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Sample records for gadolinium oxysulfide screen-film

  1. Isotopically-enriched gadolinium-157 oxysulfide scintillator screens for the high-resolution neutron imaging

    NASA Astrophysics Data System (ADS)

    Trtik, Pavel; Lehmann, Eberhard H.

    2015-07-01

    We demonstrate the feasibility of the production of isotopically-enriched gadolinium oxysulfide scintillator screens for the high spatial-resolution neutron imaging. Approximately 10 g of 157Gd2O2S:Tb was produced in the form of fine powder (particle size approximately 2 μm). The level of 157Gd enrichment was above 88%. Approximately 2.5 μm thick 157Gd2O2S:Tb scintillator screens were produced and tested for the absorption power and the light output. The results are compared to the reference screens based on natGd2O2S:Tb. The isotopically enriched screens provided increase by a factor of 3.8 and 3.6 for the absorption power and the light output, respectively. The potential of the scintillator screens based on 157Gd2O2S phosphor for the purpose of the (high-resolution) neutron imaging is discussed.

  2. Neutron imaging detector with 2 μm spatial resolution based on event reconstruction of neutron capture in gadolinium oxysulfide scintillators

    NASA Astrophysics Data System (ADS)

    Hussey, Daniel S.; LaManna, Jacob M.; Baltic, Elias; Jacobson, David L.

    2017-09-01

    We report on efforts to improve the achievable spatial resolution in neutron imaging by centroiding the scintillation light from gadolinium oxysulfide scintillators. The current state-of-the-art neutron imaging spatial resolution is about 10 μm, and many applications of neutron imaging would benefit from at least an order of magnitude improvement in the spatial resolution. The detector scheme that we have developed magnifies the scintillation light from a gadolinium oxysulfide scintillator, calculates the center of mass of the scintillation event, resulting in an event-based imaging detector with spatial resolution of about 2 μm.

  3. Gadolinium oxysulfide nanoparticles as multimodal imaging agents for T2-weighted MR, X-ray tomography and photoluminescence

    NASA Astrophysics Data System (ADS)

    Osseni, Sèmiyou. A.; Lechevallier, Sévérine; Verelst, Marc; Perriat, Pascal; Dexpert-Ghys, Jeannette; Neumeyer, David; Garcia, Robin; Mayer, Florian; Djanashvili, Kristina; Peters, Joop A.; Magdeleine, Eddy; Gros-Dagnac, Hélène; Celsis, Pierre; Mauricot, Robert

    2013-12-01

    We have synthesized gadolinium oxysulfide nanoparticles (NPs) doped with other lanthanides (Eu3+, Er3+, Yb3+) via a hydroxycarbonate precursor precipitation route followed by a sulfuration process under a H2S-Ar atmosphere at 750 °C in order to propose new multimodal nanoplatforms for Magnetic Resonance (MR), X-ray and photoluminescence imaging. Gd2O2S:Eu3+ NPs strongly absorb near UV (~300-400 nm) and re-emit strong red light (624 nm). They can be easily internalized by cancer cells, and imaged by epifluorescence microscopy under excitation in the NUV (365 nm). They are not cytotoxic for living cells up to 100 μg mL-1. Consequently, they are well adapted for in vitro imaging on cell cultures. Gd2O2S:Eu3+ NPs also show strong transverse relaxivity and strong X-ray absorption allowing their use as contrast agents for T2-weighted MRI and X-ray tomography. Our study shows that Gd2O2S:Eu3+ NPs are considerably better than commercial Ferumoxtran-10 NPs as negative contrast agents for MRI. Upconversion emission of Gd2O2S:Er; Yb (1; 8%) NPs under infrared excitation (λex = 980 nm) shows mainly red emission (~650-680 nm). Consequently, they are more specifically designed for in vivo deep fluorescence imaging, because both excitation and emission are located inside the ``transparency window'' of biological tissues (650-1200 nm). Magnetic relaxivity and X-ray absorption behaviors of Gd2O2S:Er; Yb NPs are almost similar to Gd2O2S:Eu3+ NPs.We have synthesized gadolinium oxysulfide nanoparticles (NPs) doped with other lanthanides (Eu3+, Er3+, Yb3+) via a hydroxycarbonate precursor precipitation route followed by a sulfuration process under a H2S-Ar atmosphere at 750 °C in order to propose new multimodal nanoplatforms for Magnetic Resonance (MR), X-ray and photoluminescence imaging. Gd2O2S:Eu3+ NPs strongly absorb near UV (~300-400 nm) and re-emit strong red light (624 nm). They can be easily internalized by cancer cells, and imaged by epifluorescence microscopy under

  4. 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.

  5. 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

  6. Recent advances in screen-film mammography

    SciTech Connect

    Haus, A.G.

    1987-09-01

    Today there are many dedicated mammographic x-ray units available that are capable of providing high-quality screen-film mammograms. Likewise, screen-film combinations designed for mammography are capable of providing images with appropriate contrast, resolution, and noise levels. Proper film processing is most important in order to obtain the appropriate film speed and contrast. A higher-speed screen-film combination designed for mammography can provide mammograms with significantly lower radiation dose, especially for grid and magnification techniques. Designing x-ray units and techniques as well as screen-film combinations with the singular goal of reducing radiation dose will always involve compromises and trade-offs. The key is to always consider optimizing all of the factors that affect image quality: (1) appropriate beam quality, (2) breast compression, (3) consideration of the use of grids, (4) good geometry, (5) selection of an appropriate screen-film combination, and (6) proper film processing. Optimization of all appropriate imaging factors will produce high-quality mammograms at the lowest radiation dose to the patient.52 references.

  7. Technologic improvements in screen-film mammography

    SciTech Connect

    Haus, A.G. )

    1990-03-01

    During the past 20 years, many significant technologic improvements in mammographic x-ray equipment and screen-film-processing systems have occurred. Today it is possible to obtain mammograms with higher image quality at a significantly lower radiation dose, compared with mammograms dating back about 20 years. In this review article, clinical image comparisons and technical information--including x-ray spectra, limiting geometric resolution, sensitometric characteristic curves, modulation transfer function, and noise power spectra--are used to demonstrate technologic improvements in mammographic image quality.48 references.

  8. Enhanced Luminescence of La3+-Doped Gadolinium Oxysulfide with Tunable Crystalline Size

    NASA Astrophysics Data System (ADS)

    Ding, Yu-Jie; Wang, Li-Xi; Zhang, Qi-Tu; Pan, Shi-Bing

    2017-05-01

    The concentration of La3+ in (La x Gd1-x )2O2S:Tb phosphors prepared by the sulfide fusion method from coprecipitated oxalate precursors has been tuned, and the prominent effect on the crystalline size, particle size, and luminescence properties investigated. First-principles calculations were used to characterize the charge deformation, energy gap, and crystal field. According to density functional theory, the electron density of states in conduction bands increased with increase in the La3+ concentration. The increased electronic density strengthened the repulsion and thus decreased the diffusion so as to decrease the crystalline size from 106.2 nm to 37.3 nm. The particle size of (La x Gd1-x )2O2S:Tb increased from 0.21 μm to 1.25 μm as the La3+ concentration was increased from 15 mol.% to 60 mol.%. The excitation spectrum shifted towards shorter wavelength, enhancing the luminescence intensity of (La x Gd1-x )2O2S:Tb when excited at 254 nm. Furthermore, shorter lifetime was obtained due to lower symmetry as more Gd3+ was substituted by La3+ ions.

  9. Enhanced Luminescence of La3+-Doped Gadolinium Oxysulfide with Tunable Crystalline Size

    NASA Astrophysics Data System (ADS)

    Ding, Yu-Jie; Wang, Li-Xi; Zhang, Qi-Tu; Pan, Shi-Bing

    2017-10-01

    The concentration of La3+ in (La x Gd1- x )2O2S:Tb phosphors prepared by the sulfide fusion method from coprecipitated oxalate precursors has been tuned, and the prominent effect on the crystalline size, particle size, and luminescence properties investigated. First-principles calculations were used to characterize the charge deformation, energy gap, and crystal field. According to density functional theory, the electron density of states in conduction bands increased with increase in the La3+ concentration. The increased electronic density strengthened the repulsion and thus decreased the diffusion so as to decrease the crystalline size from 106.2 nm to 37.3 nm. The particle size of (La x Gd1- x )2O2S:Tb increased from 0.21 μm to 1.25 μm as the La3+ concentration was increased from 15 mol.% to 60 mol.%. The excitation spectrum shifted towards shorter wavelength, enhancing the luminescence intensity of (La x Gd1- x )2O2S:Tb when excited at 254 nm. Furthermore, shorter lifetime was obtained due to lower symmetry as more Gd3+ was substituted by La3+ ions.

  10. Processing and characterization of new oxysulfide glasses in the Ge-Ga-As-S-O system

    SciTech Connect

    Maurel, C.; Petit, L. Dussauze, M.; Kamitsos, E.I.; Couzi, M.; Cardinal, T.; Miller, A.C.; Jain, H.; Richardson, K.

    2008-10-15

    New oxysulfide glasses have been prepared in the Ge-Ga-As system employing a two-step melting process which involves the processing of the chalcogenide glass (ChG) and its subsequent melting with amorphous GeO{sub 2} powder. Optical characterization of the synthesized oxysulfide glasses has shown that the cut-off wavelength decreases with increasing oxygen content, and this has been correlated to results of Raman and infrared (IR) spectroscopies which show the formation of new oxysulfide structural units. X-ray photoelectron spectroscopy (XPS) analysis to probe the bonding environment of oxygen atoms in the oxysulfide glass network, has revealed the preferred formation of Ga-O and Ge-O bonds in comparison to As-O bonds. This work has demonstrated that melting a ChG glass with GeO{sub 2} leads to the formation of new oxysulfide glassy materials. - Graphical abstract: In this paper, we explain how new oxysulfide glasses are prepared in the Ge-Ga-As system employing a two-step process: (1) the processing of the chalcogenide glass (ChG) and (2) the re-melting of the ChG with GeO{sub 2} powder. Raman, infrared and XPS spectroscopies show the formation of new oxysulfide structural units.

  11. 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.

  12. 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.

  13. 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.

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

    DOE PAGES

    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

  15. The BiCu{sub 1−x}OS oxysulfide: Copper deficiency and electronic properties

    SciTech Connect

    Berthebaud, D.; Guilmeau, E.; Lebedev, O.I.

    2016-05-15

    An oxysulfide series of nominal compositions BiCu{sub 1−x}OS 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 BiCu{sub 1−x}OS 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 BiCu{sub 1−x}OS oxysulfide. Local epitaxial growth of the BiCuOS oxysulfide on top of CuO is also observed. In marked contrast to the BiCu{sub 1−x}OSe oxyselenide, these results give an explanation to the limited impact of Cu deficiency on the Seebeck coefficient in BiCu{sub 1−x}OS compounds. - Graphical abstract: High resolution TEM image showing a Bi(Cu)OS/Bi{sub 2}O{sub 2}S interface and corresponding dislocation region. The Bi(Cu)OS structure adopts a rather constant Cu content (near 0.95); starting from BiCuOS leads to the formation of defects such as the Bi{sub 2}O{sub 2}S oxysulfide.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Chemism and kinetics of the oxidation of zinc-calcium oxysulfide

    NASA Astrophysics Data System (ADS)

    Gulyaeva, R. I.; Selivanov, E. N.; Mansurova, A. N.

    2013-05-01

    The sequence of phase transformations and the kinetics of the solid-phase (heating to 1273 K) oxidation of zinc-calcium oxysulfide CaZnSO with air are determined by thermodynamic, thermogravimetric, mass spectrometric, and X-ray diffraction analyses. The oxidation process is shown to be accompanied by the formation of the CaSO4 and ZnO phases depending on the heating conditions, as well as by the formation of CaO with SO2 evolution. The two-stage oxidation of CaZnSO is interpreted by the Avrami-Erofeev kinetic equations with activation energies of 190 and 422 kJ/mol.

  1. Gadolinium induces macrophage apoptosis.

    PubMed

    Mizgerd, J P; Molina, R M; Stearns, R C; Brain, J D; Warner, A E

    1996-02-01

    Gadolinium (Gd) suppresses reticuloendothelial functions in vivo by unknown mechanisms. In vitro exposure of rat alveolar macrophages to GdCl3.6H20 caused cell death, as measured by trypan blue permeability, in both dose- and time-dependent fashions. Even a 10-min exposure to Gd caused significant cell death by 24 h. The morphology of Gd-treated cells, pyknosis and karyorrhexis prior to loss of membrane integrity, suggested apoptosis. Upon flow cytometric examination, Gd-treated propidium iodide-excluding cells demonstrated light scatter changes characteristic of apoptotic cells (decreased forward and increased right angle scatter). Gel electrophoresis of DNA from Gd-treated macrophages clearly showed the ladder pattern unique to apoptotic cells. Electron-dense structures containing Gd were observed via electron spectroscopic imaging within phagosomes and also within nuclei (associated with condensed chromatin). Gadolinium, endocytosed by macrophages and distributed to nuclei, causes apoptosis of macrophages in vitro.

  2. 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.

  3. Mammographic microcalcifications: Detection with xerography, screen-film, and digitized film display

    SciTech Connect

    Smathers, R.L.; Bush, E.; Drace, J.; Stevens, M.; Sommer, F.G.; Brown, B.W.; Karras, B.

    1986-06-01

    Pulverized bone specks and aluminum oxide specks were measured by hand into sizes ranging from 0.2 mm to 1.0 mm and then arranged in clusters. These clusters were superimposed on a human breast tissue phantom, and xeromammograms and screen-film mammograms of the clusters were made. The screen-film mammograms were digitized using a high-resolution laser scanner and then displayed on cathode ray tube (CRT) monitors. Six radiologists independently counted the microcalcifications on the xeromammograms, the screen-film mammograms, and the digitized film mammograms. The xeromammograms were examined with a magnifying glass; the screen-film images were examined with a magnifying glass and by hot light; and the digitized-film images were examined by electronic magnification and image processing. The bone speck size that corresponded to a mean 50% detectability level for each technique was as follows: xeromammography, 0.550 mm; digitized film, 0.573 mm; and screen-film, 0.661 mm. We postulate that electronic magnification and image processing with edge enhancement can improve the capability of screen-film mammography to enhance the detection of microcalcifications.

  4. Mammographic microcalcifications: detection with xerography, screen-film, and digitized film display.

    PubMed

    Smathers, R L; Bush, E; Drace, J; Stevens, M; Sommer, F G; Brown, B W; Karras, B

    1986-06-01

    Pulverized bone specks and aluminum oxide specks were measured by hand into sizes ranging from 0.2 mm to 1.0 mm and then arranged in clusters. These clusters were superimposed on a human breast tissue phantom, and xeromammograms and screen-film mammograms of the clusters were made. The screen-film mammograms were digitized using a high-resolution laser scanner and then displayed on cathode ray tube (CRT) monitors. Six radiologists independently counted the microcalcifications on the xeromammograms, the screen-film mammograms, and the digitized-film mammograms. The xeromammograms were examined with a magnifying glass; the screen-film images were examined with a magnifying glass and by hot light; and the digitized-film images were examined by electronic magnification and image processing. The bone speck size that corresponded to a mean 50% detectability level for each technique was as follows: xeromammography, 0.550 mm; digitized film, 0.573 mm; and screen-film, 0.661 mm. We postulate that electronic magnification and image processing with edge enhancement can improve the capability of screen-film mammography to enhance the detection of microcalcifications.

  5. Visibility of microcalcifications in computed and screen-film mammography

    NASA Astrophysics Data System (ADS)

    Cowen, Arnold R.; Launders, Jason H.; Jadav, Mark; Brettle, David S.

    1997-08-01

    Due to the clinically and technically demanding nature of breast x-ray imaging, mammography still remains one of the few essentially film-based radiological imaging techniques in modern medical imaging. There are a range of possible benefits available if a practical and economical direct digital imaging technique can be introduced to routine clinical practice. There has been much debate regarding the minimum specification required for direct digital acquisition. One such direct digital system available is computed radiography (CR), which has a modest specification when compared with modern screen-film mammography (SFM) systems. This paper details two psychophysical studies in which the detection of simulated microcalcifications with CR has been directly compared to that with SFM. The first study found that under scatter-free conditions the minimum detectable size of microcalcification was approximately for both SFM and CR. The second study found that SFM had a 4.6% higher probability of observers being able to correctly identify the shape of diameter test details; there was no significant difference for either larger or smaller test details. From the results of these studies it has been demonstrated that the modest specification of CR, in terms of limiting resolution, does not translate into a dramatic difference in the perception of details at the limit of detectability. When judging the imaging performance of a system it is more important to compare the signal-to-noise ratio transfer spectrum characteristics, rather than simply the modulation transfer function.

  6. A comparison of the performance of modern screen-film and digital mammography systems.

    PubMed

    Monnin, P; Gutierrez, D; Bulling, S; Lepori, D; Valley, J-F; Verdun, F R

    2005-06-07

    This work compares the detector performance and image quality of the new Kodak Min-R EV mammography screen-film system with the Fuji CR Profect detector and with other current mammography screen-film systems from Agfa, Fuji and Kodak. Basic image quality parameters (MTF, NPS, NEQ and DQE) were evaluated for a 28 kV Mo/Mo (HVL = 0.646 mm Al) beam using different mAs exposure settings. Compared with other screen-film systems, the new Kodak Min-R EV detector has the highest contrast and a low intrinsic noise level, giving better NEQ and DQE results, especially at high optical density. Thus, the properties of the new mammography film approach those of a fine mammography detector, especially at low frequency range. Screen-film systems provide the best resolution. The presampling MTF of the digital detector has a value of 15% at the Nyquist frequency and, due to the spread size of the laser beam, the use of a smaller pixel size would not permit a significant improvement of the detector resolution. The dual collection reading technology increases significantly the low frequency DQE of the Fuji CR system that can at present compete with the most efficient mammography screen-film systems.

  7. A comparison of the performance of modern screen-film and digital mammography systems

    NASA Astrophysics Data System (ADS)

    Monnin, P.; Gutierrez, D.; Bulling, S.; Lepori, D.; Valley, J.-F.; Verdun, F. R.

    2005-06-01

    This work compares the detector performance and image quality of the new Kodak Min-R EV mammography screen-film system with the Fuji CR Profect detector and with other current mammography screen-film systems from Agfa, Fuji and Kodak. Basic image quality parameters (MTF, NPS, NEQ and DQE) were evaluated for a 28 kV Mo/Mo (HVL = 0.646 mm Al) beam using different mAs exposure settings. Compared with other screen-film systems, the new Kodak Min-R EV detector has the highest contrast and a low intrinsic noise level, giving better NEQ and DQE results, especially at high optical density. Thus, the properties of the new mammography film approach those of a fine mammography detector, especially at low frequency range. Screen-film systems provide the best resolution. The presampling MTF of the digital detector has a value of 15% at the Nyquist frequency and, due to the spread size of the laser beam, the use of a smaller pixel size would not permit a significant improvement of the detector resolution. The dual collection reading technology increases significantly the low frequency DQE of the Fuji CR system that can at present compete with the most efficient mammography screen-film systems.

  8. Upconversion emission of erbium-doped lanthanum oxysulfide powders for temperature sensing

    NASA Astrophysics Data System (ADS)

    Balda, Rolindes; Hakmeh, Noha; Merdrignac-Conanec, Odile; Arriandiaga, M. Angeles; Fernandez, Joaquin

    2017-02-01

    In this work we report a detailed spectroscopic study of the near-infrared to visible upconversion luminescence in Erdoped lanthanum oxysulfide crystal powders after excitation of level 4I9/2. The analysis of the decay curves of the upconversion emission indicates that energy transfer upconversion is the main mechanism responsible for the green (4S3/2) and red (4F9/2) upconversion luminescence. The temperature dependence of the green upconverted emission from the two thermally coupled 2H11/2 and 4S3/2 levels has been analyzed in the 230 K- 300 K temperature range in order to check its availability as a temperature sensor.

  9. 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

  10. 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.

  11. Proximal surface caries detection with direct-exposure and rare earth screen/film imaging

    SciTech Connect

    Lundeen, R.C.; McDavid, W.D.; Barnwell, G.M.

    1988-12-01

    This laboratory study compared five imaging systems for their diagnostic accuracy in detection of proximal surface dental caries. Ten viewers provided data on radiographic detectability of carious lesions. The diagnostic accuracy of each system was determined with receiver operating characteristic (ROC) curves by comparing viewer data with the true state of the teeth as determined microscopically. D-speed film marginally outperformed the other four systems, but the three screen/film systems matched the diagnostic accuracy of E-speed film. Radiation reductions between 62% and 92% were achieved with the screen/film systems when compared to the two conventional dental films. The feasibility of designing a screen/film bite-wing cassette was shown, but the poor diagnostic accuracy of the present bite-wing system indicated a need for a new technology in caries detection.

  12. Quality Imaging — Comparison of CR Mammography with Screen-Film Mammography

    NASA Astrophysics Data System (ADS)

    Gaona, E.; Azorín Nieto, J.; Irán Díaz Góngora, J. A.; Arreola, M.; Casian Castellanos, G.; Perdigón Castañeda, G. M.; Franco Enríquez, J. G.

    2006-09-01

    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.

  13. 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.

  14. Dose comparison between screen/film and full-field digital mammography.

    PubMed

    Gennaro, Gisella; di Maggio, Cosimo

    2006-11-01

    The study purpose was the comparison between doses delivered by a full-field digital mammography system and a screen/film mammography unit, both using the same type of X-ray tube. Exposure parameters and breast thickness were collected for 300 screen/film (GE Senographe DMR) and 296 digital mammograms (GE Senographe 2000D). The entrance surface air kerma (ESAK) was calculated from anode/filter combination, kV(p) and mAs values and breast thickness, by simulating spectra through a program based on a catalogue of experimental X-ray spectra. The average glandular dose (AGD) was also computed. Results showed an overall reduction of average glandular dose by 27% of digital over screen/film mammography. The dose saving was about 15% for thin and thick breasts, while it was between 30% and 40% for intermediate thicknesses. Full-field digital mammography dose reduction is allowed by wider dynamic range and higher efficiency of digital detector, which can be exposed at higher energy spectra than screen/film mammography, and by the separation between acquisition and displaying processes.

  15. 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.

  16. Oxysulfide LiAlSO: A Lithium Superionic Conductor from First Principles

    NASA Astrophysics Data System (ADS)

    Wang, Xuelong; Xiao, Ruijuan; Li, Hong; Chen, Liquan

    2017-05-01

    Through first-principles calculations and crystal structure prediction techniques, we identify a new layered oxysulfide LiAlSO in orthorhombic structure as a novel lithium superionic conductor. Two kinds of stacking sequences of layers of AlS2O2 are found in different temperature ranges. Phonon and molecular dynamics simulations verify their dynamic stabilities, and wide band gaps up to 5.6 eV are found by electronic structure calculations. The lithium migration energy barrier simulations reveal the collective interstitial-host ion "kick-off" hopping mode with barriers lower than 50 meV as the dominating conduction mechanism for LiAlSO, indicating it to be a promising solid-state electrolyte in lithium secondary batteries with fast ionic conductivity and a wide electrochemical window. This is a first attempt in which the lithium superionic conductors are designed by the crystal structure prediction method and may help explore other mixed-anion battery materials.

  17. 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

    2011-06-02

    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.

  18. Structure and physical properties of the polar oxysulfide CaZnOS.

    PubMed

    Sambrook, Timothy; Smura, Catherine F; Clarke, Simon J; Ok, Kang Min; Halasyamani, P Shiv

    2007-04-02

    The synthesis, structure, and electrical properties of the oxysulfide CaZnOS are reported. The white compound has a band gap of 3.7(1) eV and crystallizes in hexagonal space group P6(3)mc (No. 186) with a = 3.75726(3) A, c = 11.4013(1) A, and Z = 2. The noncentrosymmetric structure, which has few analogues, is composed of isotypic puckered hexagonal ZnS and CaO layers arranged so that ZnS3O tetrahedra are all aligned parallel, resulting in a polar structure. The compound shows type 1 non-phase-matchable second harmonic generation, determined using 1064 nm radiation, with an efficiency approximately 100 times that of alpha-SiO2 and a piezoelectric coefficient of 38 pm V-1. Although polar, CaZnOS is not ferroelectric and the pyroelectric coefficient is very small, approximately 0.0 microC m-2 K-1 between room temperature and 100 degrees C.

  19. Cast Iron Inoculation Enhanced by Supplementary Oxy-sulfides Forming Elements

    NASA Astrophysics Data System (ADS)

    Riposan, Iulian; Stan, Stelian; Uta, Valentin; Stefan, Ion

    2017-08-01

    Inoculation is one of the most important metallurgical treatments applied to the molten cast iron immediately prior to casting, to promote solidification without excessive eutectic undercooling, which favors carbides formation usually with undesirable graphite morphologies. The paper focused on the separate addition of an inoculant enhancer alloy [S, O, oxy-sulfides forming elements] with a conventional Ca-FeSi alloy, in the production of gray and ductile cast irons. Carbides formation tendency decreased with improved graphite characteristics as an effect of the [Ca-FeSi + Enhancer] inoculation combination, when compared to other Ca/Ca, Ba/Ca, RE-FeSi alloy treatments. Adding an inoculant enhancer greatly enhances inoculation, lowers inoculant consumption up to 50% or more and avoids the need to use more costly inoculants, such as a rare earth bearing alloy. The Inoculation Specific Factor [ISF] was developed as a means to more realistically measure inoculant treatment efficiency. It compares the ratio between the improved characteristic level and total inoculant consumption for this effect. Addition of any of the commercial inoculants plus the inoculant enhancer offered outstanding inoculation power [increased ISF] even at higher solidification cooling rates, even though the total enhancer addition was at a small fraction of the amount of commercial inoculant used.

