue input signal for both the electronic processing system and the video display of the unprocessed image. The video signal input to the electronic processing system is processed by a two-dimensional spatial convolution operation. The system employs charged-coupled devices (CCDs), both tapped analogue delay lines (TADs) and serial analogue delay lines (SADs), to store information in the form of analogue potentials which are constantly being updated as new sampled analogue data arrive at the input. This information is convolved with a programmed bipolar radially symmetrical hexagonal function which may be controlled and varied at each radius by the operator in real-time by adjusting a set of front panel controls or by a programmed microprocessor control. Two TV monitors are used, one for processed image display and the other for constant reference to the original image. The working prototype has a full-screen display matrix size of 200 picture elements per horizontal line by 240 lines. The matrix can be expanded vertically and horizontally for the

  10. Recent advances in Optical Computed Tomography (OCT) imaging system for three dimensional (3D) radiotherapy dosimetry

    Science.gov (United States)

    Rahman, Ahmad Taufek Abdul; Farah Rosli, Nurul; Zain, Shafirah Mohd; Zin, Hafiz M.

    2018-01-01

    Radiotherapy delivery techniques for cancer treatment are becoming more complex and highly focused, to enable accurate radiation dose delivery to the cancerous tissue and minimum dose to the healthy tissue adjacent to tumour. Instrument to verify the complex dose delivery in radiotherapy such as optical computed tomography (OCT) measures the dose from a three-dimensional (3D) radiochromic dosimeter to ensure the accuracy of the radiotherapy beam delivery to the patient. OCT measures the optical density in radiochromic material that changes predictably upon exposure to radiotherapy beams. OCT systems have been developed using a photodiode and charged coupled device (CCD) as the detector. The existing OCT imaging systems have limitation in terms of the accuracy and the speed of the measurement. Advances in on-pixel intelligence CMOS image sensor (CIS) will be exploited in this work to replace current detector in OCT imaging systems. CIS is capable of on-pixel signal processing at a very fast imaging speed (over several hundred images per second) that will allow improvement in the 3D measurement of the optical density. The paper will review 3D radiochromic dosimeters and OCT systems developed and discuss how CMOS based OCT imaging will provide accurate and fast optical density measurements in 3D. The paper will also discuss the configuration of the CMOS based OCT developed in this work and how it may improve the existing OCT system.

  11. Preliminary test of an imaging probe for nuclear medicine using hybrid pixel detectors

    International Nuclear Information System (INIS)

    Bertolucci, E.; Maiorino, M.; Mettivier, G.; Montesi, M.C.; Russo, P.

    2002-01-01

    We are investigating the feasibility of an intraoperative imaging probe for lymphoscintigraphy with Tc-99m tracer, for sentinel node radioguided surgery, using the Medipix series of hybrid detectors coupled to a collimator. These detectors are pixelated semiconductor detectors bump-bonded to the Medipix1 photon counting read-out chip (64x64 pixel, 170 μm pitch) or to the Medipix2 chip (256x256 pixel, 55 μm pitch), developed by the European Medipix collaboration. The pixel detector we plan to use in the final version of the probe is a semi-insulating GaAs detector or a 1-2 mm thick CdZnTe detector. For the preliminary tests presented here, we used 300-μm thick silicon detectors, hybridized via bump-bonding to the Medipix1 chip. We used a tungsten parallel-hole collimator (7 mm thick, matrix array of 64x64 100 μm circular holes with 170 μm pitch), and a 22, 60 and 122 keV point-like (1 mm diameter) radioactive sources, placed at various distances from the detector. These tests were conducted in order to investigate the general feasibility of this imaging probe and its resolving power. Measurements show the high resolution but low efficiency performance of the detector-collimator set, which is able to image the 122 keV source with <1 mm FWHM resolution

  12. Psychophysical evaluation of the image quality of a dynamic flat-panel digital x-ray image detector using the threshold contrast detail detectability (TCDD) technique

    Science.gov (United States)

    Davies, Andrew G.; Cowen, Arnold R.; Bruijns, Tom J. C.

    1999-05-01

    We are currently in an era of active development of the digital X-ray imaging detectors that will serve the radiological communities in the new millennium. The rigorous comparative physical evaluations of such devices are therefore becoming increasingly important from both the technical and clinical perspectives. The authors have been actively involved in the evaluation of a clinical demonstration version of a flat-panel dynamic digital X-ray image detector (or FDXD). Results of objective physical evaluation of this device have been presented elsewhere at this conference. The imaging performance of FDXD under radiographic exposure conditions have been previously reported, and in this paper a psychophysical evaluation of the FDXD detector operating under continuous fluoroscopic conditions is presented. The evaluation technique employed was the threshold contrast detail detectability (TCDD) technique, which enables image quality to be measured on devices operating in the clinical environment. This approach addresses image quality in the context of both the image acquisition and display processes, and uses human observers to measure performance. The Leeds test objects TO[10] and TO[10+] were used to obtain comparative measurements of performance on the FDXD and two digital spot fluorography (DSF) systems, one utilizing a Plumbicon camera and the other a state of the art CCD camera. Measurements were taken at a range of detector entrance exposure rates, namely 6, 12, 25 and 50 (mu) R/s. In order to facilitate comparisons between the systems, all fluoroscopic image processing such as noise reduction algorithms, were disabled during the experiments. At the highest dose rate FDXD significantly outperformed the DSF comparison systems in the TCDD comparisons. At 25 and 12 (mu) R/s all three-systems performed in an equivalent manner and at the lowest exposure rate FDXD was inferior to the two DSF systems. At standard fluoroscopic exposures, FDXD performed in an equivalent

