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Sample records for gadolinium oxysulfide screen-film

  1. Characterization of imaging performances of gadolinium-oxysulfide phosphors made for X-ray imaging by using a sedimentation process

    NASA Astrophysics Data System (ADS)

    Yun, Seungman; Han, Jong Chul; Joe, Okla; Ko, Jong Soo; Kim, Young Soo; Kim, Ho Kyung

    2012-02-01

    The development of a pixel-structured scintillator has recently been exploited to confine optical transport onto a corresponding photodiode pixel. This conceptual design of scintillators may provide high detection efficiency while preserving high spatial resolution in digital X-ray imaging detector systems. The sedimentation approach is one method to fill gadolinium-oxysulfide phosphors into a pixel-structured micro-well array. To fully understand the X-ray imaging characteristics of a pixel-structured design with sedimented gadolinium-oxysulfide phosphors, the imaging performance of gadolinium-oxysulfide phosphor layers made by using sedimentation should be characterized in advance. We have fabricated gadolinium-oxysulfide phosphor screens by using a simple sedimentation method. In order to characterize the imaging performances of the developed phosphor screens, we overlaid them onto a photodiode array with a pixel pitch of 48 microns and thus completed indirect-conversion X-ray imaging detectors. The imaging performance of the detector was investigated in terms of the modulation-transfer function (MTF), the noise-power spectrum, and the detective quantum efficiency (DQE). The results were compared with those of detectors employing commercial phosphor screens. Although the developed screen was about 1.5 times thicker than the commercial one, the X-ray sensitivity was comparable to that of the commercial phosphor. The MTF performance was worse than that of the commercial screen, and that MTF performance also governed the DQE performance of the detector over the entire spatial-frequency band. If the sedimented phosphors are pixel-structured with micro-well arrays, however, the MTF performance can be defined by using only the pixel size. Therefore, a design to enhance the X-ray sensitivity for the sedimentation method should be considered.

  2. Eu(3+) doped gadolinium oxysulfide (Gd(2)O(2)S) nanostructures-synthesis and optical and electronic properties.

    PubMed

    Thirumalai, J; Chandramohan, R; Divakar, R; Mohandas, E; Sekar, M; Parameswaran, P

    2008-10-01

    One-dimensional Eu(3+) doped gadolinium oxysulfide (Gd(2)O(2)S:Eu(3+)) nanotubes/nanorods have been synthesized via precursors of Gd(OH)(3) nanostructures using a hydrothermal technique. The blue-shifts in the optical spectra for the Gd(2)O(2)S:Eu(3+) system corresponding to the fundamental absorption and Eu(3+)-X(2-) ligand (X =  O/S) charge transfer bands (CTBs) are significant (∼0.22-0.36 eV) with respect to the bulk counterpart. The nanotubes are good candidates for investigating the size-induced electrical and optical properties of functional oxysulfides. In order to identify the origin and nature of the electronic transitions observed in the visible region, optical and photo-induced impedance measurements have been extended to the nanotubes in this report. PMID:21832604

  3. Terbium-doped gadolinium oxysulfide (Gd2O2S:Tb) scintillation-based polymer optical fibre sensor for real time monitoring of radiation dose in oncology

    NASA Astrophysics Data System (ADS)

    Lewis, E.; O'Keeffe, S.; Grattan, M.; Hounsell, A.; McCarthy, D.; Woulfe, P.; Cronin, J.; Mihai, L.; Sporea, D.; Santhanam, A.; Agazaryan, N.

    2014-05-01

    A PMMA based plastic optical fibre sensor for use in real time radiotherapy dosimetry is presented. The optical fibre tip is coated with a scintillation material, terbium-doped gadolinium oxysulfide (Gd2O2S:Tb), which fluoresces when exposed to ionising radiation (X-Ray). The emitted visible light signal penetrates the sensor optical fibre and propagates along the transmitting fibre at the end of which it is remotely monitored using a fluorescence spectrometer. The results demonstrate good repeatability, with a maximum percentage error of 0.5% and the response is independent of dose rate.

  4. Performance characteristics of high-MTF screen-film systems

    NASA Astrophysics Data System (ADS)

    Bunch, Phillip C.

    1994-05-01

    The development of specialized dyes that essentially prevent light from crossing the film base in double-coated gadolinium oxysulfide (GOS) phosphor-based radiographic systems has made it possible to design screen-film combinations with significantly improved MTF characteristics. Specifically, by using GOS-based screens with reduced light diffusion properties in combination with near-zero-crossover radiographic films, significantly improved MTF can be obtained at competitive speed and effective x-ray attenuation levels. The basic performance characteristics of such screen-film systems are described in some detail, including x-ray attenuation properties, sensitivity to scattered x-radiation, sensitometric data, contrast transfer functions, noise equivalent quanta, and detective quantum efficiency. It is also shown that high-MTF GOS screens are available that meet or exceed the performance characteristics of comparable UV-emitting yttrium tantalate phosphor-based materials.

  5. Geometric magnetic frustration in RE{sub 2}O{sub 2}S oxysulfides (RE = Sm, Eu and Gd)

    SciTech Connect

    Biondo, V.; Sarvezuk, P.W.C.; Ivashita, F.F.; Silva, K.L.; Paesano, A.; Isnard, O.

    2014-06-01

    Graphical abstract: Stacked planes in the <001> direction of an oxysulfide structure, showing the triangular nets formed by rare earth cations, which moments present geometric magnetic frustration. - Highlights: • We prepared monophasic RE{sub 2}O{sub 2}S Oxysulfides (RE = Sm, Eu and Gd). • RE{sub 2}O{sub 2}S compounds were characterized regarding structural and magnetic properties. • Mössbauer spectra were obtained for Eu{sub 2}O{sub 2}S and Gd{sub 2}O{sub 2}S at different temperatures. • Oxysulfides present geometric magnetic frustration of the rare-earth sublattice. - Abstract: RE{sub 2}O{sub 2}S oxysulfides (with RE = Sm, Eu and Gd) were prepared and characterized regarding their structural and magnetic properties. The compounds crystallized in the trigonal symmetry (space group P-3m/D{sub 3}{sup 3}d), with the lattice parameter varying linearly with the ionic radius of the RE cation. All these oxysulfides are magnetically frustrated and only the gadolinium sample showed magnetic order down to 3 K. The magnetic frustration is attributed to the spatial distribution of cations over the lattice, where the RE’s magnetic moments occupy the sites forming a triangular plane lattice, perpendicular to the direction. This geometric magnetic frustration was firstly recognized for these oxysulfides.

  6. Guided design of copper oxysulfide superconductors

    NASA Astrophysics Data System (ADS)

    Yee, Chuck-Hou; Birol, Turan; Kotliar, Gabriel

    2015-03-01

    Using the framework of chemical intuition introduced by Antipov, et. al., in his synthesis of the Hg-based high-temperature superconductors, supplemented with modern first-principles electronic structure tools, materials databases, and evolutionary algorithms capable of exploring large configurational spaces, we design a novel family of copper oxysulfides. We explore the predictions of theories based on charge-transfer energies, orbital distillation and uniaxial strain on the superconducting transition temperatures of these oxysulfides.

  7. Guided design of copper oxysulfide superconductors

    NASA Astrophysics Data System (ADS)

    Yee, Chuck-Hou; Birol, Turan; Kotliar, Gabriel

    2015-07-01

    We describe a framework for designing novel materials, combining modern first-principles electronic-structure tools, materials databases, and evolutionary algorithms capable of exploring large configurational spaces. Guided by the chemical principles introduced by Antipov et al., for the design and synthesis of the Hg-based high-temperature superconductors, we apply our framework to screen 333 proposed compositions to design a new layered copper oxysulfide, Hg(CaS)2CuO2. We evaluate the prospects of superconductivity in this oxysulfide using theories based on charge-transfer energies, orbital distillation and uniaxial strain.

  8. Kinetics and Mechanisms of Nanosilver Oxysulfidation

    PubMed Central

    Liu, Jingyu; Pennell, Kelly G.; Hurt, Robert H.

    2011-01-01

    Among the many new engineered nanomaterials, nanosilver is one of the highest priority cases for environmental risk assessment. Recent analysis of field samples from water treatment facilities suggests that silver is converted to silver sulfide, whose very low solubility may limit the bioavailability and adverse impact of silver in the environment. The present study demonstrates that silver nanoparticles react with dissolved sulfide species (HS−, S2−) under relevant but controlled laboratory conditions to produce silver sulfide nanostructures similar to those observed in the field. The reaction is tracked by time-resolved sulfide depletion measurements to yield quantitative reaction rates and stoichiometries. The reaction requires dissolved oxygen, and it is sensitive to pH and natural organic matter. Focusedion-beam analysis of surface films reveals an irregular coarse-grained sulfide phase that allows deep (> 1 μm) conversion of silver surfaces without passivation. At high sulfide concentrations, nanosilver oxysulfidation occurs by a direct particle-fluid reaction. At low sulfide concentration, quantitative kinetic analysis suggests a mechanistic switch to an oxidative dissolution/precipitation mechanism, in which the biologically active Ag+ ion is generated as an intermediate. The environmental transformation pathways for nanosilver will vary depending on the media-specific competing rates of oxidative dissolution and direct oxysulfidation. PMID:21770469

  9. Speed Of Screen Film Systems According To Temperature

    NASA Astrophysics Data System (ADS)

    Bollen, Romain

    1984-06-01

    The speed of radiographic screen film systems may strongly vary according to the ambient temperature. Temperature dependence of the conversion efficiency of the phosphors of the screen is hereby a major parameter. Data are presented for several commercial screen film systems. The phenomenon is of ter overlooked in normalisation sheets for sensitometric characteristics evaluation.

  10. [First results of mammography with a screen film (author's transl)].

    PubMed

    Paterok, E M; Säbel, M; Weishaar, J

    1979-01-01

    In order to find a convenient, "dose sparing" mammography method, 152 breasts were examined comparatively with a conventional film without intensifying screens (Definix Medical of Kodak) and with a screen film (screen: MR 50, film: Mammoray RP 3 PE FW of Agfa Gevaert). The quality of the low-dose pictures was generally satisfactory. With regard to the exposure to radiation of the breast which is considerably lower if a screen film is used, it seems necessary to develop an automatic exposure control for this method, to further ameliorate films and screens, and to optimize the technical conditions for mammography. The authors underline the possibility to use simultaneously the oblique exposure methods, which would be a further step towards a reduction of the dose. PMID:760273

  11. Reduction of iron-silicon-oxysulfide by CO gas injection

    SciTech Connect

    Tamura, M.; Tokunaga, T.

    1999-10-01

    The reduction of liquid oxysulfide in the Fe-Si-S-O system by CO gas injection has been studied by monitoring the exit gas composition. The reduction rate of oxygen was calculated from the volume of evolved CO{sub 2}. Sulfur-bearing species such as COS were close to the detection limit of the mass spectrometer, which indicated that the reduction of sulfur was very limited. The volume of evolved CO{sub 2} reached steady values 1 minute after CO injection. The reduction reaction was controlled by a chemical reaction. The observed maximum reduction rate of oxygen at 1,250 C was 8.3 x 10{sup {minus}6} g-O/cm{sup 2} s, which was within the range of the reduction rates in other melts such as iron oxide and iron silicates.

  12. Zinc oxysulfide ternary alloy nanocrystals: A bandgap modulated photocatalyst

    SciTech Connect

    Pandey, Shiv K.; Pandey, Shipra; Pandey, Avinash C.; Mehrotra, G. K.

    2013-06-10

    Herein, we report a green economic route for the synthesis of a series of Zinc Oxysulfide (ZOS) (ZnO{sub 1-x}S{sub x}; 0 {<=} x {>=} 1; x = Sulfur) alloys nanoparticles. The crystallographic features of ZnO, ZOS, and ZnS confirmed by X-Ray Diffraction and validated by Transmission Electron Microscopy reveal the variation of lattice spacing in binary and ternary compositions with homogenous elemental distribution. The photocatalytic analysis of ZOS (0.4) is performed and compared with Degussa P25 to ascertain its photocatalytic activity against methyl orange under irradiation of 365 nm UV-Vis light. A bandgap of 2.7 eV for ZOS (0.4) aptly establishes its prospects for sunlight driven photocatalysis.

  13. Molten iron oxysulfide as a superior sulfur sorbent

    SciTech Connect

    Hepworth, M.T.

    1991-01-01

    Slagging combustors with injected lime or limestone are being considered as replacements for conventional coal burners. They have advantages in that they can be staged to reduce NO{sub x} and So{sub x} emissions. Iron oxide, as an alternative to lime or limestone may be effective not only as a desulfurizing agent, but under the right conditions of oxygen potential and after combination with sulfur, the reaction products of coal gases with iron oxide can act as a flux to produce a fluid phase. The thermodynamic conditions for optimum removal of sulfur from the first stage of a coal combustor are being determined by experiment and by use of existing data. Contour plots in which the pounds Of S0{sub 2} per million Btu of calorific power are plotted on isothermal ternary phase diagrams of the iron-oxygen-sulfur system. These contour plots determine the most favorable conditions for coal combustion in the presence of added iron oxide. Lowest S0{sub 2} pressures are close to the phase boundary limit between iron saturation and the oxysulfide liquid phase. Experimental studies in which ceramic containers (99% alumina) were used to contain the liquid were hampered by the tendency for the liquid to flow up and over the walls of containing vessels presumably as a result of surface tension effects. These effects, which make equilibration measurements difficult, may be favorable with respect to producing a high degree of reactivity of the oxysulfide with coal gases and resultant rapid reaction kinetics. As result of this problem, platinum containment vessels containers appear to avoid these surface tension effects. Thermodynamic and kinetic measurements are now being explored by thermogravimetric analysis.

  14. Optimal x-ray spectra for screen-film mammography.

    PubMed

    Jennings, R J; Eastgate, R J; Siedband, M P; Ergun, D L

    1981-01-01

    Theoretical and experimental techniques have been used to study optimal x-ray for screen-film mammography. A simple model of mammographic imaging predicts optimum x-ray energies which are significantly higher than the K-characteristic energies of Mo. A subjective comparison of x-ray spectra from Mo-anode and W-anode tubes indicates that spectra produced by a W-anode tube filtered with materials of atomic number just above that of Mo are more suitable for screen-film mammography than spectra produced by the Mo-anode/Mo-filter system. The imaging performance of K-edge filtered, W-anode tube spectra was compared to the performance of Mo-anode spectra using phantom measurements and mastectomy specimen radiography. It was shown that optimal W-anode spectra can produce equal contrast with an exposure reduction of a factor of two to three, a dose reduction of a factor of two, and equal or reducing tube loading, compared to Mo-anode spectra. A computer simulation was carried out to extend the initial, monoenergetic theory to the case of real, polychromatic sources. The effects of varying filter material and thickness, tube operating potential, and breast thickness were all studied. Since W-anode x-ray tubes are considered to be better for Xerox mammography than Mo-anode tubes, this study has shown that both Xerox and screen-film techniques can be performed optimally with a single, properly designed, W-anode x-ray tube. PMID:7290015

  15. The BiCu1-xOS oxysulfide: Copper deficiency and electronic properties

    NASA Astrophysics Data System (ADS)

    Berthebaud, D.; Guilmeau, E.; Lebedev, O. I.; Maignan, A.; Gamon, J.; Barboux, P.

    2016-05-01

    An oxysulfide series of nominal compositions BiCu1-xOS with x<0.20 has been prepared and its structural properties characterized by combining powder X-ray diffraction and transmission electron microscopy techniques. It is found that this oxysulfide, crystallizing in the P4/nmm space group, tends to adopt a constant amount of copper vacancy corresponding to x=0.05 in the BiCu1-xOS formula. The presence of Cu vacancies is confirmed by HAADF-STEM analysis showing, in the Cu atomic columns, alternating peaks of different intensities in some very localized regions. For larger Cu deficiencies (x>0.05 in the nominal composition), other types of structural nanodefects are evidenced such as bismuth oxysulfides of the "BiOS" ternary system which might explain the report of superconductivity for the BiCu1-xOS oxysulfide. Local epitaxial growth of the BiCuOS oxysulfide on top of CuO is also observed. In marked contrast to the BiCu1-xOSe oxyselenide, these results give an explanation to the limited impact of Cu deficiency on the Seebeck coefficient in BiCu1-xOS compounds.

  16. [Comparison of screens and screen-film-systems (author's transl)].

    PubMed

    Maurer, H J; Goos, F

    1979-06-01

    Important details are to be payed attention in comparison of different scrreens resp. screen-film-systems: 1. Physical characteristics of different groups of luminescent materials: f.i. calcium tung-state, rare-earths compounds, double halogenides. - 2. Different types of screens: highest details up to highest speed intensifying screens, have to be defined more specifically and differentiated against to each other too. - 3. Besides intensification, resolution has to be included into consideration since one of these dates alone does not allow any statement on the total function of a screen or a screen-film-system. - 4. The technical methodological conditions of apparatuses, object and its positioning have to be defined, f.i. X-ray quality, distances, grid, and in automatically controlled exposition, if necessary, position of ionization chamber as well as absorption of cassetts and screen. - 5. Considering these points gradation curves have to include the whole necessary or interesting diagnostic range. - 6. Due to functional correlation between intensification and resolution, the resolution has to be taken in consideration due to application; its interdependence of density and object (f.i. scattered radiation) is often not taken enough in consideration. PMID:461776

  17. Computer Simulation Of Radiographic Screen-Film Images

    NASA Astrophysics Data System (ADS)

    Metter, Richard V.; Dillon, Peter L.; Huff, Kenneth E.; Rabbani, Majid

    1986-06-01

    A method is described for computer simulation of radiographic screen-film images. This method is based on a previously published model of the screen-film imaging process.l The x-ray transmittance of a test object is sampled at a pitch of 50 μm by scanning a high-resolution, low-noise direct-exposure radiograph. This transmittance is then used, along with the x-ray exposure incident upon the object, to determine the expected number of quanta per pixel incident upon the screen. The random nature of x-ray arrival and absorption, x-ray quantum to light photon conversion, and photon absorption by the film is simulated by appropriate random number generation. Standard FFT techniques are used for computing the effects of scattering. Finally, the computed film density for each pixel is produced on a high-resolution, low-noise output film by a scanning printer. The simulation allows independent specification of x-ray exposure, x-ray quantum absorption, light conversion statistics, light scattering, and film characteristics (sensitometry and gran-ularity). Each of these parameters is independently measured for radiographic systems of interest. The simulator is tested by comparing actual radiographic images with simulated images resulting from the independently measured parameters. Images are also shown illustrating the effects of changes in these parameters on image quality. Finally, comparison is made with a "perfect" imaging system where information content is only limited by the finite number of x-rays.

  18. Quantitative study on the chemical solution deposition of zinc oxysulfide

    DOE PAGESBeta

    Reinisch, Michael; Perkins, Craig L.; Steirer, K. Xerxes

    2015-11-21

    Zinc Oxysulfide (ZnOS) has demonstrated potential in the last decade to replace CdS as a buffer layer material since it is a wide-band-gap semiconductor with performance advantages over CdS (Eg = 2.4 eV) in the near UV-range for solar energy conversion. However, questions remain on the growth mechanisms of chemical bath deposited ZnOS. In this study, a detailed model is employed to calculate solubility diagrams that describe simple conditions for complex speciation control using only ammonium hydroxide without additional base. For these conditions, ZnOS is deposited via aqueous solution deposition on a quartz crystal microbalance in a continuous flow cell.more » Data is used to analyze the growth rate dependence on temperature and also to elucidate the effects of dimethylsulfoxide (DMSO) when used as a co-solvent. Activation energies (EA) of ZnOS are calculated for different flow rates and solution compositions. As a result, the measured EA relationships are affected by changes in the primary growth mechanism when DMSO is included.« less

  19. Quantitative study on the chemical solution deposition of zinc oxysulfide

    SciTech Connect

    Reinisch, Michael; Perkins, Craig L.; Steirer, K. Xerxes

    2015-11-21

    Zinc Oxysulfide (ZnOS) has demonstrated potential in the last decade to replace CdS as a buffer layer material since it is a wide-band-gap semiconductor with performance advantages over CdS (Eg = 2.4 eV) in the near UV-range for solar energy conversion. However, questions remain on the growth mechanisms of chemical bath deposited ZnOS. In this study, a detailed model is employed to calculate solubility diagrams that describe simple conditions for complex speciation control using only ammonium hydroxide without additional base. For these conditions, ZnOS is deposited via aqueous solution deposition on a quartz crystal microbalance in a continuous flow cell. Data is used to analyze the growth rate dependence on temperature and also to elucidate the effects of dimethylsulfoxide (DMSO) when used as a co-solvent. Activation energies (EA) of ZnOS are calculated for different flow rates and solution compositions. As a result, the measured EA relationships are affected by changes in the primary growth mechanism when DMSO is included.

  20. Comparison with industrial oxysulfide phosphors for solid state lighting

    NASA Astrophysics Data System (ADS)

    Pote, S. S.

    2016-05-01

    Y2O2S:Eu3+ was prepared by the flux method which is different from conventional solid state reaction and has many advantages over the conventional method in terms of ease of preparation and yield also. In this paper we have reported the crystal structure, XRD and method of preparation of Y2O2S:Eu3+ along with Eu3+ mechanism of emission and excitation with reference to solid state lighting. In the emission spectra, the strongest red-emission lines at 626 and 616 nm are due to transition from 5D0 → 7F2 level. The stronger emission at λem=626 nm confirms the formation of the oxysulfide host. We also made a comparison of our prepared sample with commercial sample from NICHIA Corporation Japan in terms of PL intensity which results that our sample is equally intense as that of NICHIA's sample. It is suggested that these characteristics can be useful for obtaining a low cost, red phosphor for the solid state lighting using near UV LED.

  1. Molten metal containment vessel with rare earth oxysulfide protective coating thereon and method of making same

    DOEpatents

    Krikorian, Oscar H.; Curtis, Paul G.

    1992-01-01

    An improved molten metal containment vessel is disclosed in which wetting of the vessel's inner wall surfaces by molten metal is inhibited by coating at least the inner surfaces of the containment vessel with one or more rare earth oxysulfide or rare earth sulfide compounds to inhibit wetting and or adherence by the molten metal to the surfaces of the containment vessel.

  2. Gadolinium photoionization process

    DOEpatents

    Paisner, J.A.; Comaskey, B.J.; Haynam, C.A.; Eggert, J.H.

    1993-04-13

    A method is provided for selective photoionization of the odd-numbered atomic mass gadolinium isotopes 155 and 157. The selective photoionization is accomplished by circular or linear parallel polarized laser beam energy effecting a three-step photoionization pathway.

  3. Gadolinium photoionization process

    DOEpatents

    Paisner, Jeffrey A.; Comaskey, Brian J.; Haynam, Christopher A.; Eggert, Jon H.

    1993-01-01

    A method is provided for selective photoionization of the odd-numbered atomic mass gadolinium isotopes 155 and 157. The selective photoionization is accomplished by circular or linear parallel polarized laser beam energy effecting a three-step photoionization pathway.

  4. Molten iron oxysulfide as a superior sulfur sorbent. Final report, [September 1989--1993

    SciTech Connect

    Hepworth, M.T.

    1993-03-31

    The studies had as original objective the analysis of conditions for using liquid iron oxysulfide as a desulfuring agent during coal gasification. Ancillary was a comparison of iron oxysulfide with lime as sorbents under conditions where lime reacts with S-bearing gases to form Ca sulfate or sulfide. Primary thrust is to determine the thermodynamic requirements for desulfurization by iron additions (e.g., taconite concentrate) during combustion in gasifiers operating at high equivalence ratios. Thermodynamic analysis of lime-oxygen-sulfur system shows why lime is injected into burners under oxidizing conditions; reducing conditions forms CaS, requiring its removal, otherwise oxidation and release of S would occur. Iron as the oxysulfide liquid has a range of stability and can be used as a desulfurizing agent, if the burner/gasifier operates in a sufficiently reducing regime (high equivalence ratio); this operating range is given and is calculable for a coal composition, temperature, stoichiometry. High moisture or hydrogen contents of the coal yield a poorer degree of desulfurization. Kinetic tests on individual iron oxide particles on substrates or Pt cups with a TGA apparatus fail to predict reaction rates within a burner. Preliminary tests on the Dynamic Containment Burner with acetylene give some promise that this system can produce the proper conditions of coal gasification for use of added iron as a sulfur sorbent.

  5. Performance characteristics of asymmetric zero-crossover screen-film systems

    NASA Astrophysics Data System (ADS)

    Bunch, Phillip C.

    1992-05-01

    The development of specialized dyes that essentially prevent light from crossing the film base in duplitized screen-film systems has made it possible to design screen-film combinations with unusual performance characteristics. Specifically, by combining front and back screens with differing light emission and resolution properties with asymmetric films with differing front and back sensitometric characteristics, it is now possible to design screen-film systems that have some or all of the following features: (1) density-dependent image blur, (2) previously impractical sensitometric curve shapes, and (3) screen-dependent system contrast. Performance characteristics of two specific systems are summarized, including sensitometric data, contrast transfer functions, noise equivalent quanta, and detective quantum efficiency. Initial clinical applications of this technology are also described, with an emphasis on thoracic radiography.

  6. [Sensitometry of Mammographic Screen-film System Using Bootstrap Aluminum Step-Wedge.].

    PubMed

    Abe, Shinji; Imada, Ryou; Terauchi, Takashi; Fujisaki, Tatsuya; Monma, Masahiko; Nishimura, Katsuyuki; Saitoh, Hidetoshi; Mochizuki, Yasuo

    2005-01-01

    Recently, a few types of step-wedges for bootstrap sensitometry with a mammographic screen-film system have been proposed. In this study, the bootstrap sensitometry with the mammographic screen-film system was studied for two types of aluminum step-wedges. Characteristic X-ray energy curves were determined using mammographic and general radiographic aluminum step-wedges devised to prevent scattered X-rays generated from one step penetrating into the region of another one, and dependence of the characteristic curves on the wedges was also discussed. No difference was found in the characteristic curves due to the difference in the step-wedges for mammography and general radiography although there was a slight difference in shape at the shoulder portion for the two types of step-wedges. Therefore, it was concluded that aluminum step-wedges for mammography and general radiography could be employed in bootstrap sensitometry with the mammographic screen-film system. PMID:16479054

  7. Quality Imaging - Comparison of CR Mammography with Screen-Film Mammography

    SciTech Connect

    Gaona, E.; Azorin Nieto, J.; Iran Diaz Gongora, J. A.; Arreola, M.; Casian Castellanos, G.; Perdigon Castaneda, G. M.; Franco Enriquez, J. G.

    2006-09-08

    The aim of this work is a quality imaging comparison of CR mammography images printed to film by a laser printer with screen-film mammography. A Giotto and Elscintec dedicated mammography units with fully automatic exposure and a nominal large focal spot size of 0.3 mm were used for the image acquisition of phantoms in screen-film mammography. Four CR mammography units from two different manufacturers and three dedicated x-ray mammography units with fully automatic exposure and a nominal large focal spot size of 0.3 mm were used for the image acquisition of phantoms in CR mammography. The tests quality image included an assessment of system resolution, scoring phantom images, Artifacts, mean optical density and density difference (contrast). In this study, screen-film mammography with a quality control program offers a significantly greater level of quality image relative to CR mammography images printed on film.

  8. Gadolinium-Induced Fibrosis.

    PubMed

    Todd, Derrick J; Kay, Jonathan

    2016-01-01

    Gadolinium-based contrast agents (GBCAs), once believed to be safe for patients with renal disease, have been strongly associated with nephrogenic systemic fibrosis (NSF), a severe systemic fibrosing disorder that predominantly afflicts individuals with advanced renal dysfunction. We provide a historical perspective on the appearance and disappearance of NSF, including its initial recognition as a discrete clinical entity, its association with GBCA exposure, and the data supporting a causative relationship between GBCA exposure and NSF. On the basis of this body of evidence, we propose that the name gadolinium-induced fibrosis (GIF) more accurately reflects the totality of knowledge regarding this disease. Use of high-risk GBCAs, such as formulated gadodiamide, should be avoided in patients with renal disease. Restriction of GBCA use in this population has almost completely eradicated new cases of this debilitating condition. Emerging antifibrotic therapies may be useful for patients who suffer from GIF. PMID:26768242

  9. Diagnostic quality versus patient exposure with five panoramic screen-film combinations

    SciTech Connect

    D'Ambrosio, J.A.; Schiff, T.G.; McDavid, W.D.; Langland, O.E.

    1986-04-01

    Five film-screen combinations were used to make five density-matched panoramic radiographs of a tissue-equivalent phantom skull using the Midwest/Morita Panoral x-ray machine. The radiographs were evaluated as to their diagnostic quality by twenty dental radiologists. The results demonstrate that proper screen-film selection can significantly reduce patient exposure without compromising diagnostic quality.

  10. Threshold perception performance with computed and screen-film radiography: implications for chest radiography.

    PubMed

    Dobbins, J T; Rice, J J; Beam, C A; Ravin, C E

    1992-04-01

    Images of a phantom obtained with computed radiography and standard screen-film imaging were compared to evaluate observer threshold perception performance with a modified contrast-detail technique. Optimum exposure necessary for performance with the imaging plate technique to match that with screen-film techniques was determined, as was comparative performance with variation in kilovoltages, plate type, spatial enhancement, and hard-copy interpolation method. It was found that computed radiography necessitates about 75%-100% more exposure than screen-film radiography to optimally match performance with Ortho-C film with Lanex regular or medium screens (Eastman Kodak, Rochester, NY) for detection of objects 0.05-2.0 cm in diameter. However, only minimal loss of detection performance (approximately 10% overall) was experienced if standard screen-film exposures were used with computed radiography. Little change in observer performance was found with variation in plate type, spatial enhancement, or method of hard-copy interpolation. However, perception performance with computed radiographic images was better at lower kilovoltages. PMID:1549669

  11. Clinical comparison of CR and screen film for imaging the critically ill neonate

    NASA Astrophysics Data System (ADS)

    Andriole, Katherine P.; Brasch, Robert C.; Gooding, Charles A.; Gould, Robert G.; Cohen, Pierre A.; Rencken, Ingo R.; Huang, H. K.

    1996-05-01

    A clinical comparison of computed radiography (CR) versus screen-film for imaging the critically-ill neonate is performed, utilizing a modified (hybrid) film cassette containing a CR (standard ST-V) imaging plate, a conventional screen and film, allowing simultaneous acquisition of perfectly matched CR and plain film images. For 100 portable neonatal chest and abdominal projection radiographs, plain film was subjectively compared to CR hardcopy. Three pediatric radiologists graded overall image quality on a scale of one (poor) to five (excellent), as well as visualization of various anatomic structures (i.e., lung parenchyma, pulmonary vasculature, tubes/lines) and pathological findings (i.e., pulmonary interstitial emphysema, pleural effusion, pneumothorax). Results analyzed using a combined kappa statistic of the differences between scores from each matched set, combined over the three readers showed no statistically significant difference in overall image quality between screen- film and CR (p equals 0.19). Similarly, no statistically significant difference was seen between screen-film and CR for anatomic structure visualization and for visualization of pathological findings. These results indicate that the image quality of CR is comparable to plain film, and that CR may be a suitable alternative to screen-film imaging for portable neonatal chest and abdominal examinations.

  12. A primer on gadolinium chemistry

    PubMed Central

    Sherry, A. Dean; Caravan, Peter; Lenkinski, Robert E.

    2010-01-01

    Gadolinium is widely known by all practitioners of MRI but few appreciate the basic solution chemistry of this trivalent lanthanide ion. Given the recent linkage between gadolinium contrast agents and nephrogenic systemic fibrosis, some basic chemistry of this ion must be more widely understood. This short primer on gadolinium chemistry is intended to provide the reader the background principles necessary to understand the basics of chelation chemistry, water hydration numbers, and the differences between thermodynamic stability and kinetic stability or inertness. We illustrate the fundamental importance of kinetic dissociation rates in determining gadolinium toxicity in vivo by presenting new data for a novel europium DOTA-tetraamide complex that is relatively unstable thermodynamically yet extraordinarily inert kinetically and also quite non-toxic. This, plus other literature evidence forms the basis of the fundamental axiom that it is the kinetic stability of a gadolinium complex, not its thermodynamic stability, that determines its in vivo toxicity. PMID:19938036

  13. Exposure factors and screen-film combinations in temporomandibular joint radiography.

    PubMed

    Thorburn, D N; Stockdill, D A; Kenyon, R P; Cowan, I; Ferguson, M M

    1991-05-01

    Exposure factors and screen-film combinations providing optimal quality are identified for transcranial and transpharyngeal temporomandibular joint views, using conventional intra-oral radiographic equipment without grids. Standardized transcranial and transpharyngeal views, using a fixed whole cadaver head, were performed. Ten readily available screen-film combinations, ranging in nominal speed 20-600, were exposed over 40-100 kV. Films were blindly and independently order ranked by three observers on the basis of sharpness and contrast of cortical outline, trabecular detail, and visualization of adjacent bony structures. Preferred screen-film combinations as a function of kV, preferred kV levels for each screen-film combination, and overall ranking irrespective of kV or screen-film combination, were established. Accepting the use of the lowest radiation dose possible for diagnostically useful radiographs but imposing arbitrarily an upper limit of 20 mGy, it was found that exposures between 50 kV and 70 kV gave the optimal result for both techniques. The amount of scattered radiation in the emergent beam differs greatly between the two techniques. The most favoured combinations for the transpharyngeal technique used screens of fine resolution. Min-r/ortho M screen and film with nominal speed 40 at 60 kV gave 8.0 mGy skin dosage at 0.8 seconds exposure; the same combination at 50 kV was the most favoured, but with skin dosage calculated at 16.7 mGy for 3.0 seconds exposure. For the transcranial technique, medium speed screens providing better differentiation of scattered radiation beams and increased speeds were preferred. Most favoured for image quality was the Lanex Fine/T-Mat G combination at 60 kV giving 17.5 mGy skin radiation dose at 1.75 seconds exposure.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1936423

  14. Comparison of two detail screen-film systems using a rheumatoid erosion model.

    PubMed

    De Smet, A A; Goin, J E; Arnett, G R; Chang, C H; Martin, N L; Rosenthal, S J

    1983-01-01

    Two detail screen-film systems, Lanex Fine/Ortho M and Lanex Fine/Ortho G, were evaluated using a radiographic model for rheumatoid erosions. Radiographs of hand bones with cortical defects using both screen-film systems were obtained. Seven observers analyzed 48 sites on each of 22 films for the presence of these cortical defects. Using analysis of variance techniques and receiver operating characteristic curves, no significant difference was found between the two systems for the detection of these subtle cortical defects. The authors conclude that although the Lanex Fine/Ortho M system provides better definition of laboratory test objects than Lanex Fine/Ortho G, the two systems do not differ when used for detection of cortical lesions. PMID:6618826

  15. Image quality and breast dose of 24 screen-film combinations for mammography.

    PubMed

    Dimakopoulou, A D; Tsalafoutas, I A; Georgiou, E K; Yakoumakis, E N

    2006-02-01

    In this study the effect of different mammographic screen-film combinations on image quality and breast dose, and the correlation between the various image quality parameters, breast dose and the sensitometric parameters of a film were investigated. Three Agfa (MR5-II, HDR, HT), two Kodak (Min-R M, Min-R 2000), one Fuji (AD-M), one Konica (CM-H) and one Ferrania (HM plus) single emulsion mammographic films were combined with three intensifying screens (Agfa HDS, Kodak Min-R 2190 and Fuji AD-MA). The film characteristics were determined by sensitometry, while the image quality and the dose to the breast of the resulting 24 screen-film combinations were assessed using a mammography quality control phantom. For each combination, three images of the phantom were acquired with optical density within three different ranges. Two observers assessed the quality of the 72 phantom images obtained, while the breast dose was calculated from the exposure data required for each image. Large differences among screen-film combinations in terms of image quality and breast dose were identified however, that, could not be correlated with the film's sensitometric characteristics. All films presented the best resolution when combined with the HDS screen at the expense of speed, and the largest speed when combined with the AD-MA screen, without degradation of the overall image quality. However, an ideal screen-film combination presenting the best image quality with the least dose was not identified. It is also worth mentioning that the best performance for a film was not necessarily obtained when this was combined with the screen provided by the same manufacturer. The results of this study clearly demonstrate that comparison of films based on their sensitometric characteristics are of limited value for clinical practice, as their performance is strongly affected by the screens with which they are combined. PMID:16489193

  16. Comparison Of Methods Used To Measure The Characteristic Curve Of Radiographic Screen/Film Systems

    NASA Astrophysics Data System (ADS)

    Wagner, Louis K.; Haus, Arthur G.; Barnes, Gary T.; Bencomo, Jose A.; Amtey, Sharad R.