  20. 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.

  1. Experience with gadolinium at yankee

    SciTech Connect

    Cacciapouti, R.J.; Sironen, M.A.; Kaptiz, D.M.; Potter, R.C.

    1985-11-01

    The Vermont Yankee nuclear power station, a boiling water reactor, has been operating with gadolinium in the fuel bundles since 1973. The gadolinium has ranged from 2.0 to 4.0 wt% in 7 x 7, 8 x 8, and retrofit 8 x 8 bundle designs. When Yankee Atomic Electric Company initiated its program in 1978 to perform reload licensing analysis, these bundles and the core designs had to be modeled accurately. The basic calculational model consists of the cross section generation code, CASMO, and the three-dimensional nodal code, SIMULATE. The gadolinium cross sections for use in CASMO were generated using MICBURN to model each gadolinium pin individually. This combination of codes has been used to calculate 11 cycles of operation at Vermont Yankee. The model has been depleted each cycle using explicit plant conditions at equilibrium xenon. At various state points, the eigenvalues, hot and cold, were calculated and tabulated for each cycle. Comparisons were made between plant-measured and SIMULATE-calculated TIP values and between process computer and SIMULATE thermal margins. The model is also used to predict future cycle operating conditions and thermal margins based on past comparisons.

  2. Diagnostic imaging and biopsy pathways following abnormal screen-film and digital screening mammography

    PubMed Central

    Hubbard, Rebecca A.; Zhu, Weiwei; Horblyuk, Ruslan; Karliner, Leah; Sprague, Brian L.; Henderson, Louise; Lee, David; Onega, Tracy; Buist, Diana SM.; Sweet, Alison

    2013-01-01

    Objective The transition from screen-film to digital mammography may have altered diagnostic evaluation of women following a positive screening examination. This study compared use and timeliness of diagnostic imaging and biopsy for women screened with screen-film or digital mammography. Materials and Methods Data were from 35,321 positive screening mammograms on 32,087 women aged 40–89 years, from 22 Breast Cancer Surveillance Consortium facilities in 2005–2008. Diagnostic pathways were classified by their inclusion of diagnostic mammography, ultrasound, magnetic resonance imaging (MRI), and biopsy. We compared time to resolution and frequency of diagnostic pathways by patient characteristics, screening exam modality, and radiology facility. Between-facility differences were evaluated by computing the proportion of mammograms receiving follow-up with a particular pathway for each facility and examining variation in these proportions across facilities. Multinomial logistic regression adjusting for age, calendar year, and facility compared odds of follow-up with each pathway. Results The median time to resolution of a positive screening mammogram was 10 days. Compared to screen-film mammograms, digital mammograms were more frequently followed by only a single diagnostic mammogram (46% vs. 36%). Pathways following digital screening mammography were also less likely to include biopsy (16% vs. 20%). However, in adjusted analyses most differences were not statistically significant (p = 0.857 for mammography only; p = 0.03 for biopsy). Substantial variability in diagnostic pathway frequency was seen across facilities. For instance, the frequency of evaluation with diagnostic mammography alone ranged from 23% to 55% across facilities. Conclusion Differences in evaluation of positive digital and screen-film screening mammograms were minor, and appeared to be largely attributable to substantial variation between radiology facilities. To guide health systems in their

  3. Diagnostic imaging and biopsy pathways following abnormal screen-film and digital screening mammography.

    PubMed

    Hubbard, Rebecca A; Zhu, Weiwei; Horblyuk, Ruslan; Karliner, Leah; Sprague, Brian L; Henderson, Louise; Lee, David; Onega, Tracy; Buist, Diana S M; Sweet, Alison

    2013-04-01

    The transition from screen-film to digital mammography may have altered diagnostic evaluation of women following a positive screening examination. This study compared the use and timeliness of diagnostic imaging and biopsy for women screened with screen-film or digital mammography. Data were obtained from 35,321 positive screening mammograms on 32,087 women aged 40-89 years, from 22 breast cancer surveillance consortium facilities in 2005-2008. Diagnostic pathways were classified by their inclusion of diagnostic mammography, ultrasound, magnetic resonance imaging, and biopsy. We compared time to resolution and frequency of diagnostic pathways by patient characteristics, screening exam modality, and radiology facility. Between-facility differences were evaluated by computing the proportion of mammograms receiving follow-up with a particular pathway for each facility and examining variation in these proportions across facilities. Multinomial logistic regression adjusting for age, calendar year, and facility compared odds of follow-up with each pathway. The median time to resolution of a positive screening mammogram was 10 days. Compared to screen-film mammograms, digital mammograms were more frequently followed by only a single diagnostic mammogram (46 vs. 36 %). Pathways following digital screening mammography were also less likely to include biopsy (16 vs. 20 %). However, in adjusted analyses, most differences were not statistically significant (p = 0.857 for mammography only; p = 0.03 for biopsy). Substantial variability in diagnostic pathway frequency was seen across facilities. For instance, the frequency of evaluation with diagnostic mammography alone ranged from 23 to 55 % across facilities. Differences in evaluation of positive digital and screen-film screening mammograms were minor, and appeared to be largely attributable to substantial variation between radiology facilities. To guide health systems in their efforts to eliminate practices that do not

  4. 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.

  5. Technical aspects of screen-film radiography, film processing, and quality control.

    PubMed

    Gray, J E

    1997-01-01

    The broad goal of quality control (QC) of screen-film radiography and film processing is to provide radiographs of consistent, high quality. Achievement of this goal requires attention to several areas, including QC of the screen-film system and photographic processor, acceptance testing of all components, and skill in analysis of film artifacts to "diagnose" the processor problems causing the aberrations. Methods to reduce waste, recycle by-products, and reuse resources such as silver are also part of the QC process. To optimize the photographic process, one should use the film, chemical solutions, processor, and screens and cassettes produced by one manufacturer or the combination recommended by the film manufacturer. Important variables in film processing (eg, density, density difference, and base plus fog) are recorded on control charts, which plot the variables as a function of time and allow easy analysis of changes in operating levels. Many variables can affect any component in the screen-film imaging system; problems caused by manufacturing batch-to-batch variation, which is perhaps the most pervasive variable, can be lessened by purchasing film, screens, and cassettes in large batches and of the same batch and by purchasing photographic chemicals in concentrated form and mixing them as needed. Acceptance testing ensures that the product meets expectations, ensures that its performance meets specifications, and establishes the operating level for the ongoing QC program.

  6. Screen film versus digital mammography: a perceptual analysis of postprocessed hard copy images

    NASA Astrophysics Data System (ADS)

    Suryanarayanan, Sankararaman; Karellas, Andrew; Vedantham, Srinivasan; Ved, Hetal; D'Orsi, Carl J.

    2002-04-01

    In this investigation we studied the imaging characteristics of a mammographic screen-film (MinR-2000, Eastman Kodak Co.) and an amorphous-silicon flat-panel digital mammography system (Senographe 2000D, GE Medical Systems) based on information perception by human observers. The focus of the study was to utilize an effective means to estimate the contrast-detail characteristics of x-ray imaging systems at various threshold levels to evaluate system performance with reduced observer subjectivity. We obtained three images of a contrast-detail phantom (CDMAM, Nuclear Associates) with screen-film and three images with digital mammography under identical exposure conditions. The digital images were printed using dry film printer (DryView 8600, Eastman Kodak Co.) after being windowed/leveled appropriately by two experienced radiologists. Seven observers reviewed the images and 'proportion correct' detection data were computed for each observer. A psychophysical signal detection model that hypothesizes a continuous decision variable internal to the observer with Gaussian probability density functions was used to fit the experimental observer data. Projection data from the detection curves at 50%, 62.5%, and 75% threshold levels were used to generate contrast-detail diagrams. Digital mammography, on average, exhibited lower (better) threshold contrast-detail characteristics compared to screen-film mammography.

  7. Comparative evaluation of the sensitometric properties of screen-film systems and conventional dental receptors for intraoral radiography

    SciTech Connect

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

    1989-12-01

    This investigation determined the sensitometric properties of 27 rare-earth screen-film combinations and compared them to E- and D-speed films and xeroradiography, the current standards for intraoral radiography. A series of exposures from base plus fog to film saturation were made to determine the Hurter and Driffield curve of each image receptor. The base plus fog, film saturation, speed, gamma, average gradient, and resolution were determined. When dental receptors and screen-film systems are compared on the basis of radiographic quality (contrast and resolution), many screen-film systems have similar resolution (greater than 10 line pairs/mm), significantly greater contrast (greater than 2.0), and a substantial speed advantage (greater than 10). Thus selected screen-film systems may be an alternative to conventional dental receptors for intraoral radiography.

  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.

  9. Gadolinium periconceptional exposure: pregnancy and neonatal outcome.

    PubMed

    De Santis, M; Straface, G; Cavaliere, A F; Carducci, B; Caruso, A

    2007-01-01

    Gadolinium derivatives are ionic paramagnetic contrast agents used to enhance magnetic resonance images, labeled as a pregnancy category C by the Food and Drug Administration because of a lack of epidemiological studies concerning first-trimester exposure. Prospective cohort study to determine whether gadolinium derivatives exposure in periconceptional period is a risk factor for pregnancy or fetal development. We report the outcome of 26 pregnant women exposed to gadolinium derivatives in the first trimester without adverse effect on pregnancy and neonatal outcome. Currently, this study represents the only prospective investigation of gadolinium derivatives in pregnancy, but more data are necessary to exclude a teratogenic risk.

  10. 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.

  11. 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.

  12. A simple method for evaluating image quality of screen-film system using a high-performance digital camera

    NASA Astrophysics Data System (ADS)

    Fujita, Naotoshi; Yamazaki, Asumi; Ichikawa, Katsuhiro; Kodera, Yoshie

    2009-02-01

    Screen-film systems are used in mammography even now. Therefore, it is important to measure their physical properties such as modulation transfer function (MTF) or noise power spectrum (NPS). The MTF and NPS of screen-film systems are mostly measured by using a microdensitometer. However, since microdensitometers are not commonly used in general hospitals, it is difficult to carry out these measurements regularly. In the past, Ichikawa et al. have measured and evaluated the physical properties of medical liquid crystal displays by using a high-performance digital camera. By this method, the physical properties of screen-film systems can be measured easily without using a microdensitometer. Therefore, we have proposed a simple method for measuring the MTF and NPS of screen-film systems by using a high-performance digital camera. The proposed method is based on the edge method (for evaluating MTF) and the one-dimensional fast Fourier transform (FFT) method (for evaluating NPS), respectively. As a result, the MTF and NPS evaluated by using the high-performance digital camera approximately corresponded with those evaluated by using a microdensitometer. It is possible to substitute the calculation of MTF and NPS by using a high-performance digital camera for that by using a microdensitometer. Further, this method also simplifies the evaluation of the physical properties of screen-film systems.

  13. Gadolinium Deposition in Humans: When Did We Learn That Gadolinium Was Deposited In Vivo?

    PubMed

    Huckle, James E; Altun, Ersan; Jay, Michael; Semelka, Richard C

    2016-04-01

    Recently, there have been numerous major peer-reviewed publications reporting deposition of gadolinium in the dentate nucleus and globus pallidus in subjects with normal renal function. This review takes a retrospective look back through the development of gadolinium-based contrast agents to describe the historical evidence of gadolinium deposition in vivo and shows that deposition in the basal ganglia should come as no surprise. Evidence for gadolinium deposition in both animal models and human patients is described. Stability differences among gadolinium contrast agents have long been recognized in vitro, and deposition of gadolinium in tissues has been described in animal models since at least 1984. The first major study that showed deposition in humans appeared in 1998 regarding patients with renal failure and in 2004 in patients with normal renal function. The historical literature indicates that gadolinium retention in healthy patients is occurring, although the clinical consequences of deposition remain unknown.

  14. Gadolinium deposition in nephrogenic fibrosing dermopathy.

    PubMed

    Boyd, Alan S; Zic, John A; Abraham, Jerrold L

    2007-01-01

    There is growing recognition of the association between the use of gadolinium-containing radiocontrast agents for magnetic resonance imaging and the serious dermal and systemic disease nephrogenic fibrosing dermopathy/nephrogenic systemic fibrosis (NFD/NSF). The pathogenesis of this entity remains unclear; however, our recent observations suggest a likely mechanism for the initial dermal manifestations of this gadolinium toxicity.

  15. 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.

  16. 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.

  17. Status of gadolinium enrichment technology at LLNL

    SciTech Connect

    Haynam, C.; Comaskey, B.; Conway, J.; Eggert, J.; Glaser, J.; Ng, E.; Paisner, J.; Solarz, R.; Worden, E.

    1993-01-01

    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.

  18. 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.

  19. Investigation of diagnostic and image quality attributes: comparison of screen-film to CR mammography

    NASA Astrophysics Data System (ADS)

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

    2006-03-01

    Digital mammography is advancing into an arena where analog has long been the gold standard. Direct digital systems may not be the favored solution for a particular site while computed radiography (CR) mammography, remains unproven worldwide. This pilot study responds to the growing desire to acquire and display digital mammographic images by exploring the acceptability of CR mammography. Images representing a range of breast tissue types were collected from 49 subjects (17 screening; 32 diagnostic) at four clinical sites. Comparison views were collected on the same breast, under the same compression, using automatic exposure control on state-of-the-art film systems followed by CR. CR images were processed and printed to a mammography printer for hard copy feature comparison. Each image pair in the study was evaluated according to 13 image quality attributes covering noise, contrast, sharpness, and image quality in the overall captured images as well as in each of several particular breast regions (periphery and skin-line, parenchyma and fatty tissue). A rating scale from 1 to 5 was used (strong preference for film=1, strong preference for CR=5). Twelve experienced mammographers at four clinical sites scored a subset of the 49 cases for a total of 64 image pair readings. There were 64 ratings for each of 13 image quality attributes for all cases and, an additional series of scores (four or five attribute ratings) for each abnormality in the category of mass, architectural distortion and microcalcification, for a total of 1069 scores. Based on the pilot study results, it was suggested that CR was equivalent or preferred to conventional screen-film for overall image quality (38% scored 3; 46% scored >3), image contrast (27% scored 3; 59% scored >3) and sharpness (28% scored 3; 50% scored >3). No preference was found when assessing noise. This pilot study also suggested that diagnostic quality was maintained in assessing abnormalities for attributes necessary to

  20. Screen-film versus digital radiography of sacroiliac joints: evaluation of image quality and dose to patients.

    PubMed

    Jablanovic, Dragoslav; Ciraj-Bjelac, Olivera; Damjanov, Nemanja; Seric, Srdjan; Radak-Perovic, Marija; Arandjic, Danijela; Maksimovic, Ruzica

    2013-06-01

    The purpose of this paper is to evaluate the image quality and dose to patients in the radiography of sacroiliac joints and to perform a clinical comparative study of digital and conventional screen-film radiography. Routine radiography of sacroiliac joint was performed in 60 patients using digital and screen-film radiography. The visibility of five anatomical regions and the overall image quality were rated by experienced radiologists. Patient dose assessment in terms of entrance surface air kerma (ESAK) was performed. The digital system showed slightly improved visualisation of specific anatomical structures. Overall image quality was significantly better in the digital when compared with the screen-film imaging system. The average ESAK was 2.4 mGy in screen-film and 3.6 mGy in digital radiography. The digital radiography provided equal or better visibility of anatomical details and overall image quality, but on higher dose levels. Therefore, the practice on digital systems must be optimised.

  1. 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…

  2. Brain gadolinium deposition after administration of gadolinium-based contrast agents.

    PubMed

    Kanda, Tomonori; Oba, Hiroshi; Toyoda, Keiko; Kitajima, Kazuhiro; Furui, Shigeru

    2016-01-01

    Gadolinium-based contrast agents (GBCAs) consist of gadolinium ions and a chelating agent that binds the gadolinium ion tightly so that its toxicity is not manifested. However, in 2013, an association between brain MRI abnormalities and a history of GBCA administration was first reported. Even in patients with normal renal function, increased signal intensity in the dentate nucleus and globus pallidus on unenhanced T1-weighted images showed a positive correlation with previous exposure to linear chelate type GBCAs, but not to macrocyclic chelate type ones. This difference of GBCAs is speculated to reflect the stability of GBCAs, and de-chelated gadolinium deposition has been strongly suspected. Using inductively coupled plasma mass spectroscopy, gadolinium was detected from patients' brains with a history of repeated GBCA administration. In some cases, the gadolinium concentration of a patient's brain with normal renal function exceeded the gadolinium concentration of the skin in nephrogenic systemic fibrosis patients, but without any histological change. The actual risk has not been documented yet, but it seems important to consider the potential unknown risks of residual gadolinium in our decisions regarding GBCA administration, and to make efforts to minimize any residual gadolinium in the patient's body.

  3. 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.

  4. 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.

  5. Influence of Upconversion Processes in the Optically-Induced Inhomogeneous Thermal Behavior of Erbium-Doped Lanthanum Oxysulfide Powders.

    PubMed

    Balda, Rolindes; Hakmeh, Noha; Barredo-Zuriarrain, Macarena; Merdrignac-Conanec, Odile; García-Revilla, Sara; Arriandiaga, M Angeles; Fernández, Joaquín

    2016-05-11

    The efficient infrared-to-visible upconversion emission present in Er-doped lanthanum oxysulfide crystal powders is used as a fine thermal sensor to determine the influence of upconversion processes on the laser-induced thermal load produced by the pump laser and to assess the potentialities of this material in order to obtain anti-Stokes laser-induced cooling. The analysis of the upconversion emission and excitation spectra as well as the decay curves indicates that energy transfer upconversion is the main mechanism responsible for the green (⁴S3/2) and red (⁴F9/2) upconversion luminescence. The dependence on temperature of the intensity ratio of upconversion emission from thermally-coupled ²H11/2 and ⁴S3/2 levels of Er(3+) in the 240-300 K temperature range has been used to estimate a relative sensitivity of 1.09 × 10(-2) K(-1). Thermal measurements performed on the powder samples by using a thermal infrared camera exhibit a very inhomogeneous heat distribution at the sample surface due to the random distribution of the pumping energy inside the sample as well as to the random properties of the thermal field. The analysis of both spectroscopic and thermal measurements show that after a transient heating induced by the background absorption, cooling of discrete regions by means of anti-Stokes processes can be observed.

  6. Are gadolinium contrast agents suitable for gadolinium neutron capture therapy?

    PubMed

    De Stasio, Gelsomina; Rajesh, Deepika; Casalbore, Patrizia; Daniels, Matthew J; Erhardt, Robert J; Frazer, Bradley H; Wiese, Lisa M; Richter, Katherine L; Sonderegger, Brandon R; Gilbert, Benjamin; Schaub, Sebastien; Cannara, Rachel J; Crawford, John F; Gilles, Mary K; Tyliszczak, Tolek; Fowler, John F; Larocca, Luigi M; Howard, Steven P; Mercanti, Delio; Mehta, Minesh P; Pallini, Roberto

    2005-06-01

    Gadolinium neutron capture therapy (GdNCT) is a potential treatment for malignant tumors based on two steps: (1) injection of a tumor-specific (157)Gd compound; (2) tumor irradiation with thermal neutrons. The GdNC reaction can induce cell death provided that Gd is proximate to DNA. Here, we studied the nuclear uptake of Gd by glioblastoma (GBM) tumor cells after treatment with two Gd compounds commonly used for magnetic resonance imaging, to evaluate their potential as GdNCT agents. Using synchrotron X-ray spectromicroscopy, we analyzed the Gd distribution at the subcellular level in: (1) human cultured GBM cells exposed to Gd-DTPA or Gd-DOTA for 0-72 hours; (2) intracerebrally implanted C6 glioma tumors in rats injected with one or two doses of Gd-DOTA, and (3) tumor samples from GBM patients injected with Gd-DTPA. In cell cultures, Gd-DTPA and Gd-DOTA were found in 84% and 56% of the cell nuclei, respectively. In rat tumors, Gd penetrated the nuclei of 47% and 85% of the tumor cells, after single and double injection of Gd-DOTA, respectively. In contrast, in human GBM tumors 6.1% of the cell nuclei contained Gd-DTPA. Efficacy of Gd-DTPA and Gd-DOTA as GdNCT agents is predicted to be low, due to the insufficient number of tumor cell nuclei incorporating Gd. Although multiple administration schedules in vivo might induce Gd penetration into more tumor cell nuclei, a search for new Gd compounds with higher nuclear affinity is warranted before planning GdNCT in animal models or clinical trials.

  7. 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.

  8. 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.

  9. Interobserver agreement and performance score comparison in quality control using a breast phantom: screen-film mammography vs computed radiography.

    PubMed

    Shimamoto, Kazuhiro; Ikeda, Mitsuru; Satake, Hiroko; Ishigaki, Satoko; Sawaki, Akiko; Ishigaki, Takeo

    2002-09-01

    Our objective was to evaluate interobserver agreement and to compare the performance score in quality control of screen-film mammography and computed radiography (CR) using a breast phantom. Eleven radiologists interpreted a breast phantom image (CIRS model X) by four viewing methods: (a) original screen-film; (b) soft-copy reading of the digitized film image; (c) hard-copy reading of CR using an imaging plate; and (d) soft-copy reading of CR. For the soft-copy reading, a 17-in. CRT monitor (1024x1536x8 bits) was used. The phantom image was evaluated using a scoring system outlined in the instruction manual, and observers judged each object using a three-point rating scale: (a) clearly seen; (b) barely seen; and (c) not seen. For statistical analysis, the kappa statistic was employed. For "mass" depiction, interobserver agreement using CR was significantly lower than when using screen-film ( p<0.05). There was no significant difference in the kappa value for detecting "microcalcification"; however, the performance score of "microcalcification" on CR hard-copy was significantly lower than on the other three viewing methods ( p<0.05). Viewing methods (film or CR, soft-copy or hard-copy) could affect how the phantom image is judged. Paying special attention to viewing conditions is recommended for quality control of CR mammograms.

  10. Incidence of immediate gadolinium contrast media reactions.

    PubMed

    Prince, Martin R; Zhang, Honglei; Zou, Zhitong; Staron, Ronald B; Brill, Paula W

    2011-02-01

    Our objective was to determine the incidence of immediate adverse events for gadolinium-based contrast agents. All gadolinium-based contrast agent adverse events reported to radiology quality assurance committees were graded according to American College of Radiology criteria and divided by the total number of injections to determine incidence during the past 10 years. For each event, an age- and examination-matched control patient was identified to compare sex, weight, creatinine, eosinophil count, allergic history and gadolinium-based contrast agent dose differences. The U.S. Food and Drug Administration (FDA) Adverse Event Reporting System (AERS) database was analyzed to compare local experience to national trends. Abdominal MRI had the highest rates of adverse events, 0.013% compared with brain (0.0045%, p < 0.001) or spine (0.0034%, p < 0.001). Adverse events were more likely in women, with a female to male ratio of 3.3, and in patients with history of prior allergic reactions (p < 0.001). Immediate adverse events rates were 0.2, 0.5, 1.2, and 3.3 per 1,000 injections for gadodiamide, gadopentetate dimeglumine, gadobenate dimeglumine, and gadoteridol, respectively. Gadobenate dimeglumine had more severe patient reactions, including three patients who arrested (defined as the patient becoming unresponsive and the code team being called), one of whom died. From 2004 to 2009, the FDA received reports on 40 gadolinium-based contrast agent U.S. deaths unrelated to nephrogenic systemic fibrosis, with an incidence per million doses of 0.15, 0.19, 0.97, 2.7, and 0.7 for gadodiamide, gadoversetimide, gadopentetate dimeglumine, gadobenate dimeglumine, and gadoteridol, respectively. This limited retrospective analysis shows that gadolinium-based contrast agents are very safe, with only rare reports of death, and raises the possibility that nonionic linear gadolinium-based contrast agents and gadopentetate dimeglumine may have fewer severe immediate adverse events

  11. 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.

  12. Motexafin gadolinium: gadolinium (III) texaphyrin, gadolinium texaphyrin, Gd-Tex, GdT2B2, PCI 0120.

    PubMed

    2004-01-01

    Motexafin gadolinium [gadolinium (III) texaphyrin, gadolinium texaphyrin, Gd-Tex, GdT2B2, PCI 0120] is a radiosensitising agent developed for use in cancer therapy. It is cytotoxic in haematological malignancies by selectively localising in cancer cells that have high rates of metabolism. Motexafin gadolinium inhibits cellular respiration resulting in the production of reactive oxygen species and inducing apoptosis. It is being developed by Pharmacyclics in the US. Bulk motexafin gadolinium is supplied to Pharmacyclics by the US company, Celanese, through a manufacturing and supply agreement between the two companies. In June 2003, at the 39th Annual Meeting of the American Society of Clinical Oncology (ASCO-2003), the importance of having an agent for the treatment of brain metastases from lung cancer was highlighted. Results of a phase III study were presented that showed that motexafin gadolinium treatment was associated with a delay in time to neurological and neurocognitive progression in lung cancer patients. This was an important finding, as 46.6% of lung cancer patients already have brain metastases at the time of initial diagnosis, compared with only 2.7% of breast cancer patients. Brain metastases are also often the only site of metastatic disease in patients with lung cancer. In December 2002, Pharmacyclics began a phase III trial of motexafin gadolinium in patients with brain metastases (brain cancer in phase table) from lung cancer in the US, Europe, Canada and Australia. The trial is known as the Study of neurologic progression with Motexafin gadolinium And Radiation Therapy (SMART) and will compare whole-brain irradiation with whole-brain irradiation plus motexafin gadolinium in 550 patients. The primary efficacy endpoint is time to neurological progression and the secondary endpoints are survival and neurocognitive function. In January 2003, the US FDA completed its Special Protocol Assessment (SPA) of the SMART trial with a positive result and by

  13. 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.