  13. Medical image compression by using three-dimensional wavelet transformation

    International Nuclear Information System (INIS)

    Wang, J.; Huang, H.K.

    1996-01-01

    This paper proposes a three-dimensional (3-D) medical image compression method for computed tomography (CT) and magnetic resonance (MR) that uses a separable nonuniform 3-D wavelet transform. The separable wavelet transform employs one filter bank within two-dimensional (2-D) slices and then a second filter bank on the slice direction. CT and MR image sets normally have different resolutions within a slice and between slices. The pixel distances within a slice are normally less than 1 mm and the distance between slices can vary from 1 mm to 10 mm. To find the best filter bank in the slice direction, the authors use the various filter banks in the slice direction and compare the compression results. The results from the 12 selected MR and CT image sets at various slice thickness show that the Haar transform in the slice direction gives the optimum performance for most image sets, except for a CT image set which has 1 mm slice distance. Compared with 2-D wavelet compression, compression ratios of the 3-D method are about 70% higher for CT and 35% higher for MR image sets at a peak signal to noise ratio (PSNR) of 50 dB. In general, the smaller the slice distance, the better the 3-D compression performance

  14. Paediatric interventional cardiology: flat detector versus image intensifier using a test object

    Science.gov (United States)

    Vano, E.; Ubeda, C.; Martinez, L. C.; Leyton, F.; Miranda, P.

    2010-12-01

    Entrance surface air kerma (ESAK) values and image quality parameters were measured and compared for two biplane angiography x-ray systems dedicated to paediatric interventional cardiology, one equipped with image intensifiers (II) and the other one with dynamic flat detectors (FDs). Polymethyl methacrylate phantoms of different thicknesses, ranging from 8 to 16 cm, and a Leeds TOR 18-FG test object were used. The parameters of the image quality evaluated were noise, signal-difference-to-noise ratio (SdNR), high contrast spatial resolution (HCSR) and three figures of merit combining entrance doses and signal-to-noise ratios or HCSR. The comparisons showed a better behaviour of the II-based system in the low contrast region over the whole interval of thicknesses. The FD-based system showed a better performance in HCSR. The FD system evaluated would need around two times more dose than the II system evaluated to reach a given value of SdNR; moreover, a better spatial resolution was measured (and perceived in conventional monitors) for the system equipped with flat detectors. According to the results of this paper, the use of dynamic FD systems does not lead to an automatic reduction in ESAK or to an automatic improvement in image quality by comparison with II systems. Any improvement also depends on the setting of the x-ray systems and it should still be possible to refine these settings for some of the dynamic FDs used in paediatric cardiology.

  15. Paediatric interventional cardiology: flat detector versus image intensifier using a test object

    Energy Technology Data Exchange (ETDEWEB)

    Vano, E [Radiology Department, Medicine School, Complutense University and San Carlos University Hospital, 28040 Madrid (Spain); Ubeda, C [Clinical Sciences Department, Faculty of the Science of Health and CIHDE, Tarapaca University, 18 de Septiembre 2222, Arica (Chile); Martinez, L C [Medical Physics and Radiation Protection Service, 12 de Octubre University Hospital, Madrid (Spain); Leyton, F [Institute of Public Health of Chile, Marathon 1000, Nunoa, Santiago (Chile); Miranda, P, E-mail: eliseov@med.ucm.e [Hemodynamic Department, Cardiovascular Service, Luis Calvo Mackenna Hospital, Avenida Antonio Varaas 360, Providencia, Santiago (Chile)

    2010-12-07

    Entrance surface air kerma (ESAK) values and image quality parameters were measured and compared for two biplane angiography x-ray systems dedicated to paediatric interventional cardiology, one equipped with image intensifiers (II) and the other one with dynamic flat detectors (FDs). Polymethyl methacrylate phantoms of different thicknesses, ranging from 8 to 16 cm, and a Leeds TOR 18-FG test object were used. The parameters of the image quality evaluated were noise, signal-difference-to-noise ratio (SdNR), high contrast spatial resolution (HCSR) and three figures of merit combining entrance doses and signal-to-noise ratios or HCSR. The comparisons showed a better behaviour of the II-based system in the low contrast region over the whole interval of thicknesses. The FD-based system showed a better performance in HCSR. The FD system evaluated would need around two times more dose than the II system evaluated to reach a given value of SdNR; moreover, a better spatial resolution was measured (and perceived in conventional monitors) for the system equipped with flat detectors. According to the results of this paper, the use of dynamic FD systems does not lead to an automatic reduction in ESAK or to an automatic improvement in image quality by comparison with II systems. Any improvement also depends on the setting of the x-ray systems and it should still be possible to refine these settings for some of the dynamic FDs used in paediatric cardiology.