    1980-08-01

    A systematic study was performed to investigate the accuracy and precision attained by four methods for determining the characteristic curve of radiographic screen/film systems. The four methods include: inverse square sensitometry, KVP adjusted bootstrap sensitometry step-wedge bootstrap sensitometry, and step wedge attenuation sensitometry. The inverse square method was used as the reference standard for accuracy. The extent of and the sources of the inaccurcies involved when using the alternative methods is discussed.

  17. A comparison of the performance of new screen-film and digital mammography systems

    NASA Astrophysics Data System (ADS)

    Monnin, P.; Gutierrez, D.; Castella, C.; Lepori, D.; Verdun, F. R.

    2006-03-01

    This work compares the detector performances of the recent Kodak Min-R EV 190/Min-R EV and current Kodak Min-R 2190/Min-R 2000 mammography screen-film combinations with the Kodak CR 850M system using the new EHR-M and standard HR plates. Basic image quality parameters (MTF, NNPS and DQE) were evaluated according to ISO 9236-3 conditions (i.e. 28 kV; Mo/Mo; HVL = 0.64 mm eq. Al) at an entrance air kerma level of 60 μGy. Compared with the Min-R 2000, the Kodak Min-R EV screen-film system has a higher contrast and an intrinsically lower noise level, leading to a better DQE. Due to a lower noise level, the new EHR-M plate improves the DQE of the CR system, in comparison with the use of the standard HR plate (30 % improvement) in a mammography cassette. Compared with the CR plates, screen-film systems still permit to resolve finer details and have a significantly higher DQE for all spatial frequencies.

  18. Preparation of Highly Crystallized Yttrium Oxysulfide Suspension via a Novel Colloidal Processing.

    PubMed

    Wang, Hong; Jiang, Tao; Xing, Ming-Ming; Fu, Yao; Peng, Yong; Luo, Xi-Xian

    2016-04-01

    High-crystallized Y2O2S suspension was synthesized by a novel two-step method of high temperature solid-state reaction and subsequent colloidal processing. The synthesis method proposed in this study retains all advantages of the high temperature solid-state reaction method. The obtained data agrees with that of the PDF card, which indicates the product is pure Y2O2S crystals. The results show that the prepared Y2O2S particles are highly crystallized without any significant defects. The fine smooth particles were almost regular, exhibiting an approximately subspherical shape. Quantitative image analysis of particles suggests a mean particle size of 120±34 nm. That is to say, the yttrium oxysulfide colloid prepared by this method have a very narrow size distribution. The obtained ethanol suspension shows Tyndall effect when irradiated with laser of wavelength 532 nm. In addition, the particles exhibit excellent dispersibility in ethanol solution. This is rarely observed for the covalent compounds, which generally present poor dispersibility in solution. As is known to all, the state of the dispersion depends on the acid leaching process. The acid leaching process facilitates the adsorption of ethanol molecules on the surface of the particles. The electrostatic repulsive force among colloidal particles will improve their rheological properties and dispersibility in solution. In this study, the particles can be dispersed well in ethanol after acid leaching. The method'proposed in this study can be extended for the preparation of mono-dispersed oxysulfide nanophosphors and may provide an efficient way for the preparation of stable covalent compound dispersions. PMID:27451744

  19. Bandgap engineering of colloidal zinc oxysulfide via lattice substitution with sulfur

    NASA Astrophysics Data System (ADS)

    Pandey, Shiv K.; Pandey, Shipra; Parashar, Vyom; Yadav, Raghvendra S.; Mehrotra, G. K.; Pandey, Avinash C.

    2014-01-01

    Zinc oxysulfide nanocrystals with zinc blende phase are synthesized through a wet-chemical method. An affirmation of the crystal structure, elemental homogeneity and phase transformation is obtained by X-ray diffraction and authenticated by electron micrographic studies. Theoretical observations have strongly supported the thermodynamic solubility limit for its (30%) formation. An anomalous bandgap bowing with modulation in bandgap from 3.74 eV (ZnO) to 3.93 eV (ZnS) was observed with a minimum bandgap of 2.7 eV. Tunable bandgap and a wide range of visible emission ascertain it as a potential material for optoelectronic and solar cell applications due to its large bandgap offsets.Zinc oxysulfide nanocrystals with zinc blende phase are synthesized through a wet-chemical method. An affirmation of the crystal structure, elemental homogeneity and phase transformation is obtained by X-ray diffraction and authenticated by electron micrographic studies. Theoretical observations have strongly supported the thermodynamic solubility limit for its (30%) formation. An anomalous bandgap bowing with modulation in bandgap from 3.74 eV (ZnO) to 3.93 eV (ZnS) was observed with a minimum bandgap of 2.7 eV. Tunable bandgap and a wide range of visible emission ascertain it as a potential material for optoelectronic and solar cell applications due to its large bandgap offsets. Electronic supplementary information (ESI) available: Experimental procedure, characterization techniques, lattice strain, XPS, TEM/HRTEM, HRSEM, EDAX, bandgap and bowing parameters calculation and PL study for whole composition. See DOI: 10.1039/c3nr04457b

  20. Laserspektroskopie Gadoliniums Fingerabdruck

    SciTech Connect

    Blaum, Klaus; Bushaw, Bruce A.; Nortershauser, Wilfried

    2003-05-31

    The minimum energy that is required to remove the first electron from e neutral atom, one call ionization energy E1. It is not only for every element of the periodic table but also even for every nuclide characteristic and therefore belongs to the most basic atomic properties. The ionization energy is important for the determination of a ‘row’ of properties, from the chemical reactivity to the color light absorbed and emitted from an atom. The value of E1 depends on the stationary state that the farthest electron originally occupies. If the electron finds itself, however, in the first excited stat, only 3.4 eV is required. Previously the ionization energy could be determined with high accuracy in the range of 10-8 by means of laser spectroscopy only for atoms with one or two valence electrons, whereby the most accurate to date result from measurements on Hydrogen. We could now, for the first time in a rare earth element, reach that kind of accuracy. Motivation for these investigations was the development of an analysis method for the ultra-trace detection of Gadolinium in tissue- and meteorite samples.

  1. Solution preparation of the amorphous molybdenum oxysulfide MoOS{sub 2} and its use for catalysis

    SciTech Connect

    Genuit, Daisy; Bezverkhyy, Igor; Afanasiev, Pavel . E-mail: afanas@catalyse.univ-lyon1.fr

    2005-09-15

    Acid condensation of aqueous MoO{sub 2}S{sub 2} {sup 2-} anion yields amorphous MoOS{sub 2} oxysulfide. This compound possesses tubular morphology and when freshly precipitated is soluble in polar organics such as acetone and ethanol. The ensemble of characterizations (IR, UV-visible, EXAFS spectroscopy) suggests that it contains cyclic or short linear oligomers of neutral molybdenum (V) oxysulfide MoOS{sub 2} core. Thermal decomposition of MoOS{sub 2} under inert atmosphere leads to the formation of a mixture of MoO{sub 2} and MoS{sub 2} phases. Promotion of MoOS{sub 2} with cobalt followed by sulfidation leads to highly active HDS catalysts.

  2. Technology assessment: observer study directly compares screen/film to CR mammography

    NASA Astrophysics Data System (ADS)

    Fletcher-Heath, Lynn; Richards, Anne; Ryan-Kron, Susan

    2007-03-01

    A new study supports and expands upon a previous reporting that computed radiography (CR) mammography offers as good, or better, image quality than state-of-the-art screen/film mammography. The suitability of CR mammography is explored through qualitative and quantitative study components: feature comparison and cancer detection rates of each modality. Images were collected from 150 normal and 50 biopsy-confirmed subjects representing a range of breast and pathology types. Comparison views were collected without releasing compression, using automatic exposure control on Kodak MIN-R films, followed by CR. Digital images were displayed as both softcopy (S/C) and hardcopy (H/C) for the feature comparison, and S/C for the cancer detection task. The qualitative assessment used preference scores from five board-certified radiologists obtained while viewing 100 screen/film-CR pairs from the cancer subjects for S/C and H/C CR output. Fifteen general image-quality features were rated, and up to 12 additional features were rated for each pair, based on the pathology present. Results demonstrate that CR is equivalent or preferred to conventional mammography for overall image quality (89% S/C, 95% H/C), image contrast (95% S/C, 98% H/C), sharpness (86% S/C, 93% H/C), and noise (94% S/C, 91% H/C). The quantitative objective was satisfied by asking 10 board-certified radiologists to provide a BI-RADS TM score and probability of malignancy per breast for each modality of the 200 cases. At least 28 days passed between observations of the same case. Average sensitivity and specificity was 0.89 and 0.82 for CR and 0.91 and 0.82 for screen/film, respectively.

  3. An examination of errors in characteristic curve measurements of radiographic screen/film systems.

    PubMed

    Wagner, L K; Barnes, G T; Bencomo, J A; Haus, A G

    1983-01-01

    The precision and accuracy achieved in the measurement of characteristic curves for radiographic screen/film systems is quantitatively investigated for three techniques: inverse square, kVp bootstrap, and step-wedge bootstrap. Precision of all techniques is generally better than +/- 1.5% while the agreement among all intensity-scale techniques is better than 2% over the useful exposure latitude. However, the accuracy of the sensitometry will depend on several factors, including linearity and energy dependence of the calibration instrument, that may introduce larger errors. Comparisons of time-scale and intensity-scale methods are made and a means of measuring reciprocity law failure is demonstrated. PMID:6877185

  4. Thermodynamic properties of gadolinium disilicide

    SciTech Connect

    Lukashenko, G.M.; Polotskaya, R.I.

    1986-11-01

    The authors determine the Gibbs energy, enthalpy, formation heat, and other thermodynamic properties of gadolinium disilicide by measuring the electromotive force in the 830-960 K temperature range in electrolytes consisting of molten tin and various chlorides. The relationship of these properties to crystal structure is briefly discussed.

  5. Determination of radiotherapy X-ray spectra using a screen-film system.

    PubMed

    Garnica-Garza, H M

    2008-10-01

    A method to determine the X-ray spectrum delivered by a medical linear accelerator is presented. This method consists of an analytical calculation of the primary spectrum using the Schiff bremsstrahlung cross-section formula. A correction factor that accounts for the scatter component of the spectrum is estimated by comparing the signal in two screen-film systems to a theoretical prediction using a model of energy deposition in such detectors. The model makes use of the quantum absorption efficiency and the average energy deposited per interacting photon concepts. These two quantities are calculated by means of Monte Carlo simulations of the screen-film systems used. This method is capable of determining the spectrum as a function of the spatial position across a plane perpendicular to the beam central axis. It does not, however, render information about the direction cosines of the X-ray fluence crossing such a plane, a requirement in order to produce a full phase-space file that can be used in conjunction with a Monte Carlo dose calculation engine. PMID:18779986

  6. Silicon Oxysulfide, OSiS: Rotational Spectrum, Quantum-Chemical Calculations, and Equilibrium Structure.

    PubMed

    Thorwirth, Sven; Mück, Leonie Anna; Gauss, Jürgen; Tamassia, Filippo; Lattanzi, Valerio; McCarthy, Michael C

    2011-06-01

    Silicon oxysulfide, OSiS, and seven of its minor isotopic species have been characterized for the first time in the gas phase at high spectral resolution by means of Fourier transform microwave spectroscopy. The equilibrium structure of OSiS has been determined from the experimental data using calculated vibration-rotation interaction constants. The structural parameters (rO-Si = 1.5064 Å and rSi-S = 1.9133 Å) are in very good agreement with values from high-level quantum chemical calculations using coupled-cluster techniques together with sophisticated additivity and extrapolation schemes. The bond distances in OSiS are very short in comparison with those in SiO and SiS. This unexpected finding is explained by the partial charges calculated for OSiS via a natural population analysis. The results suggest that electrostatic effects rather than multiple bonding are the key factors in determining bonding in this triatomic molecule. The data presented provide the spectroscopic information needed for radio astronomical searches for OSiS. PMID:26295414

  7. Reduction of absorbed dose in radiography of the breast. Experience with a new screen-film combination.

    PubMed

    Andersson, I; Andrén, L; Nilsson, M; Pettersson, C

    1977-03-01

    The mean absorbed dose in radiography of the breast with industrial film (Mamoray T3, Agfa-Gevaert), the Lo-dose system (Du Pont) and a new screen-film combination (MR 50-Mamoray RP 3, Agfa-Gevaert) was determined. The mean values were 17,2 and 1 mGy, respectively. Thus, the absorbed dose was considerably reduced by using the screen-film combination. This is of utmost importance as the potential risk of inducing malignancy is remarkably reduced, probably negligible. PMID:860660

  8. Tumor growth suppression by gadolinium-neutron capture therapy using gadolinium-entrapped liposome as gadolinium delivery agent.

    PubMed

    Dewi, Novriana; Yanagie, Hironobu; Zhu, Haito; Demachi, Kazuyuki; Shinohara, Atsuko; Yokoyama, Kazuhito; Sekino, Masaki; Sakurai, Yuriko; Morishita, Yasuyuki; Iyomoto, Naoko; Nagasaki, Takeshi; Horiguchi, Yukichi; Nagasaki, Yukio; Nakajima, Jun; Ono, Minoru; Kakimi, Kazuhiro; Takahashi, Hiroyuki

    2013-07-01

    Neutron capture therapy (NCT) is a promising non-invasive cancer therapy approach and some recent NCT research has focused on using compounds containing gadolinium as an alternative to currently used boron-10 considering several advantages that gadolinium offers compared to those of boron. In this study, we evaluated gadolinium-entrapped liposome compound as neutron capture therapy agent by in vivo experiment on colon-26 tumor-bearing mice. Gadolinium compound were injected intravenously via tail vein and allowed to accumulate into tumor site. Tumor samples were taken for quantitative analysis by ICP-MS at 2, 12, and 24 h after gadolinium compound injection. Highest gadolinium concentration was observed at about 2 h after gadolinium compound injection with an average of 40.3 μg/g of wet tumor tissue. We performed neutron irradiation at JRR-4 reactor facility of Japan Atomic Energy Research Institute in Tokaimura with average neutron fluence of 2×10¹² n/cm². The experimental results showed that the tumor growth suppression of gadolinium-injected irradiated group was revealed until about four times higher compared to the control group, and no significant weight loss were observed after treatment suggesting low systemic toxicity of this compound. The gadolinium-entrapped liposome will become one of the candidates for Gd delivery system on NCT. PMID:23743325

  9. Sensitometric analyses of screen-film systems for mammography exams in Brazil

    NASA Astrophysics Data System (ADS)

    Magalhães, L. A. G.; Drexler, G. G.; de Almeida, C. E.; Medeiros, L. L.; Ferreira, N. M. P. D.; Estrada, J. J. S.

    2015-12-01

    A determination of the sensitometric parameters of screen-film systems to evaluate their qualities was performed. The quality control of the automatic film processor was carried out to ensure a high level of efficiency. Based on ISO 9236-3, the following potentials were applied on the X-ray tubes: 25 kV, 28 kV, 30 kV and 35 kV. Four different mammography films from different manufacturers with and without screens were tested for curve shape, speed and average gradient. The results indicated that film 1 exhibited better contrast, film 3 demonstrated the highest energy dependence, and film 4 presented the largest base+fog density. None of the four mammographic films tested achieved satisfactory results in all parameters analyzed. Improvements in the manufacturing process for these films must be completed to avoid losses in the image quality.

  10. Shackleton's Antarctic Adventure: The Greatest Survival Story of All Time. Teacher's Guide To Accompany the Giant-Screen Film.

    ERIC Educational Resources Information Center

    Gibb, Reen

    This teacher's guide was developed to accompany the giant-screen film, "Shackleton's Antarctic Adventure". The activities featured use a multidisciplinary approach and target students ages 7 through 14. Teacher pages include background information and student pages include instructions and additional information for understanding the activity.…

  11. Digital versus screen-film mammography: impact of mammographic density and hormone therapy on breast cancer detection.

    PubMed

    Chiarelli, Anna M; Prummel, Maegan V; Muradali, Derek; Shumak, Rene S; Majpruz, Vicky; Brown, Patrick; Jiang, Hedy; Done, Susan J; Yaffe, Martin J

    2015-11-01

    Most studies that have examined the effects of mammographic density and hormone therapy use on breast cancer detection have included screen-film mammography. This study further examines this association in post-menopausal women screened by digital mammography. Approved by the University of Toronto Research Ethics Board, this study identified 688,418 women of age 50-74 years screened with digital or screen-film mammography from 2008 to 2009 within the Ontario Breast Screening Program. Of 2993 eligible women with invasive breast cancer, 2450 were contacted and 1421 participated (847 screen-film mammography, 574 digital direct radiography). Mammographic density was measured by study radiologists using the standard BI-RADS classification system and by a computer-assisted method. Information on hormone therapy use was collected by a telephone-administered questionnaire. Logistic regression and two-tailed tests for significance evaluated associations between factors and detection method by mammography type. Women with >75 % radiologist-measured mammographic density compared to those with <25 % were more likely to be diagnosed with an interval than screen-detected cancer, with the difference being greater for those screened with screen-film (OR = 6.40, 95 % CI 2.30-17.85) than digital mammography (OR = 2.41, 95 % CI 0.67-8.58) and aged 50-64 years screened with screen-film mammography (OR = 10.86, 95 % CI 2.96-39.57). Recent former hormone therapy users were also at an increased risk of having an interval cancer with the association being significant for women screened with digital mammography (OR = 2.08, 95 % CI 1.17-3.71). Breast screening using digital mammography lowers the risk of having an interval cancer for post-menopausal women aged 50-64 with greater mammographic density. PMID:26518019

  12. GADOLINIUM SOLUBILITY AND VOLATILITY DURING DWPF PROCESSING

    SciTech Connect

    Reboul, S

    2008-01-30

    Understanding of gadolinium behavior, as it relates to potential neutron poisoning applications at the DWPF, has increased over the past several years as process specific data have been generated. Of primary importance are phenomena related to gadolinium solubility and volatility, which introduce the potential for gadolinium to be separated from fissile materials during Chemical Process Cell (CPC) and Melter operations. Existing data indicate that gadolinium solubilities under moderately low pH conditions can vary over several orders of magnitude, depending on the quantities of other constituents that are present. With respect to sludge batching processes, the gadolinium solubility appears to be highly affected by iron. In cases where the mass ratio of Fe:Gd is 300 or more, the gadolinium solubility has been observed to be low, one milligram per liter or less. In contrast, when the ratio of Fe:Gd is 20 or less, the gadolinium solubility has been found to be relatively high, several thousands of milligrams per liter. For gadolinium to serve as an effective neutron poison in CPC operations, the solubility needs to be limited to approximately 100 mg/L. Unfortunately, the Fe:Gd ratio that corresponds to this solubility limit has not been identified. Existing data suggest gadolinium and plutonium are not volatile during melter operations. However, the data are subject to inherent uncertainties preventing definitive conclusions on this matter. In order to determine if gadolinium offers a practical means of poisoning waste in DWPF operations, generation of additional data is recommended. This includes: Gd solubility testing under conditions where the Fe:Gd ratio varies from 50 to 150; and Gd and Pu volatility studies tailored to quantifying high temperature partitioning. Additional tests focusing on crystal aging of Gd/Pu precipitates should be pursued if receipt of gadolinium-poisoned waste into the Tank Farm becomes routine.

  13. Metals Fact Sheet: Gadolinium GD

    SciTech Connect

    1992-10-01

    Gadolinium is a silvery-white, malleable, ductile metallic element used to improve the high-temperature characteristics of iron, chromium, and related metallic alloys. It was named after the French chemist, Gadolin, discoverer of yttrium. This article discusses sources of the element, the world supply and demand, and also a number of applications. With the largest thermal neutron absorption cross section of any element, one of these applications is as a burnable poison in reactors and as neutron absorbers in other nuclear devices.

  14. A volumetric method for estimation of breast density on digitized screen-film mammograms.

    PubMed

    Pawluczyk, Olga; Augustine, Bindu J; Yaffe, Martin J; Rico, Dan; Yang, Jiwei; Mawdsley, Gordon E; Boyd, Norman F

    2003-03-01

    A method is described for the quantitative volumetric analysis of the mammographic density (VBD) from digitized screen-film mammograms. The method is based on initial calibration of the imaging system with a tissue-equivalent plastic device and the subsequent correction for variations in exposure factors and film processing characteristics through images of an aluminum step wedge placed adjacent to the breast during imaging. From information about the compressed breast thickness and technique factors used for taking the mammogram as well as the information from the calibration device, VBD is calculated. First, optical sensitometry is used to convert images to Log relative exposure. Second, the images are corrected for x-ray field inhomogeneity using a spherical section PMMA phantom image. The effectiveness of using the aluminum step wedge in tracking down the variations in exposure factors and film processing was tested by taking test images of the calibration device, aluminum step wedge and known density phantoms at various exposure conditions and also at different times over one year. Results obtained on known density phantoms show that VBD can be estimated to within 5% accuracy from the actual value. A first order thickness correction is employed to correct for inaccuracy in the compression thickness indicator of the mammography units. Clinical studies are ongoing to evaluate whether VBD can be a better indicator for breast cancer risk. PMID:12674236

  15. Relative speeds of Kodak computed radiography phosphors and screen-film systems.

    PubMed

    Huda, W; Rill, L N; Bruner, A P

    1997-10-01

    Relative mAs values required to generate a constant plate readout signal for the Kodak Ektascan general purpose (GP-25) and high resolution (HR) photostimulable phosphors were measured as a function of x-ray beam quality and for a range of representative x-ray examinations. The signal intensity was determined from the exposure index (EI) generated during the read out of uniformly exposed phosphor imaging plates. These data were compared to the corresponding relative mAs values required to produce a constant film density of Lanex screen-film combinations with nominal speeds of 40, 400, and 600. The relative detection performance of the photostimulable phosphors generally decreased with increasing kVp and beam filtration. The relative response of GP-25 phosphors was independent of examination type, and modified by approximately 10% when scattered radiation was present. The HR phosphor was more efficient than a Lanex Single Fine extremity screen used with an EM-1 film. These relative response data will be useful for selecting the x-ray technique factors which minimize patient dose in x-ray examinations performed with photostimulable phosphors. PMID:9350716

  16. Toxicity of Gadolinium to Some Aquatic Microbes

    SciTech Connect

    Wilde, E.W.

    2001-01-24

    The toxicity of gadolinium to algae and bacteria was determined as part of an effort to develop a biological process to purify drums containing spent nuclear reactor heavy water moderator (D2O). This water was contaminated with high concentrations of gadolinium nitrate, a chemical used as a neutron poison during former nuclear reactor operations at the Savannah River Site (SRS) near Aiken, SC. Nuclear reactors were operated for approximately 30 years at the SRS to produce nuclear weapons materials for national defense. Throughout this period, a heavy water solution of gadolinium nitrate was utilized in a standby emergency shutdown system that could inject this chemical into the reactor moderator coolant water. The chemical was used for this purpose because the high neutron absorption cross sections of some gadolinium isotopes make gadolinium salts such as GdNO3 effective in controlling nuclear activity in aqueous systems (Gilbert et al. 1985; Rodenas et al. 1990). The use of this practice resulted in a large inventory of this degraded heavy water containing gadolinium nitrate. Microbiological and chemical studies were initiated to evaluate the potential use of bacteria and algae for water purification of the drums. Since metals are often toxic to microbes when present at concentrations substantially higher than natural environmental levels, it was hypothesized that Gd may be toxic to selected microorganisms (algae and bacteria) at the very high concentrations (average 80,000 mg/L, maximum 259,000 mg/L) present in most of the drums. Two principal components of the study included: (1) chemical and microbiological characterization of representative drums, and (2) an evaluation of the toxicity of gadolinium to selected species of algae. In addition to wastewater from nuclear production reactor operations, gadolinium waste is also generated from medical applications, especially MRI, and various electronic components including CD disks. Despite growing and widespread

  17. Molten iron oxysulfide as a superior sulfur sorbent. Technical progress report, June 1, 1991--August 31, 1991

    SciTech Connect

    Hepworth, M.T.

    1991-12-31

    Slagging combustors with injected lime or limestone are being considered as replacements for conventional coal burners. They have advantages in that they can be staged to reduce NO{sub x} and So{sub x} emissions. Iron oxide, as an alternative to lime or limestone may be effective not only as a desulfurizing agent, but under the right conditions of oxygen potential and after combination with sulfur, the reaction products of coal gases with iron oxide can act as a flux to produce a fluid phase. The thermodynamic conditions for optimum removal of sulfur from the first stage of a coal combustor are being determined by experiment and by use of existing data. Contour plots in which the pounds Of S0{sub 2} per million Btu of calorific power are plotted on isothermal ternary phase diagrams of the iron-oxygen-sulfur system. These contour plots determine the most favorable conditions for coal combustion in the presence of added iron oxide. Lowest S0{sub 2} pressures are close to the phase boundary limit between iron saturation and the oxysulfide liquid phase. Experimental studies in which ceramic containers (99% alumina) were used to contain the liquid were hampered by the tendency for the liquid to flow up and over the walls of containing vessels presumably as a result of surface tension effects. These effects, which make equilibration measurements difficult, may be favorable with respect to producing a high degree of reactivity of the oxysulfide with coal gases and resultant rapid reaction kinetics. As result of this problem, platinum containment vessels containers appear to avoid these surface tension effects. Thermodynamic and kinetic measurements are now being explored by thermogravimetric analysis.

  18. Biodistribution of gadolinium-based contrast agents, including gadolinium deposition

    PubMed Central

    Aime, Silvio; Caravan, Peter

    2010-01-01

    The biodistribution of approved gadolinium (Gd) based contrast agents (GBCA) is reviewed. After intravenous injection GBCA distribute in the blood and the extracellular space and transiently through the excretory organs. Preclinical animal studies and the available clinical literature indicate that all these compounds are excreted intact. Elimination tends to be rapid and for the most part, complete. In renally insufficient patients the plasma elimination half-life increases substantially from hours to days depending on renal function. In patients with impaired renal function and nephrogenic systemic fibrosis (NSF), the agents gadodiamide, gadoversetamide, and gadopentetate dimeglumine have been shown to result in Gd deposition in the skin and internal organs. In these cases, it is likely that the Gd is no longer present as the GBCA, but this has still not been definitively shown. In preclinical models very small amounts of Gd are retained in the bone and liver, and the amount retained correlates with the kinetic and thermodynamic stability of the GBCA with respect to Gd release in vitro. The pattern of residual Gd deposition in NSF subjects may be different than that observed in preclinical rodent models. GBCA are designed to be used via intravenous administration. Altering the route of administration and/or the formulation of the GBCA can dramatically alter the biodistribution of the GBCA and can increase the likelihood of Gd deposition. PMID:19938038

  19. Modified inverse square sensitometry for the determination of the characteristic curve of radiographic screen/film systems.

    PubMed

    Yoshida, A; Hiraki, Y; Ohkawa, Y; Yamada, T; Hashimoto, K; Aono, K

    1986-02-01

    To determine the characteristic curve of the radiographic screen/film systems in a short focal spot-film distance, the inverse square sensitometric method was modified by changing the radiation intensity with two kinds of filters. The characteristic curves obtained in the two exposure series with these two kinds of filters were overlapped to obtain a complete one. The characteristic curve thus obtained was almost the same as the one obtained by the original inverse square sensitometric method. The accuracy of the characteristic curves obtained by the modified method was well-reflected in the clinical radiographs. PMID:3962729

  20. A new continuous two-step molecular precursor route to rare-earth oxysulfides Ln{sub 2}O{sub 2}S

    SciTech Connect

    De Crom, N.

    2012-07-15

    A continuous two-step molecular precursor pathway is designed for the preparation of rare-earth oxysulfides Ln{sub 2}O{sub 2}S (Ln=Y, La, Pr, Nd, Sm-Lu). This new route involves a first oxidation step leading to the rare-earth oxysulfate Ln{sub 2}O{sub 2}SO{sub 4} which is subsequently reduced to the rare-earth oxysulfide Ln{sub 2}O{sub 2}S by switching to a H{sub 2}-Ar atmosphere. The whole process occurs at a temperature significantly lower than usual solid state synthesis (T{<=}650 Degree-Sign C) and avoids the use of dangerous sulfur-based gases, providing a convenient route to the synthesis of the entire series of Ln{sub 2}O{sub 2}S. The molecular precursors consist in heteroleptic dithiocarbamate complexes [Ln(Et{sub 2}dtc){sub 3}(phen)] and [Ln(Et{sub 2}dtc){sub 3}(bipy)] (Et{sub 2}dtc=N,N-diethyldithiocarbamate; phen=1,10-phenanthroline; bipy=2,2 Prime -bipyridine) and were synthesized by a new high yield and high purity synthesis route. The nature of the molecular precursor determines the minimum synthesis temperature and influences therefore the purity of the final Ln{sub 2}O{sub 2}S crystalline phase. - Graphical abstract: A continuous two-step molecular precursor pathway was designed for the preparation of rare-earth oxysulfides Ln{sub 2}O{sub 2}S (Ln=Y, La, Pr, Nd, Sm-Lu), starting from heteroleptic dithiocarbamate complexes. The influence of the nature of the molecular precursor on the minimum synthesis temperature and on the purity of the final Ln{sub 2}O{sub 2}S crystalline phase is discussed. Highlights: Black-Right-Pointing-Pointer A new high yield and high purity synthesis route of rare earth dithiocarbamates is described. Black-Right-Pointing-Pointer These compounds are used as precursors in a continuous process leading to rare-earth oxysulfides. Black-Right-Pointing-Pointer The oxysulfides are obtained under much more moderate conditions than previously described.

  1. Evaluation of absorbed dose in Gadolinium neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Abdullaeva, Gayane; Djuraeva, Gulnara; Kim, Andrey; Koblik, Yuriy; Kulabdullaev, Gairatulla; Rakhmonov, Turdimukhammad; Saytjanov, Shavkat

    2015-02-01

    Gadolinium neutron capture therapy (GdNCT) is used for treatment of radioresistant malignant tumors. The absorbed dose in GdNCT can be divided into four primary dose components: thermal neutron, fast neutron, photon and natural gadolinium doses. The most significant is the dose created by natural gadolinium. The amount of gadolinium at the irradiated region is changeable and depends on the gadolinium delivery agent and on the structure of the location where the agent is injected. To de- fine the time dependence of the gadolinium concentration ρ(t) in the irradiated region the pharmacokinetics of gadolinium delivery agent (Magnevist) was studied at intratumoral injection in mice and intramuscular injection in rats. A polynomial approximation was applied to the experimental data and the influence of ρ(t) on the relative change of the absorbed dose of gadolinium was studied.

  2. Structural, optical and magnetic properties of gadolinium sesquioxide nanobars synthesized via thermal decomposition of gadolinium oxalate

    SciTech Connect

    Manigandan, R.; Giribabu, K.; Suresh, R.; Vijayalakshmi, L.; Stephen, A.; Narayanan, V.

    2013-10-15

    Graphical abstract: - Highlights: • The cubic Gd{sub 2}O{sub 3} nanobars are synthesized by decomposition of C{sub 6}H{sub 20}Gd{sub 2}O{sub 22}. • The nanoparticles are rectangular bar shape with high porous surface. • The combination of magnetic and optical properties within a single particle. • The Gd{sub 2}O{sub 3} nanobars have tailorable nanostructure, wide bandgap and are paramagnetic. - Abstract: Gadolinium oxide nanobars were obtained by thermal decomposition of gadolinium oxalate, which was synthesized by the chemical precipitation method along with glycerol. The functional group analysis and formation of gadolinium oxide from gadolinium oxalate were characterized by the Fourier transform infrared spectroscopy and thermo gravimetric analyzer. The crystal structure, average crystallite size, and lattice parameter were analyzed by X-ray diffraction technique. Moreover, Raman shifts, elemental composition and morphology of the gadolinium oxide was widely investigated by the laser Raman microscope, X-ray photoelectron spectroscopy, FE-SEM-EDAX and HR-TEM, respectively. Furthermore, the optical properties like band gap, absorbance measurement of the gadolinium oxide were extensively examined. In addition, the paramagnetic property of gadolinium oxide nanobars was explored by the vibrating sample magnetometer.

  3. An investigation on patient dose in screen-film diagnostic radiology in Lhasa City, Xizang Autonomous Region, China.

    PubMed

    Du, Xiang

    2013-12-01

    This study aimed to investigate patient dose in diagnostic screen-film radiographic examinations in the city of Lhasa, China. Seven out of the twenty-six hospitals registered with the Lhasa Health Bureau were included in the investigation. The entrance surface air Kerma (ESAK) of seven conventional screen-film radiology X-ray equipment in these hospitals was measured with a QA dosimeter in September 2012. The X-ray examinations were divided into three categories: PA (posterior-anterior) chest, upper/lower limb, and AP (anterior-posterior) lumbar spine. For each category, ESAKs were calculated and analyzed. The mean ESAK was 0.6 mGy for PA chest, 0.3 mGy for upper/lower limb, and 1.8 mGy for AP lumbar spine. In addition, the mean ESAK value recorded for PA chest X-ray examinations exceeded the corresponding value recommended by the International Atomic Energy Agency (0.4 mGy). PMID:24142378

  4. Enhancement of the electron electric dipole moment in gadolinium garnets

    SciTech Connect

    Mukhamedjanov, T.N.; Dzuba, V.A.; Sushkov, O.P.

    2003-10-01

    Effects caused by the electron electric dipole moment (EDM) in gadolinium garnets are considered. Experimental studies of these effects could improve the current upper limit on the electron EDM by several orders of magnitude. We suggest a consistent theoretical model and perform calculations of observable effects in gadolinium gallium garnet and gadolinium iron garnet. Our calculation accounts for both direct and exchange diagrams.

  5. Neutron autoradiography of trace amounts of gadolinium

    SciTech Connect

    Shih, J.L.A.; Brugger, R.M. )

    1992-05-01

    This paper reports that application of gadolinium in neutron capture therapy is under evaluation. Crucial to development of this therapy is an imaging technique that would show the distribution and concentration of parts-per-million amounts of {sup 157}Gd in sliced samples. A technique that utilizes the principles of autoradiography and neutron radiography has been tried. The images taken with this method display the gadolinium distribution and its relative concentration in samples. Concentrations of {sup 157}Gd ranging from {approximately}20 to 500 ppm can be determined. The intrinsic spatial resolution of the system used in the Missouri University Research Reactor is 70 {mu}m.

  6. Deposition of rare-earth phosphate, fluoride, and oxysulfide films by gas-phase thermolysis of {beta}-diketonate complexes

    SciTech Connect

    Gorshkov, N.I.; Suglobov, D.N.; Sidorenko, G.V.

    1995-07-01

    Rare-earth fluoride, phosphate, and oxysulfide films have been obtained by gas-phase thermolysis of appropriate rare-earth mixed-ligand and tris-chelate {beta}-diketonate complexes. Gas-phase thermolysis of Ln(PTFA){sub 3} {center_dot}HMPA and Ln(HFA){sub 3}{center_dot}2HMPA (PTFA is pivaloyltrifluoroacetonate ligand and HFA is hexafluoracetylacetonate ligand, HMPA is hexamethylphosphoric triamide, Ln = Nd, Eu, Er) in a flow of air or N{sub 2}O yields a finely dispersed phosphate phase. Thermolysis of Ln(HFA){sub 3} {center_dot}DME (Ln = Nd, Eu, Er, DME is 1,2-dimethoxyethane) yields carbon-free fluoride films, whereas in the case of Er(HFA){sub 3}{center_dot}2H{sub 2}O and Er(PTFA){sub 3} erbium oxyfluoride and oxide films are deposited. Thermolysis of Nd(DPM){sub 3} (DPM is dipivaloylmethanate ligand) in hydrogen sulfide flow yields and Nd{sub 2}O{sub 2}S phase.

  7. The influence of diffusion temperature on the structural, optical and magnetic properties of manganese-doped zinc oxysulfide thin films

    NASA Astrophysics Data System (ADS)

    Polat, İ.; Aksu, S.; Altunbaş, M.; Yılmaz, S.; Bacaksız, E.