  14. 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…

  15. 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…

  16. Structural Evolution from Tin Sulfide (Selenide) Layered Structures to Novel 3- and 4-Connected Tin Oxy-sulfides

    NASA Astrophysics Data System (ADS)

    Parise, John B.; Ko, Younghee; Tan, Kemin; Nellis, David M.; Koch, Stephen

    1995-07-01

    Addition of triethylenetetramine (TETN) and tetramethylammonium (TMA+) to SnS2 and SnSe2 slurries followed by heating at 150°C under autogenous hydrothermal conditions results in novel thio and thio-oxide phases. These materials crystallize in time sequence as the added amines decompose. Initially 2-D frameworks with composition (Sn3X7)2-, X = S or Se are produced. In the case of the sulfides these are shown to transform to 2-D and 3-D oxy-sulfides frameworks which incorporate the decomposed template. The structures of two materials in this sequence have been determined from single crystal X-ray diffraction. The first, Sn3Se7 · C6N4H16CO, designated TETN-SnSe-1, crystallizes after 1 day of digestion in space group Pbca, with a = 23.553(6), b = 14.004(6), and c = 13.967(4) Å. The structure contains SnSe5 coordination polyhedra which form Sn3Se4+4 semicubes; six such semicubes are linked via Se2 bridges to form apertures in the Sn3Se2-7 sheet in (010). Similar structures occur in the TETN-SnS and TMA-SnS systems. The second material, with a framework designated SnOS-SB3, is formed after 5 days of digestion in either the TMA-SnS or TETN-SnS systems and crystallizes in C2/c, with a = 35.62(1), b = 18.468(4), c = 21.858(6) Å, and β = 115.36(1)°. The structure consists of tetrahedral clusters of composition [Sn10S20O4]8-, which are linked via single S bridges at three corners to form a 2-D framework of composition [Sn20S37O8]10-. This is one member of a theoretical structural family with composition [Sn10S20-n/2O4](8-n)-, where 0 ≤ n ≤ 4 and represents the number of connections between clusters.

  17. 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).

  18. Clinical comparison of a new digital x-ray detector system with a conventional screen film system

    NASA Astrophysics Data System (ADS)

    Kump, Kenneth S.; Shi, Shuanghe

    1999-05-01

    Twenty-five paired chest images (twenty Posterior-Anterior views and five Lateral views) were obtained under identical x- ray exposure conditions with both an amorphous silicon digital detector system and a thoracic film-screen system (InSight HC screen and InSight IT film; Kodak, Rochester, NY). The digital image data was transformed using non-linear algorithms to obtain a gray-scale appearance comparable to conventional film images. The digital images were printed at full resolution onto laser film (3M, 969). Each hard copy clinical image pair was evaluated by six radiologist experts in a blinded study. Two thirds of the radiologists' ratings showed the digital detector images 'Better' or 'Much Better' than screen-film images (p less than 0.05); Ninety-eight percent of the radiologists' ratings indicated the digital 'Equivalent,' 'Better' or 'Much Better' (p equals 0.0004) than analog film. The digital image system improvement can be explained by significantly higher DQE and an extended dynamic range. The study clearly demonstrates that clinically the new digital x- ray detector radiographic system can produce diagnostic images equivalent or superior to conventional screen film system.

  19. Cost and availability of gadolinium for nuclear fuel reprocessing plants

    SciTech Connect

    Klepper, O.H.

    1985-06-01

    Gadolinium is currently planned for use as a soluble neutron poison in nuclear fuel reprocessing plants to prevent criticality of solutions of spent fuel. Gadolinium is relatively rare and expensive. The present study was undertaken therefore to estimate whether this material is likely to be available in quantities sufficient for fuel reprocessing and at reasonable prices. It was found that gadolinium, one of 16 rare earth elements, appears in the marketplace as a by-product and that its present supply is a function of the production rate of other more prevalent rare earths. The potential demand for gadolinium in a fuel reprocessing facility serving a future fast reactor industry amounts to only a small fraction of the supply. At the present rate of consumption, domestic supplies of rare earths containing gadolinium are adequate to meet national needs (including fuel reprocessing) for over 100 years. With access to foreign sources, US demands can be met well beyond the 21st century. It is concluded therefore that the supply of gadolinium will quite likely be more than adequate for reprocessing spent fuel for the early generation of fast reactors. The current price of 99.99% pure gadolinium oxide lies in the range $50/lb to $65/lb (1984 dollars). By the year 2020, in time for reprocessing spent fuel from an early generation of large fast reactors, the corresponding values are expected to lie in the $60/lb to $75/lb (1984 dollars) price range. This increase is modest and its economic impact on nuclear fuel reprocessing would be minor. The economic potential for recovering gadolinium from the wastes of nuclear fuel reprocessing plants (which use gadolinium neutron poison) was also investigated. The cost of recycled gadolinium was estimated at over twelve times the cost of fresh gadolinium, and thus recycle using current recovery technology is not economical. 15 refs., 4 figs., 11 tabs.

  20. 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)

  1. 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.

  2. Substitution of gadolinium ethylenediaminetetraacetate with phosphites: towards gadolinium deposit in nephrogenic systemic fibrosis.

    PubMed

    Gao, Song; Chen, Mao-Long; Zhou, Zhao-Hui

    2014-01-14

    In neutral media, reactions of gadolinium ethylenediaminetetraacetates with phosphorous acid result in the formation of the mixed-ligand polymeric complex K3n[Gd(EDTA)(HPO3)]n·7nH2O () and dimeric complex Na6[Gd2(EDTA)2(HPO3)2]·2.5NaCl·21H2O () (H4EDTA = ethylenediaminetetraacetic acid) in warm solution. Further substitution with citric acid gives the monomeric gadolinium citrate with EDTA (NH4)2Na[Gd(EDTA)(H2cit)]·4H2O (). The compounds were characterized by elemental analysis, single crystal X-ray diffraction, FT-IR, ESI-MS and thermogravimetric analysis. Structural analysis indicates that three coordinated water molecules in the gadolinium ethylenediaminetetraacetate trihydrates are replaced by phosphite ions (HPO3(2-)) in the compounds and . Gadolinium atoms are octa-coordinated by EDTA and the phosphite ion, the latter links adjacent Gd-EDTA units to generate an infinite one-dimensional chain in compound and a dimeric octatomic ring in . In complex , coordinated water molecules were substituted by the α-hydroxy, α-carboxy and β-carboxy groups of citrate. Citrate is favourable for inhibiting the formation of Gd-EDTA phosphite. All the complexes are very easily soluble in water. The solution behavior of the isostructural lanthanum complexes was probed with (13)C and (31)P NMR spectra in D2O for comparison. ESI-MS analysis and recrystallization proved that complexes and dissociate to the monomeric unit of Gd-EDTA and free HPO3(2-) in aqueous solution. Substitutions of gadolinium ethylenediaminetetraacetates to and are attributed to be the cause of nephrogenic systemic fibrosis in some way.

  3. 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.

  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. Neutron Detection with Lithium Gadolinium Borate

    SciTech Connect

    J. Bart Czirr

    2000-11-12

    With the advent of a highly efficient, neutron-sensitive inorganic crystal scintillator, a new class of neutron spectrometers and dosimeters becomes feasible. The new material, lithium gadolinium borate, incorporates the three primary neutron-capturing nuclei utilized in solid-state neutron detectors. Eight isotopic permutations of the three capturing elements permit a wide range of applications throughout the neutron energy range from thermal to several MeV. The transparent inorganic crystals may be incorporated in organic plastic matrices to enhance the detection efficiency for neutrons of all energies. This summary describes a number of applications of the new scintillator in several areas of neutron detection.

  6. Performance comparison of an active matrix flat panel imager, computed radiography system, and a screen-film system at four standard radiation qualities.

    PubMed

    Monnin, P; Gutierrez, D; Bulling, S; Lepori, D; Valley, J F; Verdun, F R

    2005-02-01

    Four standard radiation qualities (from RQA 3 to RQA 9) were used to compare the imaging performance of a computed radiography (CR) system (general purpose and high resolution phosphor plates of a Kodak CR 9000 system), a selenium-based direct flat panel detector (Kodak Direct View DR 9000), and a conventional screen-film system (Kodak T-MAT L/RA film with a 3M Trimax Regular screen of speed 400) in conventional radiography. Reference exposure levels were chosen according to the manufacturer's recommendations to be representative of clinical practice (exposure index of 1700 for digital systems and a film optical density of 1.4). With the exception of the RQA 3 beam quality, the exposure levels needed to produce a mean digital signal of 1700 were higher than those needed to obtain a mean film optical density of 1.4. In spite of intense developments in the field of digital detectors, screen-film systems are still very efficient detectors for most of the beam qualities used in radiology. An important outcome of this study is the behavior of the detective quantum efficiency of the digital radiography (DR) system as a function of beam energy. The practice of users to increase beam energy when switching from a screen-film system to a CR system, in order to improve the compromise between patient dose and image quality, might not be appropriate when switching from screen-film to selenium-based DR systems.

  7. ROC study of screen-film mammography and storage phosphor digital mammography: analysis of nonconcordant classifications and implications for the approval of digital mammography systems

    NASA Astrophysics Data System (ADS)

    Freedman, Matthew T.; Artz, Dorothy S.; Hogge, Jacquelyn; Zuurbier, Rebecca A.; Jafroudi, Hamid; Lo, Shih-Chung B.; Mun, Seong K.

    1997-04-01

    A recently completed ROC study of digital mammography using a 100 micron pixel storage phosphor receptor showed that digital mammography and conventional screen film mammography were essentially equivalent in areas under the ROC curve. In this study, there were 24 biopsy proven breast cancer cases, 25 benign biopsy cases and 48 clinically normal breast images each with matched screen film and storage phosphor images. Fifteen of the 24 cancer cases were 10 mm or less in size. Of these 10 presented with microcalcifications as the sign of disease. Six radiologists not involved with the research program and without prior experience with digital mammography and who met qualification criteria under the Mammography Quality Standards Act of 1992 served as readers. This poster looks at the cases in which there was variance between the radiologists ROC classification system for the digital and screen film system in order to analyze case specific discrepancies that may indicate benefits or deficits of the digital system. Aspects of the ROC ratings are also analyzed including an evaluation of the different thresholds used by radiologists on the digital and screen film systems, the distribution of ROC ratings in normal and abnormal cases, the effect of using different gold standards of proof on the results and the effect of substituting an ACR BIRADS category agreement study as proposed by the FDA compared to the ROC study outcome.

  8. Performance of a new digital flat-panel detector system in the detection of simulated rheumatoid erosions: a comparison with a speed-class 200 screen-film system, a mammography screen-film system, and a storage-phosphor system at different levels of exposure.

    NASA Astrophysics Data System (ADS)

    Ludwig, Karl; Henschel, Andreas; Bernhardt, Thomas; Lenzen, Horst; Wormanns, Dag; Diederich, Stefan; Heindel, Walter

    2002-05-01

    The purpose of this study was to compare a large-area direct read-out flat-panel detector system with a speed class 200 screen-film system, a storage-phosphor system and a mammography screen-film system with regard to the detection of simulated rheumatoid erosions and to assess its diagnostic performance with decreasing exposure dose. The performance of a flat-panel system in such small lesions was considered especially interesting, as the spatial resolution of this system, limited by its pixel size, is considerably lower than that of conventional screen-film systems. An animal model with 160 joint specimens from 20 monkey paws was used. 640 regions were defined in these 160 meta- carpophalangeal and proximal interphalangeal joint specimens. Simulated rheumatoid erosions were created in 320 of these 640 regions. Specimens were enclosed in containers filed with water to obtain absorption and scatter radiation conditions similar to a human hand. Imaging was performed using a flat-panel system, a sped class 200 screen-film system, a mammography screen-film system and a storage- phosphor system under exactly matched conditions. Different exposure doses equivalent to speed classes of S equals 100, 200, 400, 800, 1600 and 3200 were used. Presence or absence of a lesion was assessed by three radiologists using a five level confidence scale. Receiver operating characteristic analysis was performed for a total of 21,120 observations and diagnostic performance estimated by the area under the ROC curve. The significance of differences between Az values was tested with analysis of variance. ROC-analysis showed Az values of 0.809, 0.768, 0.737, 0.710 and 0.685 for the flat-panel system, 0.770 for the screen-film system, 0.781, 0.739, 0.724 and 0.680 for the storage-phosphor system, and 0.798 for the mammography screen-film system. Analysis of variance showed significant differences for certain combinations of imaging modalities and exposure doses. The diagnostic performance of

  9. Effect of computer-aided detection on independent double reading of paired screen-film and full-field digital screening mammograms.

    PubMed

    Skaane, Per; Kshirsagar, Ashwini; Stapleton, Sandra; Young, Kari; Castellino, Ronald A

    2007-02-01

    The purpose of this study was to evaluate the performance and potential contribution of computer-aided detection (CAD) to independent double reading of paired screen-film and full-field digital screening mammograms. The cases of 3,683 women who underwent both screen-film mammography and full-field digital mammography (FFDM) with independent double reading for each technique were followed for 2 years to include cancers detected in the interval between screening rounds and cancers detected at the next screening round. Fifty-five biopsy-proven cancers were diagnosed. The baseline screening mammograms of the 55 cancers were defined as having positive findings if at least one of two independent readers scored it 2 or higher on a 5-point rating scale. The baseline mammograms of interval (n = 10) or secondround (n = 16) cancers were retrospectively classified as overlooked (n = 2), minimal sign actionable (n = 8), minimal sign nonactionable (n = 5), and normal (n = 11). The baseline mammograms of these cases of cancer were evaluated with a CAD system, and the CAD results were compared (McNemar's test for paired proportions) with the findings at prospective independent double reading of mammograms obtained with each technique. For FFDM, CAD sensitivity was 95% (37/39) compared with 64% (25/39) for double reading (p = 0.006), and for screen-film mammography, CAD sensitivity was 85% (33/39) compared with 77% (30/39) for prospective double reading (p = 0.57) of radiographically visible lesions in baseline mammograms. CAD correctly marked five (13%) of 39 cancers on screen-film mammography and 14 (36%) of 39 cancers on FFDM not detected at prospective independent double reading. CAD showed the potential to increase the cancer detection rate for FFDM and for screen-film mammography in breast cancer screening performed with independent double reading.

  10. Comparison of full-field digital mammography to screen-film mammography with respect to contrast and spatial resolution in tissue equivalent breast phantoms.

    PubMed

    Kuzmiak, Cherie M; Pisano, Etta D; Cole, Elodia B; Zeng, Donglin; Burns, Charles B; Roberto, Craig; Pavic, Dag; Lee, Yeonhee; Seo, Bo Kyoung; Koomen, Marcia; Washburn, David

    2005-10-01

    To determine if the improved contrast resolution of full-field digital mammography (FFDM) with reduced spatial resolution allows for superior or equal phantom object detection compared with screen-film mammography (SFM). Tissue equivalent breast phantoms simulating an adipose to glandular ratio of 50/50,30/70, and 20/80 were imaged according to each manufacturers' recommendation with four full-field digital mammography units (Fuji, Sectra, Fischer, and General Electric) and a screen-film mammography unit (MammoMatII 2000, Siemens, Munich, Germany). A total of 20 images were obtained in both hard- and soft-copy formats. For the purpose of soft-copy display, the screen-film hard-copy images were digitized with a 50 microm micron scanner. Six radiologists, experts in breast imaging, and three physicists, experts in scoring mammography phantoms, participated in a reader study where each reader scored each phantom for visibility of line-pairs and for 24 objects (fibers, clusters of specks, and masses). The data were recorded, entered into a database, and analyzed by a mixed-effect model. The limiting spatial resolution in line-pairs per millimeter visible with the digital units was less, regardless of display modality used, than that provided by the screen-film unit. The difference was statistically significant for the General Electric (p < 0.01) and Fuji digital mammography units (p = 0.03). With respect to the number of visible objects, a statistically significant higher number could be detected with the screen-film unit as compared to the Fischer (p < 0.01) and Sectra (p < 0.01) digital mammography units, but there was no significant difference between the other digital units and screen film. Overall, there was significantly better performance on the 50/50 phantom than with the 30/70 and 20/80 phantoms (p = 0.01, p < 0.01) for object visibility. For the digital mammography units, soft-copy display performed better than hard-copy display for the Fischer and Sectra

  11. 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.

  12. Comparison of gadolinium depletion in CASMO-4 and CASMO-3

    SciTech Connect

    Knott, D.; Edenius, M.

    1995-12-31

    Since the mid-1980s, CASMO-3 has been used to generate two-group nodal data for SIMULATE-3. Development of CASMO-3 was based on the accuracy needed to analyze {approximately} 12-month cycle lengths. Fuel designs for these annual cycles contained low gadolinium loadings in only a few pins. As cycle lengths increased from 12 to 24 months, gadolinium loadings doubled and tripled, as did the number of pins containing gadolinium. The use of heavy burnable absorber loadings has been a driving force behind the development of CASMO-4.

  13. 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).

  14. Accuracy of Soft-Copy Digital Mammography versus That of Screen-Film Mammography according to Digital Manufacturer: ACRIN DMIST Retrospective Multireader Study1

    PubMed Central

    Hendrick, R. Edward; Cole, Elodia B.; Pisano, Etta D.; Acharyya, Suddhasatta; Marques, Helga; Cohen, Michael A.; Jong, Roberta A.; Mawdsley, Gordon E.; Kanal, Kalpana M.; D'Orsi, Carl J.; Rebner, Murray; Gatsonis, Constantine

    2008-01-01

    Purpose: To retrospectively compare the accuracy for cancer diagnosis of digital mammography with soft-copy interpretation with that of screen-film mammography for each digital equipment manufacturer, by using results of biopsy and follow-up as the reference standard. Materials and Methods: The primary HIPAA-compliant Digital Mammographic Imaging Screening Trial (DMIST) was approved by the institutional review board of each study site, and informed consent was obtained. The approvals and consent included use of data for future HIPAA-compliant retrospective research. The American College of Radiology Imaging Network DMIST collected screening mammography studies performed by using both digital and screen-film mammography in 49 528 women (mean age, 54.6 years; range, 19–92 years). Digital mammography systems from four manufacturers (Fischer, Fuji, GE, and Hologic) were used. For each digital manufacturer, a cancer-enriched reader set of women screened with both digital and screen-film mammography in DMIST was constructed. Each reader set contained all cancer-containing studies known for each digital manufacturer at the time of reader set selection, together with a subset of negative and benign studies. For each reader set, six or 12 experienced radiologists attended two randomly ordered reading sessions 6 weeks apart. Each radiologist identified suspicious findings and rated suspicion of breast cancer in identified lesions by using a seven-point scale. Results were analyzed according to digital manufacturer by using areas under the receiver operating characteristic curve (AUCs), sensitivity, and specificity for soft-copy digital and screen-film mammography. Results for Hologic digital are not presented owing to the fact that few cancer cases were available. The implemented design provided 80% power to detect average AUC differences of 0.09, 0.08, and 0.06 for Fischer, Fuji, and GE, respectively. Results: No significant difference in AUC, sensitivity, or specificity

  15. Atomistic simulation of ferroelectric-ferroelastic gadolinium molybdate

    NASA Astrophysics Data System (ADS)

    Dudnikova, V. B.; Zharikov, E. V.

    2017-05-01

    Gadolinium molybdate Gd2(MoO4)3 orthorhombic ferroelectric ferroelastic (β'-phase) is simulated by the method of interatomic potentials. The simulation is performed using the GULP 4.0.1 code (General Utility Lattice Program), which is based on the minimization of the energy of the crystal structure. Parameters of the gadolinium-oxygen interatomic interaction potentials are determined by fitting to the experimental structural data and elastic constants by a procedure available in the GULP code. Atomistic modeling using the effective atomic charges and the system of interatomic potentials made it possible to obtain reasonable estimates of structural parameters, atomic coordinates, and the most important physical, mechanical, and thermodynamic properties of these crystals. Temperature dependences of the heat capacity and vibrational entropy of the crystal are obtained. The calculated parameters of gadolinium-oxygen interaction potentials can be used to simulate more complex gadolinium-containing compounds.

  16. Characterization of gadolinium and lanthanum oxide films on Si (100)

    NASA Astrophysics Data System (ADS)

    Wu, X.; Landheer, D.; Sproule, G. I.; Quance, T.; Graham, M. J.; Botton, G. A.

    2002-05-01

    High-resolution transmission electron microscopy, electron energy loss spectroscopy, and Auger electron spectroscopy, were used to study gadolinium and lanthanum oxide films deposited on Si (100) substrates using electron-beam evaporation from pressed-powder targets. As-deposited films consist of a crystalline oxide layer and an amorphous interfacial layer. A complicated distinct multilayer structure consisting of oxide layers, silicate layers, and SiO2-rich layers in thick (~30 nm) annealed films has been observed for both gadolinium and lanthanum films. For thinner annealed films (~8 nm), there is no longer a crystalline oxide layer but an amorphous gadolinium or lanthanum silicate layer and an interfacial SiO2-rich layer. The formation of the lanthanum silicate by annealing lanthanum oxide is found to be thermodynamically more favorable than the formation of gadolinium silicate.

  17. Gadolinium loaded plastic scintillators for high efficiency neutron detection

    NASA Astrophysics Data System (ADS)

    Ovechkina, Lena; Riley, Kent; Miller, Stuart; Bell, Zane; Nagarkar, Vivek

    2009-08-01

    Gadolinium has the highest thermal neutron absorption cross section of any naturally occurring element, and emits conversion electrons as well as atomic X-rays in over 50% of its neutron captures, which makes it a useful dopant in scintillators for detecting thermal neutrons. Gadolinium isopropoxide was studied as a possible dopant for styrene-based plastic scintillators as a convenient and inexpensive method to produce high-efficiency thermal neutron detectors. Plastic scintillators with gadolinium weight concentrations of up to 3% were transparent, uniform and defect-free and were characterized with spectral measurements performed under x-ray and neutron irradiation. The new material has the same characteristic emission of styrene with a maximum at approximately 425 nm, and a light output of 76% relative to the undoped plastic. A 13 mm thick sample containing 0.5% gadolinium by weight detected 46% of incident thermal neutrons, which makes this an attractive material for a variety of applications.

  18. Gadolinium-DTPA enhancement of lung radiation fibrosis

    SciTech Connect

    Werthmuller, W.C.; Schiebler, M.L.; Whaley, R.A.; Mauro, M.A.; McCartney, W.H. )

    1989-11-01

    Gadolinium-diethylenetriamine pentaacetic acid (DTPA) enhancement of radiation-induced apical pulmonary fibrosis was observed in two patients previously treated for breast cancer. In one case the fibrosis was biopsied twice, with no change in its CT appearance over 3 years. Gadolinium-DTPA may enhance benign apical fibrosis after radiation therapy and should not, in and of itself, be used as evidence of recurrent malignancy.

  19. Computer-aided detection of masses in full-field digital mammography using screen-film mammograms for training.

    PubMed

    Kallenberg, Michiel; Karssemeijer, Nico

    2008-12-07

    It would be of great value when available databases of screen-film mammography (SFM) images can be used to train full-field digital mammography (FFDM) computer-aided detection (CAD) systems, as compilation of new databases is costly. In this paper, we investigate this possibility. Firstly, we develop a method that converts an FFDM image into an SFM-like representation. In this conversion method, we establish a relation between exposure and optical density by simulation of an automatic exposure control unit. Secondly, we investigate the effects of using the SFM images as training samples compared to training with FFDM images. Our FFDM database consisted of 266 cases, of which 102 were biopsy-proven malignant masses and 164 normals. The images were acquired with systems of two different manufacturers. We found that, when we trained our FFDM CAD system with a small number of images, training with FFDM images, using a five-fold crossvalidation procedure, outperformed training with SFM images. However, when the full SFM database, consisting of 348 abnormal cases (including 204 priors) and 810 normal cases, was used for training, SFM training outperformed FFDMA training. These results show that an existing CAD system for detection of masses in SFM can be used for FFDM images without retraining.

  20. 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.

  1. Comparison of the imaging physics performance of a prototype flat-panel detector with a 400-speed screen-film system

    NASA Astrophysics Data System (ADS)

    Huda, Walter; Ogden, Kent M.; Roskopf, Marsha L.; Rush, Charles

    2001-06-01

    The performance of a digital radiography system that included a prototype flat panel detector (StingRay) was compared with a 400 speed screen-film system. The flat panel detector consisted of a 500 micrometers thick CsI scintillator with an image matrix size of 3k2. The limiting spatial resolution of screen-film (approximately 4 line pairs/mm) was superior to that of the flat panel detector (approximately 2.5 line pairs/mm). The digital detector had an excellent linearity response (r2 equals 0.997), a dynamic range of 20,000:1, and saturated at a radiation exposure of 60 mR.