  16. Two dimensional nonlinear spectral estimation techniques for breast cancer localization

    Energy Technology Data Exchange (ETDEWEB)

    Stathaki, P T; Constantinides, A G [Signal Processing Section, Department of Electrical and Electronic Engineering, Imperial College, Exhibition Road, London SW7 2BT, UK (United Kingdom)

    1994-12-31

    In this paper the problem of image texture analysis in the presence of noise is examined from a higher-order statistical perspective. The approach taken involves the use of two dimensional second order Volterra filters where the filter weights are derived from third order cumulants of the two dimensional signal. The specific application contained in this contribution is in mammography, an area in which it is difficult to discern the appropriate features. The paper describes the fundamental issues of the various components of the approach. The results of the entire texture modelling, classification and segmentation scheme contained in this paper are very encouraging. 7 refs, 2 figs.

  17. Single-lens computed tomography imaging spectrometer and method of capturing spatial and spectral information

    Science.gov (United States)

    Wilson, Daniel W. (Inventor); Johnson, William R. (Inventor); Bearman, Gregory H. (Inventor)

    2011-01-01

    Computed tomography imaging spectrometers ("CTISs") employing a single lens are provided. The CTISs may be either transmissive or reflective, and the single lens is either configured to transmit and receive uncollimated light (in transmissive systems), or is configured to reflect and receive uncollimated light (in reflective systems). An exemplary transmissive CTIS includes a focal plane array detector, a single lens configured to transmit and receive uncollimated light, a two-dimensional grating, and a field stop aperture. An exemplary reflective CTIS includes a focal plane array detector, a single mirror configured to reflect and receive uncollimated light, a two-dimensional grating, and a field stop aperture.

  18. Three-dimensional display of the pelvic viscera using multi-sliced MR images

    International Nuclear Information System (INIS)

    Ueno, Shigeru; Suto, Yasuzo.

    1995-01-01

    Accurate reconstruction of the pelvic structure is the most important factor to obtain desirable results after anorectal surgery. Preoperative evaluation of the anatomy is indispensable for choosing an appropriate operative method in each case. To facilitate the preoperative evaluation, three dimensional images of the pelvic structure of patients with anorectal malformations were constructed by computer graphics based upon two dimensional images obtained from MR-CT. Graphic data from MR images were transferred to a graphic work station. The anorectum, bladder and sphincter musculature were displayed three-dimensionally after segmenting these organs by (1) manually regioning the area containing the specific organ and (2) thresholding the area by the T 1 intensity level. The anatomy of each type of anomaly is easily recognized by the 3-D visualization of pelvic viscera and sphincter musculature with emphasis on position and shape of the musculature although there are some difficulties to visualize soft tissue organs. The advanced programs could show the graphic images from any desirable angle quickly enough to be helpful for the simulation of the surgery. Three-dimensional display can be very useful for better understanding of each anomaly and determining the operative method prior to surgery. (author)

  19. A hemispherical photoelectron spectrometer with 2-dimensional delay-line detector and integrated spin-polarization analysis

    International Nuclear Information System (INIS)

    Plucinski, L.; Oelsner, A.; Matthes, F.; Schneider, C.M.

    2010-01-01

    Photoelectron spectrometers usually allow detection of either spin-resolved energy-distribution curves (EDCs) at single emission angle, or 2D angle-vs.-energy images without spin-resolution. We have combined the two detection schemes into one spectrometer system which permits simultaneous detection of a 1D spin-resolved EDC and a 2D angular map. A state-of-the-art hemispherical analyzer is used as an energy filter. Its original scintillator detector has been replaced by a delay-line-detector (DLD), and part of the electron beam is allowed to pass through to reach the spin-polarized low energy electron diffraction (SPLEED) spin-detector mounted subsequently. The electron-optics between DLD and SPLEED contains a 90 o deflector to feature simultaneous detection of in-plane and out-of-plane spin components. These electron-optics have been optimized for high transmission to reduce acquisition times in the spin-resolved mode.