    2011-10-01

    We investigated the structural, optical and magnetic properties of Mn-doped zinc oxysulfide films. Zn(O,S) films were deposited by a spray pyrolysis method on glass substrate. A thin Mn layer evaporated on these films served as the source for the diffusion doping. The XRD pattern of undoped films revealed the presence of two wurtzite phases corresponding to ZnS and ZnO with a strong preferred orientation along the ZnS (0 0 2) hexagonal plane direction. SEM showed a similar surface morphology for the undoped and Mn-doped films, displaying regular arrays of hexagonal micro-rods perpendicular to the substrate. The optical transmission measurements showed that both undoped and Mn diffusion-doped films had a low average transmittance less than about 10%. The gap energy is decreased from 3.42 to 3.33 eV upon annealing at 400 °C. Photoluminescence studies at 300 K show that the incorporation of manganese leads to a decrease of deep level band intensity compared to undoped sample. Clear ferromagnetic loops were observed for the Mn-doped Zn(O,S) films, which might be due to the presence of point defects.

  8. Gadolinium: Central Metal of the Lanthanoids

    ERIC Educational Resources Information Center

    Laing, Michael

    2009-01-01

    The physical and chemical properties of gadolinium are compared with those of the other lanthanoids. Some properties are intermediate between those of lanthanum and lutetium; some between those of barium and hafnium; and others (unexpectedly) between those of ytterbium and lutetium. Both the remarkably high molar heat capacity of the metal and the…

  9. A toxicological study of gadolinium nitrate

    SciTech Connect

    London, J.E.

    1988-05-01

    The sensitization study in the guinea pig did not show gadolinium nitrate to have potential sensitizing properties. Skin application studies in the rabbit demonstrated that it was cutaneously a severe irritant. This material was considered an irritant in the rabbit eye application studies. 3 refs., 1 tab.

  10. Open-Framework Oxysulfide Based on the Supertetrahedral [In4Sn16O10S34](12-) Cluster and Efficient Sequestration of Heavy Metals.

    PubMed

    Zhang, Xian-Ming; Sarma, Debajit; Wu, Ya-Qin; Wang, Li; Ning, Zhi-Xue; Zhang, Fu-Qiang; Kanatzidis, Mercouri G

    2016-05-01

    The new ion-exchange oxy-sulfide material has a three-dimensional open framework comprising the pseudo-T4 supertetrahedral [In4Sn16O10S34](12-) cluster. This material has large pores and is a fast ion exchanger. It exhibits high selectivity in sequestering heavy metal ions from aqueous solutions including solutions containing heavy concentrations of sodium, calcium, ammonium, magnesium, zinc, carbonate, phosphate, and acetate ions. Moreover, the ion-exchange efficiency in competitive ion-exchange experiments involving mixtures of metal ions is significantly higher than for solutions of single metal ions. PMID:27082786

  11. High-yield radiography of the maxillofacial complex using the free focus and conventional imaging concepts. The resolution performance of nonscreen and screen-film combinations.

    PubMed

    Jensen, T W; Goldberg, A J; Randall, G J

    1983-09-01

    Free focus radiography with miniaturized dental x-ray machines may be a valuable source of "high-yield" diagnostic information in dentistry. This study evaluated the resolution performance of conventional image receptors, including nonscreen and screen-film combinations which were available in sizes suitable for panoramic free focus radiography or conventional extraoral radiography. Results with nonscreen films produced resolution performances ranging from about 10 lp/mm. to about 20 lp/mm. For each film tested, the performances in conventional radiography as well as in free focus radiography with the film in the buccal fold approached the maximum measurable of 20 lp/mm. In a mode of free focus radiography with the film positioned extraorally, there were significant variations in performance according to film brand. A significant reduction in resolution performance occurred when screen-film combinations were tested; resolution ranged between 4.0 lp/mm. and 7.4 lp/mm., with the better performance obtained with free focus radiography. The performance of a rare earth system was similar to other screen-film combinations tested in conventional radiography. In free focus radiography the performance of the rare earth system was slightly below the mean resolution for conventional screen-film combinations at 4.0 lp/mm. and 4.3 lp/mm. An example of a small cassette adapted for intraoral use was given. PMID:6579466

  12. Effect of screen/film combinations on diagnostic certainty: Hi-Plus/RPL versus Lanex/Ortho G in excretory urography.

    PubMed

    Thornbury, J R; Fryback, D G; Patterson, F E; Chiavarini, R L

    1978-01-01

    A method using radiologists' subjective judgments was developed to compare the quality of the diagnostic image information from two different screen/film combinations (Hi Plus/RPL versus Lanex/Ortho G). A sample of 148 comparison film pairs was obtained in the course of performing 74 urograms using the two film/screen combinations. Each film pair was evaluated by three radiologists, using a blind film-reading format, in regard to:(1) anatomic diagnostic criteria visualization; (2) radiologic diagnostic certainty; (3) presence or absence of quantum mottle; and (4) prediction of which film of a pair was the rare earth screen/film combination. There was a significant difference favoring Hi Plus/RPL in perceived quality of visualization of anatomic criteria. However, the difference was more of statistical rather than practical importance. Diagnostic certainty differed only marginally and slightly favored the Hi Plus/RPL combination. No signficant differences in perception of quantum mottle were attributable to either screen/film combination. Radiologists were able to correctly identify the screen/film combination a significant proportion of the time. Radiation exposure with the Lanex/Ortho G combination was about half that with the Hi Plus/RPL combination. In this study, this would seem to constitute the major factor in film/screen selection. PMID:413423

  13. Gadolinium diethylenetriaminopentaacetic acid-loaded chitosan microspheres for gadolinium neutron-capture therapy.

    PubMed

    Saha, Tapan Kumar; Ichikawa, Hideki; Fukumori, Yoshinobu

    2006-12-11

    In order to provide a suitable device that would contain water-soluble drugs, highly water-soluble gadolinium diethylenetriaminopentaacetic acid-loaded chitosan microspheres (CMS-Gd-DTPA) were prepared by the emulsion method using glutaraldehyde as a cross-linker and Span 80 as a surfactant for gadolinium neutron-capture therapy of cancer. The gadolinium content and the mass median diameter of CMS-Gd-DTPA were estimated. The size and morphology of the CMS-Gd-DTPA were strongly influenced by the initial applied weight ratio of Gd-DTPA:chitosan. FTIR spectra showed that the electrostatic interaction between chitosan and Gd-DTPA accelerated the formation of gadolinium-enriched chitosan microspheres. Sufficient amounts of glutaraldehyde and Span 80 were necessary for producing discrete CMS-Gd-DTPA. The CMS-Gd-DTPA having a mass median diameter 11.7microm and 11.6% of gadolinium could be used in Gd-NCT following intratumoral injection. PMID:17045253

  14. Method of separating and purifying gadolinium-153

    DOEpatents

    Bray, Lane A [Richland, WA; Corneillie, Todd M [Davis, CA

    2001-01-01

    The present invention is an improvement to the method of separating and purifying gadolinium from a mixture of gadolinium and europium having the steps of (a) dissolving the mixture in an acid; (b) reducing europium+3 to europium+2; and (c) precipitating the europium+2 with a sulfate ion in a superstoichiometric amount; wherein the improvement is achieved by using one or more of the following: (i) the acid is an anoic acid; (ii) the reducing is with zinc metal in the absence of a second metal or with an amount of the second metal that is ineffective in the reducing; (iii) adding a group IIA element after step (c) for precipitating the excess sulfate prior to repeating step (c); (iv) the sulfate is a sulfate salt with a monovalent cation; (v) adding cold europium+3 prior to repeating step (c).

  15. Progress Towards Laser Cooling and Trapping Gadolinium

    NASA Astrophysics Data System (ADS)

    Adhikari, Upendra; Simien, Clayton

    2016-05-01

    Lanthanide elements are of interest because of their potential for investigating next generation optical clock transitions, novel non-S ground state ultracold collisions, and the physics of quantum degenerate dipolar gases. We present our progress towards laser cooling and trapping atomic Gadolinium (Gd). A magneto-optical trap is the first step towards precision measurements, ultracold collision studies, and for probing dipolar physics of Gd. The design, construction, and performance of the apparatus will be presented.

  16. Emerging concepts for myocardial late gadolinium enhancement MRI.

    PubMed

    Doltra, Adelina; Amundsen, Brage Hoyem; Gebker, Rolf; Fleck, Eckart; Kelle, Sebastian

    2013-08-01

    Late gadolinium enhancement is a useful tool for scar detection, based on differences in the volume of distribution of gadolinium, an extracellular agent. The presence of fibrosis in the myocardium amenable to be detected with late gadolinium enhancement MRI is found not only in ischemic cardiomyopathy, in which it offers information regarding viability and prognosis, but also in a wide variety of non-ischemic cardiomyopathies. In the following review we will discuss the methodological aspects of gadolinium-based imaging, as well as its applications and anticipated future developments. PMID:23909638

  17. Configuration of automatic exposure control on mammography units for computed radiography to match patient dose of screen film systems

    NASA Astrophysics Data System (ADS)

    Yang, Chang-Ying Joseph; Huang, Weidong

    2009-02-01

    Computed radiography (CR) is considered a drop-in addition or replacement for traditional screen-film (SF) systems in digital mammography. Unlike other technologies, CR has the advantage of being compatible with existing mammography units. One of the challenges, however, is to properly configure the automatic exposure control (AEC) on existing mammography units for CR use. Unlike analogue systems, the capture and display of digital CR images is decoupled. The function of AEC is changed from ensuring proper and consistent optical density of the captured image on film to balancing image quality with patient dose needed for CR. One of the preferences when acquiring CR images under AEC is to use the same patient dose as SF systems. The challenge is whether the existing AEC design and calibration process-most of them proprietary from the X-ray systems manufacturers and tailored specifically for SF response properties-can be adapted for CR cassettes, in order to compensate for their response and attenuation differences. This paper describes the methods for configuring the AEC of three different mammography units models to match the patient dose used for CR with those that are used for a KODAK MIN-R 2000 SF System. Based on phantom test results, these methods provide the dose level under AEC for the CR systems to match with the dose of SF systems. These methods can be used in clinical environments that require the acquisition of CR images under AEC at the same dose levels as those used for SF systems.

  18. Design of linear anti-scatter grid geometry with optimum performance for screen-film and digital mammography systems

    NASA Astrophysics Data System (ADS)

    Khodajou-Chokami, H.; Sohrabpour, M.

    2015-08-01

    A detailed 3D Monte Carlo simulation of the grid geometrical parameters in screen-film mammography (SFM) and digital mammography (DM) systems has been performed. A combination of IEC 60627:2013 international standard conditions and other more clinically relevant parameters were used for this simulation. Accuracy of our results has been benchmarked with previously published data and good agreement has been obtained. Calculations in a wide range of linear anti-scatter grid geometries have been carried out. The evaluated parameters for the SFM system were the Bucky factor (BF) and contrast improvement factor (CIF) and for the DM system it was signal difference-to-noise ratio improvement factor (SIF). The CIF parameter was chosen to be nearly the same as the commercial grade, the BF and SIF were significantly improved compared to commercial grids in use today. Our optimized grid parameters for the SFM system were lead strip thickness d=12  µm, grid ratio r= 5 and strip density N=65 lines/cm. And for the DM system these parameters were d= 5  µm, r = 3 and N=100 lines/cm. Both optimized grid sets have thinner d and higher N compared to the commercial grids.

  19. Design of linear anti-scatter grid geometry with optimum performance for screen-film and digital mammography systems.

    PubMed

    Khodajou-Chokami, H; Sohrabpour, M

    2015-08-01

    A detailed 3D Monte Carlo simulation of the grid geometrical parameters in screen-film mammography (SFM) and digital mammography (DM) systems has been performed. A combination of IEC 60627:2013 international standard conditions and other more clinically relevant parameters were used for this simulation. Accuracy of our results has been benchmarked with previously published data and good agreement has been obtained. Calculations in a wide range of linear anti-scatter grid geometries have been carried out. The evaluated parameters for the SFM system were the Bucky factor (BF) and contrast improvement factor (CIF) and for the DM system it was signal difference-to-noise ratio improvement factor (SIF). The CIF parameter was chosen to be nearly the same as the commercial grade, the BF and SIF were significantly improved compared to commercial grids in use today. Our optimized grid parameters for the SFM system were lead strip thickness d = 12 µm, grid ratio r = 5 and strip density N = 65 lines/cm. And for the DM system these parameters were d = 5 µm, r = 3 and N = 100 lines/cm. Both optimized grid sets have thinner d and higher N compared to the commercial grids. PMID:26159575

  20. Effect of developer temperature changes on the sensitometric properties of direct exposure and screen-film imaging systems.

    PubMed

    Kircos, L T; Staninec, M; Chou, L S

    1989-02-01

    A heat exchanger was developed and incorporated into the recirculation system of a dental processor to maintain strict temperature control. Without the heat exchanger, developer temperature rose steadily over 8 h to a maximum of 35.7 degrees C: with the heat exchanger it was maintained, regardless of ambient conditions, at the desired temperature with virtually no fluctuation. Sensitometric properties of base and fog, speed, and average gradient were measured for D and E speed films and Lanex Regular/T-Mat G and Lanex Fast/T-Mat Hscreen-film systems at developer temperatures of 21.1, 23.8, 26.7, 29.4 and 32.2 degrees C. Small changes in these properties were found for D and E speed films: on the other hand, Lanex Regular/T-Mat G showed a 65% increase in base and fog and Lanex Fast/T-Mat H a 43% increase in average gradient over the temperature range studied. Although these changes may not be clinically significant for intra-oral and dental radiography, the variations in image quality may compromise controlled imaging experiments and clinically compromise radiographic quality when using screen-film systems. PMID:2599232

  1. A comparative evaluation of rare-earth screen-film systems. System speed, contrast, sensitometry, RMS noise, square-wave response function, and contrast-dose-detail analysis.

    PubMed

    Fearon, T; Vucich, J; Hoe, J; McSweeney, W J; Potter, B M

    1986-08-01

    We evaluated the physical characteristics and contrast-dose-detail performance of 11 rare-earth and three calcium tungstate screen-film systems. Measurements included system speed, contrast, sensitometry, RMS noise, square-wave response function, and contrast-dose-detail analysis. The major differences in physical characteristics among systems were system speed and RMS noise. Square-wave response differences were more subtle. For contrast-dose-detail analysis, the rare-earth screen-film systems and the calcium tungstate system responses were significant over a limited subject contrast range as a function of detail diameter. Relative dose efficiency in the noise-limited region is a function of the properties of the screen only and is independent of the film. PMID:3744739

  2. Resonance parameter measurements and analysis of gadolinium

    SciTech Connect

    Leinweber, G.; Barry, D. P.; Trbovich, M. J.; Burke, J. A.; Drindak, N. J.; Knox, H. D.; Ballad, R. V.; Block, R. C.; Danon, Y.; Severnyak, L. I.

    2006-07-01

    The purpose of the present work is to measure the neutron cross sections of gadolinium accurately. Gd has the highest thermal absorption cross section of any natural element. Therefore it is an important element for thermal reactor applications Neutron capture and transmission measurements were performed by the time-of-flight technique at the Rensselaer Polytechnic Inst. (RPI) LINAC facility using metallic and liquid Gd samples. The liquid samples were isotopically-enriched in either {sup 155}Gd or {sup 157}Gd. The capture measurements were made at the 25-m flight station with a sodium iodide detector, and the transmission measurements were performed at 15- and 25-m flight stations with {sup 6}Li glass scintillation detectors. The multilevel R-matrix Bayesian code SAMMY was used to extract resonance parameters. The results of the thermal region analysis are significant. Resonance parameters for the low energy doublet, at 0.025 and 0.032 eV, are presented. The thermal (2200 m/s) capture cross section of {sup 157}Gd has been measured to be 11% smaller than that calculated from ENDF/B-VI updated through release 8. Thermal capture cross sections and capture resonance integrals for each isotope as well as elemental gadolinium are presented. In the epithermal region, natural metal samples were measured in capture and transmission. Neutron interaction data up to 300 eV have been analyzed. Substantial improvement to the understanding of gadolinium cross sections is presented, particularly above 180 eV where the ENDF resolved region for {sup 155}Gd ends. (authors)

  3. Extraction-chromatographic affinage in gadolinium-153 preparation production technology

    SciTech Connect

    Melnik, M.I.; Karelin, E.A.; Kuznetsov, R.A.

    1993-12-31

    The gadolinium 153 preparation is used for production of medical gamma-sources which are applicable in bone densimeters for early diagnostics of osteoporosis. This preparation must meet strict requirements with respect to the content of europium radionuclides and specific activity. In The Research Institute of Atomic Reactors (RIAR) the gadolinium 153 is produced by neutron irradiation of Europium 151. This process is described.

  4. Light deflection in gadolinium molybdate ferroelastic crystals

    NASA Astrophysics Data System (ADS)

    Staniorowski, Piotr; Bornarel, Jean

    2000-02-01

    The deflection of a He-Ne light beam by polydomain gadolinium molybdate (GMO) crystals has been studied with respect to incidence angle icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> i on the sample at room temperature. The A and B deflected beams do not cross each other during the icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> i variation, in contrast to results and calculations previously published. The model using the Fresnel equation confirms this result. The model presented is more accurate for numerical calculation than that using the Huygens construction.

  5. Towards modeling gadolinium-lead-borate glasses

    SciTech Connect

    Rada, S.; Ristoiu, T.; Rada, M.; Coroiu, I.; Maties, V.; Culea, E.

    2010-01-15

    Infrared spectra of gadolinium-lead-borate glasses of the xGd{sub 2}O{sub 3}.(100 - x)[3B{sub 2}O{sub 3}.PbO] system, where x = 0, 5, 10, 15, 25, 35 and 50 mol.%, have been recorded to explore the role of content of gadolinium ions behaving as glass modifier. The FTIR spectroscopy data for the xGd{sub 2}O{sub 3}.(1 - x)[3B{sub 2}O{sub 3}.PbO] glasses show the structural role of lead ions as a network-formers and of the gadolinium ions network modifiers. Adding of the rare earth ion up to 35 mol.% into the glass matrix, the IR bands characteristic to the studied glasses become sharper and more pronounced. Structural changes, as recognized by analyzing band shapes of IR spectra, revealed that Gd{sub 2}O{sub 3} causes a change from the continuous borate network to the continuous lead-borate network interconnected through Pb-O-B and B-O-B bridges and the transformation of some tetrahedral [BO{sub 4}] units into trigonal [BO{sub 3}] units. Then, gadolinium ions have affinity towards [BO{sub 3}] structural units which contain non-bridging oxygens necessary for the charge compensation because the more electronegative [BO{sub 3}] structural units were implied in the formation of B-O-Gd bonds and the transformation of glass network into a glass ceramic. We propose a possible structural model of building blocks for the formation of continuous random 3B{sub 2}O{sub 3}.PbO network glass used by density functional theory (DFT) calculations. DFT calculations show that lead atoms occupy three different sites in the proposed model. The first is coordinated with six oxygen atoms forming distorted octahedral geometries. The second lead atom has an octahedral oxygen environment and the five longer Pb-O bonds are considered as participating in the metal coordination scheme. The third lead atom has ionic character. In agreement with the results offered by the experimental FTIR data, the theoretical IR data confirm that our proposed structure is highly possible.

  6. Chest radiographic image quality: comparison of asymmetric screen-film, digital storage phosphor, and digital selenium drum systems--preliminary study.

    PubMed

    Beute, G H; Flynn, M J; Eyler, W R; Samei, E; Spizarny, D L; Zylak, C J

    1998-01-01

    Conventional screen-film radiography does not display all regions of the thorax satisfactorily. Three chest radiographic techniques display both the lung and the mediastinum with good contrast. These techniques are asymmetric screen-film (ASF), digital storage phosphor (DSP), and digital selenium drum (DSD) imaging. ASF systems use two asymmetric screen-film combinations to produce a wide-latitude image of the thorax with good contrast in the lungs. In DSP systems, image data are acquired digitally with a wide dynamic range by using the optical output of a photostimulable phosphor plate; in DSD systems, the wide-range digital image data are acquired by using the electronic charge generated on a drum coated with a thin layer of amorphous selenium. The appearance of a DSP or DSD radiograph is then determined by user-selected image processing operations: tone scaling, spatial frequency processing, and dynamic range compensation. Digital chest radiographs processed with strong regional equalization provide both excellent contrast in the lungs and effective display of the mediastinum and chest wall. At visual comparison, the high lung contrast and good mediastinal, retrocardiac, and subdiaphragmatic detail provided by the DSD method distinguish it from the other two methods. PMID:9599395

  7. Characteristics and prognosis of interval cancers after biennial screen-film or full-field digital screening mammography.

    PubMed

    Weber, Roy J P; van Bommel, Rob M G; Louwman, Marieke W; Nederend, Joost; Voogd, Adri C; Jansen, Frits H; Tjan-Heijnen, Vivianne C G; Duijm, Lucien E M

    2016-08-01

    We determined the characteristics and prognosis of interval breast cancers (IC) at screen-film (SFM) and full-field digital (FFDM) screening mammography. The study population consisted of 417,746 consecutive screening mammograms (302,699 SFM screens and 115,047 FFDM screens), obtained between 2000 and 2011. During 2-year follow-up, we collected breast imaging reports, surgical reports, and pathology results. A total of 800 ICs had been diagnosed in the screened population, of which 288 detected in the first year (early ICs) and 512 in the second year (late ICs) after a negative screen. 31.3 % of early IC's and 19.1 % of late IC's, respectively, were visible in retrospect on the latest previous screens, but had been missed during screening (P < 0.001). Missed invasive ICs were larger (28.5 mm vs. 23.9 mm, P = 0.003) and showed a higher fraction of T3+cancers (16.9 vs. 8.5 %, P = 0.02) than true ICs (i.e., not visible at the latest screen). A higher portion of missed than true ICs underwent mastectomy (44.7 vs. 30.8 %, P = 0.002). We found no differences in mammographic and tumor characteristics for early ICs, detected either after SFM or FFDM. Late ICs following FFDM were more often true ICs than missed ICs (69.0 vs. 57.6 %, P = 0.03) and more often receptor triple negative (P = 0.02), compared to late ICs at SFM. Interval cancer subgroups showed comparable overall survival. Interval cancer subgroups show distinctive mammographic and tumor characteristics but a comparable overall survival. PMID:27393617

  8. Alkali metal and alkali earth metal gadolinium halide scintillators

    DOEpatents

    Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

    2016-08-02

    The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

  9. Gadolinium enrichment technology at Lawrence Livermore National Laboratory

    NASA Astrophysics Data System (ADS)

    Haynam, Christopher A.; Comaskey, Brian J.; Conway, John; Eggert, Jon; Glaser, Joseph; Ng, Edmund W.; Paisner, Jeffrey A.; Solarz, Richard W.; Worden, Earl F.

    1993-05-01

    A method based on polarization selectivity and three step laser photoionization is presented for separation of the odd isotopes of gadolinium. Measurements of the spectroscopic parameters needed to quantify the excitation pathway are discussed. Model results are presented for the efficiency of photoionization. The vapor properties of electron beam vaporized gadolinium are presented which show dramatic cooling during the expansion of the hot dense vapor into a vacuum. This results in a significant increase in the efficiency of conversion of natural feed into enriched product in the AVLIS process. Production of enriched gadolinium for use in commercial power reactors appears to be economically viable using technology in use at LLNL.

  10. Removal of gadolinium nitrate from heavy water

    SciTech Connect

    Wilde, E.W.

    2000-03-22

    Work was conducted to develop a cost-effective process to purify 181 55-gallon drums containing spent heavy water moderator (D2O) contaminated with high concentrations of gadolinium nitrate, a chemical used as a neutron poison during former nuclear reactor operations at the Savannah River Site (SRS). These drums also contain low level radioactive contamination, including tritium, which complicates treatment options. Presently, the drums of degraded moderator are being stored on site. It was suggested that a process utilizing biological mechanisms could potentially lower the total cost of heavy water purification by allowing the use of smaller equipment with less product loss and a reduction in the quantity of secondary waste materials produced by the current baseline process (ion exchange).

  11. Synthesis of gadolinium oxide magnetoliposomes for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Roberts, Danielle; Zhu, Weibe L.; Frommen, Christoph M.; Rosenzweig, Zeev

    2000-05-01

    A method for the synthesis of gadolinium oxide magnetoliposomes, i.e., nanosized gadolinium oxide magnetic particles coated by a phospholipid membrane, is presented. Magnetoliposomes were prepared by reacting lauric acid coated gadolinium oxide nanoparticles with dimyristoylphosphatidylcholine liposomes prepared using a direct injection method. The gadolinium oxide magnetoliposomes were characterized using transmission electron microscopy imaging, x-ray diffraction, and fluorescence. The magnetic properties of the magnetoliposomes were investigated with a superconducting quantum interference device magnetometer and nuclear magnetic resonance (NMR) spectrometry. Our results indicate that the magnetoliposomes contain approximately spherical nanoparticles averaging 20 nm in diameter. The occurrence of a phospholipid bilayer surrounding the magnetic particles is confirmed both by transmission electron micrographs of samples negatively stained with uranyl acetate and by digital fluorescence imaging microscopy measurements of magnetoliposomes labeled with fluorescein. The particles are paramagnetic at room temperature. NMR measurements show that the ratio between the relaxivities of the particles depends largely on their preparation.

  12. Image resolution in the midsagittal plane of the Orthopantomograph-10 using Lanex regular and T-Mat G screen-film combination.

    PubMed

    Chen, S K; Hollender, L

    1992-10-01

    Image resolution was measured in the midsagittal plane of the Orthopantomograph-10 with the use of Lanex regular and T-Mat G screen-film combination. A thin platinum edge phantom was used to obtain images for calculation of the edge response functions. Subsequently, line spread functions and modulation transfer functions of the system were calculated. Noise equivalent passband values, which were expressed in line pairs per millimeter, were derived to describe the image resolution. The noise equivalent passband values derived in this study were generally smaller than those reported in a previous study. The width of the image layer was found to be uniform at different vertical levels. PMID:1408031

  13. Gadolinium-153 as a brachytherapy isotope

    NASA Astrophysics Data System (ADS)

    Enger, Shirin A.; Fisher, Darrell R.; Flynn, Ryan T.

    2013-02-01

    The purpose of this work was to present the fundamental dosimetric characteristics of a hypothetical 153Gd brachytherapy source using the AAPM TG-43U1 dose-calculation formalism. Gadolinium-153 is an intermediate-energy isotope that emits 40-100 keV photons with a half-life of 242 days. The rationale for considering 153Gd as a brachytherapy source is for its potential of patient specific shielding and to enable reduced personnel shielding requirements relative to 192Ir, and as an isotope for interstitial rotating shield brachytherapy (I-RSBT). A hypothetical 153Gd brachytherapy source with an active core of 0.84 mm diameter, 10 mm length and specific activity of 5.55 TBq of 153Gd per gram of Gd was simulated with Geant4. The encapsulation material was stainless steel with a thickness of 0.08 mm. The radial dose function, anisotropy function and photon spectrum in water were calculated for the 153Gd source. The simulated 153Gd source had an activity of 242 GBq and a dose rate in water 1 cm off axis of 13.12 Gy h-1, indicating that it would be suitable as a low-dose-rate or pulsed-dose-rate brachytherapy source. The beta particles emitted have low enough energies to be absorbed in the source encapsulation. Gadolinium-153 has an increasing radial dose function due to multiple scatter of low-energy photons. Scattered photon dose takes over with distance from the source and contributes to the majority of the absorbed dose. The anisotropy function of the 153Gd source decreases at low polar angles, as a result of the long active core. The source is less anisotropic at polar angles away from the longitudinal axes. The anisotropy function increases with increasing distance. The 153Gd source considered would be suitable as an intermediate-energy low-dose-rate or pulsed-dose-rate brachytherapy source. The source could provide a means for I-RSBT delivery and enable brachytherapy treatments with patient specific shielding and reduced personnel shielding requirements relative to

  14. Gadolinium-153 as a brachytherapy isotope.

    PubMed

    Enger, Shirin A; Fisher, Darrell R; Flynn, Ryan T

    2013-02-21

    The purpose of this work was to present the fundamental dosimetric characteristics of a hypothetical (153)Gd brachytherapy source using the AAPM TG-43U1 dose-calculation formalism. Gadolinium-153 is an intermediate-energy isotope that emits 40-100 keV photons with a half-life of 242 days. The rationale for considering (153)Gd as a brachytherapy source is for its potential of patient specific shielding and to enable reduced personnel shielding requirements relative to (192)Ir, and as an isotope for interstitial rotating shield brachytherapy (I-RSBT). A hypothetical (153)Gd brachytherapy source with an active core of 0.84 mm diameter, 10 mm length and specific activity of 5.55 TBq of (153)Gd per gram of Gd was simulated with Geant4. The encapsulation material was stainless steel with a thickness of 0.08 mm. The radial dose function, anisotropy function and photon spectrum in water were calculated for the (153)Gd source. The simulated (153)Gd source had an activity of 242 GBq and a dose rate in water 1 cm off axis of 13.12 Gy h(-1), indicating that it would be suitable as a low-dose-rate or pulsed-dose-rate brachytherapy source. The beta particles emitted have low enough energies to be absorbed in the source encapsulation. Gadolinium-153 has an increasing radial dose function due to multiple scatter of low-energy photons. Scattered photon dose takes over with distance from the source and contributes to the majority of the absorbed dose. The anisotropy function of the (153)Gd source decreases at low polar angles, as a result of the long active core. The source is less anisotropic at polar angles away from the longitudinal axes. The anisotropy function increases with increasing distance. The (153)Gd source considered would be suitable as an intermediate-energy low-dose-rate or pulsed-dose-rate brachytherapy source. The source could provide a means for I-RSBT delivery and enable brachytherapy treatments with patient specific shielding and reduced personnel

  15. Fabrication and evaluation of a Gd2O2S:Tb phosphor screen film for development of a CMOS-based X-ray imaging detector

    NASA Astrophysics Data System (ADS)

    Park, Ji Koon; Choi, Su Rim; Noh, Si Cheol; Jung, Bong Jae; Choi, Il Hong; Kang, Sang Sik

    2014-08-01

    In this study, Gd2O2S:Tb phosphor screen films were fabricated by using a special particle-inbinder sedimentation method. The phosphor particles used in this study were manufactured in two sizes, 2.5- μm and 5- μm. To evaluate luminescence efficiency and the spatial resolution according to the thickness, we fabricated screen films with thicknesses of 120, 150, 170, and 210- μm. The spatial resolution of the fabricated films was assessed by using an edge method to measure the modulation transfer function (MTF). From the experimental results, the spatial resolution of the mammography exposures (low-energy X-ray quality) was better than that of dental radiography (high-energy X-ray quality). Also, with the same film thickness, the screen with 2.5- μm particles had better resolution than the screen with 5.0- μm particles, but it showed about 20% lower resolution than a commercial Gd2O2S:Tb screen. In the evaluation of the results for the dependence of the spatial resolution on the film's thickness, the 120- μm-thick screen showed the highest resolution, which was similar to that of a commercial screen.

  16. Studies of narrow autoionizing resonances in gadolinium

    SciTech Connect

    Bushaw, Bruce A.; Nortershauser, W.; Blaum, K.; Wendt, Klaus

    2003-06-30

    The autoionization (AI) spectrum of gadolinium between the first and second limits has been investigated by triple-resonance excitation with high-resolution cw lasers. A large number of narrow AI resonances have been observed and assigned total angular momentum J values. The resonances are further divided into members of AI Rydberg series converging to the second limit or other ''interloping'' levels. Fine structure in the Rydberg series has been identified and interpreted in terms of Jc j coupling. A number of detailed studies have been performed on the interloping resonances: These include lifetime determination by lineshape analysis, isotope shifts, hyperfine structure, and photoionization saturation parameters. The electronic structure of the interloping levels is discussed in terms of these studies. Linewidths generally decrease with increasing total angular momentum and the J = 7 resonances are extremely narrow with Lorentzian widths ranging from < 1 MHz up to 157 MHz. The strongest resonances are found to have cross-sections of {approx}10-12 cm{sup 2} and photoionization can be saturated with powers available from cw diode lasers.

  17. Distribution profile of gadolinium in gadolinium chelate-treated renally-impaired rats: role of pharmaceutical formulation.

    PubMed

    Fretellier, Nathalie; Salhi, Mariem; Schroeder, Josef; Siegmund, Heiko; Chevalier, Thibaut; Bruneval, Patrick; Jestin-Mayer, Gaëlle; Delaloge, Francette; Factor, Cécile; Mayer, Jean-François; Fabicki, Jean-Michel; Robic, Caroline; Bonnemain, Bruno; Idée, Jean-Marc; Corot, Claire

    2015-05-25

    While not acutely toxic, chronic hepatic effect of certain gadolinium chelates (GC), used as contrast agent for magnetic resonance imaging, might represent a risk in renally-impaired patients due to free gadolinium accumulation in the liver. To answer this question, this study investigated the consequences of the presence of small amounts of either a soluble gadolinium salt ("free" Gd) or low-stability chelating impurity in the pharmaceutical solution of gadoteric acid, a macrocyclic GC with high thermodynamic and kinetic stabilities, were investigated in renally-impaired rats. Renal failure was induced by adding 0.75% adenine in the diet for three weeks. The pharmaceutical and commercial solution of gadoteric acid was administered (5 daily intravenous injections of 2.5 mmol Gd/kg) either alone or after being spiked with either "free" gadolinium (i.e., 0.04% w/v) or low-stability impurity (i.e., 0.06 w/v). Another GC, gadodiamide (low thermodynamic and kinetic stabilities) was given as its commercial solution at a similar dose. Non-chelated gadolinium was tested at two doses (0.005 and 0.01 mmol Gd/kg) as acetate salt. Gadodiamide induced systemic toxicity (mortality, severe epidermal and dermal lesions) and substantial tissue Gd retention. The addition of very low amounts of "free", non-chelated gadolinium or low thermodynamic stability impurity to the pharmaceutical solution of the thermodynamically stable GC gadoteric acid resulted in substantial capture of metal by the liver, similar to what was observed in "free" gadolinium salt-treated rats. Relaxometry studies strongly suggested the presence of free and soluble gadolinium in the liver. Electron microscopy examinations revealed the presence of free and insoluble gadolinium deposits in hepatocytes and Kupffer cells of rats treated with gadoteric acid solution spiked with low-stability impurity, free gadolinium and gadodiamide, but not in rats treated with the pharmaceutical solution of gadoteric acid. The

  18. PARTITIONING OF GADOLINIUM IN THE CHEMICAL PROCESSING CELL

    SciTech Connect

    Reboul, S.; Best, D.; Stone, M.; Click, D.