  2. Effects of the Cu off-stoichiometry on transport properties of wide gap p-type semiconductor, layered oxysulfide LaCuSO

    SciTech Connect

    Goto, Yosuke Tanaki, Mai; Okusa, Yuki; Matoba, Masanori; Kamihara, Yoichi; Shibuya, Taizo; Yasuoka, Kenji

    2014-07-14

    Layered oxysulfide LaCu{sub 1−x}SO (x = 0–0.03) was prepared to elucidate the effect of Cu off-stoichiometry on their electrical and thermal transport properties. Electrical resistivity drastically decreases down from ∼10{sup 5} Ω·cm to ∼10{sup −1} Ω·cm as a result of Cu deficiency (x = 0.01) at 300 K. Thermal conductivity of the samples at 300 K, which is dominated by lattice components, is estimated to be 2.3(3) Wm{sup −1}K{sup −1}. Stoichiometric LaCuSO has an optical band gap of 3.1 eV, while broad optical absorption at photon energies of approximately 2.1 eV was observed for Cu-deficient samples. Density functional theory calculation suggests that these broad absorption structures probably originate from the in-gap states generated by the sulfur vacancies created to compensate the charge imbalance due to Cu off-stoichiometry. These results clearly demonstrate that Cu deficiency plays a crucial role in determining the electrical transport properties of Cu-based p-type transparent semiconductors.

  3. Comparison of the image quality of a high-resolution screen-film system and a digital flat panel detector system in avian radiography.

    PubMed

    Bochmann, Monika; Ludewig, Eberhard; Krautwald-Junghanns, Maria-Elisabeth; Pees, Michael

    2011-01-01

    A conventional high-resolution screen-film system was compared with a digital detector system. A total of 20 birds (14 pigeons and six psittacine birds) with an average body mass of 533g were examined in dorsoventral as well as lateral projections. Digital radiographs were acquired with the same mAs as well as half the mAs used for the conventional radiographs. Three criteria and one overall assessment were defined for each of four anatomic regions and assessed by five veterinarians using a score system. Comparison of the ratings was done by visual grading analysis. For the majority of criteria, there was no significant difference regarding image quality between the digital and screen-film projections. However, for certain criteria the quality of the digital images was significantly superior. Using the same mAs as for the conventional radiographs, the humeral joint surfaces and the honeycomb structure of the lung were assessed as superior with the digital imaging system. The tracheal rings and the delineation of the trachea from the surrounding tissue were also superior with the digital system. Assessment of the trabecular structure of the humerus was superior when the full mAs was used compared with the reduced mAs. In conclusion the digital technique is equal or superior to the conventional screen-film high-resolution system for pet birds of a medium size. With some limitations, a dose reduction is possible with the digital system. © 2011 Veterinary Radiology & Ultrasound.

  4. High Performance Anion Chromatography of Gadolinium Chelates.

    PubMed

    Hajós, Peter; Lukács, Diana; Farsang, Evelin; Horváth, Krisztian

    2016-11-01

    High performance anion chromatography (HPIC) method to separate ionic Gd chelates, [Formula: see text], [Formula: see text], [Formula: see text] and free matrix anions was developed. At alkaline pHs, polydentate complexing agents such as ethylene-diamine-tetraacetate, diethylene-triamine pentaacetate and trans-1,2-diamine-cyclohexane-tetraacetate tend to form stable Gd chelate anions and can be separated by anion exchange. Separations were studied in the simple isocratic chromatographic run over the wide range of pH and concentration of carbonate eluent using suppressed conductivity detection. The ion exchange and complex forming equilibria were quantitatively described and demonstrated in order to understand major factors in the control of selectivity of Gd chelates. Parameters of optimized resolution between concurrent ions were presented on a 3D resolution surface. The applicability of the developed method is represented by the simultaneous analysis of Gd chelates and organic/inorganic anions. Inductively coupled plasma atomic emission spectroscopy  (ICP-AES) analysis was used for confirmation of HPIC results for Gd. Collection protocols for the heart-cutting procedure of chromatograms were applied. SPE procedures were also developed not only to extract traces of free gadolinium ions from samples, but also to remove the high level of interfering anions of the complex matrices. The limit of detection, the recoverability and the linearity of the method were also presented. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Nonaqueous Synthesis of Gadolinium and Neodymium Nanoparticles

    NASA Astrophysics Data System (ADS)

    Fukuda, R.; Castro, M.; Ho, P.-C.; Attar, S.; Golden, M.; Margosan, D.

    2014-03-01

    Nanoparticles are of great interest due to their magnetic properties, such as superparamagnetism, that are not exhibited by their bulk counterparts. Gd and Nd are being tested by applying the reverse micelle method. The reverse micelle method consists of using a surfactant with a large nonpolar solvent to polar solvent ratio to form spherical cages that control the size of the products. Many studies involving the reverse micelle method employ water as the polar solvent. Since Gd and Nd are highly reactive to water, methanol is used as a replacement with hexane or heptane as the nonpolar solvent. Gadolinium chloride or neodymium nitrate are reduced using sodium borohydride after the reverse micelles encapsulate the rare earth compound. Scanning electron microscopy (SEM) and light microscopy show small, spherical clusters with diameters in the micron range. Higher magnification of the SEM melted the clusters, even after cooling the sample to 87 K. The sample was coated with Pt to prevent melting. Energy dispersive x-ray measurements were conducted to find the chemical composition of the clusters, but the sample signals were too small to make a conclusion. Future growths will use the surfactant DDAB instead of AOT since DDAB is more stable when examined with SEM. Research at California State University-Fresno is supported by NSF DMR-1104544.

  6. 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.

  7. Clinical evaluation of digital radiography based on a large-area cesium iodide-amorphous silicon flat-panel detector compared with screen-film radiography for skeletal system and abdomen.

    PubMed

    Okamura, Terue; Tanaka, Saori; Koyama, Koichi; Norihumi, Nishida; Daikokuya, Hideo; Matsuoka, Toshiyuki; Kishimoto, Kenji; Hatagawa, Masakatsu; Kudoh, Hiroaki; Yamada, Ryusaku

    2002-07-01

    The aim of this clinical study was to compare the image quality of digital radiography using the new digital Bucky system based on a flat-panel detector with that of a conventional screen-film system for the skeletal structure and the abdomen. Fifty patients were examined using digital radiography with a flat-panel detector and screen-film systems, 25 for the skeletal structures and 25 for the abdomen. Six radiologists judged each paired image acquired under the same exposure parameters concerning three observation items for the bone and six items for the abdomen. Digital radiographic images for the bone were evaluated to be similar to screen-film images at the mean of 42.2%, to be superior at 50.2%, and to be inferior at 7.6%. Digital radiographic images for the abdomen were judged to be similar to screen-film images at the mean of 43.4%, superior at 52.4%, and inferior at 4.2%; thus, digital radiographic images were estimated to be either similar as or superior to screen-film images at over 92% for the bone and abdomen. On the statistical analysis, digital radiographic images were also judged to be preferred significantly in the most items for the bone and abdomen. In conclusion, the image quality of digital radiography with a flat-panel detector was superior to that of a screen-film system under the same exposure parameters, suggesting that dose reduction is possible with digital radiography.

  8. 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

  9. Image quality and dose comparison among screen-film, computed, and CT scanned projection radiography: applications to CT urography.

    PubMed

    McCollough, C H; Bruesewitz, M R; Vrtiska, T J; King, B F; LeRoy, A J; Quam, J P; Hattery, R R

    2001-11-01

    To evaluate image quality and dose for abdominal imaging techniques that could be used as part of a computed tomographic (CT) urographic examination: screen-film (S-F) radiography or computed radiography (CR), performed with moving and stationary grids, and CT scanned projection radiography (CT SPR). An image quality phantom underwent imaging with moving and stationary grids with both a clinical S-F combination and CR plate. CT SPR was performed with six CT scanners at various milliampere second and kilovolt peak settings. Entrance skin exposure (ESE); spatial, contrast, and temporal resolutions; geometric accuracy; and artifacts were assessed. S-F or CR images, with either grid, provided image quality equivalent to that with the clinical standard, S-F with a moving grid. ESE values for both S-F and CR were 435 mR (112.2 microC/kg [1 mR = 0.258 microC/kg]) with a moving grid and 226 mR (58.3 microC/kg) with a stationary grid. All CT SPR images provided inferior spatial resolution compared with S-F or CR images. High-contrast objects generated substantial artifacts on CT SPR images. Compared with S-F, CR and CT SPR provided improved resolution of small low-contrast objects. The contrast between iodine and soft-tissue-mimicking structures on CT SPR images acquired at 80 kVp was twice that at 120 kVp. CT SPR images with acceptable noise levels required a midline ESE value of approximately 300 mR (77.4 microC/kg) at 80 kVp. S-F and CR provided better spatial resolution than did CT SPR. However, CT SPR provided improved low-contrast resolution compared with S-F, at exposures comparable to those used for S-F or CR.

  10. Use of a Mixture of Gadolinium and Iodinated Contrast for Angiography

    SciTech Connect

    Badiola, Carlos M.

    2004-03-15

    The purpose of this study was to determine if the image quality of gadolinium digital subtraction angiography (DSA) can be improved by the addition of small quantities of iodinated contrast to gadolinium. The optical density (OD) of a mixture of four parts gadolinium-based contrast to one part iodinated contrast was measured through a phantom study and compared to that of full-strength gadolinium, full strength iodinated contrast, and a 20% solution of iodinated contrast. We also compared the clinical image quality of the mixture of gadolinium-based contrast and iodinated contrast relative to full-strength gadolinium and full strength iodinated contrast during DSA. The DSA image quality of the gadolinium-iodinated contrast mixture was significantly improved relative to images obtained with full-strength gadolinium and compared favorably to that obtained with full-strength iodinated contrast. The phantom data showed that the OD of the gadolinium-iodinated contrast mixture was much greater than that of full strength gadolinium and the 20% iodinated contrast solution. The increase in OD was greater than that expected from a simple additive effect of the OD of the contrast agents. Adding a small amount of iodinated contrast to gadolinium results in a significant improvement in the radiographic density and DSA image quality of gadolinium. This simple technique appears to overcome one of the major limitations of gadolinium-based angiography-poor radiographic density-while continuing to minimize the volume of administered iodinated contrast.

  11. 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

  12. 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.

  13. Toxicological and pharmacological effects of gadolinium and samarium chlorides

    PubMed Central

    Haley, T. J.; Raymond, K.; Komesu, N.; Upham, H. C.

    1961-01-01

    A study has been made of the toxicology and pharmacology of gadolinium and samarium chlorides. The symptoms of acute toxicity following intraperitoneal injection are described. The chronic oral ingestion of both chemicals for 12 weeks produced no effects on growth or the blood picture, and only the male rats receiving gadolinium chloride showed liver damage. The pharmacological responses to both chemicals were mainly depressant on all systems studied, and death was associated with cardiovascular collapse coupled with respiratory paralysis. The greatest damage seen was on abraded skin, where non-healing ulcers were produced by both chemicals, whereas irritation of intact skin and ocular tissues was only transient in nature. PMID:13903826

  14. Gadolinium accumulation in organs of Sprague-Dawley® rats after implantation of a biodegradable magnesium-gadolinium alloy.

    PubMed

    Myrissa, Anastasia; Braeuer, Simone; Martinelli, Elisabeth; Willumeit-Römer, Regine; Goessler, Walter; Weinberg, Annelie Martina

    2017-01-15

    Biodegradable magnesium implants are under investigation because of their promising properties as medical devices. For enhancing the mechanical properties and the degradation resistance, rare earth elements are often used as alloying elements. In this study Mg10Gd pins were implanted into Sprague-Dawley® rats. The pin volume loss and a possible accumulation of magnesium and gadolinium in the rats' organs and blood were investigated in a long-term study over 36weeks. The results showed that Mg10Gd is a fast disintegrating material. Already 12weeks after implantation the alloy is fragmented to smaller particles, which can be found within the intramedullary cavity and the cortical bones. They disturbed the bone remodeling until the end of the study. The results concerning the elements' distribution in the animals' bodies were even more striking, since an accumulation of gadolinium could be observed in the investigated organs over the whole time span. The most affected tissue was the spleen, with up to 3240μgGd/kg wet mass, followed by the lung, liver and kidney (up to 1040, 685 and 207μgGd/kg). In the brain, muscle and heart, the gadolinium concentrations were much smaller (less than 20μg/kg), but an accumulation could still be detected. Interestingly, blood serum samples showed no accumulation of magnesium and gadolinium. This is the first time that an accumulation of gadolinium in animal organs was observed after the application of a gadolinium-containing degradable magnesium implant. These findings demonstrate the importance of future investigations concerning the distribution of the constituents of new biodegradable materials in the body, to ensure the patients' safety.

  15. Neutron Detection Utilizing Gadolinium Doped Hafnium Oxide Films

    DTIC Science & Technology

    2008-03-01

    emit low energy gamma rays, alpha particles, and neutron radiation . Many instruments capable of gamma detection have been available for decades...neutron detection because its interaction with neutrons creates fast electrons and gamma rays. Therefore, background gamma radiation causes a more...NEUTRON DETECTION UTILIZING GADOLINIUM DOPED HAFNIUM OXIDE FILMS THESIS Bryan D. Blasy, 2Lt

  16. 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.

  17. Gadolinium chloride pretreatment ameliorates acute cadmium-induced hepatotoxicity.

    PubMed

    Kyriakou, Loukas G; Tzirogiannis, Konstantinos N; Demonakou, Maria D; Kourentzi, Kalliopi T; Mykoniatis, Michael G; Panoutsopoulos, Georgios I

    2013-08-01

    Cadmium is a known industrial and environmental pollutant. It causes hepatotoxicity upon acute administration. Features of cadmium-induced acute hepatoxicity encompass necrosis, apoptosis, peliosis and inflammatory infiltration. Gadolinium chloride (GdCl3) may prevent cadmium-induced hepatotoxicity by suppressing Kupffer cells. The effect of GdCl3 pretreatment on a model of acute cadmium-induced liver injury was investigated. Male Wistar rats 4-5 months old were injected intraperitoneally with normal saline followed by cadmium chloride (CdCl2; 6.5 mg/kg) or GdCl3 (10 mg/kg) followed by CdCl2 (6.5 mg/kg; groups I and II, respectively). Rats of both the groups were killed at 9, 12, 16, 24, 48 and 60 h after cadmium intoxication. Liver sections were analyzed for necrosis, apoptosis, peliosis and mitoses. Liver regeneration was also evaluated by tritiated thymidine incorporation into hepatic DNA. Serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were also determined. Hepatic necrosis, hepatocyte and nonparenchymal cell apoptosis and macroscopic and microscopic types of peliosis hepatis were minimized by gadolinium pretreatment. Serum levels of AST and ALT were also greatly diminished in rats of group II. Tritiated thymidine incorporation into hepatic DNA was increased in gadolinium pretreatment rats. Kupffer cell activation was minimal in both the groups of rats. Gadolinium pretreatment attenuates acute cadmium-induced liver injury in young Wistar rats, with mechanisms other than Kupffer cell elimination.

  18. 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.

  19. Layered gadolinium hydroxides for low-temperature magnetic cooling.

    PubMed

    Abellán, Gonzalo; Espallargas, Guillermo Mínguez; Lorusso, Giulia; Evangelisti, Marco; Coronado, Eugenio

    2015-09-28

    Layered gadolinium hydroxides have revealed to be excellent candidates for cryogenic magnetic refrigeration. These materials behave as pure 2D magnetic systems with a Heisenberg-Ising critical crossover, induced by dipolar interactions. This 2D character and the possibility offered by these materials to be delaminated open the possibility of rapid heat dissipation upon substrate deposition.

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

    DOE PAGES

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

    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

  1. 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.

  2. Magnetic resonance characteristics and susceptibility weighted imaging of the brain in gadolinium encephalopathy.

    PubMed

    Samardzic, Dejan; Thamburaj, Krishnamoorthy

    2015-01-01

    To report the brain imaging features on magnetic resonance imaging (MRI) in inadvertent intrathecal gadolinium administration. A 67-year-old female with gadolinium encephalopathy from inadvertent high dose intrathecal gadolinium administration during an epidural steroid injection was studied with multisequence 3T MRI. T1-weighted imaging shows pseudo-T2 appearance with diffusion of gadolinium into the brain parenchyma, olivary bodies, and membranous labyrinth. Nulling of cerebrospinal fluid (CSF) signal is absent on fluid attenuation recovery (FLAIR). Susceptibility-weighted imaging (SWI) demonstrates features similar to subarachnoid hemorrhage. CT may demonstrate a pseudo-cerebral edema pattern given the high attenuation characteristics of gadolinium. Intrathecal gadolinium demonstrates characteristic imaging features on MRI of the brain and may mimic subarachnoid hemorrhage on susceptibility-weighted imaging. Identifying high dose gadolinium within the CSF spaces on MRI is essential to avoid diagnostic and therapeutic errors. Copyright © 2013 by the American Society of Neuroimaging.

  3. Gadolinium Brain Deposition after Macrocyclic Gadolinium Administration: A Pediatric Case-Control Study.

    PubMed

    Tibussek, Daniel; Rademacher, Christin; Caspers, Julian; Turowski, Bernd; Schaper, Jörg; Antoch, Gerald; Klee, Dirk

    2017-10-01

    Purpose To determine whether signal intensity (SI) in T1 sequences as a potential indicator of gadolinium deposition increases after repeated administration of the macrocyclic gadolinium-based contrast agents (GBCAs) gadoteridol and gadoterate meglumine in a pediatric cohort. Materials and Methods This retrospective case-control study of children with brain tumors who underwent nine or more contrast material-enhanced brain magnetic resonance (MR) imaging studies from 2008 to 2015 was approved by the local ethics board. Informed consent was obtained for MR imaging. Twenty-four case patients aged 5-18 years and appropriate control patients with nonpathologic MR neuroimaging findings (and no GBCA administration), matched for age and sex, were inculded. SI was measured on unenhanced T1-weighted MR images for the following five regions of interest (ROIs): the dentate nucleus (DN), pons, substantia nigra (SN), pulvinar thalami, and globus pallidus (GP). Paired t tests were used to compare SI and SI ratios (DN to pons, GP to thalamus) between case patients and control patients. Pearson correlations between relative signal changes and the number of GBCA administrations and total GBCA dose were calculated. Results The mean number of GBCA administrations was 14.2. No significant differences in mean SI for any ROI and no group differences were found when DN-to-pons and GP-to-pulvinar ratios were compared (DN-to-pons ratio in case patients: mean, 1.0083 ± 0.0373 [standard deviation]; DN-to-pons ratio in control patients: mean, 1.0183 ± 0.01917; P = .37; GP-to-pulvinar ratio in case patients: mean, 1.1335 ± 0.04528; and GP-to-pulvinar ratio in control patients: mean, 1.1141 ± 0.07058; P = .29). No correlation was found between the number of GBCA administrations or the total amount of GBCA administered and signal change for any ROI. (Number of GBCA applications: DN: r = -0.254, P = .31; pons: r = -0.097, P = .65; SN: r = -0.194, P = .38; GP: r = -0.175, P = .41; pulvinar: r

  4. 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.

  5. 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

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

    PubMed

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

    2016-02-01

    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. 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. 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. 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 DCN, along with Gd deposition in the cerebellum. This

  7. Mammographic density assessed on paired raw and processed digital images and on paired screen-film and digital images across three mammography systems.

    PubMed

    Burton, Anya; Byrnes, Graham; Stone, Jennifer; Tamimi, Rulla M; Heine, John; Vachon, Celine; Ozmen, Vahit; Pereira, Ana; Garmendia, Maria Luisa; Scott, Christopher; Hipwell, John H; Dickens, Caroline; Schüz, Joachim; Aribal, Mustafa Erkin; Bertrand, Kimberly; Kwong, Ava; Giles, Graham G; Hopper, John; Pérez Gómez, Beatriz; Pollán, Marina; Teo, Soo-Hwang; Mariapun, Shivaani; Taib, Nur Aishah Mohd; Lajous, Martín; Lopez-Riduara, Ruy; Rice, Megan; Romieu, Isabelle; Flugelman, Anath Arzee; Ursin, Giske; Qureshi, Samera; Ma, Huiyan; Lee, Eunjung; Sirous, Reza; Sirous, Mehri; Lee, Jong Won; Kim, Jisun; Salem, Dorria; Kamal, Rasha; Hartman, Mikael; Miao, Hui; Chia, Kee-Seng; Nagata, Chisato; Vinayak, Sudhir; Ndumia, Rose; van Gils, Carla H; Wanders, Johanna O P; Peplonska, Beata; Bukowska, Agnieszka; Allen, Steve; Vinnicombe, Sarah; Moss, Sue; Chiarelli, Anna M; Linton, Linda; Maskarinec, Gertraud; Yaffe, Martin J; Boyd, Norman F; Dos-Santos-Silva, Isabel; McCormack, Valerie A

    2016-12-19

    Inter-women and intra-women comparisons of mammographic density (MD) are needed in research, clinical and screening applications; however, MD measurements are influenced by mammography modality (screen film/digital) and digital image format (raw/processed). We aimed to examine differences in MD assessed on these image types. We obtained 1294 pairs of images saved in both raw and processed formats from Hologic and General Electric (GE) direct digital systems and a Fuji computed radiography (CR) system, and 128 screen-film and processed CR-digital pairs from consecutive screening rounds. Four readers performed Cumulus-based MD measurements (n = 3441), with each image pair read by the same reader. Multi-level models of square-root percent MD were fitted, with a random intercept for woman, to estimate processed-raw MD differences. Breast area did not differ in processed images compared with that in raw images, but the percent MD was higher, due to a larger dense area (median 28.5 and 25.4 cm(2) respectively, mean √dense area difference 0.44 cm (95% CI: 0.36, 0.52)). This difference in √dense area was significant for direct digital systems (Hologic 0.50 cm (95% CI: 0.39, 0.61), GE 0.56 cm (95% CI: 0.42, 0.69)) but not for Fuji CR (0.06 cm (95% CI: -0.10, 0.23)). Additionally, within each system, reader-specific differences varied in magnitude and direction (p < 0.001). Conversion equations revealed differences converged to zero with increasing dense area. MD differences between screen-film and processed digital on the subsequent screening round were consistent with expected time-related MD declines. MD was slightly higher when measured on processed than on raw direct digital mammograms. Comparisons of MD on these image formats should ideally control for this non-constant and reader-specific difference.

  8. Gadolinium Chelate Safety in Pregnancy: Barely Detectable Gadolinium Levels in the Juvenile Nonhuman Primate after in Utero Exposure.

    PubMed

    Prola-Netto, Joao; Woods, Mark; Roberts, Victoria H J; Sullivan, Elinor L; Miller, Christina Ann; Frias, Antonio E; Oh, Karen Y

    2017-09-04

    Purpose To determine whether gadolinium remains in juvenile nonhuman primate tissue after maternal exposure to intravenous gadoteridol during pregnancy. Materials and Methods Gravid rhesus macaques and their offspring (n = 10) were maintained, as approved by the institutional animal care and utilization committee. They were prospectively studied as part of a pre-existing ongoing research protocol to evaluate the effects of maternal malnutrition on placental and fetal development. On gestational days 85 and 135, they underwent placental magnetic resonance imaging after intravenous gadoteridol administration. Amniocentesis was performed on day 135 prior to administration of the second dose of gadoteridol. After delivery, the offspring were followed for 7 months. Tissue samples from eight different organs and from blood were harvested from each juvenile macaque. Gadolinium levels were measured by using inductively coupled plasma mass spectrometry. Results Gadolinium concentration in the amniotic fluid was 0.028 × 10(-5) %ID/g (percentage injected dose per gram of tissue) 50 days after administration of one gadoteridol dose. Gadolinium was most consistently detected in the femur (mean, 2.5 × 10(-5) %ID/g; range, [0.81-4.1] × 10(-5) %ID/g) and liver (mean, 0.15 × 10(-5) %ID/g; range, [0-0.26] × 10(-5) %ID/g). Levels were undetectable in the remaining sampled tissues, with the exception of one juvenile skin sample (0.07 × 10(-5) %ID/g), one juvenile spleen sample (0.039 × 10(-5) %ID/g), and one juvenile brain (0.095 × 10(-5) %ID/g) and kidney (0.13 × 10(-5) %ID/g) sample. Conclusion The presence of gadoteridol in the amniotic fluid after maternal injection enables confirmation that it crosses the placenta. Extremely low levels of gadolinium are found in juvenile macaque tissues after in utero exposure to two doses of gadoteridol, indicating that a very small amount of gadolinium persists after delivery. (©) RSNA, 2017.

  9. 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.

  10. [Gadolinium-based contrast agents for magnetic resonance imaging].

    PubMed

    Carrasco Muñoz, S; Calles Blanco, C; Marcin, Javier; Fernández Álvarez, C; Lafuente Martínez, J

    2014-06-01

    Gadolinium-based contrast agents are increasingly being used in magnetic resonance imaging. These agents can improve the contrast in images and provide information about function and metabolism, increasing both sensitivity and specificity. We describe the gadolinium-based contrast agents that have been approved for clinical use, detailing their main characteristics based on their chemical structure, stability, and safety. In general terms, these compounds are safe. Nevertheless, adverse reactions, the possibility of nephrotoxicity from these compounds, and the possibility of developing nephrogenic systemic fibrosis will be covered in this article. Lastly, the article will discuss the current guidelines, recommendations, and contraindications for their clinical use, including the management of pregnant and breast-feeding patients.