  20. Radiation dose reduction using a CdZnTe-based computed tomography system: Comparison to flat-panel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Le, Huy Q.; Ducote, Justin L.; Molloi, Sabee [Department of Radiological Sciences, University of California, Irvine, California 92697 (United States)

    2010-03-15

    Purpose: Although x-ray projection mammography has been very effective in early detection of breast cancer, its utility is reduced in the detection of small lesions that are occult or in dense breasts. One drawback is that the inherent superposition of parenchymal structures makes visualization of small lesions difficult. Breast computed tomography using flat-panel detectors has been developed to address this limitation by producing three-dimensional data while at the same time providing more comfort to the patients by eliminating breast compression. Flat panels are charge integrating detectors and therefore lack energy resolution capability. Recent advances in solid state semiconductor x-ray detector materials and associated electronics allow the investigation of x-ray imaging systems that use a photon counting and energy discriminating detector, which is the subject of this article. Methods: A small field-of-view computed tomography (CT) system that uses CdZnTe (CZT) photon counting detector was compared to one that uses a flat-panel detector for different imaging tasks in breast imaging. The benefits afforded by the CZT detector in the energy weighting modes were investigated. Two types of energy weighting methods were studied: Projection based and image based. Simulation and phantom studies were performed with a 2.5 cm polymethyl methacrylate (PMMA) cylinder filled with iodine and calcium contrast objects. Simulation was also performed on a 10 cm breast specimen. Results: The contrast-to-noise ratio improvements as compared to flat-panel detectors were 1.30 and 1.28 (projection based) and 1.35 and 1.25 (image based) for iodine over PMMA and hydroxylapatite over PMMA, respectively. Corresponding simulation values were 1.81 and 1.48 (projection based) and 1.85 and 1.48 (image based). Dose reductions using the CZT detector were 52.05% and 49.45% for iodine and hydroxyapatite imaging, respectively. Image-based weighting was also found to have the least beam

  1. Radiation dose reduction using a CdZnTe-based computed tomography system: Comparison to flat-panel detectors

    International Nuclear Information System (INIS)

    Le, Huy Q.; Ducote, Justin L.; Molloi, Sabee

    2010-01-01

    Purpose: Although x-ray projection mammography has been very effective in early detection of breast cancer, its utility is reduced in the detection of small lesions that are occult or in dense breasts. One drawback is that the inherent superposition of parenchymal structures makes visualization of small lesions difficult. Breast computed tomography using flat-panel detectors has been developed to address this limitation by producing three-dimensional data while at the same time providing more comfort to the patients by eliminating breast compression. Flat panels are charge integrating detectors and therefore lack energy resolution capability. Recent advances in solid state semiconductor x-ray detector materials and associated electronics allow the investigation of x-ray imaging systems that use a photon counting and energy discriminating detector, which is the subject of this article. Methods: A small field-of-view computed tomography (CT) system that uses CdZnTe (CZT) photon counting detector was compared to one that uses a flat-panel detector for different imaging tasks in breast imaging. The benefits afforded by the CZT detector in the energy weighting modes were investigated. Two types of energy weighting methods were studied: Projection based and image based. Simulation and phantom studies were performed with a 2.5 cm polymethyl methacrylate (PMMA) cylinder filled with iodine and calcium contrast objects. Simulation was also performed on a 10 cm breast specimen. Results: The contrast-to-noise ratio improvements as compared to flat-panel detectors were 1.30 and 1.28 (projection based) and 1.35 and 1.25 (image based) for iodine over PMMA and hydroxylapatite over PMMA, respectively. Corresponding simulation values were 1.81 and 1.48 (projection based) and 1.85 and 1.48 (image based). Dose reductions using the CZT detector were 52.05% and 49.45% for iodine and hydroxyapatite imaging, respectively. Image-based weighting was also found to have the least beam

  2. Image simulation of high-speed imaging by high-pressure gas ionization detector

    International Nuclear Information System (INIS)

    Miao Jichen; Liu Ximing; Wu Zhifang

    2005-01-01

    The signal of the neighbor pixels is cumulated in Freight Train Inspection System because data fetch time is shorter than ion excursion time. This paper analyzes the pertinency of neighbor pixels and designs computer simulation method to generate some emulate images such as indicator image. The result indicates the high-pressure gas ionization detector can be used in high-speed digital radiography field. (authors)

  3. X-ray imaging with photon counting hybrid semiconductor pixel detectors

    CERN Document Server

    Manolopoulos, S; Campbell, M; Snoeys, W; Heijne, Erik H M; Pernigotti, E; Raine, C; Smith, K; Watt, J; O'Shea, V; Ludwig, J; Schwarz, C

    1999-01-01

    Semiconductor pixel detectors, originally developed for particle physics experiments, have been studied as X-ray imaging devices. The performance of devices using the OMEGA 3 read-out chip bump-bonded to pixellated silicon semiconductor detectors is characterised in terms of their signal-to-noise ratio when exposed to 60 kVp X-rays. Although parts of the devices achieve values of this ratio compatible with the noise being photon statistics limited, this is not found to hold for the whole pixel matrix, resulting in the global signal-to-noise ratio being compromised. First results are presented of X-ray images taken with a gallium arsenide pixel detector bump-bonded to a new read-out chip, (MEDIPIX), which is a single photon counting read-out chip incorporating a 15-bit counter in every pixel. (author)

  4. Analysis and operation of DePFET X-ray imaging detectors

    International Nuclear Information System (INIS)