    2011-04-27

    A combination of short-term beaker tests and longer-duration Sludge Receipt and Adjustment Tank (SRAT) simulations were performed to investigate the relative partitioning behaviors of gadolinium and iron under conditions applicable to the Chemical Processing Cell (CPC). The testing was performed utilizing non-radioactive simple Fe-Gd slurries, non-radioactive Sludge Batch 6 simulant slurries, and a radioactive real-waste slurry representative of Sludge Batch 7 material. The testing focused on the following range of conditions: (a) Fe:Gd ratios of 25-100; (b) pH values of 2-6; (c) acidification via addition of nitric, formic, and glycolic acids; (d) temperatures of {approx}93 C and {approx}22 C; and (e) oxalate concentrations of <100 mg/kg and {approx}10,000 mg/kg. The purpose of the testing was to provide data for assessing the potential use of gadolinium as a supplemental neutron poison when dispositioning excess plutonium. Understanding of the partitioning behavior of gadolinium in the CPC was the first step in assessing gadolinium's potential applicability. Significant fractions of gadolinium partitioned to the liquid-phase at pH values of 4.0 and below, regardless of the Fe:Gd ratio. In SRAT simulations targeting nitric and formic acid additions of 150% acid stoichiometry, the pH dropped to a minimum of 3.5-4.0, and the maximum fractions of gadolinium and iron partitioning to solution were both {approx}20%. In contrast, in a SRAT simulation utilizing a nitric and formic acid addition under atypical conditions (due to an anomalously low insoluble solids content), the pH dropped to a minimum of 3.7, and the maximum fractions of gadolinium and iron partitioning to solution were {approx}60% and {approx}70%, respectively. When glycolic acid was used in combination with nitric and formic acids at 100% acid stoichiometry, the pH dropped to a minimum of 3.6-4.0, and the maximum fractions of gadolinium and iron partitioning to solution were 60-80% and 3-5%, respectively

  19. Gadolinium-Based Contrast Agent Accumulation and Toxicity: An Update.

    PubMed

    Ramalho, J; Semelka, R C; Ramalho, M; Nunes, R H; AlObaidy, M; Castillo, M

    2016-07-01

    In current practice, gadolinium-based contrast agents have been considered safe when used at clinically recommended doses in patients without severe renal insufficiency. The causal relationship between gadolinium-based contrast agents and nephrogenic systemic fibrosis in patients with renal insufficiency resulted in new policies regarding the administration of these agents. After an effective screening of patients with renal disease by performing either unenhanced or reduced-dose-enhanced studies in these patients and by using the most stable contrast agents, nephrogenic systemic fibrosis has been largely eliminated since 2009. Evidence of in vivo gadolinium deposition in bone tissue in patients with normal renal function is well-established, but recent literature showing that gadolinium might also deposit in the brain in patients with intact blood-brain barriers caught many individuals in the imaging community by surprise. The purpose of this review was to summarize the literature on gadolinium-based contrast agents, tying together information on agent stability and animal and human studies, and to emphasize that low-stability agents are the ones most often associated with brain deposition. PMID:26659341

  20. Gadolinium metallo nanocongregates as potential magnetosensors for detecting early stage cancers

    SciTech Connect

    Dutta, Ranu; Pandey, Avinash C.

    2015-04-27

    Gadolinium chelates and gadolinium based inorganic nanoparticles have been extensively studied, because of the high magnetic moment of gadolinium. Here, metallic gadolinium nanocongregates have been developed. Upon injecting these nanoparticles in the mice, they initially circulate in the blood stream and are localized at the cancer site, which could be visualized upon application of magnetic field hence acting as small magnetic nanosensors searching for even small cancers, detecting cancers at a very early stage.

  1. Growth of bulk gadolinium pyrosilicate single crystals for scintillators

    NASA Astrophysics Data System (ADS)

    Gerasymov, I.; Sidletskiy, O.; Neicheva, S.; Grinyov, B.; Baumer, V.; Galenin, E.; Katrunov, K.; Tkachenko, S.; Voloshina, O.; Zhukov, A.

    2011-03-01

    Ce, Pr, and La-doped gadolinium pyrosilicate Gd2Si2O7 (GPS) single crystals were grown by the Czochralski and Top Seeded Solution Growth (TSSG) techniques for the first time. Formation conditions of different pyrosilicate phases were determined. X-ray luminescence integral intensity of Ce-doped GPS is about one order of magnitude higher in comparison with gadolinium oxyorthosilicate Gd2SiO5:Ce (GSO:Ce). All samples demonstrate temperature stability of luminescence yield up to 400 K.

  2. Purification of cerium, neodymium and gadolinium for low background experiments

    NASA Astrophysics Data System (ADS)

    Boiko, R. S.; Barabash, A. S.; Belli, P.; Bernabei, R.; Cappella, F.; Cerulli, R.; Danevich, F. A.; Incicchitti, A.; Laubenstein, M.; Mokina, V. M.; Nisi, S.; Poda, D. V.; Polischuk, O. G.; Tretyak, V. I.

    2014-01-01

    Cerium, neodymium and gadolinium contain double beta active isotopes. The most interesting are 150Nd and 160Gd (promising for 0ν2β search), 136Ce (2β+ candidate with one of the highest Q2β). The main problem of compounds containing lanthanide elements is their high radioactive contamination by uranium, radium, actinium and thorium. The new generation 2β experiments require development of methods for a deep purification of lanthanides from the radioactive elements. A combination of physical and chemical methods was applied to purify cerium, neodymium and gadolinium. Liquid-liquid extraction technique was used to remove traces of Th and U from neodymium, gadolinium and for purification of cerium from Th, U, Ra and K. Co-precipitation and recrystallization methods were utilized for further reduction of the impurities. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe gamma spectrometry. As a result of the purification procedure the radioactive contamination of gadolinium oxide (a similar purification efficiency was reached also with cerium and neodymium oxides) was decreased from 0.12 Bq/kg to 0.007 Bq/kg in 228Th, from 0.04 Bq/kg to <0.006 Bq/kg in 226Ra, and from 0.9 Bq/kg to 0.04 Bq/kg in 40K. The purification methods are much less efficient for chemically very similar radioactive elements like actinium, lanthanum and lutetium.

  3. Development of gadolinium based nanoparticles having an affinity towards melanin

    NASA Astrophysics Data System (ADS)

    Morlieras, Jessica; Chezal, Jean-Michel; Miot-Noirault, Elisabeth; Roux, Amandine; Heinrich-Balard, Laurence; Cohen, Richard; Tarrit, Sébastien; Truillet, Charles; Mignot, Anna; Hachani, Roxanne; Kryza, David; Antoine, Rodolphe; Dugourd, Philippe; Perriat, Pascal; Janier, Marc; Sancey, Lucie; Lux, François; Tillement, Olivier

    2013-01-01

    Small Rigid Platforms (SRPs) are sub-5 nanometre gadolinium based nanoparticles that have been developed for multimodal imaging and theranostic applications. They are composed of a polysiloxane network surrounded by gadolinium chelates. A covalent coupling with quinoxaline derivatives has been performed. Such derivatives have proven their affinity for melanin frequently expressed in primary melanoma cases. Three different quinoxaline derivatives have been synthesised and coupled to the nanoparticles. The affinity of the grafted nanoparticles for melanin has then been shown in vitro by surface plasmon resonance on a homemade melanin grafted gold chip.Small Rigid Platforms (SRPs) are sub-5 nanometre gadolinium based nanoparticles that have been developed for multimodal imaging and theranostic applications. They are composed of a polysiloxane network surrounded by gadolinium chelates. A covalent coupling with quinoxaline derivatives has been performed. Such derivatives have proven their affinity for melanin frequently expressed in primary melanoma cases. Three different quinoxaline derivatives have been synthesised and coupled to the nanoparticles. The affinity of the grafted nanoparticles for melanin has then been shown in vitro by surface plasmon resonance on a homemade melanin grafted gold chip. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr33457g

  4. Discovery of samarium, europium, gadolinium, and terbium isotopes

    SciTech Connect

    May, E.; Thoennessen, M.

    2013-01-15

    Currently, thirty-four samarium, thirty-four europium, thirty-one gadolinium, and thirty-one terbium isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  5. Structural and magnetic phase transitions in gadolinium under high pressures and low temperatures

    SciTech Connect

    Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.; Vohra, Yogesh K.

    2014-11-07

    High pressure structural transition studies have been carried out on rare earth metal gadolinium in a diamond anvil cell at room temperature to 169 GPa. Gadolinium has been compressed to 38% of its initial volume at this pressure. With increasing pressure, a crystal structure sequence of hcp → Smtype→ dhcp → fcc → dfcc → monoclinic has been observed in our studies on gadolinium. The measured equation of state of gadolinium is presented to 169 GPa at ambient temperature. Magnetic ordering temperature of gadolinium has been studied using designer diamond anvils to a pressure of 25 GP and a temperature of 10 K. The magnetic ordering temperature has been determined from the four-point electrical resistivity measurements carried out on gadolinium. Furthermore, our experiments show that the magnetic transition temperature decreases with increasing pressure to 19 GPa and then increases when gadolinium is subjected to higher pressures.

  6. Structural and magnetic phase transitions in gadolinium under high pressures and low temperatures

    DOE PAGESBeta

    Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.; Vohra, Yogesh K.

    2014-11-07

    High pressure structural transition studies have been carried out on rare earth metal gadolinium in a diamond anvil cell at room temperature to 169 GPa. Gadolinium has been compressed to 38% of its initial volume at this pressure. With increasing pressure, a crystal structure sequence of hcp → Smtype→ dhcp → fcc → dfcc → monoclinic has been observed in our studies on gadolinium. The measured equation of state of gadolinium is presented to 169 GPa at ambient temperature. Magnetic ordering temperature of gadolinium has been studied using designer diamond anvils to a pressure of 25 GP and a temperaturemore » of 10 K. The magnetic ordering temperature has been determined from the four-point electrical resistivity measurements carried out on gadolinium. Furthermore, our experiments show that the magnetic transition temperature decreases with increasing pressure to 19 GPa and then increases when gadolinium is subjected to higher pressures.« less

  7. Linear Gadolinium-Based Contrast Agents Are Associated With Brain Gadolinium Retention in Healthy Rats

    PubMed Central

    Robert, Philippe; Violas, Xavier; Grand, Sylvie; Lehericy, Stéphane; Idée, Jean-Marc; Ballet, Sébastien; Corot, Claire

    2016-01-01

    Objectives The aim of this study was to evaluate Gd retention in the deep cerebellar nuclei (DCN) of linear gadolinium-based contrast agents (GBCAs) compared with a macrocyclic contrast agent. Materials and Methods The brain tissue retention of Gd of 3 linear GBCAs (gadobenate dimeglumine, gadopentetate dimeglumine, and gadodiamide) and a macrocyclic GBCA (gadoterate meglumine) was compared in healthy rats (n = 8 per group) that received 20 intravenous injections of 0.6 mmol Gd/kg (4 injections per week for 5 weeks). An additional control group with saline was included. T1-weighted magnetic resonance imaging was performed before injection and once a week during the 5 weeks of injections and for another 4 additional weeks after contrast period. Total gadolinium concentration was measured with inductively coupled plasma mass spectrometry. Blinded qualitative and quantitative evaluations of the T1 signal intensity in DCN were performed, as well as a statistical analysis on quantitative data. Results At completion of the injection period, all the linear contrast agents (gadobenate dimeglumine, gadopentetate dimeglumine, and gadodiamide) induced a significant increase in signal intensity in DCN, unlike the macrocyclic GBCA (gadoterate meglumine) or saline. The T1 hypersignal enhancement kinetic was fast for gadodiamide. Total Gd concentrations for the 3 linear GBCAs groups at week 10 were significantly higher in the cerebellum (1.21 ± 0.48, 1.67 ± 0.17, and 3.75 ± 0.18 nmol/g for gadobenate dimeglumine, gadopentetate dimeglumine, and gadodiamide, respectively) than with the gadoterate meglumine (0.27 ± 0.16 nmol/g, P < 0.05) and saline (0.09 ± 0.12 nmol/g, P < 0.05). No significant difference was observed between the macrocyclic agent and saline. Conclusions Repeated administrations of the linear GBCAs gadodiamide, gadobenate dimeglumine, and gadopentetate dimeglumine to healthy rats were associated with progressive and significant T1 signal hyperintensity in the

  8. Gadolinium-enhanced magnetic resonance angiography in brain death

    NASA Astrophysics Data System (ADS)

    Luchtmann, M.; Beuing, O.; Skalej, M.; Kohl, J.; Serowy, S.; Bernarding, J.; Firsching, R.

    2014-01-01

    Confirmatory tests for the diagnosis of brain death in addition to clinical findings may shorten observation time required in some countries and may add certainty to the diagnosis under specific circumstances. The practicability of Gadolinium-enhanced magnetic resonance angiography to confirm cerebral circulatory arrest was assessed after the diagnosis of brain death in 15 patients using a 1.5 Tesla MRI scanner. In all 15 patients extracranial blood flow distal to the external carotid arteries was undisturbed. In 14 patients no contrast medium was noted within intracerebral vessels above the proximal level of the intracerebral arteries. In one patient more distal segments of the anterior and middle cerebral arteries (A3 and M3) were filled with contrast medium. Gadolinium-enhanced MRA may be considered conclusive evidence of cerebral circulatory arrest, when major intracranial vessels fail to fill with contrast medium while extracranial vessels show normal blood flow.

  9. About a Gadolinium-doped Water Cherenkov LAGUNA Detector

    SciTech Connect

    Labarga, Luis

    2010-11-24

    Water Cherenkov (wC) detectors are extremely powerful apparatuses for scientific research. Nevertheless they lack of neutron tagging capabilities, which translates, mainly, into an inability to identify the anti-matter nature of the reacting incoming anti-neutrino particles. A solution was proposed by R. Beacon and M. Vagins back in 2004: by dissolving in the water a compound with nucleus with very large cross section for neutron capture like the Gadolinium, with a corresponding emission of photons of enough energy to be detected, they can tag thermal neutrons with an efficiency larger than 80%. In this talk we detail the technique and its implications in the measurement capabilities and, as well, the new backgrounds induced. We discuss the improvement on their physics program, also for the case of LAGUNA type detectors. We comment shortly the status of the pioneering R and D program of the Super-Kamiokande Collaboration towards dissolving a Gadolinium compound in its water.

  10. An organic electroluminescent device made from a gadolinium complex

    NASA Astrophysics Data System (ADS)

    Gao, D.-Q.; Huang, C.-H.; Ibrahim, K.; Liu, F.-Q.

    2002-01-01

    A gadolinium ternary complex, tris(1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone) (phenanthroline) gadolinium [Gd(PMIP) 3(Phen)] was synthesized and used as a light emitting material in the organic electroluminescent (EL) devices. The triple layer device with a structure of indium tin oxide (ITO)/ N, N'-diphenyl- N, N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) (20 nm)/Gd(PMIP) 3(Phen) (80 nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (bathocuproine or BCP) (20 nm)/Mg: Ag(200 nm)/Ag(100 nm) exhibited green emission peaking at 535 nm. A maximum luminance of 230 cd/m 2 at 17 V and a peak power efficiency of 0.02 lm/w at 9 V were obtained.

  11. About a Gadolinium-doped Water Cherenkov LAGUNA Detector

    NASA Astrophysics Data System (ADS)

    Labarga, Luis

    2010-11-01

    Water Cherenkov (wC) detectors are extremely powerful apparatuses for scientific research. Nevertheless they lack of neutron tagging capabilities, which translates, mainly, into an inability to identify the anti-matter nature of the reacting incoming anti-neutrino particles. A solution was proposed by R. Beacon and M. Vagins back in 2004: by dissolving in the water a compound with nucleus with very large cross section for neutron capture like the Gadolinium, with a corresponding emission of photons of enough energy to be detected, they can tag thermal neutrons with an efficiency larger than 80%. In this talk we detail the technique and its implications in the measurement capabilities and, as well, the new backgrounds induced. We discuss the improvement on their physics program, also for the case of LAGUNA type detectors. We comment shortly the status of the pioneering R&D program of the Super-Kamiokande Collaboration towards dissolving a Gadolinium compound in its water.

  12. Framework to predict optimal buffer layer pairing for thin film solar cell absorbers: A case study for tin sulfide/zinc oxysulfide

    SciTech Connect

    Mangan, Niall M.; Brandt, Riley E.; Steinmann, Vera; Jaramillo, R.; Poindexter, Jeremy R.; Chakraborty, Rupak; Buonassisi, Tonio; Yang, Chuanxi; Park, Helen Hejin; Zhao, Xizhu; Gordon, Roy G.

    2015-09-21

    An outstanding challenge in the development of novel functional materials for optoelectronic devices is identifying suitable charge-carrier contact layers. Herein, we simulate the photovoltaic device performance of various n-type contact material pairings with tin(II) sulfide (SnS), a p-type absorber. The performance of the contacting material, and resulting device efficiency, depend most strongly on two variables: conduction band offset between absorber and contact layer, and doping concentration within the contact layer. By generating a 2D contour plot of device efficiency as a function of these two variables, we create a performance-space plot for contacting layers on a given absorber material. For a simulated high-lifetime SnS absorber, this 2D performance-space illustrates two maxima, one local and one global. The local maximum occurs over a wide range of contact-layer doping concentrations (below 10{sup 16 }cm{sup −3}), but only a narrow range of conduction band offsets (0 to −0.1 eV), and is highly sensitive to interface recombination. This first maximum is ideal for early-stage absorber research because it is more robust to low bulk-minority-carrier lifetime and pinholes (shunts), enabling device efficiencies approaching half the Shockley-Queisser limit, greater than 16%. The global maximum is achieved with contact-layer doping concentrations greater than 10{sup 18 }cm{sup −3}, but for a wider range of band offsets (−0.1 to 0.2 eV), and is insensitive to interface recombination. This second maximum is ideal for high-quality films because it is more robust to interface recombination, enabling device efficiencies approaching the Shockley-Queisser limit, greater than 20%. Band offset measurements using X-ray photoelectron spectroscopy and carrier concentration approximated from resistivity measurements are used to characterize the zinc oxysulfide contacting layers in recent record-efficiency SnS devices. Simulations representative of these

  13. Growth and scintillation properties of gadolinium and yttrium orthovanadate crystals

    NASA Astrophysics Data System (ADS)

    Voloshina, O. V.; Baumer, V. N.; Bondar, V. G.; Kurtsev, D. A.; Gorbacheva, T. E.; Zenya, I. M.; Zhukov, A. V.; Sidletskiy, O. Ts.

    2012-02-01

    Aiming to explore the possibility of using the undoped rare-earth orthovanadates as scintillation materials, we developed the procedure for growth of gadolinium (GdVO 4) and yttrium (YVO 4) orthovanadate single crystals by Czochralski method, and determined the optimal conditions of their after-growth annealing. Optical, luminescent, and scintillation properties of YVO 4 and GdVO 4 were discussed versus known literature data. Scintillation characteristics of GdVO 4 were determined for the first time.

  14. Solid-state gadolinium{endash}magnesium hydride optical switch

    SciTech Connect

    Armitage, R.; Rubin, M.; Richardson, T.; OBrien, N.; Chen, Y.

    1999-09-01

    The optical switching properties of gadolinium{endash}magnesium hydride have been demonstrated in a solid-state electrochromic device. With positive polarization of the hydride electrode, the visible reflectance approaches 35{percent} with virtually zero transmission, while with negative polarization, the visible transmission exceeds 25{percent} at 650 nm. The switching is reversible, with intermediate optical properties between the transparent and reflecting states. {copyright} {ital 1999 American Institute of Physics.}

  15. Magnons as a Bose-Einstein Condensate in Nanocrystalline Gadolinium

    SciTech Connect

    Kaul, S. N.; Mathew, S. P.

    2011-06-17

    The recent observation [S. P. Mathew et al., J. Phys. Conf. Ser. 200, 072047 (2010)] of the anomalous softening of spin-wave modes at low temperatures in nanocrystalline gadolinium is interpreted as a Bose-Einstein condensation (BEC) of magnons. A self-consistent calculation, based on the BEC picture, is shown to closely reproduce the observed temperature variations of magnetization and specific heat at constant magnetic fields.

  16. Type of MRI contrast, tissue gadolinium, and fibrosis

    PubMed Central

    Do, Catherine; Barnes, Jeffrey L.; Tan, Chunyan

    2014-01-01

    It has been presupposed that the thermodynamic stability constant (Ktherm) of gadolinium-based MRI chelates relate to the risk of precipitating nephrogenic systemic fibrosis. The present study compared low-Ktherm gadodiamide with high-Ktherm gadoteridol in cultured fibroblasts and rats with uninephrectomies. Gadolinium content was assessed using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy in paraffin-embedded tissues. In vitro, fibroblasts demonstrated dose-dependent fibronectin generation, transforming growth factor-β production, and expression of activated myofibroblast stress fiber protein α-smooth muscle actin. There were negligible differences with respect to toxicity or proliferation between the two contrast agents. In the rodent model, gadodiamide treatment led to greater skin fibrosis and dermal cellularity than gadoteridol. In the kidney, both contrast agents led to proximal tubule vacuolization and increased fibronectin accumulation. Despite large detectable gadolinium signals in the spleen, skin, muscle, and liver from the gadodiamide-treated group, contrast-induced fibrosis appeared to be limited to the skin and kidney. These findings support the hypothesis that low-Ktherm chelates have a greater propensity to elicit nephrogenic systemic fibrosis and demonstrate that certain tissues are resistant to these effects. PMID:25100280

  17. Type of MRI contrast, tissue gadolinium, and fibrosis.

    PubMed

    Do, Catherine; Barnes, Jeffrey L; Tan, Chunyan; Wagner, Brent

    2014-10-01

    It has been presupposed that the thermodynamic stability constant (K(therm)) of gadolinium-based MRI chelates relate to the risk of precipitating nephrogenic systemic fibrosis. The present study compared low-K(therm) gadodiamide with high-K(therm) gadoteridol in cultured fibroblasts and rats with uninephrectomies. Gadolinium content was assessed using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy in paraffin-embedded tissues. In vitro, fibroblasts demonstrated dose-dependent fibronectin generation, transforming growth factor-β production, and expression of activated myofibroblast stress fiber protein α-smooth muscle actin. There were negligible differences with respect to toxicity or proliferation between the two contrast agents. In the rodent model, gadodiamide treatment led to greater skin fibrosis and dermal cellularity than gadoteridol. In the kidney, both contrast agents led to proximal tubule vacuolization and increased fibronectin accumulation. Despite large detectable gadolinium signals in the spleen, skin, muscle, and liver from the gadodiamide-treated group, contrast-induced fibrosis appeared to be limited to the skin and kidney. These findings support the hypothesis that low-K(therm) chelates have a greater propensity to elicit nephrogenic systemic fibrosis and demonstrate that certain tissues are resistant to these effects. PMID:25100280

  18. Characteristics of Gadolinium Oxide Nanoparticles Using Terahertz Spectroscopy (abstract)

    NASA Astrophysics Data System (ADS)

    Lee, Dongkyu; Maeng, Inhee; Oh, Seung Jae; Kim, Taekhoon; Cho, Byung Kyu; Lee, Kwangyeol; Son, Joo-Hiuk

    2009-04-01

    The penetration property of the terahertz electromagnetic (THz) wave is relevant to its use. We used the THz wave spectroscopy system which easily penetrates some materials that do not contain water, e.g., plastic and ceramics. The system has been developed for several purposes, including measuring the properties of semiconductors and bio-materials, and detecting plastic bombs and ceramic knives at airports. It is also used for medical imaging systems, such as magnetic resonance imaging (MRI), at some research institutes. It can show not only the difference in amplitude, but also the difference of the phase of each point of sample. MRI technology usually uses contrast agents to enhance the quality of the image. Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), made with a heavy metal ion, is commonly used as a clinical MRI contrast agent. Gadolinium oxide (Gd2O3) nanoparticle is a new contrast agent. It serves to equip the core of each particle with antibodies or ligands. It can freely circulate in blood vessels without amassing in the liver or lungs. This study shows the characteristics of gadolinium oxide nanoparticles to further advance terahertz medical imaging.

  19. Gadolinium nitride films deposited using a PEALD based process

    NASA Astrophysics Data System (ADS)

    Fang, Ziwen; Williams, Paul A.; Odedra, Rajesh; Jeon, Hyeongtag; Potter, Richard J.

    2012-01-01

    Gadolinium nitride films have been deposited on Si(100) using a plasma-enhanced ALD (PEALD) based process. The deposition was carried out using tris(methylcyclopentadienyl)gadolinium {Gd(MeCp) 3} and remote nitrogen plasma, separated by argon pulses. Films were deposited at temperatures between 150 and 300 °C and capped with tantalum nitride to prevent post-deposition oxidation. Film composition was initially assessed using EDX and selected samples were subsequently depth profiled using medium energy ion scattering (MEIS) or AES. X-ray diffraction appears to show that the films are effectively amorphous. Films deposited at 200 °C were found to have a Gd:N ratio close to 1:1 and a low oxygen incorporation (˜5%). Although the growth was affected by partial thermal decomposition of the Gd(MeCp) 3, it was still possible to obtain smooth (Ra.=˜0.7 nm) films with good thickness uniformity (97%). Less successful attempts to deposit gadolinium nitride using thermal ALD with ammonia or mono-methyl-hydrazine are also reported.

  20. Characteristics of Gadolinium Oxide Nanoparticles Using Terahertz Spectroscopy

    SciTech Connect

    Lee, Dongkyu; Maeng, Inhee; Son, Joo-Hiuk; Oh, Seung Jae; Kim, Taekhoon; Cho, Byung Kyu; Lee, Kwangyeol

    2009-04-19

    The penetration property of the terahertz electromagnetic (THz) wave is relevant to its use. We used the THz wave spectroscopy system which easily penetrates some materials that do not contain water, e.g., plastic and ceramics. The system has been developed for several purposes, including measuring the properties of semiconductors and bio-materials, and detecting plastic bombs and ceramic knives at airports. It is also used for medical imaging systems, such as magnetic resonance imaging (MRI), at some research institutes. It can show not only the difference in amplitude, but also the difference of the phase of each point of sample. MRI technology usually uses contrast agents to enhance the quality of the image. Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), made with a heavy metal ion, is commonly used as a clinical MRI contrast agent. Gadolinium oxide (Gd{sub 2}O{sub 3}) nanoparticle is a new contrast agent. It serves to equip the core of each particle with antibodies or ligands. It can freely circulate in blood vessels without amassing in the liver or lungs. This study shows the characteristics of gadolinium oxide nanoparticles to further advance terahertz medical imaging.

  1. Boosting classification performance in computer aided diagnosis of breast masses in raw full-field digital mammography using processed and screen film images

    NASA Astrophysics Data System (ADS)

    Kooi, Thijs; Karssemeijer, Nico

    2014-03-01

    The introduction of Full-Field Digital Mammography (FFDM) in breast screening has brought with it several advantages in terms and processing facilities and image quality and Computer Aided Detection (CAD) systems are now sprouting that make use of this modality. A major drawback however, is that FFDM data is still relatively scarce and therefore, CAD system's performance are inhibited by a lack of training examples. In this paper, we explore the incorporation of more ubiquitous Screen Film Mammograms (SFM) and FFDM processed by the manufacturer, in training a system for the detection of tumour masses. We compute a small set of additional quantitative features in the raw data, that make explicit use of the log-linearity of the energy imparted on the detector in raw FFDM. We explore four di erent fusion methods: a weighted average, a majority vote, a convex combination of classi er outputs, based on the training error and an additional classi er, that combines the output of the three individual label estimates. Results are evaluated based on the Partial Area Under the Curve (PAUC) around a clinically relevant operating point. All fusion methods perform signi cantly better than any of the individual classi ers but we nd no signi cant di erence between the fusion techniques.

  2. Evaluation of Doses and Image Quality in Mammography with Screen-Film, CR, and DR Detectors – Application of the ACR Phantom

    PubMed Central

    Ślusarczyk-Kacprzyk, Wioletta; Skrzyński, Witold; Fabiszewska, Ewa

    2016-01-01

    Summary Background Different methods of image quality evaluation are routinely used for analogue and digital mammography systems in Poland. In the present study, image quality for several screen-film (SF), computed radiography (CR), and fully digital (DR) mammography systems was compared directly with the use of the ACR mammography accreditation phantom. Material/Methods Image quality and mean glandular doses were measured and compared for 47 mammography systems in the Mazovia Voivodeship in Poland, including 26 SF systems, 12 CR systems, and 9 DR systems. The mean glandular dose for the breast simulated by 4.5 cm of PMMA was calculated with methods described in the “European guidelines for quality assurance in breast cancer screening and diagnosis”. Visibility of the structures in the image (fibers, microcalcifications, and masses) was evaluated with the mammographic accreditation ACR phantom. Results Image quality for DR systems was significantly higher than for SF and CR systems. Several SF systems failed to pass the image quality tests because of artifacts. The doses were within acceptable limits for all of the systems, but the doses for the CR systems were significantly higher than for the SF and DR systems. Conclusions The best image quality, at a reasonably low dose, was observed for the DR systems. The CR systems are capable of obtaining the same image quality as the SF systems, but only at a significantly higher dose. The ACR phantom can be routinely used to evaluate image quality for all types of mammographic systems.

  3. Establishing daily quality control (QC) in screen-film mammography using leeds tor (max) phantom at the breast imaging unit of USTH-Benavides Cancer Institute

    NASA Astrophysics Data System (ADS)

    Acaba, K. J. C.; Cinco, L. D.; Melchor, J. N.

    2016-03-01

    Daily QC tests performed on screen film mammography (SFM) equipment are essential to ensure that both SFM unit and film processor are working in a consistent manner. The Breast Imaging Unit of USTH-Benavides Cancer Institute has been conducting QC following the test protocols in the IAEA Human Health Series No.2 manual. However, the availability of Leeds breast phantom (CRP E13039) in the facility made the task easier. Instead of carrying out separate tests on AEC constancy and light sensitometry, only one exposure of the phantom is done to accomplish the two tests. It was observed that measurements made on mAs output and optical densities (ODs) using the Leeds TOR (MAX) phantom are comparable with that obtained from the usual conduct of tests, taking into account the attenuation characteristic of the phantom. Image quality parameters such as low contrast and high contrast details were also evaluated from the phantom image. The authors recognize the usefulness of the phantom in determining technical factors that will help improve detection of smallest pathological details on breast images. The phantom is also convenient for daily QC monitoring and economical since less number of films is expended.

  4. Development of an imaging-planning program for screen/film and computed radiography mammography for breasts with short chest wall to nipple distance

    PubMed Central

    Dong, S L; Su, J L; Yeh, Y H; Chu, T C; Lin, Y C; Chuang, K S

    2011-01-01

    Objective Imaging breasts with a short chest wall to nipple distance (CWND) using a traditional mammographic X-ray unit is a technical challenge for mammographers. The purpose of this study is the development of an imaging-planning program to assist in determination of imaging parameters of screen/film (SF) and computed radiography (CR) mammography for short CWND breasts. Methods A traditional mammographic X-ray unit (Mammomat 3000, Siemens, Munich, Germany) was employed. The imaging-planning program was developed by combining the compressed breast thickness correction, the equivalent polymethylmethacrylate thickness assessment for breasts and the tube loading (mAs) measurement. Both phantom exposures and a total of 597 exposures were used for examining the imaging-planning program. Results Results of the phantom study show that the tube loading rapidly decreased with the CWND when the automatic exposure control (AEC) detector was not fully covered by the phantom. For patient exposures with the AEC fully covered by breast tissue, the average fractional tube loadings, defined as the ratio of the predicted mAs using the imaging-planning program and mAs of the mammogram, were 1.10 and 1.07 for SF and CR mammograms, respectively. The predicted mAs values were comparable to the mAs values, as determined by the AEC. Conclusion By applying the imaging-planning program in clinical practice, the experiential dependence of the mammographer for determination of the imaging parameters for short CWND breasts is minimised. PMID:21123310

  5. Gadolinium-based contrast agents: did we miss something in the last 25 years?

    PubMed

    Beomonte Zobel, Bruno; Quattrocchi, Carlo Cosimo; Errante, Yuri; Grasso, Rosario Francesco

    2016-06-01

    In the last 24 months, several clinical and experimental studies, suggested first and demonstrated later, a progressive concentration of Gadolinium in the brain of normal renal function patients, following repeated injections of some of the commercially approved Gadolinium-Based Contrast Agents. Although, till now, Gadolinium brain deposits have not been associated to any kind of neurological signs or symptoms, they oblige the radiology community to modify the actual approach in using Gadolinium contrast media in daily practice, to reduce unknown possible risks for patients. PMID:26706453

  6. Use of Gadolinium as a Primary Criticality Control in Disposing Waste Containing Plutonium at SRS

    SciTech Connect

    Andrew, Vincent

    2005-01-04

    Use of gadolinium as a neutron poison has been proposed for disposing of several metric tons of excess plutonium at the Savannah River Site (SRS). The plutonium will first be dissolved in nitric acid in small batches. Gadolinium nitrate will then be added to the plutonium nitrate solution. The Gd-poisoned plutonium solution will be neutralized and transferred to large under-ground tanks. The pH of small batches of neutralized plutonium solution will be adjusted prior to addition of the glass frit for eventual production as glass logs. The use of gadolinium as the neutron poison would minimize the number of glass logs generated from this disposition. The primary criticality safety concerns regarding the disposal process are: (1) maintaining neutron moderation under all processing conditions since gadolinium has a very large absorption cross section for thermal neutrons, (2) characteristics of plutonium and gadolinium precipitation during the neutralization process, (3) mixing characteristics of the precipitate to ensure that plutonium would remain homogeneously mixed with gadolinium, and (4) potential separation of plutonium and gadolinium during nitric and formic acids addition. A number of experiments were conducted at the Savannah River National Laboratory to study the behavior of plutonium and gadolinium at various stages of the disposition process.

  7. Gadolinium-based contrast agent toxicity: a review of known and proposed mechanisms.

    PubMed

    Rogosnitzky, Moshe; Branch, Stacy

    2016-06-01

    Gadolinium chelates are widely used as contrast media for magnetic resonance imaging. The approved gadolinium-based contrast agents (GBCAs) have historically been considered safe and well tolerated when used at recommended dosing levels. However, for nearly a decade, an association between GBCA administration and the development of nephrogenic systemic fibrosis (NSF) has been recognized in patients with severe renal impairment. This has led to modifications in clinical practices aimed at reducing the potential and incidence of NSF development. Newer reports have emerged regarding the accumulation of gadolinium in various tissues of patients who do not have renal impairment, including bone, brain, and kidneys. Despite the observations of gadolinium accumulation in tissues regardless of renal function, very limited clinical data regarding the potential for and mechanisms of toxicity is available. This significant gap in knowledge warrants retrospective cohort study efforts, as well as prospective studies that involve gadolinium ion (Gd(3+)) testing in patients exposed to GBCA. This review examines the potential biochemical and molecular basis of gadolinium toxicity, possible clinical significance of gadolinium tissue retention and accumulation, and methods that can limit gadolinium body burden. PMID:27053146

  8. Dual-Energy X-Radiography With Gadolinium Filter

    NASA Technical Reports Server (NTRS)

    Rutt, Brian

    1987-01-01

    Image resolution increased, and cost reduced. Proposed dual-energy x-ray imaging system, continuous bremsstrahlung spectrum from x-ray tube filtered by foil of nonradioactive gadolinium or another rare-earth metal to form two-peaked energy spectrum. After passing through patient or object under examination, filtered radiation detected by array of energy-discriminating, photon-counting detectors. Detector outputs processed to form x-ray image for each peak and possibly enhanced image based on data taken at both peaks.

  9. Studies of MRI relaxivities of gadolinium-labeled dendrons

    NASA Astrophysics Data System (ADS)

    Pan, Hongmu; Daniel, Marie-Christine

    2011-05-01

    In cancer detection, imaging techniques have a great importance in early diagnosis. The more sensitive the imaging technique and the earlier the tumor can be detected. Contrast agents have the capability to increase the sensitivity in imaging techniques such as magnetic resonance imaging (MRI). Until now, gadolinium-based contrast agents are mainly used for MRI, and show good enhancement. But improvement is needed for detection of smaller tumors at the earliest stage possible. The dendrons complexed with Gd(DOTA) were synthesized and evaluated as a new MRI contrast agent. The longitudinal and transverse relaxation effects were tested and compared with commercial drug Magnevist, Gd(DTPA).

  10. Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles

    SciTech Connect

    Mukherjee, A. Banerjee, M. Basu, S.; Pal, M.

    2014-04-24

    Multiferroic bismuth ferrite (BFO) and gadolinium (Gd) doped bismuth ferrite had been synthesized by a sol-gel method. Particle size had been estimated by Transmission electron microscopy (TEM) and found to decrease with Gd doping. We studied the temperature and frequency dependence of impedance and electric modulus and calculated the grain and grain boundary resistance and capacitance of the investigated samples. We observed that electrical activation energy increases for all the doped samples. Optical band gap also increases for the doped samples which can be used in photocatalytic application of BFO.