  11. Temperature responsive gadolinium oxide nanoparticles for hyperthermia application

    NASA Astrophysics Data System (ADS)

    Paul, Nibedita; Borah, J. P.; Mohanta, Dambarudhar

    2017-05-01

    In this work we synthesized gadolinium oxide (Gd2O3) nanoparticles by a simple physico-chemical route. X-ray diffractogram (XRD) reveals cubic phase of Gd2O3 with preferred crystallographic orientation along (222) plane. The average crystallite size is found to be ˜ 3.5 nm. High resolution transmission electron microscopy (HRTEM) reveals particle size ˜9nm. UV-Vis spectra reveals two absorption peaks. The peak positioned at ˜285 and 350 nm is attributed to 8S7/2 → 6I7/2 transition of gadolinium (Gd) and the peak oxygen vacancy respectively. Room temperature PL spectra reveals various defect related emission. The prepared nanoparticles are also subjected to hyperthermia (cancer therapy) studies.

  12. 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.

  13. 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.

  14. 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.

  15. Dressler's syndrome demonstrated by late gadolinium enhancement cardiovascular magnetic resonance

    PubMed Central

    Steadman, Christopher D; Khoo, Jeffrey; Kovac, Jan; McCann, Gerry P

    2009-01-01

    A 49-year old patient presented late with an anterolateral ST-elevation myocardial infarction and was treated with rescue angioplasty to an occluded left anterior descending artery. Her recovery was complicated by low-grade pyrexia and raised inflammatory markers. Cardiovascular magnetic resonance 5 weeks after the acute presentation showed transmural infarction and global late gadolinium enhancement of the pericardium in keeping with Dressler's syndrome. PMID:19627595

  16. 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.

  17. Magnetization of 2.6 T in gadolinium thin films

    NASA Astrophysics Data System (ADS)

    Scheunert, G.; Hendren, W. R.; Ward, C.; Bowman, R. M.

    2012-10-01

    There is renewed interest in rare-earth elements and gadolinium in particular for a range of studies in coupling physics and applications. However, it is still apparent that synthesis impacts understanding of the intrinsic magnetic properties of thin gadolinium films, particularly for thicknesses of topicality. We report studies on 50 nm thick nanogranular polycrystalline gadolinium thin films on SiO2 wafers that demonstrate single-crystal like behavior. The maximum in-plane saturation magnetization at 4 K was found to be 4πMS4 K = (2.61 ± 0.26) T with a coercivity of HC4 K = (160 ± 5) Oe. A maximum Curie point of TC = (293 ± 2) K was measured via zero-field-cooled-field-cooled magnetization measurements in close agreement with values reported in bulk single crystals. Our measurements revealed magnetic transitions at T1 = (12 ± 2) K (as deposited samples) and T2 = (22 ± 2) K (depositions on heated substrates) possibly arising from the interaction of paramagnetic face-centred cubic grains with their ferromagnetic hexagonal close-packed counterparts.

  18. 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.

  19. Progress in the use of gadolinium for NCT.

    PubMed

    Cerullo, N; Bufalino, D; Daquino, G

    2009-07-01

    The evaluation of possible improvement in the use of Gd in cancer therapy, in reference to gadolinium in cancer therapy (GdNCT), has been analysed. At first the problem of the gadolinium compounds toxicity was reviewed identifying the Motexafin Gadolinium as the best. Afterwards, the spectrum of IC and Auger electrons was calculated using a special method. Afterwards, this electron source has been used as input of the PENELOPE code and the energy deposit in DNA was well defined. Taking into account that the electron yield and energy distribution are related to the neutron beam spectrum and intensity, the shaping assembly architecture was optimised through computational investigations. Finally the study of GdNCT was performed from two different points of view: macrodosimetry using MCNPX, with calculation of absorbed doses both in tumour and healthy tissues, and microdosimetry using PENELOPE, with the determination of electron RBE through the energy deposit. The equivalent doses were determined combining these two kinds of data, introducing specific figures of merit to be used in treatment planning system (TPS). According to these results, the GdNCT appears to be a fairly possible tumour therapy.

  20. Nephrogenic systemic fibrosis and the role of gadolinium contrast media.

    PubMed

    van der Molen, A J

    2008-08-01

    Nephrogenic system fibrosis is a rare disease affecting patients with severe renal insufficiency or dialysis. Its aetiology is incompletely understood. Evidence is growing that gadolinium contrast media is a major risk factor, whereby risk increases with larger cumulative doses. The role of other risk factors, such as inflammation or electrolyte disturbances, is less clear. All published cases to date received gadodiamide, gadopentetate or gadoversetamide, which are considered to be less stable due to a linear molecular structure. The aetiological significance of stability differences between the non-ionic linear, ionic linear and macrocyclic agents remains to be shown. For prevention, strict indications for MRI in risk patients can be combined with Food and Drug Administration (FDA) or European Medicines Agency (EMEA) guidelines. These recommend checking for renal impairment by history or laboratory tests. The FDA recommends avoidance of all gadolinium contrast media in patients with renal insufficiency grades 4 and 5 (glomerular filtration rate <30 mL/min per 1.73 m(2)) or any grade of acute renal failure in liver transplantation patients or candidates. The EMEA differentiates between agents and advises avoidance of only gadodiamide and gadopentetate in the same patient categories. Other gadolinium contrast media should only be used after careful consideration of risks versus benefits. Post-procedural haemodialysis is only indicated in patients on regular dialysis.

  1. 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.

  2. [CT contrast administration of iodine, gadolinium and ytterbium. In-vitro studies and animal experiments].

    PubMed

    Zwicker, C; Langer, M; Urich, V; Felix, R

    1993-03-01

    The absorption of the elements iodine, gadolinium and ytterbium in various dilutions was studied in relation to CT. Regression analysis and specific CT density measurements showed that absorption decreases from gadolinium to ytterbium and iodine. These results were confirmed by experiments using ten dogs. Boli of 0.5 molar gadolinium used for angio-CT without table movement showed the largest increase in density in the aorta and liver with an average of 190HU and 21HU respectively compared with iodine which gave 157HU and 12HU respectively. The animal experimental studies suggest that gadolinium and ytterbium are suitable contrast media for dynamic CT investigations.

  3. 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.

  4. Combination of boron and gadolinium compounds for neutron capture therapy. An in vitro study.

    PubMed

    Matsumura, A; Zhang, T; Nakai, K; Endo, K; Kumada, H; Yamamoto, T; Yoshida, F; Sakurai, Y; Yamamoto, K; Nose, T

    2005-03-01

    In neutron capture therapy, the therapeutic effect of the boron compound is based on alpha particles produced by the B(n, alpha) reaction while with the gadolinium compound the main radiation effect is from gamma rays derived from the Gd(n, gamma) reaction. The uptake and distribution within the tumor may be different among these compounds. Thus, the combination of the boron and gadolinium compounds may be beneficial for enhancing the radiation dose to the tumor. Chinese hamster fibroblast V79 cells were used. For the neutron targeting compounds, 10B (BSH) at 0, 5, 10, and 15 ppm, and 157Gd (Gd-BOPTA) at 0, 800, 1600, 2400, 3200, and 4800 ppm, were combined. The neutron irradiation was performed with thermal neutrons for 30 min. (neutron flux: 0.84 x 10(8) n/cm2/s in free air). The combination of the boron and gadolinium compounds showed an additive effect when the gadolinium concentration was lower than 1600 ppm. This additive effect decreased as a function of gadolinium concentration at 2400 ppm and resulted in no additive effect at more than 3200 ppm of gadolinium. In conclusion, the combination of the boron and gadolinium compounds can enhance the therapeutic effect with an optimum concentration ratio. When the gadolinium concentration is too high, it may weaken the boron neutron capture reaction due to the high cross-section of gadolinium compound against neutrons.

  5. Thermodynamic properties of gadolinium in Ga-Sn and Ga-Zn eutectic based alloys

    NASA Astrophysics Data System (ADS)

    Maltsev, Dmitry S.; Volkovich, Vladimir A.; Yamshchikov, Leonid F.; Chukin, Andrey V.

    2016-09-01

    Thermodynamic properties of gadolinium in Ga-Sn and Ga-Zn eutectic based alloys were studied. Temperature dependences of gadolinium activity in the studied alloys were determined at 573-1073 K employing the EMF method. Solubility of gadolinium in the Ga-Sn and Ga-Zn alloys was measured at 462-1073 K using IMCs sedimentation method. Activity coefficients as well as partial and excess thermodynamic functions of gadolinium in the studied alloys were calculated on the basis of the obtained experimental data.

  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. 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.

  8. 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.

  9. 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.

  10. Visualization of denervated muscle by gadolinium-enhanced MRI.

    PubMed

    Bendszus, M; Koltzenburg, M

    2001-11-13

    Thirty patients presenting with foot drop due to lesions of the peroneal nerve or L5 spinal root were investigated with gadolinium (Gd)-enhanced MRI of the lower leg. Significant enhancement was only seen in the denervated muscles in a pattern appropriate for the distribution of the nerve or root. In a rat model, identical changes in the denervated muscle were reproduced and seen as early as 24 hours after sciatic nerve transection. Thus, Gd-enhanced MRI is a new and sensitive technique to visualize denervated muscle.

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    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.

  13. Sensitivity of alanine dosimeters with gadolinium exposed to 6 MV photons at clinical doses.

    PubMed

    Marrale, M; Longo, A; Spanò, M; Bartolotta, A; D'Oca, M C; Brai, M

    2011-12-01

    In this study we analyzed the ESR signal of alanine dosimeters with gadolinium exposed to 6 MV linear accelerator photons. We observed that the addition of gadolinium brings about an improvement in the sensitivity to photons because of its high atomic number. The experimental data indicated that the addition of gadolinium increases the sensitivity of the alanine to 6 MV photons. This enhancement was better observed at high gadolinium concentrations for which the tissue equivalence is heavily reduced. However, information about the irradiation setup and of the radiation beam features allows one to correct for this difference. Monte Carlo simulations were carried out to obtain information on the expected effect of the addition of gadolinium on the dose absorbed by the alanine molecules inside the pellets. These results are compared with the experimental values, and the agreement is discussed.

  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. 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.

  16. 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.

  17. MRI gadolinium enhancement precedes neuroradiological findings in acute necrotizing encephalopathy.

    PubMed

    Yoshida, Takeshi; Tamura, Takuya; Nagai, Yuhki; Ueda, Hiroyuki; Awaya, Tomonari; Shibata, Minoru; Kato, Takeo; Heike, Toshio

    2013-11-01

    We report a 2-year-old Japanese boy with acute necrotizing encephalopathy (ANE) triggered by human herpes virus-6, who presented insightful magnetic resonance imaging (MRI) findings. He was admitted due to impaired consciousness and a convulsion, 2 days after the onset of an upper respiratory infection. At admission, cranial MRI showed marked gadolinium enhancement at the bilateral thalami, brainstem and periventricular white matter without abnormal findings in noncontrast MRI sequences. On the following day, noncontrast computed tomography demonstrated homogeneous low-density lesions in the bilateral thalami and severe diffuse brain edema. The patient progressively deteriorated and died on the 18th day of admission. The pathogenesis of ANE remains mostly unknown, but it has been suggested that hypercytokinemia may play a major role. Overproduced cytokines cause vascular endothelial damage and alter the permeability of the vessel wall in the multiple organs, including the brain. The MRI findings in our case demonstrate that blood-brain barrier permeability was altered prior to the appearance of typical neuroradiological findings. This suggests that alteration of blood-brain barrier permeability is the first step in the development of the brain lesions in ANE, and supports the proposed mechanism whereby hypercytokinemia causes necrotic brain lesions. This is the first report demonstrating MRI gadolinium enhancement antecedent to typical neuroradiological findings in ANE.

  18. 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.

  19. Automatic detection of the nipple in screen-film and full-field digital mammograms using a novel Hessian-based method.

    PubMed

    Casti, Paola; Mencattini, Arianna; Salmeri, Marcello; Ancona, Antonietta; Mangieri, Fabio Felice; Pepe, Maria Luisa; Rangayyan, Rangaraj Mandayam

    2013-10-01

    Automatic detection of the nipple in mammograms is an important step in computerized systems that combine multiview information for accurate detection and diagnosis of breast cancer. Locating the nipple is a difficult task owing to variations in image quality, presence of noise, and distortion and displacement of the breast tissue due to compression. In this work, we propose a novel Hessian-based method to locate automatically the nipple in screen-film and full-field digital mammograms (FFDMs). The method includes detection of a plausible nipple/retroareolar area in a mammogram using geometrical constraints, analysis of the gradient vector field by mean and Gaussian curvature measurements, and local shape-based conditions. The proposed procedure was tested on 566 mammographic images consisting of 372 randomly selected scanned films from two public databases (mini-MIAS and DDSM), and 194 digital mammograms acquired with a GE Senographe 2000D FFDM system. A radiologist independently marked the centers of the nipples for evaluation of the results. The average error obtained was 6.7 mm (22 pixels) with reference to the center of the nipple as identified by the radiologist. Only two out of the 566 detected nipples (0.35 %) had an error larger than 50 mm. The method was also directly compared with two other techniques for the detection of the nipple. The results indicate that the proposed method outperforms other algorithms presented in the literature and can be used to identify accurately the nipple on various types of mammographic images.

  20. 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. PMID:27617048

  1. 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

  2. Growth control in colon epithelial cells: gadolinium enhances calcium-mediated growth regulation.

    PubMed

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

    2012-12-01

    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.

  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

    2015-06-07

    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.

  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. Nephrogenic systemic fibrosis and gadolinium-based contrast media: updated ESUR Contrast Medium Safety Committee guidelines.

    PubMed

    Thomsen, Henrik S; Morcos, Sameh K; Almén, Torsten; Bellin, Marie-France; Bertolotto, Michele; Bongartz, Georg; Clement, Olivier; Leander, Peter; Heinz-Peer, Gertraud; Reimer, Peter; Stacul, Fulvio; van der Molen, Aart; Webb, Judith A W

    2013-02-01

    To update the guidelines of the Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) on nephrogenic systemic fibrosis and gadolinium-based contrast media. Topics reviewed include the history, clinical features and prevalence of nephrogenic systemic fibrosis and the current understanding of its pathophysiology. The risk factors for NSF are discussed and prophylactic measures are recommended. The stability of the different gadolinium-based contrast media and the potential long-term effects of gadolinium in the body have also been reviewed.

  6. New candidates for superconductors: A series of layered oxysulfides (Cu{sub 2}S{sub 2})(Sr{sub n+1}M{sub n}O{sub 3n{minus}1})

    SciTech Connect

    Otzschi, Kenji; Ogino, Hiraku; Shimoyama, Junichi; Kishio, Kohji

    1999-11-01

    The authors have discovered three new layered transition-metal oxysulfides; (Cu{sub 2}S{sub 2})(Sr{sub 2}CuO{sub 2}), (Cu{sub 2}S{sub 2})(Sr{sub 2}NiO{sub 2}) and (Cu{sub 2}S{sub 2})(Sr{sub 3}Sc{sub 2}O{sub 5}), whose compositions are generally formulated as (Cu{sub 2}S{sub 2})(Sr{sub n+1}M{sub n}O{sub 3n{minus}1}). Their structures consist of alternate stackings of perovskite-based MO{sub 2} plane(s) and Cu{sub 2}S{sub 2} layers, showing great similarity to cuprate superconductors when the Cu{sub 2}S{sub 2} layer is considered as the blocking layer. The formation of these phases is limited by the ion size of M and elasticity of the Cu{sub 2}S{sub 2} layer. The newly found (Cu{sub 2}S{sub 2})(Sr{sub 2}CuO{sub 2}) possesses the horizontally extended tetragonal CuO{sub 2} plane, making itself a possible candidate for a new superconductor.

  7. Gadolinium doped Ceria nanocrystals synthesized from mesoporous silica

    NASA Astrophysics Data System (ADS)

    Rossinyol, Emma; Pellicer, Eva; Prim, Anna; Estradé, Sònia; Arbiol, Jordi; Peiró, Francesca; Cornet, Albert; Morante, Joan Ramon

    2008-02-01

    Highly crystalline and thermally stable gadolinium doped ceria (GDC) particles have been synthesized by hard template route for the first time. This oxide is being recognized as an intermediate temperature (500-700 °C) electrolyte material for applications in solid-oxide fuel cells. The GDC particles show high crystallinity and nanometric size (2.83 ± 0.05 nm in diameter) and Raman analyses confirm the formation of the solid solution instead of a CeO2 and Gd2O3 mixture. EDX and EELS studies indicate a stoichiometry coherent with the Gd0.2Ce0.8O1.9 phase. The synthesized nanometric powder is expected to be used in solid oxide fuel cells as well as in the catalytic treatment of automobile exhaust fumes.

  8. 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.

  9. Densification Dynamics of Gadolinium-Doped Ceria upon Sintering

    NASA Astrophysics Data System (ADS)

    Sato, Kiminori

    2012-07-01

    Densification behavior upon sintering is studied for gadolinium-doped ceria (GDC) by making use of X-ray diffraction, Archimedes method, high-resolution dilatometry (DLT), and element-specific positron annihilation spectroscopy. We found high concentration of vacancy-like nano-defects at GDC-crystallite interfaces participating in densification. Time-resolved length change and positron lifetime measurements enable to discuss the densification dynamics at the particle boundary relevant to a sintering neck and inside the particles. The particle boundary largely contributes to densification at the initial stage of sintering, whereas the crystallite interface gets to be responsible for prolonged densification. The densification inside the particle is developed by the growth of the crystallites followed by the transfer of Gd atoms from the interfaces to the crystallites.

  10. The structural response of gadolinium phosphate to pressure

    SciTech Connect

    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 GdO9 polyhedra.

  11. The structural response of gadolinium phosphate to pressure

    DOE PAGES

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

    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

  12. The structural response of gadolinium phosphate to pressure

    SciTech Connect

    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 GdO9 polyhedra.

  13. 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.

  14. Geometry of electromechanically active structures in Gadolinium - doped Cerium oxides

    DOE PAGES

    Li, Yuanyuan; Kraynis, Olga; Kas, Joshua; ...

    2016-05-20

    Local distortions from average structure are important in many functional materials, such as electrostrictors or piezoelectrics, and contain clues about their mechanism of work. However, the geometric attributes of these distortions are exceedingly difficult to measure, leading to a gap in knowledge regarding their roles in electromechanical response. This task is particularly challenging in the case of recently reported non-classical electrostriction in Cerium-Gadolinium oxides (CGO), where only a small population of Ce-O bonds that are located near oxygen ion vacancies responds to external electric field. In this study, we used high-energy resolution fluorescence detection (HERFD) technique to collect X-ray absorptionmore » spectra in CGO in situ, with and without an external electric field, coupled with theoretical modeling to characterize three-dimensional geometry of electromechanically active units.« less

  15. 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.

  16. Geometry of electromechanically active structures in Gadolinium - doped Cerium oxides

    SciTech Connect

    Li, Yuanyuan; Zacharowicz, Renee; Frenkel, Anatoly I. E-mail: anatoly.frenkel@yu.edu; Kraynis, Olga; Lubomirsky, Igor E-mail: anatoly.frenkel@yu.edu; Kas, Joshua; Weng, Tsu-Chien; Sokaras, Dimosthenis

    2016-05-15

    Local distortions from average structure are important in many functional materials, such as electrostrictors or piezoelectrics, and contain clues about their mechanism of work. However, the geometric attributes of these distortions are exceedingly difficult to measure, leading to a gap in knowledge regarding their roles in electromechanical response. This task is particularly challenging in the case of recently reported non-classical electrostriction in Cerium-Gadolinium oxides (CGO), where only a small population of Ce-O bonds that are located near oxygen ion vacancies responds to external electric field. We used high-energy resolution fluorescence detection (HERFD) technique to collect X-ray absorption spectra in CGO in situ, with and without an external electric field, coupled with theoretical modeling to characterize three-dimensional geometry of electromechanically active units.

  17. Epiphyseal and physeal cartilage: normal gadolinium-enhanced MR imaging.

    PubMed

    Li, Xiaoming; Wang, Renfa; Li, Yonggang; Tang, Lihua; Hu, Junwu; Xu, Anhui

    2005-01-01

    To evaluate the normal appearance of epiphyseal and physeal cartilage on Gadolinium (Gd)-enhanced MR imaging. The appearance and enhancement ratios of 20 proximal and distal femoral epiphyses in 10 normal piglets were analyzed on Gd-enhanced MR images. The correlation of the MR imaging appearance with corresponding histological findings of immature epiphyses was examined. Our results showed that Gd-enhanced MRI could differentiate the differences in enhancement between physeal and epiphyseal cartilage and show vascular canals within the epiphyseal cartilage. Enhanced ratios in the physeal were greater than those in the epiphyseal cartilage (P < 0.005). It is concluded that Gd-enhanced MR imaging reveals epiphyseal vascular canals and shows difference in enhancement of physeal and epiphyseal cartilage.

  18. Fabrication and Characterization of Gadolinium Phosphate Neutron Absorber

    SciTech Connect

    Lessing, Paul Alan; Erickson, Arnold Wendell

    2003-12-01

    Hydrated gadolinium phosphate (GdPO4·1H2O) was synthesized by reacting high purity dissolved salts (gadolinium nitrates or chlorides) with phosphoric acid. The hydrated powders were shown to be extremely insoluble in water with a Ksp measured to be between 2.07 E-14 and 4.76 E-13. Calcination to between 800 and 1000 °C resulted in the formation of GdPO4 in a monazite (monoclinic) crystal structure. This was correlated with the first exothermic differential thermal analysis (DTA) peak (864.9–883.4 °C). The DTA also showed small peaks in the 1200–1250 °C range, that could be associated with a change from the monazite (monoclinic) crystal structure to the xenotime (tetragonal) crystal structure. However, calcination of a sample to 1400 °C, followed by relatively rapid cooling and XRD, showed the structure was still monazite (monoclinic). DTA results showed a melting point at 1899–1920 °C (endothermic peak). It was therefore concluded that the melting point probably was the melting of the monazite (monoclinic) phase, but may have been xenotime if a phase change at 1200–1250 °C was reversible and very rapid. The higher part of the melting range was achieved with material derived using the slightly higher purity nitrate salt. The results show that GdPO4 is an excellent candidate for a chemically stable, water-insoluble neutron absorber for inclusion in spent nuclear fuel canisters.

  19. Immediate hypersensitivity reaction to gadolinium-based MR contrast media.

    PubMed

    Jung, Jae-Woo; Kang, Hye-Ryun; Kim, Min-Hye; Lee, Whal; Min, Kyung-Up; Han, Moon-Hee; Cho, Sang-Heon

    2012-08-01

    To determine the incidence and risk factors of immediate hypersensitivity reactions to gadolinium-based magnetic resonance (MR) contrast agents. Institutional review board approval and a waiver of informed consent were obtained. A retrospective study of patients who had been given gadolinium-based MR contrast media between August 2004 and July 2010 was performed by reviewing their electronic medical records. In addition to data on immediate hypersensitivity reaction, the kinds of MR contrast media and demographic data including age, sex, and comorbidity were collected. To compare the groups, the χ(2) test, Fisher exact test, χ(2) test for trend, Student t test, analysis of variance test, and multiple logistic regression test were performed. A total of 112 immediate hypersensitivity reactions (0.079% of 141 623 total doses) were identified in 102 patients (0.121% of 84 367 total patients). Among the six evaluated MR contrast media, gadodiamide had the lowest rate (0.013%) of immediate hypersensitivity reactions, while gadobenate dimeglumine had the highest rate (0.22%). The rate for immediate hypersensitivity reactions was significantly higher in female patients (odds ratio = 1.687; 95% confidence interval: 1.143, 2.491) and in patients with allergies and asthma (odds ratio = 2.829; 95% confidence interval: 1.427, 5.610). Patients with a previous history of immediate hypersensitivity reactions had a higher rate of recurrence after reexposure to MR contrast media (30%) compared with the incidence rate in total patients (P < .0001). The incidence of immediate hypersensitivity reactions increased depending on the number of times patients were exposed to MR contrast media (P for trend = .036). The most common symptom was urticaria (91.1%), and anaphylaxis occurred in 11 cases (9.8%). The mortality rate was 0.0007% because of one fatality. The incidence of immediate hypersensitivity reactions to MR contrast media was 0.079%, and the recurrence rate of hypersensitivity

  20. 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.

  1. Theoretical study of structure and stability of small gadolinium carboxylate complexes in liquid scintillator solvents.

    PubMed

    Huang, Pin-Wen

    2014-09-01

    The structural properties of three small gadolinium carboxylate complexes in three liquid scintillator solvents (pseudocumene, linear alkylbenzene, and phenyl xylylethane) were theoretically investigated using density functional theory (B3LYP/LC-RECP) and polarizable continuum model (PCM). The average interaction energy between gadolinium atom and carboxylate ligand (E(int)) and the energy difference of the highest singly occupied molecular orbital and lowest unoccupied molecular orbital (Δ(SL)) were calculated to evaluate and compare the relative stability of these complexes in solvents. The calculation results show that the larger (with a longer alkyl chain) gadolinium carboxylate complex has greater stability than the smaller one, while these gadolinium carboxylates in linear alkylbenzene were found to have greater stability than those in the other two solvents.