    Lauf, Thomas

    2011-01-01

    The latest active pixel sensor for X-ray imaging spectroscopy developed at the Max-Planck-Halbleiterlabor (HLL) is the Depleted P-channel Field Effect Transistor (DePFET). This detector type unites detector and first stage amplification and has excellent energy resolution, low noise readout at high speed and low power consumption. This is combined with the possibility of random accessibility of pixels and on-demand readout. In addition it possesses all advantages of a sidewards depleted device, i.e. 100% fill factor and very good quantum efficiency. In the course of the development of DePFET detectors the need of a data analysis software for DePFET devices became apparent. A new tool was developed within the scope of this thesis, which should enable scientists to analyze DePFET data, but also be flexible enough so it can be adapted to new device variants and analysis challenges. A modular concept was thus implemented: a base program running an analysis by individual steps encapsulating algorithms, which can be interchanged. The result is a flexible, adaptable, and expandable analysis software. The software was used to investigate and qualify different structural variants of DePFET detectors. Algorithms to examine detector effects and methods to correct them were developed and integrated into the software. This way, a standard analysis suite for DePFET data was built up which is used at the HLL. Beside the planned use as detector for the wide field imager in the space X-ray observatory IXO, DePFET matrices will be used as focal plane array on the Mercury Imaging X-ray Spectrometer on board the Mercury probe BepiColombo which is scheduled for launch in 2014. The developed analysis software was used in the detector development for this mission to qualify test structures, analyze detector effects and study experimental results. In the course of this development, detector prototypes were studied in respect of linearity, charge collection and detection efficiency in an

  5. Analysis and operation of DePFET X-ray imaging detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lauf, Thomas

    2011-04-28

    The latest active pixel sensor for X-ray imaging spectroscopy developed at the Max-Planck-Halbleiterlabor (HLL) is the Depleted P-channel Field Effect Transistor (DePFET). This detector type unites detector and first stage amplification and has excellent energy resolution, low noise readout at high speed and low power consumption. This is combined with the possibility of random accessibility of pixels and on-demand readout. In addition it possesses all advantages of a sidewards depleted device, i.e. 100% fill factor and very good quantum efficiency. In the course of the development of DePFET detectors the need of a data analysis software for DePFET devices became apparent. A new tool was developed within the scope of this thesis, which should enable scientists to analyze DePFET data, but also be flexible enough so it can be adapted to new device variants and analysis challenges. A modular concept was thus implemented: a base program running an analysis by individual steps encapsulating algorithms, which can be interchanged. The result is a flexible, adaptable, and expandable analysis software. The software was used to investigate and qualify different structural variants of DePFET detectors. Algorithms to examine detector effects and methods to correct them were developed and integrated into the software. This way, a standard analysis suite for DePFET data was built up which is used at the HLL. Beside the planned use as detector for the wide field imager in the space X-ray observatory IXO, DePFET matrices will be used as focal plane array on the Mercury Imaging X-ray Spectrometer on board the Mercury probe BepiColombo which is scheduled for launch in 2014. The developed analysis software was used in the detector development for this mission to qualify test structures, analyze detector effects and study experimental results. In the course of this development, detector prototypes were studied in respect of linearity, charge collection and detection efficiency in an

  6. Current state-of-the-art industrial and research applications using room-temperature CdTe and CdZnTe solid state detectors

    International Nuclear Information System (INIS)

    Eisen, Y.

    1996-01-01

    Improvements of CdTe crystal quality and significant progress in the growth of large ingots of high resistivity CdZnTe material enable the fabrication of larger area detectors in single element form or monolithic arrays. These advances allow for the development of imaging devices of improved spatial resolution for industrial, research and medical applications. CdTe and CdZnTe detectors operate in single photon counting mode or in current mode (charge integrating mode). The paper presents advantages of CdTe and CdZnTe over common scintillator type detectors, but also presents the shortcomings of the former detectors with respect to charge collection which limit the yields of good spectrometers. The paper reviews industrial and research applications utilizing these detectors and in particular describes in detail two imaging systems for security screening and custom inspection. These systems are characterized by large dynamic range and good spatial resolution and are composed of large arrays of CdTe spectrometers and discriminator grade detectors. A wide energy range detector assembly, for astrophysical research of gamma ray bursts composed of CdTe, HgI 2 and CdZnTe spectrometers in two dimensional arrays is also presented. (orig.)

  7. New medical imaging systems exploiting the energy dispersive X-ray diffraction with spectrometric CdZnTe based detector

    International Nuclear Information System (INIS)

    Barbes, Damien

    2016-01-01

    This thesis studies the interest of measuring the coherent scattering of X-rays for breast diagnosis imaging. Nowadays, most of X-ray-based medical imaging techniques use the information of X-rays attenuation through the tissues. It is the case for mammography, the most common breast imaging modality. The recent emergence of energy resolved detectors (based on semiconductors in particular) allows to consider using another phenomenon: the coherent X-ray scattering. Measurement of diffracted spectra can provide new information related to the molecular structure of the examined tissues, in order to improve their characterization and therefore improve the final diagnosis. Two modalities are considered: the breast cancer detection in vivo, following a suspicious mammography result, or biopsy analysis. The coherent scattering measurement system developed during this thesis work uses energy-resolved CdZnTe-based detectors, these detectors combining performances (energy resolution, sensitivity, spatial resolution, and compactness) promising for clinical application. This system is also based on the detector pixelation, which allows to provide an imaging modality capable of characterizing analyzed materials or tissues in one direction without any translation or rotation. A complete study of the measurement system is proposed in this thesis, structured in three main parts: modeling and simulation of the system, development of the processing of the data measured by the detector in order to image and characterize the analyzed sample and finally, designing of a new and more complex experimental setup based on a whole detector and multi-slit collimation system. An experimental validation is proposed for each of these three parts. (author) [fr