  11. Ascorbate and endocytosed Motexafin gadolinium induce lysosomal rupture.

    PubMed

    Berndt, Carsten; Kurz, Tino; Bannenberg, Sarah; Jacob, Ralf; Holmgren, Arne; Brunk, Ulf T

    2011-08-28

    Motexafin gadolinium (MGd) sensitizes malignant cells to ionizing radiation, although the underlying mechanisms for uptake and sensitization are both unclear. Here we show that MGd is endocytosed by the clathrin-dependent pathway with ensuing lysosomal membrane permeabilization, most likely via formation of reactive oxygen species involving redox-active metabolites, such as ascorbate. We propose that subsequent apoptosis is a synergistic effect of irradiation and high MGd concentrations in malignant cells due to their pronounced endocytic activity. The results provide novel insights into the mode of action of this promising anti-cancer drug, which is currently under clinical trials. PMID:21492999

  12. Gadolinium-based nanoparticles for theranostic MRI-radiosensitization.

    PubMed

    Lux, François; Sancey, Lucie; Bianchi, Andrea; Crémillieux, Yannick; Roux, Stéphane; Tillement, Olivier

    2015-01-01

    A rapid development of gadolinium-based nanoparticles is observed due to their attractive properties as MRI-positive contrast agents. Indeed, they display high relaxivity, adapted biodistribution and passive uptake in the tumor thanks to enhanced permeability and retention effect. In addition to these imaging properties, it has been recently shown that they can act as effective radiosensitizers under different types of irradiation (radiotherapy, neutron therapy or hadron therapy). These new therapeutic modalities pave the way to therapy guided by imaging and to personalized medicine. PMID:25715316

  13. Magnetoresistance of polycrystalline gadolinium with varying grain size

    SciTech Connect

    Chakravorty, Manotosh Raychaudhuri, A. K.

    2015-01-21

    In this paper, we report a study of evolution of low field magnetoresistance (MR) of Gadolinium as the grain size in the sample is changed from few microns (∼4 μm) to the nanoscopic regime (∼35 nm). The low field MR has a clear effect on varying grain size. In large grain sample (few μm), the magnetic domains are controlled by local anisotropy field determined mainly by the magnetocrystalline anisotropy. The low field MR clearly reflects the temperature dependence of the magnetocrystalline anisotropy. For decreasing gain size, the contribution of spin disorder at the grain boundary increases and enhances the local anisotropy field.

  14. Gadolinium Thin Foils in a Plasma Panel Sensor as an Alternative to 3He

    SciTech Connect

    Varner Jr, Robert L; Beene, James R; Friedman, Dr. Peter S.

    2010-01-01

    Gadolinium has long been investigated as a detector for neutrons. It has a thermal neutron capture cross-section that is unparalleled among stable elements, because of the isotopes $^{155,157}$Gd. As a replacement for $^3$He, gadolinium has a significant defect, it produces many gamma-rays with an energy sum of 8 MeV. It also produces conversion electrons, mostly 29 keV in energy. The key to replacing $^3$He with gadolinium is using a gamma-blind electron detector to detect the conversion electrons. We suggest that coupling a layer of gadolinium to a Plasma Panel Sensor (PPS) can provide highly efficient, nearly gamma-blind detection of the conversion. The PPS is a proposed detector under development as a dense array of avalanche counters based on plasma display technology. We will present simulations of the response of prototypes of this detector and considerations of the use of gadolinium in the PPS.

  15. The preparation of organic infrared semiconductor phthalocyanine gadolinium (III) and its optical and structural characterizations

    NASA Astrophysics Data System (ADS)

    Tang, Li-bin; Ji, Rong-bin; Song, Li-yuan; Chen, Xue-mei; Ma, Yu; Wang, Yi-feng; Qian, Ming; Song, Lei; Su, Hai-ying; Zhuang, Ji-sheng; Yang, Rui-yu

    2009-07-01

    In order to increase the species of organic infrared semiconductor, we synthesized organic infrared semiconductor phthalocyanine gadolinium by using o-phthalodinitrile and GdCl3 as reactants, ammonium molybdate as catalyzer. Under light and dark field modes of microscope, the translucency emerald-like powder of phthalocyanine gadolinium has been observed, the size of the small grain for the sample is around 5μm in diameter, the size of larger grain may reach to several tens of microns. The main vibrational peaks in FT-IR spectrum and Raman spectrum have been assigned. Elementary analysis shows that the experimental data of phthalocyanine gadolinium in the main agree with those of calculated data. The UV-Vis absorption spectrum of the sample indicates the sandwich-like structure of phthalocyanine gadolinium. The organic infrared semiconductor phthalocyanine gadolinium thin film on quartz substrate has been prepared with our synthesized powdered sample by using solution method. The characterizations of XRD and UV-Vis-NIR absorption have been carried out for the phthalocyanine gadolinium thin film on quartz substrate, XRD shows that phthalocyanine gadolinium diffractions occur at 2θ=6.851,8.290 and 8.820 degrees, the corresponding plane spacings (d) for the diffraction peaks are 12.8921, 10.6570, and 10.0176Å.The diffraction peaks locate at low diffraction angle, suggesting that the molecular size of the phthalocyanine gadolinium is big that causes the large spacing of crystal planes. The UV-Vis-NIR absorption of phthalocyanine gadolinium thin film on quartz substrate implies that within near infrared band there is a absorption in the 1.3~2.0μm wavelength range peaked at ca. 1.75μm, indicating the important potential application value of phthalocyanine gadolinium in the field of organic infrared optoelectronics.

  16. The relationship between thermodynamics and the toxicity of gadolinium complexes.

    PubMed

    Cacheris, W P; Quay, S C; Rocklage, S M

    1990-01-01

    The suitability of gadolinium complexes as magnetic resonance imaging contrast agents depends on a number of factors. A thermodynamic relationship to toxicity exists if one assumes that the chemotoxicity of the intact complex is minimal but that the toxicity of the components of the complex (free metal and uncomplexed ligands) is substantial. Release of Gd3+ from the complex is responsible for the toxicity associated with gadolinium complexes; this release appears to be a consequence of Zn2+, Cu2+, and Ca2+ transmetallation in vivo. This hypothesis is supported by acute toxicity experiments, which demonstrate that despite a 50-fold range of LD50 values for four Gd complexes, all become lethally toxic when they release precisely the same quantity of Gd3+, and by subchronic rodent toxicity experiments, which demonstrate a set of gross and microscopic findings similar to those known to be caused by Zn2+ deficiency. Finally, this hypothesis predicts that subtle changes in formulation can further enhance the intrinsic safety of these complexes. PMID:2118207

  17. Mitochondrial dysfunction induced by different concentrations of gadolinium ion.

    PubMed

    Zhao, Jie; Zhou, Zhi-Qiang; Jin, Jian-Cheng; Yuan, Lian; He, Huan; Jiang, Feng-Lei; Yang, Xiao-Gang; Dai, Jie; Liu, Yi

    2014-04-01

    Gadolinium-based compounds are the most widely used paramagnetic contrast agents in magnetic resonance imaging on the world. But the tricationic gadolinium ion (Gd(3+)) could induce cell apoptosis probably because of its effects on mitochondria. Until now, the mechanism about how Gd(3+) interacts with mitochondria is not well elucidated. In this work, mitochondrial swelling, collapsed transmembrane potential and decreased membrane fluidity were observed to be important factors for mitochondrial permeability transition pore (mtPTP) opening induced by Gd(3+). The protection effect of CsA (Cyclosporin A) could confirm high concentration of Gd(3+) (500 μM) would trigger mtPTP opening. Moreover, mitochondrial outer membrane breakdown and volume expansion observed clearly by transmission electron microscopy and the release of Cyt c (Cytochrome c) could explain the mtPTP opening from another aspect. In addition, MBM(+) (monobromobimane(+)) and DTT (dithiothreitol) could protect thiol (-SH) groups from oxidation so that the toxicity of Gd(3+) might be resulted from the chelation of -SH of membrane proteins by free Gd(3+). Gd(3+) could inhibit the initiation of mitochondrial membrane lipid peroxidation, so it might interact with anionic lipids too. These findings will highly contribute to the safe applications of Gd-based agents. PMID:24321333

  18. Gadolinium-hydrogen ion exchange of zirconium phosphate

    NASA Technical Reports Server (NTRS)

    Liu, D. C.; Power, J. L.

    1972-01-01

    The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

  19. Magnetic Surfactants and Polymers with Gadolinium Counterions for Protein Separations.

    PubMed

    Brown, Paul; Bromberg, Lev; Rial-Hermida, M Isabel; Wasbrough, Matthew; Hatton, T Alan; Alvarez-Lorenzo, Carmen

    2016-01-26

    New magnetic surfactants, (cationic hexadecyltrimethlyammonium bromotrichlorogadolinate (CTAG), decyltrimethylammonium bromotrichlorogadolinate (DTAG), and a magnetic polymer (poly(3-acrylamidopropyl)trimethylammonium tetrachlorogadolinate (APTAG)) have been synthesized by the simple mixing of the corresponding surfactants and polymer with gadolinium metal ions. A magnetic anionic surfactant, gadolinium tri(1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate) (Gd(AOT)3), was synthesized via metathesis. Both routes enable facile preparation of magnetically responsive magnetic polymers and surfactants without the need to rely on nanocomposites or organic frameworks with polyradicals. Electrical conductivity, surface tensiometry, SQUID magnetometry, and small-angle neutron scattering (SANS) demonstrate surface activity and self-aggregation behavior of the magnetic surfactants similar to their magnetically inert parent analogues but with added magnetic properties. The binding of the magnetic surfactants to proteins enables efficient separations under low-strength (0.33 T) magnetic fields in a new, nanoparticle-free approach to magnetophoretic protein separations and extractions. Importantly, the toxicity of the magnetic surfactants and polymers is, in some cases, lower than that of their halide analogues. PMID:26725503

  20. Dielectric and magnetic properties of some gadolinium silica nanoceramics

    SciTech Connect

    Coroiu, I. Pascuta, P. Bosca, M. Culea, E.

    2013-11-13

    Some nanostructure gadolinium silica glass-ceramics were obtained undergoing a sol gel method and a heat-treatment at 1000°C about two hours. The magnetic and dielectric properties of these samples were studied. The magnetic properties were evidenced performing susceptibility measurements in the 80-300K temperature range. A Curie-Weiss behavior has acquired. The values estimated for paramagnetic Curie temperature being small and positive suggest the presence of weak ferromagnetic interactions between Gd{sup 3+} ions. The dielectric properties were evaluated from dielectric permittivity (ε{sub r}) and dielectric loss (tanδ) measurements at the frequency 1 kHz, 10 kHz and 100 kHz, in the 25-225°C temperature range and dielectric dispersion at room temperature for 79.5 kHz - 1GHz frequency area. The dielectric properties suggest that the main polarization mechanism corresponds to interfacial polarization, characteristic for polycrystalline-structured dielectrics. The polycrystalline structure of the samples is due to the polymorphous transformations of the nanostructure silica crystallites in the presence of gadolinium oxide. They were highlighted by SEM micrographs.

  1. Hepatobiliary MR Imaging with Gadolinium Based Contrast Agents

    PubMed Central

    Frydrychowicz, Alex; Lubner, Meghan G.; Brown, Jeffrey J.; Merkle, Elmar M.; Nagle, Scott K.; Rofsky, Neil M.; Reeder, Scott B.

    2011-01-01

    The advent of gadolinium-based “hepatobiliary” contrast agents offers new opportunities for diagnostic MRI and has triggered a great interest for innovative imaging approaches to the liver and bile ducts. In this review article we will discuss the imaging properties of the two gadolinium-based hepatobiliary contrast agents currently available in the USA, gadobenate dimeglumine and gadoxetic acid, as well as important pharmacokinetic differences that affect their diagnostic performance. We will review potential applications, protocol optimization strategies, as well as diagnostic pitfalls. A variety of illustrative case examples will be used to demonstrate the role of these agents in detection and characterization of liver lesions as well as for imaging the biliary system. Changes in MR protocols geared towards optimizing workflow and imaging quality will also be discussed. It is our aim that the information provided in this article will facilitate the optimal utilization of these agents, and will stimulate the reader‘s pursuit of new applications for future benefit. PMID:22334493

  2. Growth Control in Colon Epithelial Cells: Gadolinium Enhances Calcium-Mediated Growth Regulation

    PubMed Central

    Attili, Durga; Jenkins, Brian; Aslam, Muhammad Nadeem; Dame, Michael K.

    2013-01-01

    Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1–5 µM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet. PMID:23008064

  3. Gadolinium nanoparticles and contrast agent as radiation sensitizers.

    PubMed

    Taupin, Florence; Flaender, Mélanie; Delorme, Rachel; Brochard, Thierry; Mayol, Jean-François; Arnaud, Josiane; Perriat, Pascal; Sancey, Lucie; Lux, François; Barth, Rolf F; Carrière, Marie; Ravanat, Jean-Luc; Elleaume, Hélène

    2015-06-01

    The goal of the present study was to evaluate and compare the radiosensitizing properties of gadolinium nanoparticles (NPs) with the gadolinium contrast agent (GdCA) Magnevist(®) in order to better understand the mechanisms by which they act as radiation sensitizers. This was determined following either low energy synchrotron irradiation or high energy gamma irradiation of F98 rat glioma cells exposed to ultrasmall gadolinium NPs (GdNPs, hydrodynamic diameter of 3 nm) or GdCA. Clonogenic assays were used to quantify cell survival after irradiation in the presence of Gd using monochromatic x-rays with energies in the 25 keV-80 keV range from a synchrotron and 1.25 MeV gamma photons from a cobalt-60 source. Radiosensitization was demonstrated with both agents in combination with X-irradiation. At the same concentration (2.1 mg mL(-1)), GdNPS had a greater effect than GdCA. The maximum sensitization-enhancement ratio at 4 Gy (SER4Gy) was observed at an energy of 65 keV for both the nanoparticles and the contrast agent (2.44   ±   0.33 and 1.50   ±   0.20, for GdNPs and GdCA, respectively). At a higher energy (1.25 MeV), radiosensitization only was observed with GdNPs (1.66   ±   0.17 and 1.01   ±   0.11, for GdNPs and GdCA, respectively). The radiation dose enhancements were highly 'energy dependent' for both agents. Secondary-electron-emission generated after photoelectric events appeared to be the primary mechanism by which Gd contrast agents functioned as radiosensitizers. On the other hand, other biological mechanisms, such as alterations in the cell cycle may explain the enhanced radiosensitizing properties of GdNPs. PMID:25988839

  4. Gadolinium nanoparticles and contrast agent as radiation sensitizers

    NASA Astrophysics Data System (ADS)

    Taupin, Florence; Flaender, Mélanie; Delorme, Rachel; Brochard, Thierry; Mayol, Jean-François; Arnaud, Josiane; Perriat, Pascal; Sancey, Lucie; Lux, François; Barth, Rolf F.; Carrière, Marie; Ravanat, Jean-Luc; Elleaume, Hélène

    2015-06-01

    The goal of the present study was to evaluate and compare the radiosensitizing properties of gadolinium nanoparticles (NPs) with the gadolinium contrast agent (GdCA) Magnevist® in order to better understand the mechanisms by which they act as radiation sensitizers. This was determined following either low energy synchrotron irradiation or high energy gamma irradiation of F98 rat glioma cells exposed to ultrasmall gadolinium NPs (GdNPs, hydrodynamic diameter of 3 nm) or GdCA. Clonogenic assays were used to quantify cell survival after irradiation in the presence of Gd using monochromatic x-rays with energies in the 25 keV-80 keV range from a synchrotron and 1.25 MeV gamma photons from a cobalt-60 source. Radiosensitization was demonstrated with both agents in combination with X-irradiation. At the same concentration (2.1 mg mL-1), GdNPS had a greater effect than GdCA. The maximum sensitization-enhancement ratio at 4 Gy (SER4Gy) was observed at an energy of 65 keV for both the nanoparticles and the contrast agent (2.44   ±   0.33 and 1.50   ±   0.20, for GdNPs and GdCA, respectively). At a higher energy (1.25 MeV), radiosensitization only was observed with GdNPs (1.66   ±   0.17 and 1.01   ±   0.11, for GdNPs and GdCA, respectively). The radiation dose enhancements were highly ‘energy dependent’ for both agents. Secondary-electron-emission generated after photoelectric events appeared to be the primary mechanism by which Gd contrast agents functioned as radiosensitizers. On the other hand, other biological mechanisms, such as alterations in the cell cycle may explain the enhanced radiosensitizing properties of GdNPs.

  5. Extracellular gadolinium-based contrast media: an overview.

    PubMed

    Bellin, Marie-France; Van Der Molen, Aart J

    2008-05-01

    Increasing use is made of extracellular MRI contrast agents that alter the image contrast following intravenous administration; they predominantly shorten the T1 relaxation time of tissues. The degree and location of these changes provide substantial diagnostic information. However gadolinium-based contrast agents (Gd-CA) are not inert drugs. They may cause acute non-renal adverse reactions (e.g. anaphylactoid reactions), acute renal adverse reactions (e.g. contrast induced nephropathy), delayed adverse reactions (nephrogenic systemic fibrosis) and problems at the site of injection (e.g. local necrosis). This review describes the current status of Gd-CA, their mechanism of action, chemical structure, pharmacokinetics, dosage, elimination, nephrotoxicity and adverse events. PMID:18358659

  6. Mechanism of inhibition of ribonucleotide reductase with motexafin gadolinium (MGd)

    SciTech Connect

    Zahedi Avval, Farnaz; Berndt, Carsten; Pramanik, Aladdin; Holmgren, Arne

    2009-02-13

    Motexafin gadolinium (MGd) is an expanded porphyrin anticancer agent which selectively targets tumor cells and works as a radiation enhancer, with promising results in clinical trials. Its mechanism of action is oxidation of intracellular reducing molecules and acting as a direct inhibitor of mammalian ribonucleotide reductase (RNR). This paper focuses on the mechanism of inhibition of RNR by MGd. Our experimental data present at least two pathways for inhibition of RNR; one precluding subunits oligomerization and the other direct inhibition of the large catalytic subunit of the enzyme. Co-localization of MGd and RNR in the cytoplasm particularly in the S-phase may account for its inhibitory properties. These data can elucidate an important effect of MGd on the cancer cells with overproduction of RNR and its efficacy as an anticancer agent and not only as a general radiosensitizer.

  7. Defect induced mobility enhancement: Gadolinium oxide (100) on Si(100)

    SciTech Connect

    Sitaputra, W.; Tsu, R.

    2012-11-26

    Growth of predominantly single crystal (100)-oriented gadolinium oxide (Gd{sub 2}O{sub 3}) on a p-type Si(100) and growth of a polycrystal with a predominant Gd{sub 2}O{sub 3}(100) crystallite on a n-type Si(100) was performed using molecular beam epitaxy. Despite a poorer crystal structure than Gd{sub 2}O{sub 3}(110), an enhancement in carrier mobility can be found only from the Gd{sub 2}O{sub 3}(100)/n-type Si(100) interface. The mobility of 1715-1780 cm{sup 2}/V {center_dot} s was observed at room temperature, for carrier concentration >10{sup 20} cm{sup -3}. This accumulation of the electrons and the mobility enhancement may arise from the two-dimensional confinement due to charge transfer across the interface similar to transfer doping.

  8. The structural response of gadolinium phosphate to pressure

    DOE PAGESBeta

    Heffernan, Karina M.; Ross, Nancy L.; Spencer, Elinor C.; Boatner, Lynn A.

    2016-06-16

    In this study, accurate elastic constants for gadolinium phosphate (GdPO4) have been measured by single-crystal high-pressure diffraction methods. The bulk modulus of GdPO4 determined under hydrostatic conditions, 128.1(8) GPa (K'=5.8(2)), is markedly different from that obtained with GdPO4 under non-hydrostatic conditions (160(2) GPa), which indicates the importance of shear stresses on the elastic response of this phosphate. Finally, high pressure Raman and diffraction analysis indicate that the PO4 tetrahedra behave as rigid units in response to pressure and that contraction of the GdPO4 structure is facilitated by bending/twisting of the Gd–O–P links that result in increased distortion in the GdO9more » polyhedra.« less

  9. The structural response of gadolinium phosphate to pressure

    NASA Astrophysics Data System (ADS)

    Heffernan, Karina M.; Ross, Nancy L.; Spencer, Elinor C.; Boatner, Lynn A.

    2016-09-01

    Accurate elastic constants for gadolinium phosphate (GdPO4) have been measured by single-crystal high-pressure diffraction methods. The bulk modulus of GdPO4 determined under hydrostatic conditions, 128.1(8) GPa (Kʹ=5.8(2)), is markedly different from that obtained with GdPO4 under non-hydrostatic conditions (160(2) GPa), which indicates the importance of shear stresses on the elastic response of this phosphate. High pressure Raman and diffraction analysis indicate that the PO4 tetrahedra behave as rigid units in response to pressure and that contraction of the GdPO4 structure is facilitated by bending/twisting of the Gd-O-P links that result in increased distortion in the GdO9 polyhedra.

  10. Strategies for the preparation of bifunctional gadolinium(III) chelators

    PubMed Central

    Frullano, Luca; Caravan, Peter

    2012-01-01

    The development of gadolinium chelators that can be easily and readily linked to various substrates is of primary importance for the development high relaxation efficiency and/or targeted magnetic resonance imaging (MRI) contrast agents. Over the last 25 years a large number of bifunctional chelators have been prepared. For the most part, these compounds are based on ligands that are already used in clinically approved contrast agents. More recently, new bifunctional chelators have been reported based on complexes that show a more potent relaxation effect, faster complexation kinetics and in some cases simpler synthetic procedures. This review provides an overview of the synthetic strategies used for the preparation of bifunctional chelators for MRI applications. PMID:22375102

  11. Sintering and mechanical properties of gadolinium-doped ceria ceramics

    NASA Astrophysics Data System (ADS)

    Yasuda, K.; Uemura, K.; Shiota, T.

    2012-01-01

    Gadolinium-doped ceria (GDC) ceramics were made by sintering at various temperatures from 1000°C to 1400°C in air. The true density and apparent density were measured to calculate the relative density of GDC ceramics. The change in relative density revealed that densification of GDC ceramics increased up to 1200°C, and thereafter turned downward. It was suggested that pores were formed at 1300°C and 1400°C due to non-stoichiometry of ceria. JIS-type specimens were cut from the sintered body and tested by 4-point bending. Young's modulus and bending strength decreased with increasing the sintering temperature from 1200°C to 1400°C, corresponding to the change in the relative density.

  12. Safety profiles of gadolinium chelates in juvenile rats differ according to the risk of dissociation.

    PubMed

    Fretellier, Nathalie; Maazouz, Meryam; Luseau, Alexandrine; Baudimont, Fannie; Jestin-Mayer, Gaëlle; Bourgery, Simon; Rasschaert, Marlène; Bruneval, Patrick; Factor, Cécile; Mecieb, Fatiha; Idée, Jean-Marc; Corot, Claire

    2014-12-01

    This study was designed to compare the safety of two gadolinium chelates (GCs), used as contrast agents for magnetic resonance imaging, in juvenile rats. Juvenile rats received five intravenous administrations (between postnatal day [PND] 4 and 18) of gadoteric acid (macrocyclic ionic GC), gadodiamide (linear nonionic GC) or saline, and sacrificed at PND 25. Gadodiamide induced mortality, alopecia and hyperpigmentation of dorsal skin. Two gadodiamide-treated rats presented severe epidermal and dermal lesions. No abnormal signs were detected following administration of gadoteric acid. Higher tissue gadolinium concentrations were found in the gadodiamide group compared to the gadoteric acid group. Dissociation of gadodiamide was observed in skin and liver, with the presence of dissociated and soluble gadolinium. In conclusion, repeated administration of gadoteric acid was well tolerated by juvenile rats. In contrast, gadodiamide induced significant toxicity and more marked tissue gadolinium retention (at least partly in the dissociated and soluble form). PMID:25462783

  13. Insights into the use of gadolinium and gadolinium/boron-based agents in imaging-guided neutron capture therapy applications.

    PubMed

    Deagostino, Annamaria; Protti, Nicoletta; Alberti, Diego; Boggio, Paolo; Bortolussi, Silva; Altieri, Saverio; Crich, Simonetta Geninatti

    2016-05-01

    Gadolinium neutron capture therapy (Gd-NCT) is currently under development as an alternative approach for cancer therapy. All of the clinical experience to date with NCT is done with (10)B, known as boron neutron capture therapy (BNCT), a binary treatment combining neutron irradiation with the delivery of boron-containing compounds to tumors. Currently, the use of Gd for NCT has been getting more attention because of its highest neutron cross-section. Although Gd-NCT was first proposed many years ago, its development has suffered due to lack of appropriate tumor-selective Gd agents. This review aims to highlight the recent advances for the design, synthesis and biological testing of new Gd- and B-Gd-containing compounds with the task of finding the best systems able to improve the NCT clinical outcome. PMID:27195428

  14. Density of Gadolinium Nitrate Solutions for the High Flux Isotope Reactor

    SciTech Connect

    Taylor, Paul Allen; Lee, Denise L

    2009-05-01

    In late 1992, the High Flux Isotope Reactor (HFIR) was planning to switch the solution contained in the poison injection tank from cadmium nitrate to gadolinium nitrate. The poison injection system is an emergency system used to shut down the reactor by adding a neutron poison to the cooling water. This system must be able to supply a minimum of 69 pounds of gadolinium to the reactor coolant system in order to guarantee that the reactor would become subcritical. A graph of the density of gadolinium nitrate solutions over a concentration range of 5 to 30 wt% and a temperature range of 15 to 40{sup o}C was prepared. Routine density measurements of the solution in the poison injection tank are made by HFIR personnel, and an adaptation of the original graph is used to determine the gadolinium nitrate concentration. In late 2008, HFIR personnel decided that the heat tracing that was present on the piping for the poison injection system could be removed without any danger of freezing the solution; however, the gadolinium nitrate solution might get as cold as 5{sup o}C. This was outside the range of the current density-concentration correlation, so the range needed to be expanded. This report supplies a new density-concentration correlation that covers the extended temperature range. The correlation is given in new units, which greatly simplifies the calculation that is required to determine the pounds of gadolinium in the tank solution. The procedure for calculating the amount of gadolinium in the HFIR poison injection system is as follows: (1) Calculate the usable volume in the system; (2) Measure the density of the solution; (3) Calculate the gadolinium concentration using the following equation: Gd(lb/ft{sup 3}) = measured density (g/mL) x 34.681 - 34.785; (4) Calculate the amount of gadolinium in the system using the following equation: Amount of Gd(lb) = Gd concentration (lb/ft{sup 3}) x usable volume (ft{sup 3}). The equation in step 3 is exact for a temperature of

  15. Gadolinium Use in Spine Pain Management Procedures for Patients with Contrast Allergies: Results in 527 Procedures

    SciTech Connect

    Safriel, Yair Ang, Roberto; Ali, Muhammed

    2008-03-15

    Introduction. To review the safety and efficacy of gadolinium in spine pain management procedures in patients at high risk for a contrast reaction and who are not suitable candidates for the use of standard non-ionic contrast. Methods. We reviewed records over a 61-month period of all image-guided spinal pain management procedures where patients had allergies making them unsuitable candidates for standard non-ionic contrast and where gadolinium was used to confirm needle tip placement prior to injection of medication. Results. Three hundred and four outpatients underwent 527 procedures. A spinal needle was used in all but 41 procedures. Gadolinium was visualized using portable C-arm fluoroscopy in vivo allowing for confirmation of needle tip location. The gadolinium dose ranged from 0.2 to 10 ml per level. The highest dose received by one patient was 15.83 ml intradiscally during a three-level discogram. Three hundred and one patients were discharged without complication or known delayed complications. One patient had documented intrathecal injection but without sequelae and 2 patients who underwent cervical procedures experienced seizures requiring admission to the intensive care unit. Both the latter patients were discharged without any further complications. Conclusion. Based on our experience we recommend using gadolinium judiciously for needle tip confirmation. We feel more confident using gadolinium in the lumbar spine and in cervical nerve blocks. Gadolinium should probably not be used as an injectate volume expander. The indications for gadolinium use in cervical needle-guided spine procedures are less clear and use of a blunt-tipped needle should be considered.

  16. Crystal Structure, Electronic Structure, and Photocatalytic Activity of Oxysulfides: La2Ta2ZrS2O8, La2Ta2TiS2O8, and La2Nb2TiS2O8.

    PubMed

    Goto, Yosuke; Seo, Jeongsuk; Kumamoto, Kazunori; Hisatomi, Takashi; Mizuguchi, Yoshikazu; Kamihara, Yoichi; Katayama, Masao; Minegishi, Tsutomu; Domen, Kazunari

    2016-04-01

    The novel oxysulfides La2Ta2ZrS2O8 (LTZSO), La2Ta2TiS2O8 (LTTSO), and La2Nb2TiS2O8 (LNTSO) were synthesized, and their crystal structures, electronic structures, and photocatalytic activities for water splitting under visible light were investigated. Density functional theory calculations showed that these compounds are direct-band-gap semiconductors. Close to the conduction band minimum, the main contribution to the band structure comes from the d orbitals of Zr or Ti ions, while the region near the valence band maximum is associated with the 3p orbitals of S ions. The absorption-edge wavelength was determined to be 540 nm for LTZSO and 700 nm for LTTSO and LNTSO. An analysis of the crystal structure using synchrotron X-ray diffraction revealed that these compounds contained antisite defects at transition metal ion sites, and these were considered to be the origin of the broad absorption at wavelengths longer than that corresponding to band-gap excitation. LTZSO was revealed to be active in the oxygen evolution reaction from aqueous solution containing a sacrificial electron acceptor under visible-light illumination. This result was supported by the band alignment and flat-band potential determined by photoelectron spectroscopy and Mott-Schottky plots. PMID:27008368

  17. XAFS study of gadolinium and samarium bisporphyrinate complexes.

    PubMed

    Agondanou, J H; Spyroulias, G A; Purans, J; Tsikalas, G; Souleau, C; Coutsolelos, A G; Bénazeth, S

    2001-11-19

    The comparative X-ray absorption spectroscopy study of gadolinium and samarium bisporphyrinate complexes represented by the formulas Gd(III)H(oep)(tpp), Gd(III)(oep)(2), Gd(III)H(tpp)(2) and Sm(III)H(oep)(tpp), Sm(III)(oep)(2), Sm(III)H(tpp)(2) is reported. The XAFS spectra are recorded on the LURE-DCI storage ring (Orsay, France) in transmission mode on the microcrystalline samples at the Gd and Sm L(3) edges. The local environment for Ln(3+) ions has been reconstructed applying one-shell and two-shell XAFS analysis procedures. The protonated and nonprotonated bisporphyrinate complexes present different XAFS features. After our analysis on the title derivatives, the gadolinium ion (at 80 K) is found to be bonded: (i) to eight nitrogen atoms at R(Gd-N) 2.50 A, for Gd(III)(oep)(2) [Debye-Waller (DW) factor 0.004 A(2)]; (ii) to seven nitrogen atoms at R(Gd-N) 2.49 A, for Gd(III)H(oep)(tpp) [DW factor 0.005 A(2)] and one nitrogen at long distance; and (iii) to six nitrogen atoms at R(Gd-N) 2.50 A [DW factor 0.006 A(2)] and two nitrogen atoms at long distance for Gd(III)H(tpp)(2). A similar coordination sphere has been detected for the corresponding Sm derivatives. So, the samarium ion (at room temperature) is bonded: (i) to eight nitrogen atoms at R(Sm-N) 2.53 A, for Sm(III)(oep)(2) [DW factor 0.006 A(2)]; (ii) to seven nitrogen atoms at R(Sm-N) 2.53 A, for Sm(III)H(oep)(tpp) [DW factor 0.006 A(2)] and one nitrogen at long distance; and (iii) to six nitrogen atoms at R(Sm-N) 2.50 A, for Sm(III)H(tpp)(2) [DW factor 0.006 A(2)] and two nitrogen atoms at long distance. As far as concerns Ln(III)(oep)(2) complexes, the increase of Ln-N distance in the series Gd(3+) < Eu(3+) < Sm(3+) reflects an increase in the ionic radii, which are in good agreement with previously published XRD data on Eu(III)(oep)(2). Moreover, the protonated Ln(III)H(oep)(tpp) and Ln(III)H(tpp)(2) complexes possess systematically shorter distances of about 0.02 A between the XAFS and XRD data. This

  18. Cationic gadolinium chelate for magnetic resonance imaging of cartilaginous defects.

    PubMed

    Nwe, Kido; Huang, Ching-Hui; Qu, Feini; Warden-Rothman, Robert; Zhang, Clare Y; Mauck, Robert L; Tsourkas, Andrew

    2016-05-01

    The ability to detect meniscus defects by magnetic resonance arthrography (MRA) can be highly variable. To improve the delineation of fine tears, we synthesized a cationic gadolinium complex, (Gd-DOTA-AM4 )(2+) , that can electrostatically interact with Glycosaminoglycans (GAGs). The complex has a longitudinal relaxivity (r1) of 4.2 mM(-1) s(-1) and is highly stable in serum. Its efficacy in highlighting soft tissue tears was evaluated in comparison to a clinically employed contrast agent (Magnevist) using explants obtained from adult bovine menisci. In all cases, Gd-DOTA-AM4 appeared to improve the ability to detect the soft tissue defect by providing increased signal intensity along the length of the tear. Magnevist shows a strong signal near the liquid-meniscus interface, but much less contrast is observed within the defect at greater depths. This provides initial evidence that cationic contrast agents can be used to improve the diagnostic accuracy of MRA. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26853708

  19. Impedance spectroscopic characterization of gadolinium substituted cobalt ferrite ceramics

    SciTech Connect

    Rahman, Md. T. Ramana, C. V.

    2014-10-28

    Gadolinium (Gd) substituted cobalt ferrites (CoFe{sub 2−x}Gd{sub x}O{sub 4}, referred to CFGO) with variable Gd content (x = 0.0–0.4) have been synthesized by solid state ceramic method. The crystal structure and impedance properties of CFGO compounds have been evaluated. X-ray diffraction measurements indicate that CFGO crystallize in the inverse spinel phase. The CFGO compounds exhibit lattice expansion due to substitution of larger Gd ions into the crystal lattice. Impedance spectroscopy analysis was performed under a wide range of frequency (f = 20 Hz–1 MHz) and temperature (T = 303–573 K). Electrical properties of Gd incorporated Co ferrite ceramics are enhanced compared to pure CoFe{sub 2}O{sub 4} due to the lattice distortion. Impedance spectroscopic analysis illustrates the variation of bulk grain and grain-boundary contributions towards the electrical resistance and capacitance of CFGO materials with temperature. A two-layer heterogeneous model consisting of moderately conducting grain interior (ferrite-phase) regions separated by insulating grain boundaries (resistive-phase) accurately account for the observed temperature and frequency dependent electrical characteristic of CFGO ceramics.

  20. Gadolinium Doped Water Cherenkov Detector for use as Neutron Detector

    NASA Astrophysics Data System (ADS)

    Davis, Patrick; Woltman, Brian; Mei, Dongming; Sun, Yongchen; Thomas, Keenan; Perevozchikov, Oleg

    2010-11-01

    Background characterization is imperative to the success of rare event physics research such as neutrinoless double-beta decay and dark matter searches. There are a number of different ways to measure backgrounds from muon-induced processes and other forms of high energy events. In our current research, we are constructing a research and development project for the feasibility of a Gadolinium doped water Cherenkov detector as a neutron detector. We are constructing a 46 liter acrylic housing for the Gd-doped water consisting of two acrylic cone sections connected to a middle acrylic cylinder to increase volume while still using 5 inch photo multiplier tubes (PMTs) on either end. I will present the challenges of a Gd-doped water detector and the reasons why our design should be much more successful than past metal housed detectors. I will also discuss our current progress and future goals of our detector including its use in characterizing the background in the future underground laboratory in the Sanford Lab, soon to be DUSEL.