  2. Characteristics of gadolinium-DTPA complex: a potential NMR contrast agent

    SciTech Connect

    Weinmann, H.J.; Brasch, R.C.; Press, W.R.; Wesbey, G.E.

    1984-03-01

    Chelation of the rare-earth element gadolinium (Gd) with diethylenetriaminepentaacetic acid (DTPA) results in a strongly paramagnetic, stable complex that is well tolerated in animals. The strongly paramagnetic gadolinium complex reduces hydrogen-proton relaxation times even in low concentrations (less than 0.01 mmol/L). The pharmacokinetic behavior of intravenously delivered Gd-DTPA is similar to the well known iodinated contrast agents used in urography and angiography; excretion is predominately through the kidneys with greater than 90% recovery in 24 hr. The intravenous LD/sub 50/ of the meglumine salt of Gd-DTPA is 10 mmol/kg for the rat; in vivo there is no evidence of dissociation of the gadolinium ion from the DTPA ligand. The combination of strong proton relaxation, in-vivo stability, rapid urinary excretion, and high tolerance favors the further development and the potential clinical application of gadolinium-DTPA as a contrast enhancer in magnetic resonance imaging.

  3. 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

  4. 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.

  5. Application of extracellular gadolinium-based MRI contrast agents and the risk of nephrogenic systemic fibrosis.

    PubMed

    Heverhagen, J T; Krombach, G A; Gizewski, E

    2014-07-01

    Nephrogenic systemic fibrosis (NSF) is a serious, sometimes fatal disease. Findings in recent years have shown that a causal association between gadolinium containing contrast media and NSF is most likely. Therefore, the regulatory authorities have issued guidelines on the use of gadolinium-containing contrast media which have reduced the number of new cases of NSF to almost zero. However, it is for precisely this reason that the greatest care must still be taken to ensure that these guidelines are complied with. The most important factors are renal function, the quantity of gadolinium administered and coexisting diseases such as inflammation. All of these factors crucially influence the quantity of gadolinium released from the chelat in the body. This free gadolinium is thought to be the trigger for NSF. Other important factors are the stability of the gadolinium complex and furthermore the route of its elimination from the body. Partial elimination via the liver might be an additional protective mechanism. In conclusion, despite the NSF risk, contrast-enhanced MRI is a safe diagnostic procedure which can be used reliably and safely even in patients with severe renal failure, and does not necessarily have to be replaced by other methods.

  6. Gadolinium contrast agent-induced CD163+ ferroportin+ osteogenic cells in nephrogenic systemic fibrosis.

    PubMed

    Swaminathan, Sundararaman; Bose, Chhanda; Shah, Sudhir V; Hall, Kimberly A; Hiatt, Kim M

    2013-09-01

    Gadolinium-based contrast agents are linked to nephrogenic systemic fibrosis in patients with renal insufficiency. The pathology of nephrogenic systemic fibrosis is characterized by abnormal tissue repair: fibrosis and ectopic ossification. The mechanisms by which gadolinium could induce fibrosis and ossification are not known. We examined in vitro the effect of a gadolinium-based contrast agent on human peripheral blood mononuclear cells for phenotype and function relevant to the pathology of nephrogenic systemic fibrosis using immunofluorescence, flow cytometry, real-time PCR, and osteogenic assays. We also examined tissues from patients with nephrogenic systemic fibrosis, using IHC to identify the presence of cells with phenotype induced by gadolinium. Gadolinium contrast induced differentiation of human peripheral blood mononuclear cells into a unique cellular phenotype--CD163(+) cells expressing proteins involved in fibrosis and bone formation. These cells express fibroblast growth factor (FGF)23, osteoblast transcription factors Runt-related transcription factor 2, and osterix, and show an osteogenic phenotype in in vitro assays. We show in vivo the presence of CD163(+)/procollagen-1(+)/osteocalcin(+) cells in the fibrotic and calcified tissues of nephrogenic systemic fibrosis patients. Gadolinium contrast-induced CD163(+)/ferroportin(+)/FGF23(+) cells with osteogenic potential may play a role in systemic fibrosis and ectopic ossification in nephrogenic systemic fibrosis.

  7. Improvement of ESR dosimetry for thermal neutron beams through the addition of gadolinium.

    PubMed

    Brai, M; Marrale, M; Gennaro, G; Bartolotta, A; D'Oca, M C; Rosi, G

    2007-09-07

    In this paper, the addition of gadolinium is proposed as a useful tool to enhance the electron spin resonance (ESR) sensitivity of organic compounds to thermal neutrons. The target of this work is the detection, through the ESR technique, of the thermal neutron fluence in a mixed field of photons and neutrons. Gadolinium was chosen because it has a very high capture cross section to thermal neutrons; its nuclear reaction with thermal neutrons induces complex inner shell transitions that generate, besides other particles, Auger electrons, which in turn release their energy in the neighborhood (only several nanometers) of the place of reaction. Gadolinium was added to two organic molecules: alanine and ammonium tartrate. The main result obtained was a greater neutron sensitivity for dosimeters with gadolinium than for those without gadolinium for both organic molecules used. Since a dosimeter pair is required to discriminate between the two components of a mixed field, we studied the response of each dosimeter pair irradiated in a mixed field. Through a blind test we verified the usefulness of this dosimetric system and we obtained an estimate of the fluence in the mixed field with a relative uncertainty of 3%, when the pair composed of an alanine dosimeter and a dosimeter with alanine and gadolinium is used.

  8. Allergic-like breakthrough reactions to gadolinium contrast agents after corticosteroid and antihistamine premedication.

    PubMed

    Dillman, Jonathan R; Ellis, James H; Cohan, Richard H; Strouse, Peter J; Jan, Sophia C

    2008-01-01

    The objective of our study was to determine the number and severity of allergic-like breakthrough reactions to i.v. gadolinium-containing contrast agents in children and adults after premedication with corticosteroids and antihistamines. Contrast material reaction forms from the department of radiology for pediatric (under 19 years old) and adult patients were reviewed for the time period from January 1, 2001, through December 31, 2006. All documented allergic-like reactions to i.v. gadolinium-containing contrast media after premedication with corticosteroids and antihistamines were identified. Forms were evaluated for reaction manifestations, management, and patient outcome. Our institutional electronic medical record system was accessed for each individual patient to identify pertinent medical history, including demographic information, history of allergic-like reaction to contrast media (gadolinium- or iodine-containing), and additional factors that led to prophylactic premedication. Eight patients experienced nine allergic-like reactions after the i.v. administration of gadolinium-containing contrast media despite premedication. A single patient had two breakthrough reactions. Six breakthrough reactions were mild, and three were moderate. No severe or fatal breakthrough reaction occurred. Eight of nine breakthrough reactions occurred in adults. All patients who experienced breakthrough reactions had a history of allergic-like reaction to either gadolinium- or iodine-containing contrast media. Allergic-like reactions to gadolinium-containing contrast media can occur despite premedication with corticosteroids and antihistamines.

  9. High Levels of Gadolinium Deposition in the Skin of a Patient With Normal Renal Function.

    PubMed

    Roberts, Donna R; Lindhorst, Scott M; Welsh, Cynthia T; Maravilla, Kenneth R; Herring, Mary N; Braun, K Adam; Thiers, Bruce H; Davis, W Clay

    2016-05-01

    The aim of this study was to assess gadolinium deposition in the skin of a patient with normal renal function, based on estimated glomerular filtration rate values greater than 59 mL/min/1.73 m(2) after exposure to large cumulative doses of gadolinium-based contrast agents (GBCAs). The patient underwent 61 contrasted brain MRI scans over the course of 11 years. Skin biopsies from the forearm and lower extremity were analyzed with inductively coupled plasma mass spectrometry (ICP-MS), laser ablation ICP-MS, and hydrophilic interaction liquid chromatography ICP-MS. The ICP-MS demonstrated high levels of gadolinium deposition (14.5 ± 0.4 μg/g), similar to previously reported gadolinium levels within the skin of patients with nephrogenic systemic fibrosis. The laser ablation ICP-MS demonstrated deposition of gadolinium within the deep layers of skin. Speciation analysis using hydrophilic interaction liquid chromatography ICP-MS demonstrated the presence of intact gadolinium-chelate species, although most of the gadolinium present could not be further characterized. Light microscopy demonstrated increased CD34 immunoreactivity in the connective tissue septations of the subcutaneous adipose tissue. The patient had no history of skin disorders and did not have a history of nephrogenic systemic fibrosis but did have severe joint contractures of unknown etiology. Our results, in contradiction to published literature, suggest that in patients with normal renal function, exposure to GBCAs in extremely high cumulative doses can lead to significant gadolinium deposition in the skin. This finding is in line with more recent reports of gadolinium deposition in the brain of patients with normal renal function. Future studies are required to address possible clinical consequences of gadolinium deposition in the skin, brain, and potentially other organs in patients with normal renal function. We recommend, in addition to following current US Food and Drug Administration and

  10. Chemical and mass spectrographic analysis of nuclear-grade gadolinium oxide (Gd/sub 2/O/sub 3/) powder

    SciTech Connect

    Not Available

    1981-01-01

    Analytical procedures to determine compliance of gadolinium oxide powders with specifications are presented. The following methods are described in detail: carbon by direct combustion - thermal conductivity method; total chlorine and fluorine by pyrohydrolysis ion-selective electrode method; loss of weight on ignition; sulfur by combustion - iodometric titration method; impurity elements by a spark-source mass spectrographic method; and gadolinium content in gadolinium oxide by impurity correction method. (JMT)

  11. Mammographic findings of women recalled for diagnostic work-up in digital versus screen-film mammography in a population-based screening program.

    PubMed

    Lipasti, Seppo; Anttila, Ahti; Pamilo, Martti

    2010-06-01

    Limited information is available concerning differences in the radiological findings of women recalled for diagnostic work-up in digital mammography (DM) versus screen-film mammography (SFM) screening. To compare the radiological findings, their positive predictive values (PPVs) for cancer and other process indicators of DM screening performed by computed radiography (CR) technology and SFM screening in a population-based program. The material consisted of women, 50-59 years of age, who were invited for screening: 30 153 women with DM in 2007-2008 and 32 939 women with SFM in 1999-2000. The attendance rate was 77.7% (23 440) in the DM arm and 83.8% (27 593) in the SFM arm. In the DM arm, 1.71% of those screened (401) and in the SFM arm 1.59% (438) were recalled for further work-up. The images resulting in the recall were classified as: 1) tumor-like mass, 2) parenchymal distortion/asymmetry, 3) calcifications, and 4) combination of mass and calcifications. The distributions of the various radiological findings and their PPVs for cancer were compared in both study groups. The recall rates, cancer detection rates, test specificities, and PPVs of the DM and SFM groups were also compared. Women were recalled for diagnostic work-up most often due to tumor-like mass. It was more common in SFM (1.08% per woman screened) than in DM (0.93%). The second most common finding was parenchymal distortion and asymmetry, more often in DM (0.58%) than in SFM (0.37%). Calcifications were the third most common finding. DM exposed calcifications more often (0.49%) than SFM (0.26%). The PPVs for cancer of the recalls were higher in DM than in SFM in all subgroups of radiological findings. The test specificities were similar (DM 98.9%, SFM 98.8%). Significantly more cancers were detected by DM (cancer detection rate 0.623% per woman screened, n=146) than by SFM (cancer detection rate 0.406% per woman screened, n=112). The PPVs for cancer of all recalls for diagnostic work-up were

  12. X-Ray Fluorescence Analysis of Yttrium-Iron-Gadolinium Solutions Used to Prepare Spray Dried Powders.

    DTIC Science & Technology

    IRON, * GADOLINIUM , *X RAY SPECTROSCOPY, *YTTRIUM, COMPUTER PROGRAMS, SOLUTIONS(MIXTURES), QUALITY CONTROL, NITRIC ACID, RARE EARTH ELEMENTS, CHEMICAL ANALYSIS, FERRITES , PHASE SHIFT CIRCUITS, YTTRIUM IRON GARNET.

  13. 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).

  14. Nanocrystalline gadolinium doped ceria: combustion synthesis and electrical characterization.

    PubMed

    Dutta, Atanu; Patra, Saheli; Bedekar, Vinila; Tyagi, A K; Basu, R N

    2009-05-01

    Twenty mol% gadolinium doped ceria powders were prepared by citrate-nitrate combustion synthesis technique. Two different sources of cerium viz. cerium nitrate and ammonium ceric nitrate were used in different oxidant-to-fuel ratios. The crystallite size of the synthesized powders ranged 5-27 nm was obtained depending on the preparation conditions with average particle size in the range 0.64-1.26 microm. Although, the powders were found to be agglomerated in nature, these powders were highly sinter-active as they showed very high sintered density (> or = 95%) when sintered at 1250 degrees C having grain size in the range of 200-500 nm. The electrical conductivity was found to depend on the temperature with two distinct regimes at a transition point of 350 degrees C. The grain boundary showed a significant role in the total conductivity with its activation energy dependent on the material preparation conditions. The activation energy of total conduction was found to be significantly low (-0.5 eV) in the temperature range of 400-700 degrees C, this property is unique for application as an electrolyte for solid oxide fuel cell operating in the low temperature range. It was found that a fuel-deficient combustion reaction using cerium nitrate as the oxidant yielded the best quality powder which showed a maximum electrical conductivity of -1.74 x 10(-2) S/cm at 600 degrees C.

  15. Ordered structures of defect clusters in gadolinium-doped ceria.

    PubMed

    Li, Zhi-Peng; Mori, Toshiyuki; Ye, Fei; Ou, Dingrong; Zou, Jin; Drennan, John

    2011-06-14

    The nano-domain, with short-range ordered structure, has been widely observed in rare-earth-doped ceria. Atomistic simulation has been employed to investigate the ordering structure of the nano-domain, as a result of aggregation and segregation of dopant cations and the associated oxygen vacancies in gadolinium-doped ceria. It is found that the binding energy of defect cluster increases as a function of cluster size, which provides the intrinsic driving force for the defect cluster growth. However, the ordered structures of the defect clusters are different from the chain model as previously reported. Adjacent oxygen vacancies prefer to locate along <110>/2 lattice vector, which results in a unique stable structure (isosceles triangle) formation. Such isosceles triangle structure can act as the smallest unit of cluster growth to form a symmetric dumbbell structure. This unique dumbbell structure is hence considered as a building block for the development of larger defect clusters, leading to nano-domain formation in rare-earth-doped ceria.

  16. Ordered structures of defect clusters in gadolinium-doped ceria

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Peng; Mori, Toshiyuki; Ye, Fei; Ou, Dingrong; Zou, Jin; Drennan, John

    2011-06-01

    The nano-domain, with short-range ordered structure, has been widely observed in rare-earth-doped ceria. Atomistic simulation has been employed to investigate the ordering structure of the nano-domain, as a result of aggregation and segregation of dopant cations and the associated oxygen vacancies in gadolinium-doped ceria. It is found that the binding energy of defect cluster increases as a function of cluster size, which provides the intrinsic driving force for the defect cluster growth. However, the ordered structures of the defect clusters are different from the chain model as previously reported. Adjacent oxygen vacancies prefer to locate along <110>/2 lattice vector, which results in a unique stable structure (isosceles triangle) formation. Such isosceles triangle structure can act as the smallest unit of cluster growth to form a symmetric dumbbell structure. This unique dumbbell structure is hence considered as a building block for the development of larger defect clusters, leading to nano-domain formation in rare-earth-doped ceria.

  17. Gadolinium-loaded gel scintillators for neutron and antineutrino detection

    SciTech Connect

    Riddle, Catherine Lynn; Akers, Douglas William; Demmer, Ricky Lynn; Paviet, Patricia Denise; Drigert, Mark William

    2016-11-29

    A gadolinium (Gd) loaded scintillation gel (Gd-ScintGel) compound allows for neutron and gamma-ray detection. The unique gel scintillator encompasses some of the best features of both liquid and solid scintillators, yet without many of the disadvantages associated therewith. Preferably, the gel scintillator is a water soluble Gd-DTPA compound and water soluble fluorophores such as: CdSe/ZnS (or ZnS) quantum dot (Q-dot) nanoparticles, coumarin derivatives 7-hydroxy-4-methylcoumarin, 7-hydroxy-4-methylcoumarin-3-acetic acid, 7-hydroxycoumarin-3-carboxylic acid, and Alexa Fluor 350 as well as a carbostyril compound, carbostyril 124 in a stable water-based gel, such as methylcellulose or polyacrylamide polymers. The Gd-loaded ScintGel allows for a homogenious distribution of the Gd-DTPA and the fluorophores, and yields clean fluorescent emission peaks. A moderator, such as deuterium or a water-based clear polymer, can be incorporated in the Gd-ScintGel. The gel scintillators can be used in compact detectors, including neutron and antineutrino detectors.

  18. Late Gadolinium Enhancement in Patients with Nonischemic Dilated Cardiomyopathy.

    PubMed

    Memon, Sarfaraz; Ganga, Harsha V; Kluger, Jeffrey

    2016-07-01

    One-third of all patients with heart failure have nonischemic dilated cardiomyopathy (NIDM). Five-year mortality from NIDM is as high as 20% with sudden cardiac death (SCD) as the cause in 30% of the deaths. Currently, the left ventricular ejection fraction (LVEF) is used as the main criteria to risk stratify patients requiring an implantable cardioverter defibrillator (ICD) to prevent SCD. However, LVEF does not necessarily reflect myocardial propensity for electrical instability leading to ventricular tachycardia (VT) or ventricular fibrillation (VF). Due to the differential risk in various subgroups of patients for arrhythmic death, it is important to identify appropriate patients for ICD implantation so that we can optimize healthcare resources and avoid the complications of ICDs in individuals who are unlikely to benefit. We performed a systematic search and review of clinical trials of NIDM and the use of ICDs and cardiac magnetic resonance imaging with late gadolinium enhancement (LGE) for risk stratification. LGE identifies patients with NIDM who are at high risk for SCD and enables optimized patient selection for ICD placement, while the absence of LGE may reduce the need for ICD implantation in patients with NIDM who are at low risk for future VF/VT or SCD.

  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. Electronic transport in gadolinium atomic-size contacts

    NASA Astrophysics Data System (ADS)

    Olivera, B.; Salgado, C.; Lado, J. L.; Karimi, A.; Henkel, V.; Scheer, E.; Fernández-Rossier, J.; Palacios, J. J.; Untiedt, C.

    2017-02-01

    We report on the fabrication, transport measurements, and density functional theory (DFT) calculations of atomic-size contacts made of gadolinium (Gd). Gd is known to have local moments mainly associated with f electrons. These coexist with itinerant s and d bands that account for its metallic character. Here we explore whether and how the local moments influence electronic transport properties at the atomic scale. Using both scanning tunneling microscope and lithographic mechanically controllable break junction techniques under cryogenic conditions, we study the conductance of Gd when only few atoms form the junction between bulk electrodes made of the very same material. Thousands of measurements show that Gd has an average lowest conductance, attributed to single-atom contact, below 2/e2 h . Our DFT calculations for monostrand chains anticipate that the f bands are fully spin polarized and insulating and that the conduction may be dominated by s , p , and d bands. We also analyze the electronic transport for model nanocontacts using the nonequilibrium Green's function formalism in combination with DFT. We obtain an overall good agreement with the experimental results for zero bias and show that the contribution to the electronic transport from the f channels is negligible and that from the d channels is marginal.

  1. Gadolinium-Based Contrast Agents for MR Cancer Imaging

    PubMed Central

    Zhou, Zhuxian; Lu, Zheng-Rong

    2013-01-01

    Magnetic resonance imaging (MRI) is a clinical imaging modality effective for anatomical and functional imaging of diseased soft tissues, including solid tumors. MRI contrast agents have been routinely used for detecting tumor at an early stage. Gadolinium based contrast agents are the most commonly used contrast agents in clinical MRI. There have been significant efforts to design and develop novel Gd(III) contrast agents with high relaxivity, low toxicity and specific tumor binding. The relaxivity of the Gd(III) contrast agents can be increased by proper chemical modification. The toxicity of Gd(III) contrast agents can be reduced by increasing the agents’ thermodynamic and kinetic stability, as well as optimizing their pharmacokinetic properties. The increasing knowledge in the field of cancer genomics and biology provides an opportunity for designing tumor-specific contrast agents. Various new Gd(III) chelates have been designed and evaluated in animal models for more effective cancer MRI. This review outlines the design and development, physicochemical properties, and in vivo properties of several classes of Gd(III)-based MR contrast agents for tumor imaging. PMID:23047730

  2. DNA surface modified gadolinium phosphate nanoparticles as MRI contrast agents.

    PubMed

    Dumont, Matthieu F; Baligand, Celine; Li, Yichen; Knowles, Elisabeth S; Meisel, Mark W; Walter, Glenn A; Talham, Daniel R

    2012-05-16

    Oligonucleotide modified gadolinium phosphate nanoparticles have been prepared and their magnetic resonance relaxivity properties measured. Nanoparticles of GdPO4·H2O were synthesized in a water/oil microemulsion using IGEPAL CO-520 as surfactant, resulting in 50 to 100 nm particles that are highly dispersible and stable in water. Using surface modification chemistry previously established for zirconium phosphonate surfaces, the particles are directly modified with 5'-phosphate terminated oligonucleotides, and the specific interaction of the divalent phosphate with Gd(3+) sites at the surface is demonstrated. The ability of the modified nanoparticles to act as MRI contrast agents was determined by performing MR relaxivity measurements at 14.1 T. Solutions of nanopure water, Feridex, and Omniscan (FDA approved contrast agents) in 0.25% agarose were used for comparison and control purposes. MRI data confirm that GdPO4·H2O nanoparticles have relaxivities (r1, r2) comparable to those of commercially available contrast agents. In addition, the data suggest that biofunctionalization of the surface of the nanoparticles does not prevent their function as MRI contrast agents.

  3. Analytical Interference in Serum Iron Determination Reveals Iron Versus Gadolinium Transmetallation With Linear Gadolinium-Based Contrast Agents

    PubMed Central

    Fretellier, Nathalie; Poteau, Nathalie; Factor, Cécile; Mayer, Jean-François; Medina, Christelle; Port, Marc; Idée, Jean-Marc; Corot, Claire

    2014-01-01

    Objectives The purposes of this study were to evaluate the risk for analytical interference with gadolinium-based contrast agents (GBCAs) for the colorimetric measurement of serum iron (Fe3+) and to investigate the mechanisms involved. Materials and Methods Rat serum was spiked with several concentrations of all molecular categories of GBCAs, ligands, or “free” soluble gadolinium (Gd3+). Serum iron concentration was determined by 2 different colorimetric methods at pH 4.0 (with a Vitros DT60 analyzer or a Cobas Integra 400 analyzer). Secondly, the cause of interference was investigated by (a) adding free soluble Gd3+ or Mn2+ to serum in the presence of gadobenic acid or gadodiamide and (b) electrospray ionization mass spectrometry. Results Spurious decrease in serum Fe3+ concentration was observed with all linear GBCAs (only with the Vitros DT60 technique occurring at pH 4.0) but not with macrocyclic GBCAs or with free soluble Gd3+. Spurious hyposideremia was also observed with the free ligands present in the pharmaceutical solutions of the linear GBCAs gadopentetic acid and gadodiamide (ie, diethylene triamine pentaacetic acid and calcium-diethylene triamine pentaacetic acid bismethylamide, respectively), suggesting the formation of Fe-ligand chelate. Gadobenic acid-induced interference was blocked in a concentration-dependent fashion by adding a free soluble Gd3+ salt. Conversely, Mn2+, which has a lower affinity than Gd3+ and Fe3+ for the ligand of gadobenic acid (ie, benzyloxypropionic diethylenetriamine tetraacetic acid), was less effective (interference was only partially blocked), suggesting an Fe3+ versus Gd3+ transmetallation phenomenon at pH 4.0. Similar results were observed with gadodiamide. Mass spectrometry detected the formation of Fe-ligand with all linear GBCAs tested in the presence of Fe3+ and the disappearance of Fe-ligand after the addition of free soluble Gd3+. No Fe-ligand chelate was found in the case of the macrocyclic GBCA gadoteric

  4. Serum netrin-1 in relation to gadolinium-enhanced magnetic resonance imaging in early multiple sclerosis.

    PubMed

    Voortman, M M; Pekar, T; Bachmayer, D; Archelos, J-J; Stojakovic, T; Scharnagl, H; Ropele, S; Pichler, A; Enzinger, C; Fuchs, S; Fazekas, F; Seifert-Held, T; Khalil, M

    2017-01-01

    Netrin-1, a secreted laminin-related protein, is known to regulate not only axonal guidance and neuronal cell migration, but also blood-brain barrier integrity and inflammation. Two preliminary studies reported altered serum netrin-1 levels in multiple sclerosis; however, associations with longitudinal clinical and magnetic resonance imaging activity have not been investigated. We aimed to assess serum netrin-1 in multiple sclerosis and controls with respect to disease activity and its temporal dynamics. Serum netrin-1 was assessed by enzyme-linked immunosorbent assay in 79 patients with clinically isolated syndrome or multiple sclerosis, and 30 non-inflammatory neurological disease controls. In patients, serum samples were collected immediately prior to gadolinium-enhanced 3 T magnetic resonance imaging at two time points (initial contrast-enhancing gadolinium+ n = 47, non-enhancing gadolinium- n = 32; reference gadolinium- n = 70; median time-lag 1.4, interquartile range 1.0-2.3 years). Serum netrin-1 levels were similar in clinically isolated syndrome, multiple sclerosis and controls, and gadolinium+ and gadolinium- patients. Among gadolinium+ patients, serum netrin-1 was decreased in clinically active (n = 8) vs non-active patients (n = 39; p = 0.041). Serum netrin-1 showed no temporal dynamics in multiple sclerosis and was unrelated to clinical data. Serum netrin-1 levels show no multiple sclerosis specific changes and are not sensitive for detection of subclinical disease activity. Netrin-1 changes during relapses may deserve further examination.