  8. Three-dimensional x-ray stereometry from paired coplanar images: a progress report.

    Science.gov (United States)

    Baumrind, S; Moffitt, F H; Curry, S

    1983-10-01

    More than fifty years ago, Broadbent reported the development of a three-dimensional cephalometric method which complexed information from pairs of x-ray images oriented in two planes at right angles to each other. Empirical problems have prevented the routine clinical use of this "biplanar" method, notwithstanding its obvious conceptual brilliance. The present article reports on recent work toward the development of an alternative method of three-dimensional cephalometry in which the two images of each x-ray pair are positioned in the same plane rather than being at right angles to each other. It is believed that this "coplanar" method avoids many of the technical problems that have limited the use of the Broadbent method.

  9. Optimal Padding for the Two-Dimensional Fast Fourier Transform

    Science.gov (United States)

    Dean, Bruce H.; Aronstein, David L.; Smith, Jeffrey S.

    2011-01-01

    One-dimensional Fast Fourier Transform (FFT) operations work fastest on grids whose size is divisible by a power of two. Because of this, padding grids (that are not already sized to a power of two) so that their size is the next highest power of two can speed up operations. While this works well for one-dimensional grids, it does not work well for two-dimensional grids. For a two-dimensional grid, there are certain pad sizes that work better than others. Therefore, the need exists to generalize a strategy for determining optimal pad sizes. There are three steps in the FFT algorithm. The first is to perform a one-dimensional transform on each row in the grid. The second step is to transpose the resulting matrix. The third step is to perform a one-dimensional transform on each row in the resulting grid. Steps one and three both benefit from padding the row to the next highest power of two, but the second step needs a novel approach. An algorithm was developed that struck a balance between optimizing the grid pad size with prime factors that are small (which are optimal for one-dimensional operations), and with prime factors that are large (which are optimal for two-dimensional operations). This algorithm optimizes based on average run times, and is not fine-tuned for any specific application. It increases the amount of times that processor-requested data is found in the set-associative processor cache. Cache retrievals are 4-10 times faster than conventional memory retrievals. The tested implementation of the algorithm resulted in faster execution times on all platforms tested, but with varying sized grids. This is because various computer architectures process commands differently. The test grid was 512 512. Using a 540 540 grid on a Pentium V processor, the code ran 30 percent faster. On a PowerPC, a 256x256 grid worked best. A Core2Duo computer preferred either a 1040x1040 (15 percent faster) or a 1008x1008 (30 percent faster) grid. There are many industries that

  10. Assessment of Normal Eyeball Protrusion Using Computed Tomographic Imaging and Three-Dimensional Reconstruction in Korean Adults.

    Science.gov (United States)

    Shin, Kang-Jae; Gil, Young-Chun; Lee, Shin-Hyo; Kim, Jeong-Nam; Yoo, Ja-Young; Kim, Soon-Heum; Choi, Hyun-Gon; Shin, Hyun Jin; Koh, Ki-Seok; Song, Wu-Chul

    2017-01-01

    The aim of the present study was to assess normal eyeball protrusion from the orbital rim using two- and three-dimensional images and demonstrate the better suitability of CT images for assessment of exophthalmos. The facial computed tomographic (CT) images of Korean adults were acquired in sagittal and transverse views. The CT images were used in reconstructing three-dimensional volume of faces using computer software. The protrusion distances from orbital rims and the diameters of eyeballs were measured in the two views of the CT image and three-dimensional volume of the face. Relative exophthalmometry was calculated by the difference in protrusion distance between the right and left sides. The eyeball protrusion was 4.9 and 12.5 mm in sagittal and transverse views, respectively. The protrusion distances were 2.9 mm in the three-dimensional volume of face. There were no significant differences between right and left sides in the degree of protrusion, and the difference was within 2 mm in more than 90% of the subjects. The results of the present study will provide reliable criteria for precise diagnosis and postoperative monitoring using CT imaging of diseases such as thyroid-associated ophthalmopathy and orbital tumors.

  11. Equivalence of two-dimensional gravities

    International Nuclear Information System (INIS)

    Mohammedi, N.