  1. Gadolinium oxide nanoparticles as potential multimodal imaging and therapeutic agents.

    PubMed

    Kim, Tae Jeong; Chae, Kwon Seok; Chang, Yongmin; Lee, Gang Ho

    2013-01-01

    Potentials of hydrophilic and biocompatible ligand coated gadolinium oxide nanoparticles as multimodal imaging agents, drug carriers, and therapeutic agents are reviewed. First of all, they can be used as advanced T1 magnetic resonance imaging (MRI) contrast agents because they have r1 larger than those of Gd(III)-chelates due to a high density of Gd(III) per nanoparticle. They can be further functionalized by conjugating other imaging agents such as fluorescent imaging (FI), X-ray computed tomography (CT), positron emission tomography (PET), and single photon emission tomography (SPECT) agents. They can be also useful for drug carriers through morphology modifications. They themselves are also potential CT and ultrasound imaging (USI) contrast and thermal neutron capture therapeutic (NCT) agents, which are superior to commercial iodine compounds, air-filled albumin microspheres, and boron ((10)B) compounds, respectively. They, when conjugated with targeting agents such as antibodies and peptides, will provide enhanced images and be also very useful for diagnosis and therapy of diseases (so called theragnosis). PMID:23432005

  2. Susceptibility-Based Analysis Of Dynamic Gadolinium Bolus Perfusion MRI

    PubMed Central

    Bonekamp, David; Barker, Peter B.; Leigh, Richard; van Zijl, Peter C.M.; Li, Xu

    2014-01-01

    Purpose An algorithm is developed for the reconstruction of dynamic, gadolinium (Gd) bolus MR perfusion images of the human brain, based on quantitative susceptibility mapping (QSM). Methods The method is evaluated in 5 perfusion scans obtained from 4 different patients scanned at 3T, and compared to the conventional analysis based on changes in the transverse relaxation rate ΔR2* and to theoretical predictions. QSM images were referenced to ventricular CSF for each dynamic of the perfusion sequence. Results Images of cerebral blood flow and blood volume were successfully reconstructed from the QSM-analysis, and were comparable to those reconstructed using ΔR2*. The magnitudes of the Gd-associated susceptibility effects in gray and white matter were consistent with theoretical predictions. Conclusion QSM-based analysis may have some theoretical advantages compared to ΔR2*, including a simpler relationship between signal change and Gd concentration. However, disadvantages are its much lower contrast-to-noise ratio, artifacts due to respiration and other effects, and more complicated reconstruction methods. More work is required to optimize data acquisition protocols for QSM-based perfusion imaging. PMID:24604343

  3. LASERS: Efficient neodymium-doped gadolinium gallium garnet crystal laser

    NASA Astrophysics Data System (ADS)

    Doroshenko, Maxim E.; Osiko, Vyacheslav V.; Sigachev, V. B.; Timoshechkin, M. I.

    1991-07-01

    An investigation was made of the stimulated emission parameters of a laser utilizing a gadolinium gallium garnet crystal doped with neodymium ions (YAG:Nd) at the 1.062 μm wavelength. The free-running efficiency was the highest so far achieved for flashlamp-pumped lasers utilizing unsensitized garnets. For an active element 8 mm in diameter and 120 mm long the absolute efficiency was 5.4% and the differential efficiency was 5.9%. The average free-running power was 170 W. A comparison was made of the optical powers of thermal lenses in cylindrical GGG:Nd and YAG:Nd active elements and this was found to be 2.4 times higher for a GGG:Nd crystal at the same pump powers. It was shown that by using traditional methods of compensating for the thermal lens in cylindrical active elements, it is possible to develop pulsed GGG:Nd crystal lasers having an average output power higher than 100 W, an efficiency of ~ 4%, and an angular divergence of less than 10 mrad.

  4. Hybrid Calcium Phosphate-Polymeric Micelles Incorporating Gadolinium Chelates for Imaging-Guided Gadolinium Neutron Capture Tumor Therapy.

    PubMed

    Mi, Peng; Dewi, Novriana; Yanagie, Hironobu; Kokuryo, Daisuke; Suzuki, Minoru; Sakurai, Yoshinori; Li, Yanmin; Aoki, Ichio; Ono, Koji; Takahashi, Hiroyuki; Cabral, Horacio; Nishiyama, Nobuhiro; Kataoka, Kazunori

    2015-06-23

    Gadolinium (Gd) chelates-loaded nanocarriers have high potential for achieving magnetic resonance imaging (MRI)-guided Gd neutron capture therapy (GdNCT) of tumors. Herein, we developed calcium phosphate micelles hybridized with PEG-polyanion block copolymers, and incorporated with the clinical MRI contrast agent Gd-diethylenetriaminepentaacetic acid (Gd-DTPA/CaP). The Gd-DTPA/CaP were nontoxic to cancer cells at the concentration of 100 μM based on Gd-DTPA, while over 50% of the cancer cells were killed by thermal neutron irradiation at this concentration. Moreover, the Gd-DTPA/CaP showed a dramatically increased accumulation of Gd-DTPA in tumors, leading to the selective contrast enhancement of tumor tissues for precise tumor location by MRI. The enhanced tumor-to-blood distribution ratio of Gd-DTPA/CaP resulted in the effective suppression of tumor growth without loss of body weight, indicating the potential of Gd-DTPA/CaP for safe cancer treatment. PMID:26033034

  5. The use of iodinated and gadolinium contrast media during pregnancy and lactation.

    PubMed

    Webb, Judith A W; Thomsen, Henrik S; Morcos, Sameh K

    2005-06-01

    The use of iodinated or gadolinium-based contrast media in pregnant or lactating women often causes concerns in the radiology department because of the principle of not exposing a fetus or neonate to any drugs. Because of the uncertainty about the use of contrast media during pregnancy and lactation, the Contrast Media Safety Committee of the European Society of Urogenital Radiology decided to review the literature and draw up guidelines. An extensive literature search was carried out and summarized in a report. Based on the limited information available, simple guidelines have been drawn up. The report and guidelines were discussed at the 11th European Symposium on Urogenital Radiology in Santiago de Compostela, Spain. Mutagenic and teratogenic effects have not been described after administration of gadolinium or iodinated contrast media. Free iodide in radiographic contrast medium given to the mother has the potential to depress fetal/neonatal thyroid function. Neonatal thyroid function should be checked during the 1st week if iodinated contrast media have been given during pregnancy. No effect on the fetus has been seen after gadolinium contrast media. Only tiny amounts of iodinated or gadolinium-based contrast medium given to a lactating mother reach the milk, and only a minute proportion entering the baby's gut is absorbed. The very small potential risk associated with absorption of contrast medium may be considered insufficient to warrant stopping breast-feeding for 24 h following either iodinated or gadolinium contrast agents. PMID:15609057

  6. Gadolinium-containing MRI contrast agents: important variations on a theme for NSF.

    PubMed

    Kuo, Phillip H

    2008-01-01

    Millions of doses of gadolinium-based contrast agents (GBCAs) are administered annually to improve the clinical utility of magnetic resonance imaging. All the approved agents incorporate one atom of the rare earth metal gadolinium into a chelate to improve the safety of the ordinarily toxic free gadolinium. The undeniable epidemiologic link between GBCAs and nephrogenic systemic fibrosis (NSF) has prompted renewed investigation into the different chemical properties of the GBCAs despite their clinical interchangeability. Gadolinium-based contrast agents can be divided into different categories: linear versus macrocyclic structure, ionic versus nonionic, and non-protein-binding versus protein-binding agents. The GBCAs differ significantly with respect to transmetallation and kinetic and thermodynamic stability and therefore their propensity to release free gadolinium, which is hypothesized to induce NSF. That gadodiamide, with its susceptibility to transmetallation and relatively low thermodynamic and kinetic stability, is associated with the most cases of NSF supports this hypothesis. On the other hand, the greater stability of a macrocyclic agent hypothetically would confer a greater safety margin with regard to NSF. Because few published data on an experimental model of NSF exist, continuing vigilance is necessary to report new cases of NSF, especially with regard to the agents with small market share. PMID:18180006

  7. Extraction of gadolinium from high flux isotope reactor control plates. [Alternative method

    SciTech Connect

    Kohring, M.W.

    1987-04-01

    Gadolinium-153 is an important radioisotope used in the diagnosis of various bone disorders. Recent medical and technical developments in the detection and cure of osteoporosis, a bone disease affecting an estimated 50 million people, have greatly increased the demand for this isotope. The Oak Ridge National Laboratory (ORNL) has produced /sup 153/Gd since 1980 primarily through the irradiation of a natural europium-oxide powder followed by the chemical separation of the gadolinium fraction from the europium material. Due to the higher demand for /sup 153/Gd, an alternative production method to supplement this process has been investigated. This process involves the extraction of gadolinium from the europium-bearing region of highly radioactive, spent control plates used at the High Flux Isotope Reactor (HFIR) with a subsequent re-irradiation of the extracted material for the production of the /sup 153/Gd. Based on the results of experimental and calculational analyses, up to 25 grams of valuable gadolinium (greater than or equal to60% enriched in /sup 152/Gd) resides in the europium-bearing region of the HFIR control components of which 70% is recoverable. At a specific activity yield of 40 curies of /sup 153/Gd for each gram of gadolinium re-irradiated, 700 one-curie sources can be produced from each control plate assayed.

  8. Tumor-induced lymph node alterations detected by MRI lymphography using gadolinium nanoparticles

    PubMed Central

    Partridge, S. C.; Kurland, B. F.; Liu, C.-L.; Ho, R. J. Y.; Ruddell, A.

    2015-01-01

    Contrast-enhanced MRI lymphography shows potential to identify alterations in lymph drainage through lymph nodes (LNs) in cancer and other diseases. MRI studies have typically used low molecular weight gadolinium contrast agents, however larger gadolinium-loaded nanoparticles possess characteristics that could improve the specificity and sensitivity of lymphography. The performance of three gadolinium contrast agents with different sizes and properties was compared by 3T MRI after subcutaneous injection. Mice bearing B16-F10 melanoma footpad tumors were imaged to assess tumor-induced alterations in lymph drainage through tumor-draining popliteal and inguinal LNs versus contralateral uninvolved drainage. Gadolinium lipid nanoparticles were able to identify tumor-induced alterations in contrast agent drainage into the popliteal LN, while lower molecular weight or albumin-binding gadolinium agents were less effective. All of the contrast agents distributed in foci around the cortex and medulla of tumor-draining popliteal LNs, while they were restricted to the cortex of non-draining LNs. Surprisingly, second-tier tumor-draining inguinal LNs exhibited reduced uptake, indicating that tumors can also divert LN drainage. These characteristics of tumor-induced lymph drainage could be useful for diagnosis of LN pathology in cancer and other diseases. The preferential uptake of nanoparticle contrasts into tumor-draining LNs could also allow selective targeting of therapies to tumor-draining LNs. PMID:26497382

  9. CHARACTERIZATION OF AN ADVANCED GADOLINIUM NEUTRON ABSORBER ALLOY BY MEANS OF NEUTRON TRANSMISSION

    SciTech Connect

    Gregg W. Wachs

    2007-09-01

    Neutron transmission experiments were performed on samples of an advanced nickel-chromium-molybdenum-gadolinium (Ni-Cr-Mo-Gd) neutron absorber alloy. The primary purpose of the experiments was to demonstrate the thermal neutron absorbing capability of the alloy at specific gadolinium dopant levels. The new alloy is to be deployed for criticality control of highly enriched DOE SNF. For the transmission experiments, alloy test samples were fabricated with 0.0, 1.58 and 2.1 wt% natural gadolinium dispersed in a Ni-Cr-Mo base alloy. The transmission experiments were successfully carried out at the Los Alamos Neutron Science Center (LANSCE). Measured data from the neutron transmission experiments were compared to calculated results derived from a simple exponential transmission formula using only radiative capture cross sections. Excellent agreement between the measured and calculated results demonstrated the expected strong thermal absorption capability of the gadolinium poison and in addition, verified the measured elemental composition of the alloy test samples. The good agreement also indirectly confirmed that the gadolinium was dispersed fairly uniformly in the alloy and the ENDF VII radiative capture cross section data were accurate.

  10. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R. A.

    2012-03-12

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 °C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. At 25 °C, for 6 M HNO{sub 3}, 11 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2.5 g/L and 0.8 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}. The solubility of Gd in 4 M HNO{sub 3} with 0.15 M oxalate at 10 °C is about 1.5 g/L. For 6 M HNO{sub 3} with 0.15 M oxalate, the solubility of Gd at 10

  11. Patterns of late gadolinium enhancement in Duchenne muscular dystrophy carriers

    PubMed Central

    2014-01-01

    Background This study was designed to assess whether cardiovascular magnetic resonance imaging (CMR) in Duchenne muscular dystrophy carriers (DMDc) may index any cell milieu elements of LV dysfunction and whether this cardiac phenotype may be related to genotype. The null hypothesis was that myocardial fibrosis, assessed by late gadolinium enhancement (LGE), might be similarly accounted for in DMDc and gender and age-matched controls. Methods Thirty DMDc patients had CMR and genotyping with 37 gender and age-matched controls. Systolic and diastolic LV function was assessed by 2D-echocardiography. Results Absolute and percent LGE were higher in muscular symptomatic (sym) than asymptomatic (asy) DMDc (1.77 ± 0.27 vs 0.76 ± 0.17 ml; F = 19.6, p < 0.0001 and 1.86 ± 0.26% vs 0.68 ± 0.17%, F = 22.1, p < 0.0001, respectively). There was no correlation between LGE and age. LGE was seen most frequently in segments 5 and 6; segment 5 was involved in all asy-DMDc. Subepicardial LGE predominated, compared to the mid-myocardial one (11 out of 14 DMDc). LGE was absent in the subendocardium. No correlations were seen between genotyping (type of mutation, gene region and protein domain), confined to the exon’s study, and cardiac phenotype. Conclusions A typical myocardial LGE-pattern location (LV segments 5 and 6) was a common finding in DMDc. LGE was more frequently subepicardial plus midmyocardial in sym-DMDc, with normal LV systolic and diastolic function. No genotype-phenothype correlation was found. PMID:25008475

  12. Utility of late gadolinium enhancement in pediatric cardiac MRI.

    PubMed

    Etesami, Maryam; Gilkeson, Robert C; Rajiah, Prabhakar

    2016-07-01

    Late gadolinium enhancement (LGE) cardiac magnetic resonance (MR) imaging sequence is increasingly used in the evaluation of pediatric cardiovascular disorders, and although LGE might be a normal feature at the sites of previous surgeries, it is pathologically seen as a result of extracellular space expansion, either from acute cell damage or chronic scarring or fibrosis. LGE is broadly divided into ischemic and non-ischemic patterns. LGE caused by myocardial infarction occurs in a vascular distribution and always involves the subendocardial portion, progressively involving the outer regions in a waveform pattern. Non-ischemic cardiomyopathies can have a mid-myocardial (either linear or patchy), subepicardial or diffuse subendocardial distribution. Idiopathic dilated cardiomyopathy can have a linear mid-myocardial pattern, while hypertrophic cardiomyopathy can have fine, patchy enhancement in hypertrophied and non-hypertrophied segments as well as right ventricular insertion points. Myocarditis and sarcoidosis have a mid-myocardial or subepicardial pattern of LGE. Fabry disease typically affects the basal inferolateral segment while Danon disease typically spares the septum. Pericarditis is characterized by diffuse or focal pericardial thickening and enhancement. Thrombus, the most common non-neoplastic cardiac mass, is characterized by absence of enhancement in all sequences, while neoplastic masses show at least some contrast enhancement, depending on the pathology. Regardless of the etiology, presence of LGE is associated with a poor prognosis. In this review, we describe the technical modifications required for performing LGE cardiac MR sequence in children, review and illustrate the patterns of LGE in children, and discuss their clinical significance. PMID:26718199

  13. Gadolinium block of calcium channels: influence of bicarbonate.

    PubMed

    Boland, L M; Brown, T A; Dingledine, R

    1991-11-01

    The selectivity of block of voltage-activated barium (Ba2+) currents by lanthanide ions was studied in a rat dorsal root ganglion (DRG) cell line (F11-B9), rat and frog peripheral neurons, and rat cardiac myocytes using the whole-cell patch clamp technique. Gadolinium (Gd3+) produced a dose-dependent and complete inhibition of whole-cell Ba2+ current in all cells studied, including cells expressing identified dihydropyridine-sensitive L-type currents and omega-conotoxin-sensitive N-type currents. Like Gd3+, lutetium (Lu3+) and lanthanum (La3+) blocked all Ba2+ current with little selectivity for different components of the whole-cell current. Gd3+ block of Ba2+ currents was incomplete, however, when sodium bicarbonate (5-22.6 mM) was added to the standard HEPES-buffered external Ba2+ solution. In rat DRG neurons and F11-B9 cells, a fraction of the whole-cell Ba2+ current recorded in the presence of bicarbonate was resistant to block by saturating concentrations of Gd3+ (50-100 microM). The resistant current inactivated more rapidly than the original current giving the appearance that, under these conditions, Gd3+ block is more selective for the slowly inactivating component of the whole-cell current. Bicarbonate modification of Gd3+ block occurred both before and after omega-conotoxin block of N-type currents in rat DRG neurons, suggesting that even in the presence of bicarbonate, Gd3+ block was not selective for N-type currents. PMID:1786527

  14. Status of the Super-Kamiokande gadolinium project

    NASA Astrophysics Data System (ADS)

    Mori, Takaaki

    2013-12-01

    The diffuse flux of neutrinos released from all past supernova explosions in the universe is known as the supernova relic neutrinos (SRN). Super-Kamiokande (SK) has conducted searches for these SRN events via their inverse beta decay interactions in the detector, in the process establishing the world's best limits on this still unobserved flux. These limits are within about a factor of two of the theoretically predicted fluxes. But these searches are background limited, and without some major improvement further progress will be difficult. The addition of gadolinium (Gd) compound into the SK detector was proposed to reduce background. Gd has the largest thermal neutron capture cross-section among all stable nuclei and emits an 8 MeV γ cascade following the capture. By coincidental tagging of positrons with the γ rays from Gd neutron capture, we can identify the dominant SRN signal in SK: inverse beta decay. This Gd-loading technique should allow SK to make the world's first observation of a SRN signal. We will demonstrate the principle of a Gd-doped water Cherenkov detector (transparency of the Gd-doped water, Gd-doped water circulation method, neutron capture efficiency, etc) with a dedicated test facility named EGADS. EGADS consists of a 200 ton water Cherenkov detector, a Gd dissolving pre-treatment device, a Gd-capable water circulation system, and a custom-built water transparency measurement device. We have evaluated Gd-doped water circulation using the main EGADS water system since 2012. The evaluation of the overall performance of EGADS will start in 2013 after PMT installation.

  15. The High Radiosensitizing Efficiency of a Trace of Gadolinium-Based Nanoparticles in Tumors

    PubMed Central

    Dufort, Sandrine; Le Duc, Géraldine; Salomé, Murielle; Bentivegna, Valerie; Sancey, Lucie; Bräuer-Krisch, Elke; Requardt, Herwig; Lux, François; Coll, Jean-Luc; Perriat, Pascal; Roux, Stéphane; Tillement, Olivier

    2016-01-01

    We recently developed the synthesis of ultrasmall gadolinium-based nanoparticles (GBN), (hydrodynamic diameter <5 nm) characterized by a safe behavior after intravenous injection (renal clearance, preferential accumulation in tumors). Owing to the presence of gadolinium ions, GBN can be used as contrast agents for magnetic resonance imaging (MRI) and as radiosensitizers. The attempt to determine the most opportune delay between the intravenous injection of GBN and the irradiation showed that a very low content of radiosensitizing nanoparticles in the tumor area is sufficient (0.1 μg/g of particles, i.e. 15 ppb of gadolinium) for an important increase of the therapeutic effect of irradiation. Such a promising and unexpected result is assigned to a suited distribution of GBN within the tumor, as revealed by the X-ray fluorescence (XRF) maps. PMID:27411781

  16. The High Radiosensitizing Efficiency of a Trace of Gadolinium-Based Nanoparticles in Tumors.

    PubMed

    Dufort, Sandrine; Le Duc, Géraldine; Salomé, Murielle; Bentivegna, Valerie; Sancey, Lucie; Bräuer-Krisch, Elke; Requardt, Herwig; Lux, François; Coll, Jean-Luc; Perriat, Pascal; Roux, Stéphane; Tillement, Olivier

    2016-01-01

    We recently developed the synthesis of ultrasmall gadolinium-based nanoparticles (GBN), (hydrodynamic diameter <5 nm) characterized by a safe behavior after intravenous injection (renal clearance, preferential accumulation in tumors). Owing to the presence of gadolinium ions, GBN can be used as contrast agents for magnetic resonance imaging (MRI) and as radiosensitizers. The attempt to determine the most opportune delay between the intravenous injection of GBN and the irradiation showed that a very low content of radiosensitizing nanoparticles in the tumor area is sufficient (0.1 μg/g of particles, i.e. 15 ppb of gadolinium) for an important increase of the therapeutic effect of irradiation. Such a promising and unexpected result is assigned to a suited distribution of GBN within the tumor, as revealed by the X-ray fluorescence (XRF) maps. PMID:27411781

  17. Magnetocaloric effect of an Fe-based metallic glass compared to benchmark gadolinium

    NASA Astrophysics Data System (ADS)

    Waske, A.; Hermann, H.; Mattern, N.; Skokov, K.; Gutfleisch, O.; Eckert, J.

    2012-12-01

    We report on the magnetocaloric effect in an Fe-based metallic glass (Fe80B12Nb8) as compared to the benchmark material gadolinium. From temperature-dependent magnetization measurements, the magnetic entropy change was calculated using the thermodynamic Maxwell relations. The adiabatic temperature change was directly measured for both materials using a dedicated setup. An analysis of the magnetic transition in amorphous Fe80B12Nb8 and crystalline gadolinium using a mean field and a phenomenological model was carried out. It was shown that both materials, in particular crystalline gadolinium, which does not possess structural disorder but merely a fluctuation of the exchange integral, can be described using the Handrich model for the magnetic transition of disordered materials. Furthermore, the Landau theory of second-order phase transitions quantitatively describes the magnetic entropy change and its dependence on the applied field very well for both materials with different definitions of disorder.

  18. Effect of gadolinium on the properties of Pr-Dy-Fe-Co-B materials

    NASA Astrophysics Data System (ADS)

    Kablov, E. N.; Ospennikova, O. G.; Piskorskii, V. P.; Rezchikova, I. I.; Valeev, R. A.; Korolev, D. V.

    2015-11-01

    Sintered (Pr1- x- y Dy x Gd y )13-14(Fe1- z Co z )balB6-7 materials ( x = 0.18-0.58, y = 0.05-0.33, z = 0.2-0.36) have been studied. The magnetic moments of gadolinium ions and those of the sublattice formed by Fe and Co ions are shown to be ordered antiferromagnetically. It is noted that an increase in the content of gadolinium, which substitutes for dysprosium, leads to an increase in residual induction B r , a decrease in coercive force H cJ , and an increase in the absolute value of the temperature coefficient of induction. The opposite effect takes place in the case of substitution of gadolinium for praseodymium in materials with a fixed dysprosium content.

  19. The High Radiosensitizing Efficiency of a Trace of Gadolinium-Based Nanoparticles in Tumors

    NASA Astrophysics Data System (ADS)

    Dufort, Sandrine; Le Duc, Géraldine; Salomé, Murielle; Bentivegna, Valerie; Sancey, Lucie; Bräuer-Krisch, Elke; Requardt, Herwig; Lux, François; Coll, Jean-Luc; Perriat, Pascal; Roux, Stéphane; Tillement, Olivier

    2016-07-01

    We recently developed the synthesis of ultrasmall gadolinium-based nanoparticles (GBN), (hydrodynamic diameter <5 nm) characterized by a safe behavior after intravenous injection (renal clearance, preferential accumulation in tumors). Owing to the presence of gadolinium ions, GBN can be used as contrast agents for magnetic resonance imaging (MRI) and as radiosensitizers. The attempt to determine the most opportune delay between the intravenous injection of GBN and the irradiation showed that a very low content of radiosensitizing nanoparticles in the tumor area is sufficient (0.1 μg/g of particles, i.e. 15 ppb of gadolinium) for an important increase of the therapeutic effect of irradiation. Such a promising and unexpected result is assigned to a suited distribution of GBN within the tumor, as revealed by the X-ray fluorescence (XRF) maps.

  20. Contrasting behaviour of anthropogenic gadolinium and natural rare earth elements in estuaries and the gadolinium input into the North Sea

    NASA Astrophysics Data System (ADS)

    Kulaksız, Serkan; Bau, Michael

    2007-08-01

    All major rivers in northwestern Germany that flow into the North Sea, including the Weser River, display rare earth element (REE) patterns with large positive gadolinium (Gd) anomalies that indicate the presence of anthropogenic Gd derived from contrast agents used in magnetic resonance imaging. This microcontaminant cannot be removed by common sewage treatment technology and enters rivers and lakes with the discharge from waste water treatment plants. As elsewhere, a large fraction of the natural dissolved REE in the Weser River are associated with colloids. These colloids aggregate during mixing of freshwater and seawater in the low-salinity part of the Weser Estuary and the dissolved REE are partially removed from the river water together with the colloids. In marked contrast to the natural REE, the anthropogenic Gd behaves conservatively during this estuarine mixing and transits through the Weser Estuary almost unaffected. This indicates that the speciation of anthropogenic Gd is different from that of natural Gd and suggests a long environmental half-life of the anthropogenic Gd complexes used as contrast agents. The amount of anthropogenic Gd introduced into seawater via rivers is significant and produces anthropogenic positive Gd anomalies in coastal seawater. This is observed in the southwestern North Sea, off the coast of the East Frisian Islands, where anthropogenic Gd is mostly derived from the rivers Rhine and Thames. Its long environmental half-life and conservative estuarine behaviour suggest that anthropogenic Gd might be utilized as a pseudo-natural far-field tracer for truly dissolved riverine REE input into seawater and for discharge from waste water treatment plants and for sewage in river, ground and drinking water. The widespread distribution of anthropogenic Gd is an example of how the increasing use of "exotic" (ultra)trace elements in high-tech processes will in the future significantly hamper studies of the distribution and geochemical

  1. Gadolinium-phthalein complexone as a contrast agent for hepatobiliary MR imaging

    SciTech Connect

    Kawamura, Y.; Endo, K.; Koizumi, M.; Watanabe, Y.; Saga, T.; Konishi, J.; Horiuchi, K.; Yokoyama, A.

    1989-01-01

    Gadolinium-phthalein complexone (Gd-PC) was developed as a hepatobiliary magnetic resonance (MR) contrast agent. Phthalein complexone is one of the iminodiacetic acid derivatives and a structural analogue of bromosulfophthalein. Gadolinium-PC substantially enhanced signal intensity of normal functioning livers on T1-weighted MR images. Contrast enhancement of rabbit liver and gradual accumulation of high intensity bile in the gallbladder were observed after intravenous injection of 0.05 and 0.1 mmol/kg Gd-PC. However, 0.1 mmol/kg of Gd-DTPA caused little effect on liver MR.

  2. Structural and optical properties of Nd3+ doped gadolinium oxide 1D nanorods

    NASA Astrophysics Data System (ADS)

    Boopathi, G.; Raj, S. Gokul; Kumar, G. Ramesh; Mohan, R.

    2014-04-01

    Neodymium doped gadolinium hydroxide [Nd:Gd(OH)3] nanorods were successfully synthesized at 60 °C through co-precipitation method. The dopant percentage was maintained at 5% and calcination was done at 750 °C temperature for 1 hour to form the respective neodymium doped gadolinium oxide [Nd:Gd2O3] nanorods. The as-formed and annealed products were investigated in detail by using powder X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) with an energy dispersive X-ray spectrum (EDX), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) spectrophotometry.

  3. Gadolinium-Conjugated Gold Nanoshells for Multimodal Diagnostic Imaging and Photothermal Cancer Therapy

    PubMed Central

    Coughlin, Andrew J.; Ananta, Jeyarama S.; Deng, Nanfu; Larina, Irina V.; Decuzzi, Paolo

    2014-01-01

    Multimodal imaging offers the potential to improve diagnosis and enhance the specificity of photothermal cancer therapy. Toward this goal, we have engineered gadolinium-conjugated gold nanoshells and demonstrated that they enhance contrast for magnetic resonance imaging, X-Ray, optical coherence tomography, reflectance confocal microscopy, and two-photon luminescence. Additionally, these particles effectively convert near-infrared light to heat, which can be used to ablate cancer cells. Ultimately, these studies demonstrate the potential of gadolinium-nanoshells for image-guided photothermal ablation. PMID:24115690

  4. Structural, morphological and optical investigations on Sm{sup 3+} doped gadolinium oxide nanorods

    SciTech Connect

    Boopathi, G.; Mohan, R.; Raj, S. Gokul; Kumar, G. Ramesh

    2014-04-24

    One dimensional uniform Sm{sup 3+} doped gadolinium hydroxide nanorods have been prepared via simple co– precipitation technique at 60 °C temperature for 1 hour. The samples were calcinated at 750 °C to obtain Sm{sup 3+} doped gadolinium oxide nanorods. The 1D nanorods were then subjected to different characterization techniques to ascertain its structural stability and its morphology were investigated using high–resolution transmission electron microscopy. Photoluminescence (PL) spectrophotometry was investigated and the obtained results were discussed in detail.

  5. Structural and optical properties of Nd{sup 3+} doped gadolinium oxide 1D nanorods

    SciTech Connect

    Boopathi, G. Mohan, R.; Raj, S. Gokul; Kumar, G. Ramesh

    2014-04-24

    Neodymium doped gadolinium hydroxide [Nd:Gd(OH)3] nanorods were successfully synthesized at 60 °C through co-precipitation method. The dopant percentage was maintained at 5% and calcination was done at 750 °C temperature for 1 hour to form the respective neodymium doped gadolinium oxide [Nd:Gd{sub 2}O{sub 3}] nanorods. The as-formed and annealed products were investigated in detail by using powder X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) with an energy dispersive X-ray spectrum (EDX), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) spectrophotometry.

  6. Misconnections in the Critically Ill: Injection of High-Dose Gadolinium into an External Ventricular Drain.

    PubMed

    Singh, Sumit; Rejai, Sepehr; Antongiorgi, Zarah; Gonzalez, Nestor; Stelzner, Matthias

    2016-03-01

    We report an unfortunate case of accidental administration of intrathecal gadolinium through an external ventricular drain in a postcraniotomy patient during magnetic resonance imaging of the brain. The incident occurred after the venous contrast line was connected mistakenly to the ventricular drainage catheter. The patient subsequently developed confusion, aphasia, and right facial droop with new computed tomography evidence of diffuse cerebral edema and stroke. Review of the magnetic resonance image revealed the inappropriate presence of subarachnoid gadolinium. Despite all interventions, the patient developed irreversible neurologic disability. We address the clinical sequelae, management strategies, and factors contributing to the catheter misconnection that led to this event. PMID:26462163

  7. A Manganese Alternative to Gadolinium for MRI Contrast.

    PubMed

    Gale, Eric M; Atanasova, Iliyana P; Blasi, Francesco; Ay, Ilknur; Caravan, Peter

    2015-12-16

    Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) are routinely used to diagnose soft tissue and vascular abnormalities. However, safety concerns limit the use of iodinated and gadolinium (Gd)-based CT and MRI contrast media in renally compromised patients. With an estimated 14% of the US population suffering from chronic kidney disease (CKD), contrast media compatible with renal impairment is sorely needed. We present the new manganese(II) complex [Mn(PyC3A)(H2O)](-) as a Gd alternative. [Mn(PyC3A)(H2O)](-) is among the most stable Mn(II) complexes at pH 7.4 (log KML = 11.40). In the presence of 25 mol equiv of Zn at pH 6.0, 37 °C, [Mn(PyC3A)(H2O)](-) is 20-fold more resistant to dissociation than [Gd(DTPA)(H2O)](2-). Relaxivity of [Mn(PyC3A)(H2O)](-) in blood plasma is comparable to commercial Gd contrast agents. Biodistribution analysis confirms that [Mn(PyC3A)(H2O)](-) clears via a mixed renal/hepatobiliary pathway with >99% elimination by 24 h. [Mn(PyC3A)(H2O)](-) was modified to form a bifunctional chelator and 4 chelates were conjugated to a fibrin-specific peptide to give Mn-FBP. Mn-FBP binds the soluble fibrin fragment DD(E) with Kd = 110 nM. Per Mn relaxivity of Mn-FBP is 4-fold greater than [Mn(PyC3A)(H2O)](-) and increases 60% in the presence of fibrin, consistent with binding. Mn-FBP provided equivalent thrombus enhancement to the state of the art Gd analogue, EP-2104R, in a rat model of arterial thrombosis. Mn metabolite analysis reveals no evidence of dechelation and the probe was >99% eliminated after 24 h. [Mn(PyC3A)(H2O)](-) is a lead development candidate for an imaging probe that is compatible with renally compromised patients. PMID:26588204

  8. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R.

    2012-02-22

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. For 6 M HNO{sub 3}, 10.5 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2 g/L and 0.25 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}.

  9. Late Gadolinium Enhancement Among Survivors of Sudden Cardiac Arrest

    PubMed Central

    Neilan, Tomas G.; Farhad, Hoshang; Mayrhofer, Thomas; Shah, Ravi V.; Dodson, John A.; Abbasi, Siddique A.; Danik, Stephan B.; Verdini, Daniel J.; Tokuda, Michifumi; Tedrow, Usha B.; Jerosch-Herold, Michael; Hoffmann, Udo; Ghoshhajra, Brian B.; Stevenson, William G.; Kwong, Raymond Y.

    2016-01-01

    OBJECTIVES The aim of this study was to describe the role of contrast-enhanced cardiac magnetic resonance (CMR) in the workup of patients with aborted sudden cardiac arrest (SCA) and in the prediction of long-term outcomes. BACKGROUND Myocardial fibrosis is a key substrate for SCA, and late gadolinium enhancement (LGE) on a CMR study is a robust technique for imaging of myocardial fibrosis. METHODS We performed a retrospective review of all survivors of SCA who were referred for CMR studies and performed follow-up for the subsequent occurrence of an adverse event (death and appropriate defibrillator therapy). RESULTS After a workup that included a clinical history, electrocardiogram, echocardiography, and coronary angiogram, 137 patients underwent CMR for workup of aborted SCA (66% male; mean age 56 ± 11 years; left ventricular ejection fraction 43 ± 12%). The presenting arrhythmias were ventricular fibrillation (n = 105 [77%]) and ventricular tachycardia (n = 32 [23%]). Overall, LGE was found in 98 patients (71%), with an average extent of 9.9 ± 5% of the left ventricular myocardium. CMR imaging provided a diagnosis or an arrhythmic substrate in 104 patients (76%), including the presence of an infarct-pattern LGE in 60 patients (44%), noninfarct LGE in 21 (15%), active myocarditis in 14 (10%), hypertrophic cardiomyopathy in 3 (2%), sarcoidosis in 3, and arrhythmogenic cardiomyopathy in 3. In a median follow-up of 29 months (range 18 to 43 months), there were 63 events. In a multivariable analysis, the strongest predictors of recurrent events were the presence of LGE (adjusted hazard ratio: 6.7; 95% CI: 2.38 to 18.85; p < 0.001) and the extent of LGE (hazard ratio: 1.15; 95% CI: 1.11 to 1.19; p < 0.001). CONCLUSIONS Among patients with SCA, CMR with contrast identified LGE in 71% and provided a potential arrhythmic substrate in 76%. In follow-up, both the presence and extent of LGE identified a group at markedly increased risk of future adverse events. PMID

  10. A gadolinium(iii) complex that shows room-temperature phosphorescence in the crystalline state.

    PubMed

    Nakai, Hidetaka; Kitagawa, Kazuhiro; Seo, Juncheol; Matsumoto, Takahiro; Ogo, Seiji

    2016-07-19

    This paper presents a gadolinium(iii) complex that shows blue phosphorescence in the crystalline state at room temperature under air atmosphere; color of the crystals can be changed to pale-green from blue by doping of 1-naphthol. PMID:27221814

  11. The structure of rare earth thin films: holmium and gadolinium on yttrium

    NASA Astrophysics Data System (ADS)

    Bentall, M. J.; Cowley, R. A.; Ward, R. C. C.; Wells, M. R.; Stunault, A.

    2003-11-01

    Single-crystal holmium and gadolinium layers have been grown on yttrium substrates using the molecular beam epitaxy technique and their structures investigated using high resolution x-ray scattering. The experiments were performed using a Philips MRD diffractometer in Oxford, and with the XMaS facility at the ESRF. Holmium layers with a thickness below T_{\\mathrm {c}}'=115\

  12. A water-soluble gadolinium metallofullerenol: facile preparation, magnetic properties and magnetic resonance imaging application.