  5. The presence of the gadolinium-based contrast agent depositions in the brain and symptoms of gadolinium neurotoxicity - A systematic review

    PubMed Central

    Olchowy, Cyprian; Cebulski, Kamil; Łasecki, Mateusz; Chaber, Radosław; Olchowy, Anna; Kałwak, Krzysztof; Zaleska-Dorobisz, Urszula

    2017-01-01

    Background and purpose Gadolinium based contrast agents (GBCAs) are widely used in magnetic resonance imaging, but recently, high signal intensity in the cerebellum structures was reported after repeated administrations of contrast- enhanced magnetic resonance images. The aim of this systematic review was to investigate the association between increased signal intensity in the dentate nucleus and globus pallidus in the brain and repeated administrations of GBCAs. Additionally, we focused on possible short- and long-term consequences of gadolinium use in those patients. Methods Systematic review of retrospective investigations in PubMed and Medline was performed in July 2016. Primary outcomes included the presence of increased signal intensity within the dentate nucleus and globus pallidus on unenhanced T1-weighted MR images in patients following administrations of GBCAs. Two independent reviewers were responsible for search and data extraction. Results 25 publications satisfied inclusion criteria (19 magnetic resonance images analyses, 3 case reports; 3 autopsy studies). Magnetic resonance images of 1247 patients with increased signal intensity on unenhanced T1-weighted MR images were analyzed as well as tissue specimens from 27 patients. Signal intensity correlated positively with the exposure to GBCAs and was greater after serial administrations of linear nonionic than cyclic contrast agents. Gadolinium was detected in all tissue examinations. Conclusions High signal intensity in the dentate nucleus and globus pallidus on unenhanced T1-weighted magnetic resonance images were associated with previous administration of GBCAs. Signal intensity correlated negatively with stability of contrast agents. Clinical significance of gadolinium deposition in the brain remains unclear. There is a strong need for further research to identify type of gadolinium deposited in the brain as well as to gather knowledge about long-term consequences. PMID:28187173

  6. Separation of bone from iodine- and gadolinium-based contrast agents using dual energy CT

    NASA Astrophysics Data System (ADS)

    Chong, Daniel Y.; Angel, Erin; Kim, Hyun J.; Cole, Graham B.; Boyadzhyan, Lousine; Panknin, Christoph; Gomez, Ana M.; Goldin, Jonathan G.; Brown, Matthew S.; McNitt-Gray, Michael F.

    2008-03-01

    This study aims to evaluate the separability of bone from iodine- and gadolinium-based intravenous contrast agents using dual energy CT techniques in a phantom. The phantom was prepared containing varying concentrations of iodine-based contrast, gadolinium-based contrast, and calcium hydroxyapatite (to simulate bone). Thirteen iodine concentrations from 0.1 to 12 mg/mL, twelve gadolinium concentrations from 0.72 to 34.42 mg/mL, and four calcium concentrations from 0 to 200 mg/mL were used. These phantoms were scanned on a dual source CT using two different source spectra, producing one set of data at 80 kVp and another at 140 kVp. On each resulting image, the mean HU was measured at every concentration level for iodine, gadolinium, and calcium, and plotted on a graph of HU value at 80 versus 140 kVp. Linear regression was used to produce a best-fit line for each material. These lines were compared to test for a difference of slopes between calcium and iodine as well as between calcium and gadolinium. Each material exhibited a linear relationship between the HU values at 140 and 80 kVp (R2 = 0.99) and demonstrated a unique slope to this line. The slope for iodine was 2.00, for gadolinium was 1.63, and for calcium was 1.55. The slopes of the calcium and iodine lines were significantly different (p < 0.05), while the slopes of the calcium and gadolinium lines were not significantly different (p > 0.05). Our results suggest that while it is technically feasible to separate iodine from bone, gadolinium-based contrast does not appear to be as readily separable from bone as iodine. This result is surprising as the atomic number and k-edge of calcium (Z = 20, k-edge = 4 keV) are closer to iodine (Z = 53, k-edge = 33 keV) than to gadolinium (Z = 64, k-edge = 50 keV).

  7. The dosimetric impact of gadolinium-based contrast media in GBM brain patient plans for a MRI-Linac

    NASA Astrophysics Data System (ADS)

    Bilal Ahmad, Syed; Paudel, Moti Raj; Sarfehnia, Arman; Kim, Anthony; Pang, Geordi; Ruschin, Mark; Sahgal, Arjun; Keller, Brian M.

    2017-08-01

    Dosimetric effects of gadolinium based contrast media (Gadovist) were evaluated for the Elekta MRI linear accelerator using the research version of the Monaco treatment planning system (TPS). In order to represent a gadolinium uptake, the contrast was manually assigned to a phantom as well as to the gross tumour volume (GTV) of 6 glioblastoma multiforme (GBM) patients. A preliminary estimate of the dose enhancement, due to gadolinium, was performed using the phantom irradiated with a single beam. A more complicated assessment was performed for the GBM patients using a 7 field IMRT technique. The material table in Monaco was modified in order to identify the presence of a non-biological material. The dose distribution was modelled using GPUMCD (MC algorithm in Monaco) for an unmodified (or default) material table (DMT) as well as for a modified (or custom) material table (CMT) for both the phantom and patients. Various concentrations ranging between 8 and 157 mg ml-1 were used to represent the gadolinium uptake in the patient’s GTV. It was assumed that the gadolinium concentration remained the same for the entire course of radiation treatment. Results showed that at the tissue-Gadovist interface, inside the phantom, dose scored using the DMT was 7% lower compared to that using the CMT for 157 mg ml-1 concentration of gadolinium. Dosimetric differences in the case of the patient study were measured using the DVH parameters. D 50% was higher by 6% when the DMT was used compared to the CMT for dose modelling for a gadolinium concentration of 157 mg ml-1. This difference decreased gradually with decreasing concentration of gadolinium. It was concluded that dosimetric differences can be quantified in Monaco if the tumour-gadolinium concentration is more than 23 mg ml-1. If the gadolinium concentration is lower than 23 mg ml-1, then a correction for the presence of gadolinium may not be necessary in the TPS.

  8. Compensated gadolinium-loaded plastic scintillators for thermal neutron detection (and counting)

    SciTech Connect

    Dumazert, Jonathan; Coulon, Romain; Bertrand, Guillaume H. V.; Hamel, Matthieu; Sguerra, Fabien; Dehe-Pittance, Chrystele; Normand, Stephane; Mechin, Laurence

    2015-07-01

    Plastic scintillator loading with gadolinium-rich organometallic complexes shows a high potential for the deployment of efficient and cost-effective neutron detectors. Due to the low-energy photon and electron signature of thermal neutron capture by gadolinium-155 and gadolinium-157, alternative treatment to Pulse Shape Discrimination has to be proposed in order to display a trustable count rate. This paper discloses the principle of a compensation method applied to a two-scintillator system: a detection scintillator interacts with photon radiation and is loaded with gadolinium organometallic compound to become a thermal neutron absorber, while a non-gadolinium loaded compensation scintillator solely interacts with the photon part of the incident radiation. Posterior to the nonlinear smoothing of the counting signals, a hypothesis test determines whether the resulting count rate after photon response compensation falls into statistical fluctuations or provides a robust image of a neutron activity. A laboratory prototype is tested under both photon and neutron irradiations, allowing us to investigate the performance of the overall compensation system in terms of neutron detection, especially with regards to a commercial helium-3 counter. The study reveals satisfactory results in terms of sensitivity and orientates future investigation toward promising axes. (authors)

  9. 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.

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

    PubMed

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

    2015-10-26

    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.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. Magnetization and coercivity of nanocrystalline gadolinium iron garnet

    NASA Astrophysics Data System (ADS)

    Nguyet, Dao Thi Thuy; Duong, Nguyen Phuc; Satoh, Takuya; Anh, Luong Ngoc; Hien, Than Duc

    2013-04-01

    Gadolinium iron garnet (GdIG) nanoparticles with mean particle size of about 37 nm have been synthesized by citrate precursor gel formation followed by annealing at 800 °C for 2 hours. Magnetic behavior of clustered GdIG nanoparticles was studied in temperature range from 5 K to above Curie temperature. The sample shows a magnetization compensation temperature Tcomp˜286.5 K and a Curie temperature TC˜560 K. In comparison with the bulk saturation magnetization, the sample exhibits lower spontaneous magnetization in the temperature region from 5 K to Tcomp whereas higher spontaneous magnetization is observed at higher temperatures up to near the Curie point. The magnetization curves show a differential susceptibility in high fields which increases sharply below 50 K. At very low temperatures, irreversibility was observed in the magnetization loops, enduring in the fields up to ˜12.5 kOe. The spontaneous magnetization, high-field susceptibility and low-temperature irreversible effect were discussed based on a model for the interacting particles consisting of ferrimagnetically aligned core spins and disordered spins in surface layer which become frozen at low temperatures. We proposed a mechanism for the enhancement of the spontaneous magnetization above Tcomp in which the Gd and Fe spins in the surface layer are largely decoupled at high temperatures and the surface Fe spins realign to the magnetic moment of the core. The magnetic coercivity Hc at low temperatures is governed by the effective anisotropy whereas in the vicinity of the compensation point a peak in the coercive force shows up as a result of the so-called paraprocess with the maximum value of 1.2 kOe at Tcomp and by further increasing temperature the coercivity decreases and eventually vanishes at about 500 K. The interparticle interactions were found to play an important role in the hysteresis behavior of the sample.

  16. Gadolinium-Enhanced Magnetic Resonance Angiography for Pulmonary Embolism

    PubMed Central

    Stein, Paul D.; Chenevert, Thomas L.; Fowler, Sarah E.; Goodman, Lawrence R.; Gottschalk, Alexander; Hales, Charles A.; Hull, Russell D.; Jablonski, Kathleen A.; Leeper, Kenneth V.; Naidich, David P.; Sak, Daniel J.; Sostman, H. Dirk; Tapson, Victor F.; Weg, John G.; Woodard, Pamela K.

    2011-01-01

    Background The accuracy of gadolinium-enhanced magnetic resonance pulmonary angiography and magnetic resonance venography for diagnosing pulmonary embolism has not been determined conclusively. Objective To investigate performance characteristics of magnetic resonance angiography, with or without magnetic resonance venography, for diagnosing pulmonary embolism. Design Prospective, multicenter study from 10 April 2006 to 30 September 2008. (ClinicalTrials.gov registration number: NCT00241826) Setting 7 hospitals and their emergency services. Patients 371 adults with diagnosed or excluded pulmonary embolism. Measurements Sensitivity, specificity, and likelihood ratios were measured by comparing independently read magnetic resonance imaging with the reference standard for diagnosing pulmonary embolism. Reference standard diagnosis or exclusion was made by using various tests, including computed tomographic angiography and venography, ventilation–perfusion lung scan, venous ultra-sonography, D-dimer assay, and clinical assessment. Results Magnetic resonance angiography, averaged across centers, was technically inadequate in 25% of patients (92 of 371). The proportion of technically inadequate images ranged from 11% to 52% at various centers. Including patients with technically inadequate images, magnetic resonance angiography identified 57% (59 of 104) with pulmonary embolism. Technically adequate magnetic resonance angiography had a sensitivity of 78% and a specificity of 99%. Technically adequate magnetic resonance angiography and venography had a sensitivity of 92% and a specificity of 96%, but 52% of patients (194 of 370) had technically inadequate results. Limitation A high proportion of patients with suspected embolism was not eligible or declined to participate. Conclusion Magnetic resonance pulmonary angiography should be considered only at centers that routinely perform it well and only for patients for whom standard tests are contraindicated. Magnetic

  17. The structural response of gadolinium phosphate to pressure

    SciTech Connect

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

    2016-09-15

    Accurate elastic constants for gadolinium phosphate (GdPO{sub 4}) have been measured by single-crystal high-pressure diffraction methods. The bulk modulus of GdPO{sub 4} determined under hydrostatic conditions, 128.1(8) GPa (K′=5.8(2)), is markedly different from that obtained with GdPO{sub 4} 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 PO{sub 4} tetrahedra behave as rigid units in response to pressure and that contraction of the GdPO{sub 4} structure is facilitated by bending/twisting of the Gd–O–P links that result in increased distortion in the GdO{sub 9} polyhedra. - Graphical abstract: A high-pressure single crystal diffraction study of GdPO{sub 4} with the monazite structure is presented. The elastic behaviour of rare-earth phosphates are believed to be sensitive to shear forces. The bulk modulus of GdPO{sub 4} measured under hydrostatic conditions is 128.1(8) GPa. Compression of the structure is facilitated by bending/twisting of the Gd−O−P links that result in increased distortion in the GdO{sub 9} polyhedra. Display Omitted - Highlights: • The elastic responses of rare-earth phosphates are sensitive to shear forces. • The bulk modulus of GdPO{sub 4} measured under hydrostatic conditions is 128.1(8) GPa. • Twisting of the inter-polyhedral links allows compression of the GdPO{sub 4} structure. • Changes to the GdO{sub 9} polyhedra occur in response to pressure (<7.0 GPa).

  18. Biodistribution of ultra small gadolinium-based nanoparticles as theranostic agent: application to brain tumors.

    PubMed

    Miladi, Imen; Duc, Géraldine Le; Kryza, David; Berniard, Aurélie; Mowat, Pierre; Roux, Stéphane; Taleb, Jacqueline; Bonazza, Pauline; Perriat, Pascal; Lux, François; Tillement, Olivier; Billotey, Claire; Janier, Marc

    2013-09-01

    Gadolinium-based nanoparticles are novel objects with interesting physical properties, allowing their use for diagnostic and therapeutic applications. Gadolinium-based nanoparticles were imaged following intravenous injection in healthy rats and rats grafted with 9L gliosarcoma tumors using magnetic resonance imaging and scintigraphic imaging. Quantitative biodistribution using gamma-counting of each sampled organ confirmed that these nanoparticles were rapidly cleared essentially by renal excretion. Accumulation of these nanoparticles in 9L gliosarcoma tumors implanted in the rat brain was quantitated. This passive and long-duration accumulation of gadolinium-based nanoparticles in tumor, which is related to disruption of the blood-brain barrier, is in good agreement with the use of these nanoparticles as radiosensitizers for brain tumors.

  19. Measurement of gamma-ray production from thermal neutron capture on gadolinium for neutrino experiments

    NASA Astrophysics Data System (ADS)

    Yano, Takatomi

    2017-02-01

    Recently, several scientific applications of gadolinium are found in neutrino physics experiments. Gadolinium-157 is the nucleus, which has the largest thermal neutron capture cross-section among all stable nuclei. Gadolinium-155 also has the large cross-section. These neutron capture reactions provide the gamma-ray cascade with the total energy of about 8 MeV. This reaction is applied for several neutrino experiments, e.g. reactor neutrino experiments and Gd doped large water Cherenkov detector experiments, to recognize inverse-beta-decay reaction. A good Gd(n,γ) simulation model is needed to evaluate the detection efficiency of the neutron capture reaction, i.e. the efficiency of IBD detection. In this presentation, we will report the development and study status of a Gd(n,γ) calculation model and comparison with our experimental data taken at ANNRI/MLF beam line, J-PARC.

  20. 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

  1. Modeling gadolinium-bearing fuel in Ringhals PWRs using CASMO/SIMULATE

    SciTech Connect

    Kurcyusz, E. )

    1993-01-01

    Ringhals units 2, 3, and 4 are Westinghouse three-loop, 157-assembly pressurized water reactors (PWRs) operated by Vattenfall. Originally, all three reactors were loaded in an out-in scheme using reload fuel without burnable poisons. In recent cycles, gadolinium-bearing fuel was introduced to enable a low-leakage loading pattern and minimize fuel cycle costs. This paper focuses on the Fragema 17 x 17 AFA design with peripheral gadolinium rods loaded in units 3 and 4. The Ringhals units are modeled using the Studsvik core management system, consisting of the CASMO-3 transport theory lattice physics code,and the SIMULATE-3 advanced nodal reactor analysis code. The results of the studies verifying the accuracy of CASMO-3/SIMULATE-3 on the assemblies with peripheral gadolinium rods are presented in this paper. The verification was carried out against CASMO-3 color-set calculations and measured reactor data.

  2. 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.

  3. 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

  4. Dislocation associated incubational domain formation in lightly gadolinium-doped ceria.

    PubMed

    Li, Zhi-Peng; Mori, Toshiyuki; Ye, Fei; Ou, Ding Rong; Zou, Jin; Drennan, John

    2011-02-01

    Nanosized incubational domain was observed in 10 at.% gadolinium-doped ceria (GDC) using high-resolution transmission electron microscopy. Dislocations were extensively observed in 10 at.% GDC instead of heavily doped 25 at.% GDC. By Fast Fourier Transform and Inverse Fast Fourier Transform analysis, it was noticed that the incubational domain existing in 10 at.% GDC has different lattice spacing and orientation from the neighboring ceria matrix. Furthermore, dislocations were usually observed in the interface region between the incubational domain and the ceria matrix. Based on experimental results, the formation mechanism of dislocation associated incubational domain in lightly gadolinium-doped ceria is rationalized.

  5. 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.

  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.

  7. Gadolinium-conjugated gold nanoshells for multimodal diagnostic imaging and photothermal cancer therapy.

    PubMed

    Coughlin, Andrew J; Ananta, Jeyarama S; Deng, Nanfu; Larina, Irina V; Decuzzi, Paolo; West, Jennifer L

    2014-02-12

    Multimodal imaging offers the potential to improve diagnosis and enhance the specificity of photothermal cancer therapy. Toward this goal, gadolinium-conjugated gold nanoshells are engineered and it is 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.

  8. 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.

  9. 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

  10. Magnetic studies of a detonation nanodiamond with the surface modified by gadolinium ions

    NASA Astrophysics Data System (ADS)

    Osipov, V. Yu.; Aleksenskiy, A. E.; Takai, K.; Vul', A. Ya.

    2015-11-01

    The diamond nanoparticle surface is modified with Gd(III) ions by ion exchange with carboxyl group protons during the reaction of nanodiamond hydrosol with an aqueous solution of gadolinium nitrate. The results of the study by electron paramagnetic resonance and static magnetization measurements at low temperatures confirm the attachment of gadolinium ions to the surface of the diamond particle ˜5 nm in size. A spatial model of the arrangement of ions, in which the ion is located away from the surface by no more than 0.4 nm, is proposed.

  11. Dark-blood late gadolinium enhancement without additional magnetization preparation.

    PubMed

    Holtackers, Robert J; Chiribiri, Amedeo; Schneider, Torben; Higgins, David M; Botnar, René M

    2017-08-23

    This study evaluates a novel dark-blood late gadolinium enhancement (LGE) cardiovascular magnetic resonance imaging (CMR) method, without using additional magnetization preparation, and compares it to conventional bright-blood LGE, for the detection of ischaemic myocardial scar. LGE is able to clearly depict myocardial infarction and macroscopic scarring from viable myocardium. However, due to the bright signal of adjacent left ventricular blood, the apparent volume of scar tissue can be significantly reduced, or even completely obscured. In addition, blood pool signal can mimic scar tissue and lead to false positive observations. Simply nulling the blood magnetization by choosing shorter inversion times, leads to a negative viable myocardium signal that appears equally as bright as scar due to the magnitude image reconstruction. However, by combining blood magnetization nulling with the extended grayscale range of phase-sensitive inversion-recovery (PSIR), a darker blood signal can be achieved whilst a dark myocardium and bright scar signal is preserved. LGE was performed in nine male patients (63 ± 11y) using a PSIR pulse sequence, with both conventional viable myocardium nulling and left ventricular blood nulling, in a randomized order. Regions of interest were drawn in the left ventricular blood, viable myocardium, and scar tissue, to assess contrast-to-noise ratios. Maximum scar transmurality, scar size, circumferential scar angle, and a confidence score for scar detection and maximum transmurality were also assessed. Bloch simulations were performed to simulate the magnetization levels of the left ventricular blood, viable myocardium, and scar tissue. Average scar-to-blood contrast was significantly (p < 0.001) increased by 99% when nulling left ventricular blood instead of viable myocardium, while scar-to-myocardium contrast was maintained. Nulling left ventricular blood also led to significantly (p = 0.038) higher expert confidence in scar detection

  12. 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.

  13. 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}.

  14. Syntheses, structures, magnetism, and optical properties of gadolinium scandium chalcogenides

    SciTech Connect

    Jin Gengbang; Choi, Eun Sang; Albrecht-Schmitt, Thomas E.

    2009-05-15

    Three gadolinium scandium chalcogenides have been synthesized using Sb{sub 2}Q{sub 3} (Q=S, Se) fluxes at 975 deg. C. Gd{sub 3.04}Sc{sub 0.96}S{sub 6}, GdScS{sub 3}, and Gd{sub 1.05}Sc{sub 0.95}Se{sub 3} are crystallized in U{sub 3}ScS{sub 6} type, GdFeO{sub 3} type, and UFeS{sub 3} type structures, respectively. The magnetic susceptibilities for these compounds follow the Curie-Weiss law above their transition temperatures. The effective magnetic moments are close to calculated values for free Gd{sup 3+} ions. The Weiss constants for Gd{sub 3.04}Sc{sub 0.96}S{sub 6}, GdScS{sub 3}, and Gd{sub 1.05}Sc{sub 0.95}Se{sub 3} are determined to be -3.3(1), -4.5(4), and 1.5(1) K, respectively. Gd{sub 3.04}Sc{sub 0.96}S{sub 6} orders antiferromagnetically below 9 K. GdScS{sub 3} exhibits an antiferromagnetic ordering below 3 K with a weak ferromagnetism. Gd{sub 1.05}Sc{sub 0.95}Se{sub 3} undergoes a ferromagnetic transition around 5 K. The optical band gaps for Gd{sub 3.04}Sc{sub 0.96}S{sub 6}, GdScS{sub 3}, and Gd{sub 1.05}Sc{sub 0.95}Se{sub 3} are 1.5, 2.1, and 1.2 eV, respectively. - Graphical abstract: A view of the three-dimensional structure of Gd{sub 3.04}Sc{sub 0.96}S{sub 6} along the c axis.

  15. A Manganese Alternative to Gadolinium for MRI Contrast

    PubMed Central

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

    2016-01-01

    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 amongst the most stable Mn(II) complexes at pH 7.4 (log KML = 11.40). In the presence of 25 mol equiv. 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 24h. [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 analog, 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 hr. [Mn(PyC3A)(H2O)]- is a lead development candidate for an imaging probe that is compatible with renally compromised patients. PMID:26588204

  16. Tissue deposition of gadolinium and development of NSF: a convergence of factors.

    PubMed

    Perazella, Mark A

    2008-01-01

    Gadolinium-based contrast (GBC) exposure has recently been linked to the development of nephrogenic systemic fibrosis (NSF) in patients with underlying kidney disease and may in fact be the previously unrecognized trigger for the fibrosing process. As NSF is fairly rare in this patient population, a number of permissive factors are likely required for GBC exposure to initiate fibrosis. Advanced kidney disease is an absolute requirement whereas vascular injury and an inflammatory state, and a mix of co-factors including increased serum phosphate and calcium concentrations and iron overload further enhance risk. The combination of these events allows excess circulating gadolinium, which dissociates from its chelate to leak out of vessels and deposit in tissues. Free or bound tissue gadolinium, a rare earth metal of the lanthanoid series, promotes fibrosis via either direct binding to the collagen helix or, once the metal has been engulfed by macrophages, through the production of free oxygen radicals, cytokines, and other profibrotic factors that attract circulating fibrocytes to tissues. These fibrocytes then differentiate into fibroblast-like spindle cells that produce connective tissue matrix and other angiogenic and growth factors that further enhance tissue fibrosis. Direct gadolinium activation of transglutaminases on these tissue fibroblast-like cells may also promote fibrosis.