    1990-01-01

    The authors find the relationship between the Jackiw-Teitelboim model of two-dimensional gravity and the SL(2,R) induced gravity. These are shown to be related to a two-dimensional gauge theory obtained by dimensionally reducing the Chern-Simons action of the 2 + 1 dimensional gravity. The authors present an explicit solution to the equations of motion of the auxiliary field of the Jackiw-Teitelboim model in the light-cone gauge. A renormalization of the cosmological constant is also given

  12. The value of unenhanced multi-detector computed tomography ...

    African Journals Online (AJOL)

    Introduction: Unenhanced computed tomography (CT) is used to detect urinary tract calculi with high accuracy. The development of multi-detector CT (MDCT) allows reconstructions in coronal, sagittal and oblique directions. Objective: To compare MDCT with three-dimensional (3D) ultrasound (US) imaging in evaluating ...

  13. Three-dimensional Ca2+ imaging advances understanding of astrocyte biology.

    Science.gov (United States)

    Bindocci, Erika; Savtchouk, Iaroslav; Liaudet, Nicolas; Becker, Denise; Carriero, Giovanni; Volterra, Andrea

    2017-05-19

    Astrocyte communication is typically studied by two-dimensional calcium ion (Ca 2+ ) imaging, but this method has not yielded conclusive data on the role of astrocytes in synaptic and vascular function. We developed a three-dimensional two-photon imaging approach and studied Ca 2+ dynamics in entire astrocyte volumes, including during axon-astrocyte interactions. In both awake mice and brain slices, we found that Ca 2+ activity in an individual astrocyte is scattered throughout the cell, largely compartmented between regions, preponderantly local within regions, and heterogeneously distributed regionally and locally. Processes and endfeet displayed frequent fast activity, whereas the soma was infrequently active. In awake mice, activity was higher than in brain slices, particularly in endfeet and processes, and displayed occasional multifocal cellwide events. Astrocytes responded locally to minimal axonal firing with time-correlated Ca 2+ spots. Copyright © 2017, American Association for the Advancement of Science.

  14. 3-D Spatial Resolution of 350 μm Pitch Pixelated CdZnTe Detectors for Imaging Applications.

    Science.gov (United States)

    Yin, Yongzhi; Chen, Ximeng; Wu, Heyu; Komarov, Sergey; Garson, Alfred; Li, Qiang; Guo, Qingzhen; Krawczynski, Henric; Meng, Ling-Jian; Tai, Yuan-Chuan

    2013-02-01

    We are currently investigating the feasibility of using highly pixelated Cadmium Zinc Telluride (CdZnTe) detectors for sub-500 μ m resolution PET imaging applications. A 20 mm × 20 mm × 5 mm CdZnTe substrate was fabricated with 350 μ m pitch pixels (250 μ m anode pixels with 100 μ m gap) and coplanar cathode. Charge sharing among the pixels of a 350 μ m pitch detector was studied using collimated 122 keV and 511 keV gamma ray sources. For a 350 μ m pitch CdZnTe detector, scatter plots of the charge signal of two neighboring pixels clearly show more charge sharing when the collimated beam hits the gap between adjacent pixels. Using collimated Co-57 and Ge-68 sources, we measured the count profiles and estimated the intrinsic spatial resolution of 350 μ m pitch detector biased at -1000 V. Depth of interaction was analyzed based on two methods, i.e., cathode/anode ratio and electron drift time, in both 122 keV and 511 keV measurements. For single-pixel photopeak events, a linear correlation between cathode/anode ratio and electron drift time was shown, which would be useful for estimating the DOI information and preserving image resolution in CdZnTe PET imaging applications.

  15. Single-shot imaging with higher-dimensional encoding using magnetic field monitoring and concomitant field correction.

    Science.gov (United States)

    Testud, Frederik; Gallichan, Daniel; Layton, Kelvin J; Barmet, Christoph; Welz, Anna M; Dewdney, Andrew; Cocosco, Chris A; Pruessmann, Klaas P; Hennig, Jürgen; Zaitsev, Maxim

    2015-03-01

    PatLoc (Parallel Imaging Technique using Localized Gradients) accelerates imaging and introduces a resolution variation across the field-of-view. Higher-dimensional encoding employs more spatial encoding magnetic fields (SEMs) than the corresponding image dimensionality requires, e.g. by applying two quadratic and two linear spatial encoding magnetic fields to reconstruct a 2D image. Images acquired with higher-dimensional single-shot trajectories can exhibit strong artifacts and geometric distortions. In this work, the source of these artifacts is analyzed and a reliable correction strategy is derived. A dynamic field camera was built for encoding field calibration. Concomitant fields of linear and nonlinear spatial encoding magnetic fields were analyzed. A combined basis consisting of spherical harmonics and concomitant terms was proposed and used for encoding field calibration and image reconstruction. A good agreement between the analytical solution for the concomitant fields and the magnetic field simulations of the custom-built PatLoc SEM coil was observed. Substantial image quality improvements were obtained using a dynamic field camera for encoding field calibration combined with the proposed combined basis. The importance of trajectory calibration for single-shot higher-dimensional encoding is demonstrated using the combined basis including spherical harmonics and concomitant terms, which treats the concomitant fields as an integral part of the encoding. © 2014 Wiley Periodicals, Inc.