    PubMed

    Li, Jie; Wang, Taishan; Feng, Yongqiang; Zhang, Ying; Zhen, Mingming; Shu, Chunying; Jiang, Li; Wang, Yuqing; Wang, Chunru

    2016-06-01

    A new water-soluble gadolinium metallofullerenol was prepared through a solid-liquid reaction. It was characterized to have an enhanced effective magnetic moment, and improved T1-weighted relaxivity and magnetic resonance imaging performance in the liver. This material prepared by a facile method has wide application as a contrast agent and biological medicine. PMID:27064096

  13. High Sensitivity of Late Gadolinium Enhancement for Predicting Microscopic Myocardial Scarring in Biopsied Specimens in Hypertrophic Cardiomyopathy

    PubMed Central

    Konno, Tetsuo; Hayashi, Kenshi; Fujino, Noboru; Nagata, Yoji; Hodatsu, Akihiko; Masuta, Eiichi; Sakata, Kenji; Nakamura, Hiroyuki; Kawashiri, Masa-aki; Yamagishi, Masakazu

    2014-01-01

    Background Myocardial scarring can be assessed by cardiac magnetic resonance imaging with late gadolinium enhancement and by endomyocardial biopsy. However, accuracy of late gadolinium enhancement for predicting microscopic myocardial scarring in biopsied specimens remains unknown in hypertrophic cardiomyopathy. We investigated whether late gadolinium enhancement in the whole heart reflects microscopic myocardial scarring in the small biopsied specimens in hypertrophic cardiomyopathy. Methods and Results Twenty-one consecutive patients with hypertrophic cardiomyopathy who were examined both by cardiac magnetic resonance imaging and by endomyocardial biopsy were retrospectively studied. The right interventricular septum was the target site for endomyocardial biopsy in all patients. Late gadolinium enhancement in the ventricular septum had an excellent sensitivity (100%) with a low specificity (40%) for predicting microscopic myocardial scarring in biopsied specimens. The sensitivity of late gadolinium enhancement in the whole heart remained 100% with a specificity of 27% for predicting microscopic myocardial scarring in biopsied specimens. Quantitative assessments of fibrosis revealed that the extent of late gadolinium enhancement in the whole heart was the only independent variable related to the microscopic collagen fraction in biopsied specimens (β  =  0.59, 95% confident interval: 0.15 – 1.0, p  =  0.012). Conclusions Although there was a compromise in the specificity, the sensitivity of late gadolinium enhancement was excellent for prediction of microscopic myocardial scarring in hypertrophic cardiomyopathy. Moreover, the severity of late gadolinium enhancement was independently associated with the quantitative collagen fraction in biopsied specimens in hypertrophic cardiomyopathy. These findings indicate that late gadolinium enhancement can reflect both the presence and the extent of microscopic myocardial scarring in the small biopsied specimens in

  14. Acute adverse reactions to magnetic resonance contrast media--gadolinium chelates.

    PubMed

    Li, A; Wong, C S; Wong, M K; Lee, C M; Au Yeung, M C

    2006-05-01

    The objective of this study was to evaluate the clinical safety of intravenous gadolinium-based contrast media used in patients who underwent MRI at a single institution. Acute adverse reactions to intravenous gadolinium-based contrast media used for MRI at the Princess Margaret Hospital, Hong Kong, SAR, from January 1999 to November 2004 were recorded in an incidence log book. The medical records of patients' demographics were retrospectively reviewed and the nature, frequency and severity of the adverse reactions were investigated and documented. The incidence of acute adverse reactions to intravenous gadolinium-based contrast media was 0.48% (45 patients with 46 adverse reactions). The severity of these adverse reactions were 96% mild, 2% moderate (one patient developed shortness of breath that required oxygen supplementation and intravenous steroidal management) and 2% severe (one patient developed an anaphylactoid reaction, but successfully recovered through timely resuscitation). No patients were recorded as having contrast extravasation and none died as a result of any adverse reaction. Among the 45 patients who developed adverse reactions, three patients (6.7%) had prior adverse reactions to iodinated contrast media, three (6.7%) had prior reactions to a different gadolinium-based contrast agent, one (2%) had asthma and nine (20%) had a history of drug/food allergy. Overall, 41% of the adverse reactions were not documented in the final MRI report or the clinical medical records. Gadolinium-based contrast media are safe and well tolerated by the vast majority of patients. In our study, the adverse reaction rate (0.48%) and the incidence of severe anaphylactoid reaction (0.01%) concur with those reported in the literature. Although most of the symptoms are mild and transient, these adverse reactions must be accurately documented and managed. PMID:16632615

  15. Tracing gadolinium-based contrast agents from surface water to drinking water by means of speciation analysis.

    PubMed

    Birka, Marvin; Wehe, Christoph A; Hachmöller, Oliver; Sperling, Michael; Karst, Uwe

    2016-04-01

    In recent decades, a significant amount of anthropogenic gadolinium has been released into the environment as a result of the broad application of contrast agents for magnetic resonance imaging (MRI). Since this anthropogenic gadolinium anomaly has also been detected in drinking water, it has become necessary to investigate the possible effect of drinking water purification on these highly polar microcontaminats. Therefore, a novel highly sensitive method for speciation analysis of gadolinium is presented. For that purpose, the hyphenation of hydrophilic interaction liquid chromatography (HILIC) and inductively coupled plasma-mass spectrometry (ICP-MS) was employed. In order to enhance the detection power, sample introduction was carried out by ultrasonic nebulization. In combination with a novel HILIC method using a diol-based stationary phase, it was possible to achieve superior limits of detection for frequently applied gadolinium-based contrast agents below 20pmol/L. With this method, the contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A were determined in concentrations up to 159pmol/L in samples from several waterworks in a densely populated region of Germany alongside the river Ruhr as well as from a waterworks near a catchment lake. Thereby, the direct impact of anthropogenic gadolinium species being present in the surface water on the amount of anthropogenic gadolinium in drinking water was shown. There was no evidence for the degradation of contrast agents, the release of Gd(3+) or the presence of further Gd species. PMID:26931429

  16. Biocompatible Polyhydroxyethylaspartamide-based Micelles with Gadolinium for MRI Contrast Agents

    NASA Astrophysics Data System (ADS)

    Jeong, Sang Young; Kim, Hyo Jeong; Kwak, Byung-Kook; Lee, Ha-Young; Seong, Hasoo; Shin, Byung Cheol; Yuk, Soon Hong; Hwang, Sung-Joo; Cho, Sun Hang

    2010-12-01

    Biocompatible poly-[ N-(2-hydroxyethyl)- d, l-aspartamide]-methoxypoly(ethyleneglycol)-hexadecylamine (PHEA-mPEG-C16) conjugated with 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid-gadolinium (DOTA-Gd) via ethylenediamine (ED) was synthesized as a magnetic resonance imaging (MRI) contrast agent. Amphiphilic PHEA-mPEG-C16-ED-DOTA-Gd forms micelle in aqueous solution. All the synthesized materials were characterized by proton nuclear magnetic resonance (1H NMR). Micelle size and shape were examined by dynamic light scattering (DLS) and atomic force microscopy (AFM). Micelles with PHEA-mPEG-C16-ED-DOTA-Gd showed higher relaxivities than the commercially available gadolinium contrast agent. Moreover, the signal intensity of a rabbit liver was effectively increased after intravenous injection of PHEA-mPEG-C16-ED-DOTA-Gd.

  17. Hypertrophic olivary degeneration with gadolinium enhancement after posterior fossa surgery in a child with medulloblastoma.

    PubMed

    Nowak, Johannes; Alkonyi, Balint; Rutkowski, Stefan; Homola, György A; Warmuth-Metz, Monika

    2014-05-01

    Hypertrophic olivary degeneration (HOD) is a rare transsynaptic form of degeneration occurring secondary to the disruption of the dentato-rubro-olivary pathway ("Guillain-Mollaret triangle"). HOD can be caused by ischemic, hemorrhagic, traumatic, or neoplastic lesions, and it can also occur following posterior fossa surgery. MRI characteristics of HOD include T2 signal increase and hypertrophy. To date, blood–brain barrier disruption has not been reported in HOD. Here, we present the first case of HOD with temporary gadolinium enhancement in a 10-year-old child 7 months after resection of a posterior fossa medulloblastoma. The recognition of gadolinium enhancement as a radiological feature of HOD may help to distinguish between this benign secondary condition and tumor recurrence. PMID:24122017

  18. Determination of stability constants and acute toxicity of potential hepatotropic gadolinium complexes.

    PubMed

    Mikiciuk-Olasik, Elzbieta; Wojewoda, Emilia; Bilichowski, Ireneusz; Witczak, Małgorzata; Karwowski, Bolesław; Wagrowska-Danilewicz, Małgorzata; Stasikowska, Olga

    2010-01-01

    Due to their high specificity for the hepatobiliary system, iminodiacetic acid derivatives are known to form a class of hepatobiliary agents. In this paper we present new hepatotropic gadolinium complexes to be used as potential MRI contrast agents. Derivatives of N-(2-phenylamine-2-oxoethyl) iminodiacetic acid are introduced as ligands into such complexes. In this way, we hope to achieve a valuable diagnostic tool for investigating of pathological changes in the liver. Stability constants of complexes were determined by potentiometric titration in 0.1 mol L(-1) NaNO3 solution at 20.0 +/- 0.1 degrees C. Stability and selectivity constants were also determined for endogenous metal ions such as Cu2+, Ca2+, and Zn2+ with the use of SUPERQUAD computer program. Acute toxicity of new gadolinium complexes was assessed in mice and histopathology examinations were carried out. PMID:20369788

  19. Gadolinium-based nanoparticles for highly efficient T1-weighted magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Lim, Eun-Kyung; Kang, Byunghoon; Choi, Yuna; Jang, Eunji; Han, Seungmin; Lee, Kwangyeol; Suh, Jin-Suck; Haam, Seungjoo; Huh, Yong-Min

    2014-06-01

    We developed Pyrene-Gadolinium (Py-Gd) nanoparticles as pH-sensitive magnetic resonance imaging (MRI) contrast agents capable of showing a high-Mr signal in cancer-specific environments, such as acidic conditions. Py-Gd nanoparticles were prepared by coating Py-Gd, which is a complex of gadolinium with pyrenyl molecules, with pyrenyl polyethyleneglycol PEG using a nano-emulsion method. These particles show better longitudinal relaxation time (T1) MR signals in acidic conditions than they do in neutral conditions. Furthermore, the particles exhibit biocompatibility and MR contrast effects in both in vitro and in vivo studies. From these results, we confirm that Py-Gd nanoparticles have the potential to be applied for accurate cancer diagnosis and therapy.

  20. Thermodynamic property evaluation and magnetic refrigeration cycle analysis for gadolinium gallium garnet

    SciTech Connect

    Murphy, R.W.

    1994-12-01

    Based on relevant material property data and previous model formulations, a magnetothermodynamic property map for gadolinium gallium garnet (Gd{sub 3}Ga{sub 5}O{sub 12}) was adapted for refrigeration cycle analysis in the temperature range 4-40 K and the magnetic field range 0-6 T. Employing methods similar to those previously developed for other materials and temperature ranges, assessments of limitations and relative performance were made for Carnot, ideal regenerative, and pseudo-constant field regenerative cycles. It was found that although Carnot cycle limitations on available temperature lift for gadolinium gallium garnet are not as severe as the limitations for materials previously examined, considerable improvement in cooling capacity and temperature lift combinations can be achieved by using regenerative cycles if serious loss mechanisms are avoided.

  1. Detection of anthropogenic gadolinium in the Brisbane River plume in Moreton Bay, Queensland, Australia.

    PubMed

    Lawrence, Michael G

    2010-07-01

    Wastewater effluent is known to contain macro and micropollutants, which may be deleterious to environmental health. One such class of micropollutants is chelated gadolinium, which are used as MRI contrast agents. As these MRI contrast agents can be assumed to behave conservatively during estuarine mixing, it is possible to calculate how much wastewater is represented in any particular sample. In this study, the percentage contribution of wastewater at specific locations in Moreton Bay, Qld, were determined by calculating the additional anthropogenic gadolinium contribution to the total rare earth element concentrations. Wastewater contributions were measured at concentrations as low as 0.2%, demonstrating the applicability of this technique for wastewater effluent plume mapping. PMID:20409563

  2. First measurements with new high-resolution gadolinium-GEM neutron detectors

    NASA Astrophysics Data System (ADS)

    Pfeiffer, D.; Resnati, F.; Birch, J.; Etxegarai, M.; Hall-Wilton, R.; Höglund, C.; Hultman, L.; Llamas-Jansa, I.; Oliveri, E.; Oksanen, E.; Robinson, L.; Ropelewski, L.; Schmidt, S.; Streli, C.; Thuiner, P.

    2016-05-01

    European Spallation Source instruments like the macromolecular diffractometer (NMX) require an excellent neutron detection efficiency, high-rate capabilities, time resolution, and an unprecedented spatial resolution in the order of a few hundred micrometers over a wide angular range of the incoming neutrons. For these instruments solid converters in combination with Micro Pattern Gaseous Detectors (MPGDs) are a promising option. A GEM detector with gadolinium converter was tested on a cold neutron beam at the IFE research reactor in Norway. The μTPC analysis, proven to improve the spatial resolution in the case of 10B converters, is extended to gadolinium based detectors. For the first time, a Gd-GEM was successfully operated to detect neutrons with a measured efficiency of 11.8% at a wavelength of 2 Åand a position resolution better than 250 μm.

  3. The evolution of gadolinium based contrast agents: from single-modality to multi-modality.

    PubMed

    Zhang, Li; Liu, Ruiqing; Peng, Hui; Li, Penghui; Xu, Zushun; Whittaker, Andrew K

    2016-05-19

    Gadolinium-based contrast agents are extensively used as magnetic resonance imaging (MRI) contrast agents due to their outstanding signal enhancement and ease of chemical modification. However, it is increasingly recognized that information obtained from single modal molecular imaging cannot satisfy the higher requirements on the efficiency and accuracy for clinical diagnosis and medical research, due to its limitation and default rooted in single molecular imaging technique itself. To compensate for the deficiencies of single function magnetic resonance imaging contrast agents, the combination of multi-modality imaging has turned to be the research hotpot in recent years. This review presents an overview on the recent developments of the functionalization of gadolinium-based contrast agents, and their application in biomedicine applications. PMID:27159645

  4. Gadolinium concentration analysis in brain phantom by X-ray fluorescence.

    PubMed

    Almalki, Musaed; Majid, Samir Abdul; Butler, Philip H; Reinisch, Lou

    2010-06-01

    We have measured the X-ray fluorescence from gadolinium as a function of concentration and position in tumors of different sizes and shapes in a head phantom. The gadolinium fluorescence was excited with a 36 GBq Am-241 source. The fluorescence signal was detected with a CdTe detector and a multi-channel analyzer. The fluorescence peak was clearly separated from the scattered X-rays. Concentrations of 5.62-78.63 mg/ml of Gd ion were used in 1, 2, and 3 cm diameter spherical tumors and a 2x4 cm oblate spheroid tumor. The data show trends approaching saturation for the highest concentrations, probably due to reabsorption in the tumor. A comparison of X-ray photographic imaging and densitometer measurements to determine concentration is also presented. PMID:20596811

  5. Gadolinium-modulated 19F signals from Perfluorocarbon Nanoparticles as a New Strategy for Molecular Imaging

    PubMed Central

    Neubauer, Anne M.; Myerson, Jacob; Caruthers, Shelton D.; Hockett, Franklin D.; Winter, Patrick M.; Chen, Junjie; Gaffney, Patrick J.; Robertson, J. David; Lanza, Gregory M.; Wickline, Samuel A.

    2008-01-01

    Recent advances in the design of fluorinated nanoparticles for magnetic resonance molecular imaging have enabled specific detection of 19F nuclei, providing unique and quantifiable spectral signatures. However, a pressing need for signal enhancement exists because the total 19F in imaging voxels is often limited. By directly incorporating a relaxation agent (gadolinium) into the lipid monolayer that surrounds the perfluorocarbon, a marked augmentation of the 19F signal from 200nm nanoparticles was achieved. This design increases the magnetic relaxation rate of the 19F nuclei 4-fold at 1.5 T and effects a 125% increase in signal, an effect which is maintained when they are targeted to human plasma clots. By varying the surface concentration of gadolinium, the relaxation effect can be quantitatively modulated to tailor particle properties. This novel strategy dramatically improves the sensitivity and range of 19F MRI/MRS and forms the basis for designing contrast agents capable of sensing their surface chemistry. PMID:18956457

  6. The evolution of gadolinium based contrast agents: from single-modality to multi-modality

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Liu, Ruiqing; Peng, Hui; Li, Penghui; Xu, Zushun; Whittaker, Andrew K.

    2016-05-01

    Gadolinium-based contrast agents are extensively used as magnetic resonance imaging (MRI) contrast agents due to their outstanding signal enhancement and ease of chemical modification. However, it is increasingly recognized that information obtained from single modal molecular imaging cannot satisfy the higher requirements on the efficiency and accuracy for clinical diagnosis and medical research, due to its limitation and default rooted in single molecular imaging technique itself. To compensate for the deficiencies of single function magnetic resonance imaging contrast agents, the combination of multi-modality imaging has turned to be the research hotpot in recent years. This review presents an overview on the recent developments of the functionalization of gadolinium-based contrast agents, and their application in biomedicine applications.

  7. Optical absorption of Ni2+ and Ni3+ ions in gadolinium gallium garnet epitaxial films

    NASA Astrophysics Data System (ADS)

    Vasileva, N. V.; Gerus, P. A.; Sokolov, V. O.; Plotnichenko, V. G.

    2012-12-01

    Single-crystal Ni-doped gadolinium gallium garnet films were grown for the first time from supercooled Bi2O3-B2O3-based melt solutions by liquid-phase epitaxy. Optical absorption bands due to Ni2+, Ni3+ and Bi3+ ions were observed in those films. Interpretation and tabulation of all absorption bands of nickel ions occupying octahedral and tetrahedral sites in the garnet lattice are presented.

  8. Nickel-based gadolinium alloy for neutron adsorption application in RAM packages.

    SciTech Connect

    Mizia, Ronald A.; Dupont, John Neuman; McConnell, Paul E.; Robino, Charles Victor

    2005-02-01

    The National Spent Nuclear Fuel Program, located at the Idaho National Laboratory (INL), coordinates and integrates national efforts in management and disposal of US Department of Energy (DOE)-owned spent nuclear fuel. These management functions include development of standardised systems for long-term disposal in the proposed Yucca Mountain repository. Nuclear criticality control measures are needed in these systems to avoid restrictive fissile loading limits because of the enrichment and total quantity of fissile material in some types of the DOE spent nuclear fuel. This need is being addressed by development of corrosion-resistant, neutron-absorbing structural alloys for nuclear criticality control. This paper outlines results of a metallurgical development programme that is investigating the alloying of gadolinium into a nickel-chromium-molybdenum alloy matrix. Gadolinium has been chosen as the neutron absorption alloying element due to its high thermal neutron absorption cross section and low solubility in the expected repository environment. The nickel-chromium-molybdenum alloy family was chosen for its known corrosion performance, mechanical properties, and weldability. The workflow of this programme includes chemical composition definition, primary and secondary melting studies, ingot conversion processes, properties testing, and national consensus codes and standards work. The microstructural investigation of these alloys shows that the gadolinium addition is present in the alloy as a gadolinium-rich second phase. The mechanical strength values are similar to those expected for commercial Ni-Cr-Mo alloys. The alloys have been corrosion tested with acceptable results. The initial results of weldability tests have also been acceptable. Neutronic testing in a moderated critical array has generated favourable results. An American Society for Testing and Materials material specification has been issued for the alloy and a Code Case has been submitted to the

  9. Gadolinium uptake by brain cancer cells: Quantitative analysis with X-PEEM spectromicroscopy for cancer therapy

    NASA Astrophysics Data System (ADS)

    De Stasio, Gelsomina; Gilbert, B.; Perfetti, P.; Margaritondo, G.; Mercanti, D.; Ciotti, M. T.; Casalbore, P.; Larocca, L. M.; Rinelli, A.; Pallini, R.

    2000-05-01

    We present the first X-PEEM spectromicroscopy semi-quantitative data, acquired on Gd in glioblastoma cell cultures from human brain cancer. The cells were treated with a Gd compound for the optimization of GdNCT (Gadolinium Neutron Capture Therapy). We analyzed the kinetics of Gd uptake as a function of exposure time, and verified that a quantitative analytical technique gives the same results as our MEPHISTO X-PEEM, demonstrating the feasibility of semi-quantitative spectromicroscopy.

  10. Phospholipid micelle encapsulated gadolinium oxide nanoparticles for imaging and gene delivery

    PubMed Central

    Dixit, Suraj; Das, Mahasweta; Alwarappan, Subbiah; Goicochea, Nancy L.; Howell, Mark; Mohapatra, Subhra

    2014-01-01

    We encapsulated gadolinium oxide (Gd2O3) nanoparticles within phospholipid micelles as a novel low cytotoxic T1-weighted MRI imaging contrast agent (MGdNPs) that can also deliver small molecules such as DNA plasmids. MGdNPs show relatively good MRI relaxivity values, negligible cytotoxicity, excellent cellular uptake and expression of DNA plasmids in vivo. Biodistribution studies in mice show that intranasal and intraperitoneal administration of MGdNPs can effectively target specific organs. PMID:24724012

  11. Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy.

    PubMed

    Enger, Shirin A; Rezaei, Arash; Munck af Rosenschöld, Per; Lundqvist, Hans

    2006-01-01

    Restenosis is a major problem after balloon angioplasty and stent implantation. The aim of this study is to introduce gadolinium neutron capture brachytherapy (GdNCB) as a suitable modality for treatment of stenosis. The utility of GdNCB in intravascular brachytherapy (IVBT) of stent stenosis is investigated by using the GEANT4 and MCNP4B Monte Carlo radiation transport codes. To study capture rate, Kerma, absorbed dose and absorbed dose rate around a Gd-containing stent activated with neutrons, a 30 mm long, 5 mm diameter gadolinium foil is chosen. The input data is a neutron spectrum used for clinical neutron capture therapy in Studsvik, Sweden. Thermal neutron capture in gadolinium yields a spectrum of high-energy gamma photons, which due to the build-up effect gives an almost flat dose delivery pattern to the first 4 mm around the stent. The absorbed dose rate is 1.33 Gy/min, 0.25 mm from the stent surface while the dose to normal tissue is in order of 0.22 Gy/min, i.e., a factor of 6 lower. To spare normal tissue further fractionation of the dose is also possible. The capture rate is relatively high at both ends of the foil. The dose distribution from gamma and charge particle radiation at the edges and inside the stent contributes to a nonuniform dose distribution. This will lead to higher doses to the surrounding tissue and may prevent stent edge and in-stent restenosis. The position of the stent can be verified and corrected by the treatment plan prior to activation. Activation of the stent by an external neutron field can be performed days after catherization when the target cells start to proliferate and can be expected to be more radiation sensitive. Another advantage of the nonradioactive gadolinium stent is the possibility to avoid radiation hazard to personnel. PMID:16485408

  12. Hyperintense Dentate Nuclei on T1-Weighted MRI: Relation to Repeat Gadolinium Administration

    PubMed Central

    Adin, M.E.; Kleinberg, L.; Vaidya, D.; Zan, E.; Mirbagheri, S.; Yousem, D.M.

    2016-01-01

    BACKGROUND AND PURPOSE A hyperintense appearance of the dentate nucleus on T1-weighted MR images has been related to various clinical conditions, but the etiology remains indeterminate. We aimed to investigate the possible associations between a hyperintense appearance of the dentate nucleus on T1-weighted MR images in patients exposed to radiation and factors including, but not limited to, the cumulative number of contrast-enhanced MR images, amount of gadolinium administration, dosage of ionizing radiation, and patient demographics. MATERIALS AND METHODS The medical records of 706 consecutive patients who were treated with brain irradiation at The Johns Hopkins Medical Institutions between 1995 and 2010 were blindly reviewed by 2 readers. RESULTS One hundred eighty-four subjects were included for dentate nuclei analysis. Among the 184 subjects who cumulatively underwent 2677 MR imaging studies following intravenous gadolinium administration, 103 patients had hyperintense dentate nuclei on precontrast T1-weighted MR images. The average number of gadolinium-enhanced MR imaging studies performed in the group with normal dentate nuclei was significantly lower than that of the group with hyperintense dentate nuclei. The average follow-up time was 62.5 months. No significant difference was observed between hyperintense and normal dentate nuclei groups in terms of exposed radiation dose, serum creatinine and calcium/phosphate levels, patient demographics, history of chemotherapy, and strength of the scanner. No dentate nuclei abnormalities were found on the corresponding CT scans of patients with hyperintense dentate nuclei (n = 44). No dentate nuclei abnormalities were found in 53 healthy volunteers. CONCLUSIONS Repeat performance of gadolinium-enhanced studies likely contributes to a long-standing hyperintense appearance of dentate nuclei on precontrast T1-weighted-MR images. PMID:26294649

  13. Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

    NASA Astrophysics Data System (ADS)

    Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane; Méchin, Laurence; Hamel, Matthieu

    2016-08-01

    Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

  14. Proposed experiment to measure {gamma}-rays from the thermal neutron capture of gadolinium

    SciTech Connect

    Yano, Takatomi; Ou, I.; Izumi, T.; Yamaguchi, R.; Mori, T.; Sakuda, M.

    2012-11-12

    Gadolinium-157 ({sup 157}Gd) has the largest thermal neutron capture cross section among any stable nuclei. The thermal neutron capture yields {gamma}-ray cascade with total energy of about 8 MeV. Because of these characteristics, Gd is applied for the recent neutrino detectors. Here, we propose an experiment to measure the multiplicity and the angular correlation of {gamma}-rays from the Gd neutron capture. With these information, we expect the improved identification of the Gd neutron capture.

  15. Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy

    SciTech Connect

    Enger, Shirin A.; Rezaei, Arash; Munck af Rosenschoeld, Per; Lundqvist, Hans

    2006-01-15

    Restenosis is a major problem after balloon angioplasty and stent implantation. The aim of this study is to introduce gadolinium neutron capture brachytherapy (GdNCB) as a suitable modality for treatment of stenosis. The utility of GdNCB in intravascular brachytherapy (IVBT) of stent stenosis is investigated by using the GEANT4 and MCNP4B Monte Carlo radiation transport codes. To study capture rate, Kerma, absorbed dose and absorbed dose rate around a Gd-containing stent activated with neutrons, a 30 mm long, 5 mm diameter gadolinium foil is chosen. The input data is a neutron spectrum used for clinical neutron capture therapy in Studsvik, Sweden. Thermal neutron capture in gadolinium yields a spectrum of high-energy gamma photons, which due to the build-up effect gives an almost flat dose delivery pattern to the first 4 mm around the stent. The absorbed dose rate is 1.33 Gy/min, 0.25 mm from the stent surface while the dose to normal tissue is in order of 0.22 Gy/min, i.e., a factor of 6 lower. To spare normal tissue further fractionation of the dose is also possible. The capture rate is relatively high at both ends of the foil. The dose distribution from gamma and charge particle radiation at the edges and inside the stent contributes to a nonuniform dose distribution. This will lead to higher doses to the surrounding tissue and may prevent stent edge and in-stent restenosis. The position of the stent can be verified and corrected by the treatment plan prior to activation. Activation of the stent by an external neutron field can be performed days after catherization when the target cells start to proliferate and can be expected to be more radiation sensitive. Another advantage of the nonradioactive gadolinium stent is the possibility to avoid radiation hazard to personnel.

  16. Assembly of Double-Hydrophilic Block Copolymers Triggered by Gadolinium Ions: New Colloidal MRI Contrast Agents.

    PubMed

    Frangville, Camille; Li, Yichen; Billotey, Claire; Talham, Daniel R; Taleb, Jacqueline; Roux, Patrick; Marty, Jean-Daniel; Mingotaud, Christophe

    2016-07-13

    Mixing double-hydrophilic block copolymers containing a poly(acrylic acid) block with gadolinium ions in water leads to the spontaneous formation of polymeric nanoparticles. With an average diameter near 20 nm, the nanoparticles are exceptionally stable, even after dilution and over a large range of pH and ionic strength. High magnetic relaxivities were measured in vitro for these biocompatible colloids, and in vivo magnetic resonance imaging on rats demonstrates the potential utility of such polymeric assemblies. PMID:27224089

  17. Study of the Photon Strength Functions for Gadolinium Isotopes with the DANCE Array

    SciTech Connect

    Dashdorj, D.; Mitchell, G. E.; Baramsai, B.; Chankova, R.; Chyzh, A.; Walker, C.; Agvaanluvsan, U.; Becker, J. A.; Parker, W.; Sleaford, B.; Wu, C. Y.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Krticka, M.

    2009-03-10

    The gadolinium isotopes are interesting for reactor applications as well as for medicine and astrophysics. The gadolinium isotopes have some of the largest neutron capture cross sections. As a consequence they are used in the control rod in reactor fuel assembly. From the basic science point of view, there are seven stable isotopes of gadolinium with varying degrees of deformation. Therefore they provide a good testing ground for the study of deformation dependent structure such as the scissors mode. Decay gamma rays following neutron capture on Gd isotopes are detected by the DANCE array, which is located at flight path 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation and close packing of the detector array enable gamma-ray multiplicity measurements. The calorimetric properties of the DANCE array coupled with the neutron time-of-flight technique enables one to gate on a specific resonance of a specific isotope in the time-of-flight spectrum and obtain the summed energy spectrum for that isotope. The singles gamma-ray spectrum for each multiplicity can be separated by their DANCE cluster multiplicity. Various photon strength function models are used for comparison with experimentally measured DANCE data and provide insight for understanding the statistical decay properties of deformed nuclei.

  18. Thermal Excitation of Gadolinium-Based Contrast Agents Using Spin Resonance

    PubMed Central

    Fridjhon, Peter; Rubin, David M.

    2016-01-01

    Theoretical and experimental investigations into the thermal excitation of liquid paramagnetic contrast agents using the spin resonance relaxation mechanism are presented. The electronic spin-lattice relaxation time τ1e of gadolinium-based contrast agents, which is estimated at 0.1 ns, is ten orders of magnitude faster than the relaxation time of protons in water. The shorter relaxation time is found to significantly increase the rate of thermal energy deposition. To the authors’ knowledge this is the first study of gadolinium based contrast agents in a liquid state used as thermal agents. Analysis shows that when τ1e and other experimental parameters are optimally selected, a maximum theoretical heating rate of 29.4 °C.s−1 could be achieved which would suffice for clinical thermal ablation of neoplasms. The experimental results show a statistically significant thermal response for two out of the four contrast agents tested. The results are compared to the simulated estimates via analysis of a detailed model of the system. While these experimentally determined temperature rises are small and thus of no clinical utility, their presence supports the theoretical analysis and strongly suggests that the chemical structure of the selected compounds plays an important role in this mechanism of heat deposition. There exists an opportunity for the development of alternative gadolinium-based compounds with an order of magnitude longer τ1e in a diluted form to be used as an efficient hyperthermia agent for clinical use. PMID:27341338

  19. Thermal Excitation of Gadolinium-Based Contrast Agents Using Spin Resonance.

    PubMed

    Dinger, Steven C; Fridjhon, Peter; Rubin, David M

    2016-01-01

    Theoretical and experimental investigations into the thermal excitation of liquid paramagnetic contrast agents using the spin resonance relaxation mechanism are presented. The electronic spin-lattice relaxation time τ1e of gadolinium-based contrast agents, which is estimated at 0.1 ns, is ten orders of magnitude faster than the relaxation time of protons in water. The shorter relaxation time is found to significantly increase the rate of thermal energy deposition. To the authors' knowledge this is the first study of gadolinium based contrast agents in a liquid state used as thermal agents. Analysis shows that when τ1e and other experimental parameters are optimally selected, a maximum theoretical heating rate of 29.4 °C.s-1 could be achieved which would suffice for clinical thermal ablation of neoplasms. The experimental results show a statistically significant thermal response for two out of the four contrast agents tested. The results are compared to the simulated estimates via analysis of a detailed model of the system. While these experimentally determined temperature rises are small and thus of no clinical utility, their presence supports the theoretical analysis and strongly suggests that the chemical structure of the selected compounds plays an important role in this mechanism of heat deposition. There exists an opportunity for the development of alternative gadolinium-based compounds with an order of magnitude longer τ1e in a diluted form to be used as an efficient hyperthermia agent for clinical use. PMID:27341338

  20. Large Scale Testing and Development of Gadolinium Trichloride for Use in Neutron Detection in Large Water

    SciTech Connect

    Mark Vagine

    2007-09-18

    Water Cherenkov detectors have been used for many years as inexpensive, effective detectors for neutrino interactions and nucleon decay searches. While many important measurements have been made with these detectors a major drawback has been their inability to detect the absorption of thermal neutrons. We believe an inexpensive, effective technique could be developed to overcome this situation via the addition to water of a solute with a large neutron cross section and energetic gamma daughters which would make neutrons detectable. Gadolinium seems an excellent candidate especially since in recent years it has become very inexpensive, now less than $8 per kilogram in the form of commercially-available gadolinium trichloride, GdCl{sub 3}. This non-toxic, non-reactive substance is highly soluble in water. Neutron capture on gadolinium yields a gamma cascade which would be easily seen in detectors like Super-Kamiokande. We have begun to investigate the use of GdCl{sub 3} as a possible upgrade for the Super-Kamiokande detector with a view toward improving its performance as a detector for atmospheric neutrinos, supernova neutrinos, wrong-sign solar neutrinos, reactor neutrinos, proton decay, and also as a target for the coming T2K long-baseline neutrino experiment. This large-scale investigation, conducted in the one kiloton water Cherenkov detector built for the K2K long-baseline experiment, follows up on highly promising benchtop-scale work previously carried out with the assistance of a 2003 Advanced Detector Research Program grant.

  1. Pineapple juice labeled with gadolinium: a convenient oral contrast for magnetic resonance cholangiopancreatography.

    PubMed

    Coppens, Emmanuel; Metens, Thierry; Winant, Catherine; Matos, Celso

    2005-10-01

    The aim of our study was to prepare in vitro a pineapple juice (PJ) solution labeled with a minimal gadolinium concentration working as a negative contrast agent in heavily T2-weighted imaging and to assess that solution in vivo as a negative oral contrast agent for magnetic resonance cholangiopancreatography (MRCP). Three PJs were compared in vitro according to their T2. Increasing concentrations of gadolinium (Gd)-DOTA in PJ were assessed in vitro for T2 reduction. Single-shot turbo spin echo T2-weighted MR cholangiopancreatograms were obtained for 35 patients with suspected biliopancreatic duct disease, before and after ingestion of the PJ/Gd-DOTA solution. Signal intensity (SI) measurements of gastroduodenal lumens, pancreatobiliary ducts, and image quality scores were obtained systematically before and after contrast ingestion. The in vitro selected Gd-DOTA concentration in the PJ was 2.76 mmol/l. Ingestion of 180 ml of PJ labeled with 1 ml of Gd-DOTA eliminated efficiently the gastroduodenal SI in MRCP, improving significantly the rates of complete visualization of the pancreatobiliary ducts (P<0.01) and the MRCP image quality scores (P<0.05). All patients easily ingested the contrast solution and found the solution palatable. PJ labeled with gadolinium constituted an efficient and convenient negative oral contrast agent for MRCP. PMID:15999215

  2. Breakthrough reactions of iodinated and gadolinium contrast media after oral steroid premedication protocol

    PubMed Central

    2014-01-01

    Background Adverse reactions to iodinated and gadolinium contrast media are an important clinical issue. Although some guidelines have proposed oral steroid premedication protocols to prevent adverse reactions, some patients may have reactions to contrast media in spite of premedication (breakthrough reaction; BTR). The purpose of this study was to assess the frequency, type and severity of BTR when following an oral steroid premedication protocol. Methods All iodinated and gadolinium contrast-enhanced radiologic examinations between August 2011 and February 2013 for which the premedication protocol was applied in our institution were assessed for BTRs. Results The protocol was applied to a total of 252 examinations (153 patients, ages 15–87 years; 63 males, 90 females). Of these, 152 were for prior acute adverse reactions to contrast media, 85 were for a history of bronchial asthma, and 15 were for other reasons. There were 198 contrast enhanced CTs and 54 contrast enhanced MRIs. There were nine BTR (4.5%) for iodinated contrast media, and only one BTR (1.9%) for gadolinium contrast media: eight were mild and one was moderate. No patient who had a mild index reaction (IR) had a severe BTR. Conclusion Incidence of BTRs when following the premedication protocol was low. This study by no means proves the efficacy of premedication, but provides some support for following a premedication protocol to improve safety of contrast-enhanced examinations when prior adverse reactions are mild, or when there is a history of asthma. PMID:25287952

  3. Selective Filtration of Gadolinium Trichloride for Use in Neutron Detection in Large Water Cherenkov Detectors

    SciTech Connect

    Vagins, Mark R.