  16. The SUMO Ship Detector Algorithm for Satellite Radar Images

    Directory of Open Access Journals (Sweden)

    Harm Greidanus

    2017-03-01

    Full Text Available Search for Unidentified Maritime Objects (SUMO is an algorithm for ship detection in satellite Synthetic Aperture Radar (SAR images. It has been developed over the course of more than 15 years, using a large amount of SAR images from almost all available SAR satellites operating in L-, C- and X-band. As validated by benchmark tests, it performs very well on a wide range of SAR image modes (from Spotlight to ScanSAR and resolutions (from 1–100 m and for all types and sizes of ships, within the physical limits imposed by the radar imaging. This paper describes, in detail, the algorithmic approach in all of the steps of the ship detection: land masking, clutter estimation, detection thresholding, target clustering, ship attribute estimation and false alarm suppression. SUMO is a pixel-based CFAR (Constant False Alarm Rate detector for multi-look radar images. It assumes a K distribution for the sea clutter, corrected however for deviations of the actual sea clutter from this distribution, implementing a fast and robust method for the clutter background estimation. The clustering of detected pixels into targets (ships uses several thresholds to deal with the typically irregular distribution of the radar backscatter over a ship. In a multi-polarization image, the different channels are fused. Azimuth ambiguities, a common source of false alarms in ship detection, are removed. A reliability indicator is computed for each target. In post-processing, using the results of a series of images, additional false alarms from recurrent (fixed targets including range ambiguities are also removed. SUMO can run in semi-automatic mode, where an operator can verify each detected target. It can also run in fully automatic mode, where batches of over 10,000 images have successfully been processed in less than two hours. The number of satellite SAR systems keeps increasing, as does their application to maritime surveillance. The open data policy of the EU

  17. Terahertz detectors for long wavelength multi-spectral imaging.

    Energy Technology Data Exchange (ETDEWEB)

    Lyo, Sungkwun Kenneth; Wanke, Michael Clement; Reno, John Louis; Shaner, Eric Arthur; Grine, Albert D.

    2007-10-01

    The purpose of this work was to develop a wavelength tunable detector for Terahertz spectroscopy and imaging. Our approach was to utilize plasmons in the channel of a specially designed field-effect transistor called the grating-gate detector. Grating-gate detectors exhibit narrow-linewidth, broad spectral tunability through application of a gate bias, and no angular dependence in their photoresponse. As such, if suitable sensitivity can be attained, they are viable candidates for Terahertz multi-spectral focal plane arrays. When this work began, grating-gate gate detectors, while having many promising characteristics, had a noise-equivalent power (NEP) of only 10{sup -5} W/{radical}Hz. Over the duration of this project, we have obtained a true NEP of 10{sup -8} W/{radical}Hz and a scaled NEP of 10{sup -9}W/{radical}Hz. The ultimate goal for these detectors is to reach a NEP in the 10{sup -9{yields}-10}W/{radical}Hz range; we have not yet seen a roadblock to continued improvement.

  18. Two-dimensional metamaterial optics

    International Nuclear Information System (INIS)

    Smolyaninov, I I

    2010-01-01

    While three-dimensional photonic metamaterials are difficult to fabricate, many new concepts and ideas in the metamaterial optics can be realized in two spatial dimensions using planar optics of surface plasmon polaritons. In this paper we review recent progress in this direction. Two-dimensional photonic crystals, hyperbolic metamaterials, and plasmonic focusing devices are demonstrated and used in novel microscopy and waveguiding schemes

  19. Wigner functions from the two-dimensional wavelet group.

    Science.gov (United States)

    Ali, S T; Krasowska, A E; Murenzi, R

    2000-12-01

    Following a general procedure developed previously [Ann. Henri Poincaré 1, 685 (2000)], here we construct Wigner functions on a phase space related to the similitude group in two dimensions. Since the group space in this case is topologically homeomorphic to the phase space in question, the Wigner functions so constructed may also be considered as being functions on the group space itself. Previously the similitude group was used to construct wavelets for two-dimensional image analysis; we discuss here the connection between the wavelet transform and the Wigner function.

  20. Three-dimensional super-resolution imaging for fluorescence emission difference microscopy

    Energy Technology Data Exchange (ETDEWEB)

    You, Shangting; Kuang, Cuifang, E-mail: cfkuang@zju.edu.cn; Li, Shuai; Liu, Xu; Ding, Zhihua [State key laboratory of modern optical instrumentations, Zhejiang University, Hangzhou 310027 (China)

    2015-08-15

    We propose a method theoretically to break the diffraction limit and to improve the resolution in all three dimensions for fluorescence emission difference microscopy. We produce two kinds of hollow focal spot by phase modulation. By incoherent superposition, these two kinds of focal spot yield a 3D hollow focal spot. The optimal proportion of these two kinds of spot is given in the paper. By employing 3D hollow focal spot, super-resolution image can be yielded by means of fluorescence emission difference microscopy, with resolution enhanced both laterally and axially. According to computation result, size of point spread function of three-dimensional super-resolution imaging is reduced by about 40% in all three spatial directions with respect to confocal imaging.