    2013-04-10

    Water Cherenkov detectors have been used for many years as inexpensive, effective detectors for neutrino interactions and nucleon decay searches. While many important measurements have been made with these detectors a major drawback has been their inability to detect the absorption of thermal neutrons. We believe an inexpensive, effective technique could be developed to overcome this situation via the addition to water of a solute with a large neutron cross section and energetic gamma daughters which would make neutrons detectable. Gadolinium seems an excellent candidate especially since in recent years it has become very inexpensive, now less than $8 per kilogram in the form of commercially-available gadolinium trichloride, GdCl{sub 3}. This non-toxic, non-reactive substance is highly soluble in water. Neutron capture on gadolinium yields a gamma cascade which would be easily seen in detectors like Super-Kamiokande. We have been investigating the use of GdCl{sub 3} as a possible upgrade for the Super-Kamiokande detector with a view toward improving its performance as a detector for atmospheric neutrinos, supernova neutrinos, wrong-sign solar neutrinos, reactor neutrinos, proton decay, and also as a target for the coming T2K long-baseline neutrino experiment. This focused study of selective water filtration and GdCl{sub 3} extraction techniques, conducted at UC Irvine, followed up on highly promising benchtop-scale and kiloton-scale work previously carried out with the assistance of 2003 and 2005 Advanced Detector Research Program grants.

  4. T1 assessment of hip joint cartilage following intra-articular gadolinium injection: a pilot study.

    PubMed

    Bittersohl, Bernd; Hosalkar, Harish S; Kim, Young-Jo; Werlen, Stefan; Trattnig, Siegfried; Siebenrock, Klaus A; Mamisch, Tallal C

    2010-10-01

    This pilot study defines the feasibility of cartilage assessment in symptomatic femoroacetabular impingement patients using intra-articular delayed gadolinium-enhanced MRI of cartilage (ia-dGEMRIC). Nine patients were scanned preliminary to study the contrast infiltration process into hip joint cartilage. Twenty-seven patients with symptomatic femoroacetabular impingement were subsequently scanned with intra-articular delayed gadolinium-enhanced MRI of cartilage. These T(1) findings were correlated to morphological findings. Zonal variations were studied. This pilot study demonstrates a significant difference between the pre- and postcontrast T(1) values (P < 0.001) remaining constant for 45 min. We noted higher mean T(1) values in morphologically normal-appearing cartilage than in damaged cartilage, which was statistically significant for all zones except the anterior-superior zone. Intraobserver (0.972) and interobserver correlation coefficients (0.933) were statistically significant. This study outlines the feasibility of intra-articular delayed gadolinium-enhanced MRI of cartilage for assessment of cartilage changes in patients with femoroacetabular impingement. It can also define the topographic extent and differing severities of cartilage damage. PMID:20872764

  5. Gadolinium-148 and other spallation production cross section measurements for accelerator target facilities

    NASA Astrophysics Data System (ADS)

    Kelley, Karen Corzine

    At the Los Alamos Neutron Science Center accelerator complex, protons are accelerated to 800 MeV and directed to two tungsten targets, Target 4 at the Weapons Neutron Research facility and the 1L target at the Lujan Center. The Department of Energy requires hazard classification analyses to be performed on these targets and places limits on certain radionuclide inventories in the targets to avoid characterizing the facilities as "nuclear facilities." Gadolinium-148 is a radionuclide created from the spallation of tungsten. Allowed isotopic inventories are particularly low for this isotope because it is an alpha-particle emitter with a 75-year half-life. The activity level of Gadolinium-148 is low, but it encompasses almost two-thirds of the total dose burden for the two tungsten targets based on present yield estimates. From a hazard classification standpoint, this severely limits the lifetime of these tungsten targets. The cross section is not well-established experimentally and this is the motivation for measuring the Gadolinium-148 production cross section from tungsten. In a series of experiments at the Weapons Neutron Research facility, Gadolinium-148 production was measured for 600- and 800-MeV protons on tungsten, tantalum, and gold. These experiments used 3 mum thin tungsten, tantalum, and gold foils and 10 mum thin aluminum activation foils. In addition, spallation yields were determined for many short-lived and long-lived spallation products with these foils using gamma and alpha spectroscopy and compared with predictions of the Los Alamos National Laboratory codes CEM2k+GEM2 and MCNPX. The cumulative Gadolinium-148 production cross section measured from tantalum, tungsten, and gold for incident 600-MeV protons were 15.2 +/- 4.0, 8.31 +/- 0.92, and 0.591 +/- 0.155, respectively. The average production cross sections measured at 800 MeV were 28.6 +/- 3.5, 19.4 +/- 1.8, and 3.69 +/- 0.50 for tantalum, tungsten, and gold, respectively. These cumulative

  6. Simple method for quantification of gadolinium magnetic resonance imaging contrast agents using ESR spectroscopy.

    PubMed

    Takeshita, Keizo; Kinoshita, Shota; Okazaki, Shoko

    2012-01-01

    To develop an estimation method of gadolinium magnetic resonance imaging (MRI) contrast agents, the effect of concentration of Gd compounds on the ESR spectrum of nitroxyl radical was examined. A solution of either 4-oxo-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPONE) or 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL) was mixed with a solution of Gd compound and the ESR spectrum was recorded. Increased concentration of gadolinium-diethylenetriamine pentaacetic acid chelate (Gd-DTPA), an MRI contrast agent, increased the peak-to-peak line widths of ESR spectra of the nitroxyl radicals, in accordance with a decrease of their signal heights. A linear relationship was observed between concentration of Gd-DTPA and line width of ESR signal, up to approximately 50 mmol/L Gd-DTPA, with a high correlation coefficient. Response of TEMPONE was 1.4-times higher than that of TEMPOL as evaluated from the slopes of the lines. The response was slightly different among Gd compounds; the slopes of calibration curves for acua[N,N-bis[2-[(carboxymethyl)[(methylcarbamoyl)methyl]amino]ethyl]glycinato(3-)]gadolinium hydrate (Gd-DTPA-BMA) (6.22 μT·L/mmol) and gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid chelate (Gd-DOTA) (6.62 μT·L/mmol) were steeper than the slope for Gd-DTPA (5.45 μT·L/mmol), whereas the slope for gadolinium chloride (4.94 μT·L/mmol) was less steep than that for Gd-DTPA. This method is simple to apply. The results indicate that this method is useful for rough estimation of the concentration of Gd contrast agents if calibration is carried out with each standard compound. It was also found that the plot of the reciprocal square root of signal height against concentrations of contrast agents could be useful for the estimation if a constant volume of sample solution is taken and measured at the same position in the ESR cavity every time. PMID:22223372

  7. Incorporation of Integral Fuel Burnable Absorbers Boron and Gadolinium into Zirconium-Alloy Fuel Clad Material

    SciTech Connect

    Sridharan, K.; Renk, T.J.; Lahoda, E.J.; Corradini, M.L

    2004-12-14

    Long-lived fuels require the use of higher enrichments of 235U or other fissile materials. Such high levels of fissile material lead to excessive fuel activity at the beginning of life. To counteract this excessive activity, integral fuel burnable absorbers (IFBA) are added to some rods in the fuel assembly. The two commonly used IFBA elements are gadolinium, which is added as gadolinium-oxide to the UO2 powder, and boron, which is applied as a zirconium-diboride coating on the UO2 pellets using plasma spraying or chemical vapor deposition techniques. The incorporation of IFBA into the fuel has to be performed in a nuclear-regulated facility that is physically separated from the main plant. These operations tend to be very costly because of their small volume and can add from 20 to 30% to the manufacturing cost of the fuel. Other manufacturing issues that impact cost and performance are maintaining the correct levels of dosing, the reduction in fuel melting point due to gadolinium-oxide additions, and parasitic neutron absorption at fuel's end-of-life. The goal of the proposed research is to develop an alternative approach that involves incorporation of boron or gadolinium into the outer surface of the fuel cladding material rather than as an additive to the fuel pellets. This paradigm shift will allow for the introduction of the IFBA in a non-nuclear regulated environment and will obviate the necessity of additional handling and processing of the fuel pellets. This could represent significant cost savings and potentially lead to greater reproducibility and control of the burnable fuel in the early stages of the reactor operation. The surface alloying is being performed using the IBEST (Ion Beam Surface Treatment) process developed at Sandia National Laboratories. IBEST involves the delivery of energetic ion beam pulses onto the surface of a material, near-surface melting, and rapid solidification. The non-equilibrium nature of such processing allows for surface

  8. Comparison of high-MTF and reduced-noise radiographic imaging systems

    NASA Astrophysics Data System (ADS)

    Bunch, Phillip C.

    1995-05-01

    The objective imaging characteristics of a wide range of gandolinium oxysulfide-based, zero- crossover, screen-film combinations are presented and compared. It is shown that complex high-spatial frequency versus low-spatial frequency performance tradeoffs are found among these systems, when these systems are examined in terms of sensitometric response, modulation transfer function, noise equivalent quanta, and detective quantum efficiency.

  9. A feasibility study to determine the potential of in vivo detection of gadolinium by x-ray fluorescence (XRF) following gadolinium-based contrast-enhanced MRI.

    PubMed

    Mostafaei, F; McNeill, F E; Chettle, D R; Noseworthy, M D

    2015-01-01

    The feasibility of using a (109)Cd γ-ray induced K x-ray fluorescence (K-XRF) system for the in vivo detection of gadolinium (Gd) in bone has been investigated. The K-XRF bone measurement system employs an array of four detectors, and is normally used for the non-invasive study of bone lead levels. The system was used to measure bone simulating phantoms doped with varying levels of gadolinium and fixed amounts of sodium (Na), chlorine (Cl) and calcium (Ca). The detection limits for bare bone phantoms, using a source of activity 0.17 GBq, were determined to be 3.9 ppm and 6.5 ppm (µg Gd per gram phantom) for the Kα1 and Kα2 Gd x-ray peaks, respectively. This leads to an overall detection limit of 3.3 ppm (µg Gd per gram phantom). Layers of plastic were used to simulate overlying soft tissue and this permitted prediction of a detection limit, using the current strength of our radioisotope source, of 6.1 ppm to 8.6 ppm (µg Gd per gram phantom) for fingers with 2-4 mm of overlying tissue. With a new source of activity 5 GBq, we predict that this system could achieve a detection limit of 4-5.6 µg Gd g(-1) Ca. This is within the range of levels (2-30 µg Gd g(-1) Ca) previously found in the bone of patients receiving Gd based contrast imaging agents. The technique is promising and warrants further investigation. PMID:25501799

  10. Effects of gadolinium oxide nanoparticles on the oxidative burst from human neutrophil granulocytes

    NASA Astrophysics Data System (ADS)

    Abrikossova, Natalia; Skoglund, Caroline; Ahrén, Maria; Bengtsson, Torbjörn; Uvdal, Kajsa

    2012-07-01

    We have previously shown that gadolinium oxide (Gd2O3) nanoparticles are promising candidates to be used as contrast agents in magnetic resonance (MR) imaging applications. In this study, these nanoparticles were investigated in a cellular system, as possible probes for visualization and targeting intended for bioimaging applications. We evaluated the impact of the presence of Gd2O3 nanoparticles on the production of reactive oxygen species (ROS) from human neutrophils, by means of luminol-dependent chemiluminescence. Three sets of Gd2O3 nanoparticles were studied, i.e. as synthesized, dialyzed and both PEG-functionalized and dialyzed Gd2O3 nanoparticles. In addition, neutrophil morphology was evaluated by fluorescent staining of the actin cytoskeleton and fluorescence microscopy. We show that surface modification of these nanoparticles with polyethylene glycol (PEG) is essential in order to increase their biocompatibility. We observed that the as synthesized nanoparticles markedly decreased the ROS production from neutrophils challenged with prey (opsonized yeast particles) compared to controls without nanoparticles. After functionalization and dialysis, more moderate inhibitory effects were observed at a corresponding concentration of gadolinium. At lower gadolinium concentration the response was similar to that of the control cells. We suggest that the diethylene glycol (DEG) present in the as synthesized nanoparticle preparation is responsible for the inhibitory effects on the neutrophil oxidative burst. Indeed, in the present study we also show that even a low concentration of DEG, 0.3%, severely inhibits neutrophil function. In summary, the low cellular response upon PEG-functionalized Gd2O3 nanoparticle exposure indicates that these nanoparticles are promising candidates for MR-imaging purposes.

  11. Delayed gadolinium-enhanced magnetic resonance imaging of hip joint cartilage: pearls and pitfalls

    PubMed Central

    Bittersohl, Bernd; Zilkens, Christoph; Kim, Young-Jo; Werlen, Stefan; Siebenrock, Klaus A.; Mamisch, Tallal C.; Hosalkar, Harish S.

    2011-01-01

    With the increasing advances in hip joint preservation surgery, accurate diagnosis and assessment of femoral head and acetabular cartilage status is becoming increasingly important. Magnetic resonance imaging (MRI) of the hip does present technical difficulties. The fairly thin cartilage lining necessitates high image resolution and high contrast-to-noise ratio (CNR). With MR arthrography (MRA) using intraarticular injected gadolinium, labral tears and cartilage clefts may be better identified through the contrast medium filling into the clefts. However, the ability of MRA to detect varying grades of cartilage damage is fairly limited and early histological and biochemical changes in the beginning of osteoarthritis (OA) cannot be accurately delineated. Traditional MRI thus lacks the ability to analyze the biological status of cartilage degeneration. The technique of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is sensitive to the charge density of cartilage contributed by glycosaminoglycans (GAGs), which are lost early in the process of OA. Therefore, the dGEMRIC technique has a potential to detect early cartilage damage that is obviously critical for decision-making regarding time and extent of intervention for joint-preservation. In the last decade, cartilage imaging with dGEMRIC has been established as an accurate and reliable tool for assessment of cartilage status in the knee and hip joint. This review outlines the current status of dGEMRIC for assessment of hip joint cartilage. Practical modifications of the standard technique including three-dimensional (3D) dGEMRIC and dGEMRIC after intra-articular gadolinium instead of iv-dGEMRIC will also be addressed. PMID:22053252

  12. Delayed gadolinium-enhanced magnetic resonance imaging of hip joint cartilage: pearls and pitfalls.

    PubMed

    Bittersohl, Bernd; Zilkens, Christoph; Kim, Young-Jo; Werlen, Stefan; Siebenrock, Klaus A; Mamisch, Tallal C; Hosalkar, Harish S

    2011-01-01

    With the increasing advances in hip joint preservation surgery, accurate diagnosis and assessment of femoral head and acetabular cartilage status is becoming increasingly important. Magnetic resonance imaging (MRI) of the hip does present technical difficulties. The fairly thin cartilage lining necessitates high image resolution and high contrast-to-noise ratio (CNR). With MR arthrography (MRA) using intraarticular injected gadolinium, labral tears and cartilage clefts may be better identified through the contrast medium filling into the clefts. However, the ability of MRA to detect varying grades of cartilage damage is fairly limited and early histological and biochemical changes in the beginning of osteoarthritis (OA) cannot be accurately delineated. Traditional MRI thus lacks the ability to analyze the biological status of cartilage degeneration. The technique of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is sensitive to the charge density of cartilage contributed by glycosaminoglycans (GAGs), which are lost early in the process of OA. Therefore, the dGEMRIC technique has a potential to detect early cartilage damage that is obviously critical for decision-making regarding time and extent of intervention for joint-preservation. In the last decade, cartilage imaging with dGEMRIC has been established as an accurate and reliable tool for assessment of cartilage status in the knee and hip joint.This review outlines the current status of dGEMRIC for assessment of hip joint cartilage. Practical modifications of the standard technique including three-dimensional (3D) dGEMRIC and dGEMRIC after intra-articular gadolinium instead of iv-dGEMRIC will also be addressed. PMID:22053252

  13. Bioconjugation of luminescent silicon quantum dots to gadolinium ions for bioimaging applications

    NASA Astrophysics Data System (ADS)

    Erogbogbo, Folarin; Chang, Ching-Wen; May, Jasmine L.; Liu, Liwei; Kumar, Rajiv; Law, Wing-Cheung; Ding, Hong; Yong, Ken Tye; Roy, Indrajit; Sheshadri, Mukund; Swihart, Mark T.; Prasad, Paras N.

    2012-08-01

    Luminescent imaging agents and MRI contrast agents are desirable components in the rational design of multifunctional nanoconstructs for biological imaging applications. Luminescent biocompatible silicon quantum dots (SiQDs) and gadolinium chelates can be applied for fluorescence microscopy and MRI, respectively. Here, we report the first synthesis of a nanocomplex incorporating SiQDs and gadolinium ions (Gd3+) for biological applications. The nanoconstruct is composed of a PEGylated micelle, with hydrophobic SiQDs in its core, covalently bound to DOTA-chelated Gd3+. Dynamic light scattering reveals a radius of 85 nm for these nanoconstructs, which is consistent with the electron microscopy results depicting radii ranging from 25 to 60 nm. Cellular uptake of the probes verified that they maintain their optical properties within the intracellular environment. The magnetic resonance relaxivity of the nanoconstruct was 2.4 mM-1 s-1 (in terms of Gd3+ concentration), calculated to be around 6000 mM-1 s-1 per nanoconstruct. These desirable optical and relaxivity properties of the newly developed probe open the door for use of SiQDs in future multimodal applications such as tumour imaging.Luminescent imaging agents and MRI contrast agents are desirable components in the rational design of multifunctional nanoconstructs for biological imaging applications. Luminescent biocompatible silicon quantum dots (SiQDs) and gadolinium chelates can be applied for fluorescence microscopy and MRI, respectively. Here, we report the first synthesis of a nanocomplex incorporating SiQDs and gadolinium ions (Gd3+) for biological applications. The nanoconstruct is composed of a PEGylated micelle, with hydrophobic SiQDs in its core, covalently bound to DOTA-chelated Gd3+. Dynamic light scattering reveals a radius of 85 nm for these nanoconstructs, which is consistent with the electron microscopy results depicting radii ranging from 25 to 60 nm. Cellular uptake of the probes verified that they

  14. A case of delayed onset nephrogenic systemic fibrosis after gadolinium based contrast injection.

    PubMed

    Do, Jong Geol; Kim, Young Bum; Lee, Dae Gu; Hwang, Ji Hye

    2012-12-01

    Nephrogenic systemic fibrosis (NSF) is a rare fibrosing disorder of the skin and joints that occurs in patients with advanced renal insufficiency. This condition is progressive and can be seriously disabling. Gadolinium based contrast agent (GBCA) has been identified as a potential cause of this condition. A 56-years-old man in hemodialysis developed stiffness and contracture of the whole limbs eight years after frequent GBCA exposure for cervical magnetic resonance imaging. For the first time in Korea, we report late-onset nephrogenic systemic fibrosis after GBCA exposure and performed an electrophysiologic study of this condition. PMID:23342325

  15. Caustic Precipitation of Plutonium Using Gadolinium as the Neutron Poison for Disposition to High Level Waste

    SciTech Connect

    Bronikowski, M.G.

    2002-06-24

    Nuclear Materials Management Division (NMMD) has proposed that up to 100 kg of the plutonium (Pu) solutions stored in H-Canyon be precipitated with a nuclear poison and dispositioned to H-Area Tank Farm. The use of gadolinium (Gd) as the poison would greatly reduce the number of additional glass logs resulting from this disposition. This report summarizes the characteristics of the precipitation process and addresses criticality concerns in the Nuclear Criticality Safety Evaluation. No problems were found with the nature of the precipitate or the neutralization process.

  16. Active extravasation of gadolinium-based contrast agent into the subdural space following lumbar puncture.

    PubMed

    Kothari, Pranay D; Hanser, Evelyn M; Wang, Harrison; Farid, Nikdokht

    2016-01-01

    A 38year-old male presented with cauda equina syndrome following multiple lumbar puncture attempts. Lumbar spine magnetic resonance imaging (MRI) showed a subdural hematoma and an area of apparent contrast enhancement in the spinal canal on sagittal post-contrast images. Axial post-contrast images obtained seven minutes later demonstrated an increase in size and change in shape of the region of apparent contrast enhancement, indicating active extravasation of the contrast agent. This is the first reported case of active extravasation of gadolinium-based contrast agent in the spine. PMID:27317202

  17. Fragmenting gadolinium: mononuclear polyoxometalate-based magnetic coolers for ultra-low temperatures.

    PubMed

    Martínez-Pérez, María-José; Montero, Oscar; Evangelisti, Marco; Luis, Fernando; Sesé, Javier; Cardona-Serra, Salvador; Coronado, Eugenio

    2012-08-16

    The polyoxometalate clusters with formula [Gd(W(5) O(18) )(2) ](9-) and [Gd(P(5) W(30) O(110) )](12-) each carry a single magnetic ion of gadolinium, which is the most widespread element among magnetic refrigerant materials. In an adiabatic demagnetization, the lowest attainable temperature is limited by the presence of magnetic interactions that bring about magnetic order below a critical temperature. We demonstrate that this limitation can be overcome by chemically engineering the molecules in such a way to effectively screen all magnetic interactions, suggesting their use as ultra-low-temperature coolers. PMID:22718245

  18. Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T1 contrast ability

    NASA Astrophysics Data System (ADS)

    Ni, Kaiyuan; Zhao, Zhenghuan; Zhang, Zongjun; Zhou, Zijian; Yang, Li; Wang, Lirong; Ai, Hua; Gao, Jinhao

    2016-02-01

    High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis.High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy

  19. High-resolution, three-step resonance ionization mass spectrometry of gadolinium

    NASA Astrophysics Data System (ADS)

    Blaum, K.; Bushaw, B. A.; Nörtershäuser, W.; Wendt, K.

    2001-08-01

    High-resolution resonance ionization mass spectrometry has been used to measure triple-resonance autoionization (AI) spectra of gadolinium. Al resonances as narrow as 10 MHz have been observed and isotope shifts and hyperfine structure have been measured in selected AI states. The strongest AI state observed at 49663.576 cm-1 with a photoionization cross section of >3.6×10-15 cm2 was found to have an overall detection efficiency of >3×10-5, allowing application to a number of ultratrace determination problems. Analytical measurements with a diode-laser-based system have been successfully performed on bio-medical tissue samples.

  20. Size-dependent Strain in Epitaxial (001)Gadolinium-doped Ceria Nanoislands

    SciTech Connect

    V Solovyov; M Gibert; T Puig; X Obradors

    2011-12-31

    We report size-dependent strain in epitaxial gadolinium doped ceria nanoislands, which was determined by synchrotron x-ray diffraction. Reciprocal space sections of symmetric, (004) and asymmetric, (224) reflections are approximated by a model assuming size-dependent strain of the islands using real-space size distribution obtained by atomic force microscopy. We show that the islands smaller than 40 nm are subjected to a high level of lateral tensile strain and normal compression. The lateral to normal strain ratio determined from the reciprocal map analysis suggests that lateral tension is the primary stress generator, possibly due to oxygen vacancy ordering on the island-substrate interface.

  1. Modification of the crystal structure of gadolinium gallium garnet by helium ion irradiation

    SciTech Connect

    Ostafiychuk, B. K.; Yaremiy, I. P. Yaremiy, S. I.; Fedoriv, V. D.; Tomyn, U. O.; Umantsiv, M. M.; Fodchuk, I. M.; Kladko, V. P.

    2013-12-15

    The structure of gadolinium gallium garnet (GGG) single crystals before and after implantation by He{sup +} ions has been investigated using high-resolution X-ray diffraction methods and the generalized dynamic theory of X-ray scattering. The main types of growth defects in GGG single crystals and radiation-induced defects in the ion-implanted layer have been determined. It is established that the concentration of dislocation loops in the GGG surface layer modified by ion implantation increases and their radius decreases with an increase in the implantation dose.

  2. Structural and chemical analysis of gadolinium halides encapsulated within WS2 nanotubes

    NASA Astrophysics Data System (ADS)

    Anumol, E. A.; Enyashin, Andrey N.; Batra, Nitin M.; Costa, Pedro M. F. J.; Deepak, Francis Leonard

    2016-06-01

    The hollow cavities of nanotubes serve as templates for the growth of size- and shape-confined functional nanostructures, giving rise to novel materials and properties. In this work, considering their potential application as MRI contrast agents, gadolinium halides are encapsulated within the hollow cavities of WS2 nanotubes by capillary filling to obtain GdX3@WS2 nanotubes (where X = Cl, Br or I and @ means encapsulated in). Aberration corrected scanning/transmission electron microscopy (S/TEM) and spectroscopy is employed to understand the morphology and composition of the GdI3@WS2 nanotubes. The three dimensional morphology is studied with STEM tomography but understanding the compositional information is non-trivial due to the presence of multiple high atomic number elements. Therefore, energy dispersive X-ray spectroscopy (EDS) tomography was employed revealing the three dimensional chemical composition. Molecular dynamics simulations of the filling procedure shed light into the mechanics behind the formation of the confined gadolinium halide crystals. The quasi-1D system employed here serves as an example of a TEM-based chemical nanotomography method that could be extended to other materials, including beam-sensitive soft materials.The hollow cavities of nanotubes serve as templates for the growth of size- and shape-confined functional nanostructures, giving rise to novel materials and properties. In this work, considering their potential application as MRI contrast agents, gadolinium halides are encapsulated within the hollow cavities of WS2 nanotubes by capillary filling to obtain GdX3@WS2 nanotubes (where X = Cl, Br or I and @ means encapsulated in). Aberration corrected scanning/transmission electron microscopy (S/TEM) and spectroscopy is employed to understand the morphology and composition of the GdI3@WS2 nanotubes. The three dimensional morphology is studied with STEM tomography but understanding the compositional information is non-trivial due to the

  3. Gadolinium-Enhanced Angiography for Diagnosis and Interventional Treatment of Subclavian Artery Stenosis Prior to Fistula Creation

    SciTech Connect

    Termote, Bruno; Maleux, Geert Heye, Sam; Fourneau, Inge; Claes, Kathleen

    2008-07-15

    We report the use of gadolinium-based contrast agent for both diagnostic and interventional subclavian angiography in two azotemic patients, presenting with an asymptomatic, high-grade stenosis of the left subclavian artery, ipsilateral to the site of choice for native fistula creation. Angiographic imaging performed with diluted gadolinium-based contrast material was clear enough to perform successful subclavian artery stenting, resulting in normalization of the arterial blood pressure in the afferent artery of the dialysis fistula. Clinically, no decrease in residual renal function and no other complication were noted immediately or a longer period after the interventional treatment.

  4. Structural and chemical analysis of gadolinium halides encapsulated within WS2 nanotubes.

    PubMed

    Anumol, E A; Enyashin, Andrey N; Batra, Nitin M; Costa, Pedro M F J; Deepak, Francis Leonard

    2016-06-16

    The hollow cavities of nanotubes serve as templates for the growth of size- and shape-confined functional nanostructures, giving rise to novel materials and properties. In this work, considering their potential application as MRI contrast agents, gadolinium halides are encapsulated within the hollow cavities of WS2 nanotubes by capillary filling to obtain GdX3@WS2 nanotubes (where X = Cl, Br or I and @ means encapsulated in). Aberration corrected scanning/transmission electron microscopy (S/TEM) and spectroscopy is employed to understand the morphology and composition of the GdI3@WS2 nanotubes. The three dimensional morphology is studied with STEM tomography but understanding the compositional information is non-trivial due to the presence of multiple high atomic number elements. Therefore, energy dispersive X-ray spectroscopy (EDS) tomography was employed revealing the three dimensional chemical composition. Molecular dynamics simulations of the filling procedure shed light into the mechanics behind the formation of the confined gadolinium halide crystals. The quasi-1D system employed here serves as an example of a TEM-based chemical nanotomography method that could be extended to other materials, including beam-sensitive soft materials. PMID:27250645

  5. Effect of solid-phase amorphization on the spectral characteristics of europium-doped gadolinium molybdate

    NASA Astrophysics Data System (ADS)

    Shmurak, S. Z.; Kiselev, A. P.; Kurmasheva, D. M.; Red'Kin, B. S.; Sinitsyn, V. V.

    2010-05-01

    A method is proposed for detecting spectral characteristics of optically inactive molybdates of rare-earth elements by their doping with rare-earth ions whose luminescence lies in the transparency region of all structural modifications of the sample. Gadolinium molybdate is chosen as the object of investigations, while europium ions are used as an optically active and structurally sensitive admixture. It is shown that after the action of a high pressure under which gadolinium molybdate passes to the amorphous state, the spectral characteristics of Gd1.99Eu0.01(MoO4)3 (GMO:Eu) change radically; namely, considerable line broadening is observed in the luminescence spectra and the luminescence excitation spectra, while the long-wave threshold of optical absorption is shifted considerably (by approximately 1.1 eV) towards lower energies. It is found that by changing the structural state of GMO:Eu by solid-state amorphization followed by annealing, the spectral characteristics of the sample can be purposefully changed. This is extremely important for solving the urgent problem of designing high-efficiency light-emitting diodes producing “white” light.

  6. Disparate ultrafast dynamics of itinerant and localized magnetic moments in gadolinium metal.

    PubMed

    Frietsch, B; Bowlan, J; Carley, R; Teichmann, M; Wienholdt, S; Hinzke, D; Nowak, U; Carva, K; Oppeneer, P M; Weinelt, M

    2015-01-01

    The Heisenberg-Dirac intra-atomic exchange coupling is responsible for the formation of the atomic spin moment and thus the strongest interaction in magnetism. Therefore, it is generally assumed that intra-atomic exchange leads to a quasi-instantaneous aligning process in the magnetic moment dynamics of spins in separate, on-site atomic orbitals. Following ultrashort optical excitation of gadolinium metal, we concurrently record in photoemission the 4f magnetic linear dichroism and 5d exchange splitting. Their dynamics differ by one order of magnitude, with decay constants of 14 versus 0.8 ps, respectively. Spin dynamics simulations based on an orbital-resolved Heisenberg Hamiltonian combined with first-principles calculations explain the particular dynamics of 5d and 4f spin moments well, and corroborate that the 5d exchange splitting traces closely the 5d spin-moment dynamics. Thus gadolinium shows disparate dynamics of the localized 4f and the itinerant 5d spin moments, demonstrating a breakdown of their intra-atomic exchange alignment on a picosecond timescale. PMID:26355196

  7. Microcalorimetric studies on the energy release of isolated rat mitochondria under different concentrations of gadolinium (III).

    PubMed

    Zhao, Jie; Ma, Long; Xiang, Xun; Guo, Qing-Lian; Jiang, Feng-Lei; Liu, Yi

    2016-06-01

    Gadolinium-based compounds are most widely utilized for paramagnetic contrast agents, but, the toxicological mechanism of gadolinium (Gd) had not been fully elucidated since the first report about Gd anomaly. In this work, we analyzed the effect of Gd(3+) on mitochondria in vitro by microcalorimetry. Microcalorimetry can provide detailed kinetic and thermodynamic information from thermogenic curve. At the tested concentration, Gd(3+) induced the increase of growth rate constant (k1). At high concentration (100-500 μM), the maximum power output time (tm), the decline rate constant (-k2) and the time of activity recovery phase (tR) decreased with the addition of Gd(3+) and the maximum power output (Pm) increased. At low concentration (0-100 μM), the changes were different from high concentration. From the results we concluded that the effect of different concentrations of Gd(3+) had a relationship with time, high concentration of Gd(3+) induced mitochondrial energy metabolism disturb however low concentration may promote mitochondrial adaption to physiological stresses. The effect of low concentration of Gd(3+) need more work to elucidate the mechanism. The results of total heat output (Q) and mitochondrial respiratory activities suggested high concentrations of Gd(3+) could accelerate adenosine triphosphate (ATP) consumption under respiratory system damaged. PMID:27031804

  8. Evaluation of gadolinium compounds potentially suitable for magnetic resonance using Gd-153 scintigraphy

    SciTech Connect

    Engelstad, B.; Huberty, J.; White, D.; Wynne, C.; Ramos, E.; Goldberg, H.

    1985-05-01

    Gd-153 is not customarily considered for scintigraphy, yet it: 1) is available at acceptable cost, 2) has a 242 day half-life suitable for prolonged animal studies and 3) has 97 keV (40%) and 103 keV (59%) photopeaks suitable for conventional scintigraphy. Gd-153 (10-15 ..mu..Ci; 370-555 kBq) was administered to normal rats in 5 forms: 1) carrier 0.1 mmole/kg Gd-EIDA (diethyl iminodiacetic acid), 2) tracer (<.1 umole/kg) Gd-EIDA, 3) tracer Gd-ISIDA (diisopropyl iminodiacetic acid), 4) tracer GdCl/sub 3/, and 5) tracer Gd-DTPA. Scintigraphy, performed continuously for 90 minutes following intravenous injection and at intervals at up to 2 weeks, depicted: 1) rapid, partial hepatobiliary and renal clearance of tracer Gd-EIDA and Gd-ISIDA; 2) slow blood clearance and partial hepatobiliary clearance of carrier Gd-EIDA; and 3) prolonged reticuloendothelial retention of all IDA complexes, similar to GdCl3. Whole body and tissue distribution data paralleled the scintigraphic findings. Gd-153 scintigraphy provides a simple method to assess balance, distribution, kinetics, and stability of new paramagnetic contrast agents, and bis-iminodiacetate gadolinium complexes, unlike technetium analogues, lack effective stability to prevent gadolinium hydrolysis or translocation.

  9. High Relaxivity Gadolinium Hydroxypyridonate-Viral Capsid Conjugates: Nano-sized MRI Contrast Agents

    SciTech Connect

    Meux, Susan C.; Datta, Ankona; Hooker, Jacob M.; Botta, Mauro; Francis, Matthew B.; Aime, Silvio; Raymond, Kenneth N.

    2007-08-29

    High relaxivity macromolecular contrast agents based on the conjugation of gadolinium chelates to the interior and exterior surfaces of MS2 viral capsids are assessed. The proton nuclear magnetic relaxation dispersion (NMRD) profiles of the conjugates show up to a five-fold increase in relaxivity, leading to a peak relaxivity (per Gd{sup 3+} ion) of 41.6 mM{sup -1}s{sup -1} at 30 MHz for the internally modified capsids. Modification of the exterior was achieved through conjugation to flexible lysines, while internal modification was accomplished by conjugation to relatively rigid tyrosines. Higher relaxivities were obtained for the internally modified capsids, showing that (1) there is facile diffusion of water to the interior of capsids and (2) the rigidity of the linker attaching the complex to the macromolecule is important for obtaining high relaxivity enhancements. The viral capsid conjugated gadolinium hydroxypyridonate complexes appear to possess two inner-sphere water molecules (q = 2) and the NMRD fittings highlight the differences in the local motion for the internal ({tau}{sub RI} = 440 ps) and external ({tau}{sub RI} = 310 ps) conjugates. These results indicate that there are significant advantages of using the internal surface of the capsids for contrast agent attachment, leaving the exterior surface available for the installation of tissue targeting groups.

  10. Development of a gadolinium-loaded liquid scintillator for the Hanaro short baseline prototype detector

    NASA Astrophysics Data System (ADS)

    Yeo, In Sung; Joo, Kyung Kwang; So, Sun Heang; Song, Sook Hyung; Kim, Hong Joo; So, Jung Ho; Park, Kang Soon; Ma, Kyung Ju; Jeon, Eun Ju; Kim, Jin Yu; Kim, Young Duk; Lee, Jason; Lee, Jeong-Yeon; Sun, Gwang-Min

    2014-02-01

    We propose a new experiment on the site of the Korea Atomic Energy Research Institute (KAERI) located at Daejeon, Korea. The Hanaro short baseline (SBL) nuclear reactor with a thermal power output 30 MW is used to investigate a reactor neutrino anomaly. A Hanaro SBL prototype detector having a 60- l volume has been constructed ˜6 m away from the reactor core. A gadolinium (Gd)-loaded liquid scintillator (LS) is used as an active material to trigger events. The selection of the LS is guided by physical and technical requirements, as well as safety considerations. A linear alkyl benzene (LAB) is used as a base solvent of the Hanaro SBL prototype detector. Three g/ l of PPO and 30 mg/ l of bis-MSB are dissolved to formulate the LAB-based LS. Then, a 0.5% gadolinium (Gd) complex with carboxylic acid is loaded into the LAB-based LS by using the liquidliquid extraction method. In this paper, we will summarize all the characteristics of the Gd-loaded LAB-based LS for the Hanaro prototype detector.