  17. A Polymeric Fastener can Easily Functionalize Liposome Surfaces with Gadolinium for Enhanced Magnetic Resonance Imaging

    PubMed Central

    Smith, Cartney E.; Shkumatov, Artem; Withers, Sarah G.; Glockner, James F.; Misra, Sanjay; Roy, Edward J.; Wong, Chun-Ho; Zimmerman, Steven C.; Kong, Hyunjoon

    2013-01-01

    Common methods of loading magnetic resonance imaging (MRI) contrast agents into nanoparticles often suffer from challenges related to particle formation, complex chemical modification/purification steps, and reduced contrast efficiency. This study presents a simple, yet advanced process to address these issues by loading gadolinium, an MRI contrast agent, exclusively on a liposome surface using a polymeric fastener. The fastener, so named for its ability to physically link the two functional components together, consisted of chitosan substituted with diethylenetriaminepentaacetic acid (DTPA) to chelate gadolinium, as well as octadecyl chains to stabilize the modified chitosan on the liposome surface. The assembly strategy, mimicking the mechanisms by which viruses and proteins naturally anchor to a cell, provided greater T1 relaxivity than liposomes loaded with gadolinium in both the interior and outer leaflet. Gadolinium-coated liposomes were ultimately evaluated in vivo using murine ischemia models to highlight the diagnostic capability of the system. Taken together, this process decouples particle assembly and functionalization, and therefore has considerable potential to enhance imaging quality while alleviating many of the difficulties associated with multifunctional particle fabrication. PMID:24083377

  18. [Physico-chemical and toxicological profile of gadolinium chelates as contrast agents for magnetic resonance imaging].

    PubMed

    Idée, J-M; Fretellier, N; Thurnher, M M; Bonnemain, B; Corot, C

    2015-07-01

    Gadolinium chelates (GC) are contrast agents widely used to facilitate or to enable diagnosis using magnetic resonance imaging (MRI). From a regulatory viewpoint, GC are drugs. GC have largely contributed to the success of MRI, which has become a major component of clinician's diagnostic armamentarium. GC are not metabolised and are excreted by the kidneys. They distribute into the extracellular compartment. Because of its high intrinsic toxicity, gadolinium must be administered as a chelate. GC can be classified according to two key molecular features: (a) nature of the chelating moiety: either macrocyclic molecules in which gadolinium is caged in the pre-organized cavity of the ligand, or linear, open-chain molecules, (b) ionicity: Gd chelates can be ionic (meglumine or sodium salts) or non-ionic. The thermodynamic and kinetic stabilities of the various GCs differ according to these structural characteristics. The kinetic stability of macrocyclic GCs is much higher than that of linear GCs and the thermodynamic stability of ionic GCs is generally higher than that of non-ionic GC, thus leading to a lower risk of gadolinium dissociation. This class of drugs has enjoyed an excellent reputation in terms of safety for a long time, until a causal link with a recently-described serious disease, nephrogenic systemic fibrosis (NSF), was evidenced. It is acknowledged that the vast majority of NSF cases are related to the administration of some linear CG in renally-impaired patients. Health authorities, worldwide, released recommendations which drastically reduced the occurrence of new cases.

  19. Gadolinium chloride as a contrast agent for imaging wood composite components by magnetic resonance

    Treesearch

    Thomas L. Eberhardt; Chi-Leung So; Andrea Protti; Po-Wah So

    2009-01-01

    Although paramagnetic contrast agents have an established track record in medical uses of magnetic resonance imaging (MRI), only recently has a contrast agent been used for enhancing MRI images of solid wood specimens. Expanding on this concept, wood veneers were treated with a gadolinium-based contrast agent and used in a model system comprising three-ply plywood...

  20. Use of gadolinium chloride as a contrast agent for imaging spruce knots by magnetic resonance

    Treesearch

    Thomas L. Eberhardt; Chi-Leung So; Amy H. Herlihy; Po-Wah So

    2006-01-01

    Treatments of knot-containing spruce wood blocks with a paramagnetic salt, gadolinium (III) chloride, in combination with solvent pretreatments, were evaluated as strategies to enhance the visualization of wood features by magnetic resonance imaging (MRI). Initial experiments with clear wood and excised knot samples showed differences in moisture uptake after...

  1. Gadolinium-enhanced computed tomography cystogram to diagnose bladder augment rupture in patients with iodine sensitivity.

    PubMed

    Newport, John Paul; Dusseault, Beau N; Butler, Carina; Pais, Vernon M

    2008-05-01

    Anaphylactic reaction to iodinated contrast is a potentially life-threatening complication of diagnostic imaging studies. We report the successful use of gadolinium as an alternative contrast agent for computed tomography cystogram in a patient with a history of anaphylactic reaction to iodinated contrast. This technique allowed us rapidly to diagnose a rupture of her bladder augmentation and pursue operative repair.

  2. Gadolinium-labeled quantum dots for molecular magnetic resonance imaging: R1 versus R2 mapping.

    PubMed

    Oostendorp, Marlies; Douma, Kim; Hackeng, Tilman M; Post, Mark J; van Zandvoort, Marc A M J; Backes, Walter H

    2010-07-01

    Quantum dots labeled with paramagnetic gadolinium chelates can be applied as contrast agent for preclinical molecular MRI combined with fluorescence microscopy. Besides increasing the longitudinal relaxation rate, gadolinium-labeled quantum dots may increase the transverse relaxation rate, which might be related to their magnetic properties. Furthermore, molecular MRI experiments are primarily conducted at high magnetic fields, where longitudinal relaxation rate becomes less effective, and the use of transverse relaxation rate as a source of contrast may become attractive. Consequently, the optimal method of contrast enhancement using gadolinium-labeled quantum dots is a priori unknown. The objective of this study was to compare longitudinal relaxation rate- and transverse relaxation rate-based contrast enhancement, proton visibility, and changes thereof induced by gadolinium-labeled quantum dots targeted to the angiogenic vasculature of murine tumors, using in vivo longitudinal and transverse relaxation rate mapping. At a field strength of 7 T, longitudinal relaxation rate-based measures were superior to transverse relaxation rate-based measures in detecting both the level and spatial extent of contrast agent-induced relaxation rate changes. (c) 2010 Wiley-Liss, Inc.

  3. Removal of gadolinium, a neutron poison from the moderator system of nuclear reactors.

    PubMed

    Rufus, A L; Kumar, Padma S; Jeena, K; Velmurugan, S

    2017-08-03

    Gadolinium as gadolinium nitrate is used as neutron poison in the moderator system for regulating and controlling the power generation of Pressurized Heavy Water Reactors (PHWR) and proposed to be used in Advanced Heavy Water Reactors (AHWR) owing to its high neutron absorption cross section. Removal of the added gadolinium nitrate (Gd(3+) and NO3(-)) from the system after its intended use is done using ion exchange resins. In the present investigation, attempts have been made to optimize the ion exchange process for generation of low radioactive waste and maximize utilization of the ion exchange resins by employing different types of resins and different modes of operation. The investigations revealed that use of mixed bed (MB) resin column consisting of Strong Acid Cation (SAC) resin and Strong Base Anion (SBA) resin followed by SAC resin column is efficient in removing the Gd(3+) and NO3(-) from the system besides maintaining the pH of the moderator system in the desirable regime, where gadolinium does not get precipitated as its hydroxide. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Preparation of 152Gd targets from a small quantity of gadolinium oxide in a pyrochemical reaction

    NASA Astrophysics Data System (ADS)

    Lipski, A. R.

    1995-02-01

    A simple method utilizing small amounts (< 5 mg) of isotopically enriched material for the production of gadolinium targets is discussed. An electrostatically focused e-gun is used in the procedure in which 152Gd 2O 3 powder undergoes reduction-distillation and deposition onto an Fe foil.

  5. Myocardial late gadolinium enhancement in specific cardiomyopathies by cardiovascular magnetic resonance: a preliminary experience.

    PubMed

    Silva, Caterina; Moon, James C; Elkington, Andrew G; John, Anna S; Mohiaddin, Raad H; Pennell, Dudley J

    2007-12-01

    Late gadolinium enhancement cardiovascular magnetic resonance (CMR) can visualize myocardial interstitial abnormalities. The aim of this study was to assess whether regions of abnormal myocardium can also be visualized by late enhancement gadolinium CMR in the specific cardiomyopathies. A retrospective review of all referrals for gadolinium CMR with specific cardiomyopathy over 20 months. Nine patients with different specific cardiomyopathies were identified. Late enhancement was demonstrated in all patients, with a mean signal intensity of 390 +/- 220% compared with normal regions. The distribution pattern of late enhancement was unlike the subendocardial late enhancement related to coronary territories found in myocardial infarction. The affected areas included papillary muscles (sarcoid), the mid-myocardium (Anderson-Fabry disease, glycogen storage disease, myocarditis, Becker muscular dystrophy) and the global sub-endocardium (systemic sclerosis, Loeffler's endocarditis, amyloid, Churg-Strauss). Focal myocardial late gadolinium enhancement is found in the specific cardiomyopathies, and the pattern is distinct from that seen in infarction. Further systematic studies are warranted to assess whether the pattern and extent of late enhancement may aid diagnosis and prognostic assessment.

  6. Criticality experiments with low enriched UO/sub 2/ fuel rods in water containing dissolved gadolinium

    SciTech Connect

    Bierman, S.R.; Murphy, E.S.; Clayton, E.D.; Keay, R.T.

    1984-02-01

    The results obtained in a criticality experiments program performed for British Nuclear Fuels, Ltd. (BNFL) under contract with the United States Department of Energy (USDOE) are presented in this report along with a complete description of the experiments. The experiments involved low enriched UO/sub 2/ and PuO/sub 2/-UO/sub 2/ fuel rods in water containing dissolved gadolinium, and are in direct support of BNFL plans to use soluble compounds of the neutron poison gadolinium as a primary criticality safeguard in the reprocessing of low enriched nuclear fuels. The experiments were designed primarily to provide data for validating a calculation method being developed for BNFL design and safety assessments, and to obtain data for the use of gadolinium as a neutron poison in nuclear chemical plant operations - particularly fuel dissolution. The experiments program covers a wide range of neutron moderation (near optimum to very under-moderated) and a wide range of gadolinium concentration (zero to about 2.5 g Gd/l). The measurements provide critical and subcritical k/sub eff/ data (1 greater than or equal to k/sub eff/ greater than or equal to 0.87) on fuel-water assemblies of UO/sub 2/ rods at two enrichments (2.35 wt % and 4.31 wt % /sup 235/U) and on mixed fuel-water assemblies of UO/sub 2/ and PuO/sub 2/-UO/sub 2/ rods containing 4.31 wt % /sup 235/U and 2 wt % PuO/sub 2/ in natural UO/sub 2/ respectively. Critical size of the lattices was determined with water containing no gadolinium and with water containing dissolved gadolinium nitrate. Pulsed neutron source measurements were performed to determine subcritical k/sub eff/ values as additional amounts of gadolinium were successively dissolved in the water of each critical assembly. Fission rate measurements in /sup 235/U using solid state track recorders were made in each of the three unpoisoned critical assemblies, and in the near-optimum moderated and the close-packed poisoned assemblies of this fuel.

  7. High sensitivity of late gadolinium enhancement for predicting microscopic myocardial scarring in biopsied specimens in hypertrophic cardiomyopathy.

    PubMed

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

    2014-01-01

    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. 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). 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 hypertrophic cardiomyopathy.

  8. 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

  9. Nickel-based Gadolinium Alloy for Neutron Adsorption Application in Ram Packages

    SciTech Connect

    Gregg Wachs; James Sterbentz; William Hurt; P. E. McConnell; C. V. Robino; F. Tovesson; T. S. Hill

    2007-10-01

    Neutron transmission experiments were performed on samples of an advanced nickel-chromium-molybdenum-gadolinium (Ni-Cr-Mo-Gd) neutron absorber alloy and chromium-nickel (Cr-Ni) stainless steel, modified by the addition of boron. The primary purpose of the experiments was to demonstrate the thermal neutron absorbing capability of the materials at specific gadolinium and boron dopant levels. The Ni-Cr-Mo-Gd alloy is envisioned to be deployed for criticality control of highly enriched U.S. Department of Energy (DOE)-owned spent nuclear fuel (SNF). For these transmission experiments, test samples were fabricated with 0.0, 1.58 and 2.1 wt% natural gadolinium dispersed in a Ni-Cr-Mo base alloy and 1.16 wt% boron in stainless steel. 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 total neutron cross sections. Excellent agreement between the measured and calculated results demonstrated the expected strong thermal absorption capability of the gadolinium and boron elements and in addition, verified the measured elemental composition of the Ni-Cr-Mo-Gd alloy and borated stainless steel test samples. The good agreement also indirectly confirmed that the size and distribution of the gadolinium in both the hot-top (as-cast) and Ni-Cr-Mo-Gd converted to plate was not a discriminator related to neutron absorption. Moreover, the Evaluated Nuclear Data File (ENDF VII) total neutron cross section data were accurate.

  10. 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.

  11. Impact of gadolinium-157 containing nanoscale magnetosensitive composites on morfofunctional properties of cells in vitro.

    PubMed

    Lavrenchuk, H Y; Shevchenko, Y B; Petranovska, A L; Asmolkova, V S; Oksamytnyi, V M; Kozlovska, I V; Yavorska, O H

    2014-09-01

    Objective - to investigate the morphofunctional cells properties under the action of magneticallybased nanocomposites containing gadolinium-157. Materials and methods. Experimental studies are performed in cell culture line L929 Nanocomposites based on magnetite modified by functional amino groups chemically fixed by diethylenetriaminepentaacetic acid (DTPA) and gadolinium - (Fe3O4/γ-APS/DTPA-Gd) were studied (1), also by meso-2,3-dimercaptosuccinic acid (DMSA) - (Fe3O4/DMSA-Gd), which binds to the hydroxyl group of magnetite surface (2); gadolinium was adsorbed from a solution of gadolinium sulfate. Reagent 3 - magnetic substance Fe3O4 with sodium oleate. Morphofunctional characteristics of cell culture were evaluated in various terms by standard indicators of sustainability: proliferative and mitotic activity and the number of giant multinuclear cells, apoptosis. Results and conclusions. We established that magnetdriven nanocomposites with gadolinium modified by DTPA and DMSA, were more biocompatibile to cells: incubation of cells with neutron capture agents (NCA) in the studied range of concentrations showed no toxicity, except maximum concentration, while decreasing cells adhesive properties. For all nanocomposites we observed decrease in mitotic activity in the background of the control cell population density, which may indicate synchronization of cell division. We found that the stabilized by sodium oleate ferrite caused destructive changes in cell culture only at concentrations of 500 μg / ml, but reduced mitotic activity in cell culture in 3-5 times in the whole range of concentrations. It is shown that magnetdriven nanocomposites induce different levels of apoptosis in cultured cells depending on the concentration of the reactants.

  12. Pressure-Induced Phase Transitions In Gadolinium Iron Borate

    NASA Astrophysics Data System (ADS)

    Kharlamova, S. A.; Struzhkin, V. V.; Sinogeikin, S. V.; Gavriliuk, A. G.; Brown, D.; Toellner, T.; Zhao, J.; Lerche, M.; Lyubutin, I. S.; Ovchinnikov, S. G.; Alp, E. E.; Sturhahn, W.

    2007-12-01

    An understanding of spin crossover (SC) dynamics is relevant to understanding of a role or participation of SC in natural systems including lower Mantle minerals, heme proteins as well as from fundamental science of view. For example, pressure-induced electronic spin transitions of Fe2+ and Fe3+ iron occur in magnesiowustite, silicate perovskite and post-perovskite which are abundant minerals in the Earth's lower mantle [1-3]. Such a SC phenomenon has recently been observed in a number of magnetic minerals FeBO3 [4, 5], BiFeO3 [6], Fe2O3 [7], and Y3Fe5O12 [8], (La, Pr)FeO3 [9, 10]. In those cases, iron ions are in the trivalent state Fe3+ and the high-spin-low-spin (HS-LS) crossover is manifested as the collapse of the local magnetic moment and as the transition of the antiferromagnet to a paramagnetic state. For example, in FeBO3 at low temperatures a spin-crossover and some magnetic transitions with two triple points were found [4, 5]. Gadolinium iron borate, GdFe3(BO3)4 is also a system with SEC and recently, we have reported on phase transitions induced by high pressures in this material [11, 12]. We studied the structural and magnetic behavior of GdFe573(BO3)4 at high pressures and temperatures using a diamond anvil cell and a Synchrotron Mossbauer Spectroscopy technique. The hyperfine parameters and results obtained from the experiments are discussed. Based on our experimental data and theoretical calculation a tentative magnetic P-T phase diagram and an equation of states of GdFe573(BO3)4 are proposed. Important features of the phase diagram are a spin crossover, insulator-semiconductor transition and possible presence of two triple points where magnetic and paramagnetic phases of the high-spin and low-spin states coexist. 1. J. Badro, J.-P. Rueff, G. Vankó, et al., Science 305, 383 (2004). 2. J. M. Jackson, W. Sturhahn, G. Shen, et al., American Mineralogist 90, 199 (2005). 3. J.Li, V.V. Struzhkin, H.-K. Mao, et al., PNAS 101, 14027 (2004). 4. I.A. Troyan

  13. Comparison of an amorphous silicon/cesium iodide flat-panel digital chest radiography system with screen/film and computed radiography systems--a contrast-detail phantom study.

    PubMed

    Rong, X J; Shaw, C C; Liu, X; Lemacks, M R; Thompson, S K

    2001-11-01

    Flat-panel (FP) based digital radiography systems have recently been introduced as a new and improved digital radiography technology; it is important to evaluate and compare this new technology with currently widely used conventional screen/film (SF) and computed radiography (CR) techniques. In this study, the low-contrast performance of an amorphous silicon/cesium iodide (aSi/Csl)-based flat-panel digital chest radiography system is compared to those of a screen/film and a computed radiography system by measuring their contrast-detail curves. Also studied were the effects of image enhancement in printing the digital images and dependence on kVp and incident exposure. It was found that the FP system demonstrated significantly better low-contrast performance than the SF or CR systems. It was estimated that a dose savings of 70%-90% could be achieved to match the low-contrast performance of the FP images to that of the SF images. This dose saving was also found to increase with the object size. No significant difference was observed in low-contrast performances between the SF and CR systems. The use of clinical enhancement protocols for printing digital images was found to be essential and result in better low-contrast performance. No significant effects were observed for different kVps. From the results of this contrast-detail phantom study, the aSi/CsI-based flat-panel digital chest system should perform better under clinical situations for detection of low-contrast objects such as lung nodules. However, proper processing prior to printing would be essential to realizing this better performance.

  14. 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.

  15. 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.

  16. Nanoamplifiers synthesized from gadolinium and gold nanocomposites for magnetic resonance imaging.

    PubMed

    Tian, Xiumei; Shao, Yuanzhi; He, Haoqiang; Liu, Huan; Shen, Yingying; Huang, Wenlin; Li, Li

    2013-04-21

    We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential.

  17. Frontiers of X-ray spectromicroscopy in biology and medicine: Gadolinium in brain cancer

    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.

    2000-02-01

    We present the first feasibility test of spectromicroscopy on the microlocalization of gadolinium in brain cancer tissue. A gadolinium compound was injected to the patients before the brain tumor was extracted with surgery, and we looked for Gd in the tumor tissue. The goal of the experiment was to understand if Gd Neutron Capture Therapy (GdNCT) is viable for clinical tests, i.e. if there is enough Gd, and it is localized near the nuclei of tumor cells. The experiments were performed using the MEPHISTO X-ray PhotoElectron Emission Microscope (X-PEEM) at the Wisconsin Synchrotron Radiation Center. The present results demonstrate the feasibility of the experiment, and suggest how to improve the sample preparation and data acquisition to achieve the goal.

  18. 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.

  19. Renal function, nephrogenic systemic fibrosis and other adverse reactions associated with gadolinium-based contrast media.

    PubMed

    Canga, Ana; Kislikova, Maria; Martínez-Gálvez, María; Arias, Mercedes; Fraga-Rivas, Patricia; Poyatos, Cecilio; de Francisco, Angel L M

    2014-01-01

    Nephrogenic systemic fibrosis is a fibrosing disorder that affects patients with impaired renal function and is associated with the administration of gadolinium-based contrast media used in MRI. Despite being in a group of drugs that were considered safe, report about this potentially serious adverse reaction was a turning point in the administration guidelines of these contrast media. There has been an attempt to establish safety parameters to identify patients with risk factors of renal failure. The close pharmacovigilance and strict observation of current regulations, with special attention being paid to the value of glomerular filtration, have reduced the published cases involving the use of gadolinium-based contrast media. In a meeting between radiologists and nephrologists we reviewed the most relevant aspects currently and recommendations for its prevention.

  20. Regression of gadolinium-enhanced lesions in patients affected by neurofibromatosis type 1.

    PubMed

    Lucchetta, Marta; Manara, Renzo; Perilongo, Giorgio; Clementi, Maurizio; Trevisson, Eva

    2016-03-01

    Neurofibromatosis type I is a genetic condition with an autosomal dominant transmission characterized by neurocutaneous involvement and a predisposition to tumor development. Central nervous system manifestations include benign areas of dysmyelination and possibly hazardous glial tumors whose clinical management may result challenging. Here, we report on three patients diagnosed with Neurofibromatosis type I whose brain MRI follow-up showed the presence of gadolinium-enhancing lesions which spontaneously regressed. In none of the three cases, the lesions showed any clinical correlate and eventually presented a striking reduction in size while gadolinium enhancement disappeared despite no specific therapy administration during the follow-up. Although their nature remains undetermined, these lesions presented a benign evolution. However, they might be misdiagnosed as potentially life-threatening tumors. Hitherto, a similar behavior has been described only in scattered cases and we believe these findings may be of particular interest for the clinical management of patients affected by neurofibromatosis type I.

  1. The role of gadolinium chelates in the mechanism of nephrogenic systemic fibrosis: A critical update.

    PubMed

    Idée, Jean-Marc; Fretellier, Nathalie; Robic, Caroline; Corot, Claire

    2014-11-01

    Nephrogenic systemic fibrosis (NSF) is an iatrogenic scleroderma-like fibrosing systemic disorder occurring in patients with severe or end-stage renal disease. It was established as a new clinical entity in the year 2000. A causal role for gadolinium chelates (GC), widely used as contrast agents for magnetic resonance imaging, was suggested six years later. It rapidly appeared that the occurrence of NSF was associated with prior administration of GCs with lower thermodynamic stability, leading to warnings being published by health authorities and learned societies worldwide. Although a role for the chelated form of the less stable GCs has been proposed, the most commonly accepted hypothesis involves the gradual release of dissociated gadolinium in the body, leading to systemic fibrosis. However, the entire chain of events is still not fully understood in a causal way and many uncertainties remain.

  2. The performance of hafnium and gadolinium self powered neutron detectors in the TREAT reactor

    NASA Astrophysics Data System (ADS)

    Imel, G. R.; Hart, P. R.

    1996-05-01

    The use of gadolinium and hafnium self powered neutron detectors in a transient reactor is described in this paper. The detectors were calibrated to the fission rate of U-235 using calibrated fission chambers; the calibration factors were tested in two reactors in steady state and found to be consistent. Calibration of the detectors in transient reactor conditions was done by using uranium wires that were analyzed by radiochemistry techniques to determine total fissions during the transient. This was correlated to the time-integrated current of the detectors during the transient. A temperature correction factor was derived to account for self-shielding effects in the hafnium and gadolinium detectors. The dynamic response of the detectors under transient conditions was studied, and found to be excellent.

  3. A new gadolinium-loaded liquid scintillator for reactor neutrino detection

    NASA Astrophysics Data System (ADS)

    Ding, Yayun; Zhang, Zhiyong; Liu, Jinchang; Wang, Zhimin; Zhou, Pengju; Zhao, Yuliang

    2008-01-01

    A high flash point, low toxicity gadolinium-loaded liquid scintillator (Gd-LS) has been developed for the detection of reactor neutrino. Carboxylic acid 3,5,5-trimethylhexanoic acid is used as complexing ligand to form organo-complex with gadolinium chloride, and 2,5-diphenyloxazole (PPO), and 1,4-bis[2-methylstyryl]benzene (bis-MSB) are used as primary fluor and wavelength shifter, respectively. The scintillator base is linear alkyl benzene (LAB). The Gd-LS prepared with such recipe has long attenuation length, high light yield and long-term stability. Eight hundred liters of Gd-LS (1 g/L Gd) was synthesized and tested in a prototype detector at Institute of High Energy Physics. Preliminary results of the obviously peaks corresponding to neutron captured by H and Gd give an additional evidence that such Gd-LS are very promising for anti-neutrino detection.

  4. 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.

  5. 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.

  6. The statistical decay properties of Gadolinium isotopes using the DANCE array

    NASA Astrophysics Data System (ADS)

    Dashdorj, D.; Mitchell, G.; Baramsai, B.; Chankova, R.; Chyzh, A.; Walker, C.

    2008-10-01

    The gadolinium isotopes are interesting for reactor applications as well as for medicine and astrophysics. There are seven stable isotopes of gadolinium with varying deformation. Decay γ 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 γ-ray multiplicity measurements. The calorimetric property 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 γ-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.

  7. Gadolinium/terbium hybrid macromolecular complexes for bimodal imaging of atherothrombosis

    NASA Astrophysics Data System (ADS)

    Nghĩa, Nguyen Tráeng; Tinet, Eric; Ettori, Dominique; Beilvert, Anne; Pavon-Djavid, Graciela; Maire, Murielle; Ou, Phalla; Tualle, Jean-Michel; Chaubet, Frédéric

    2017-07-01

    We developed a fluorescence imaging microscope system intended for the localization within artery slices of a gadolinium-based macromolecular biospecific magnetic resonance (MR) contrast agent used for the visualization of atherothrombosis. As the contrast agent is not initially fluorescent, we substitute some gadolinium ions for terbium ions to make them fluorescent while preserving their chemical characteristics. A long fluorescence emission time constant enables us to have a suitable signal-to-noise ratio, despite a low intensity, using pulsed illumination and time-gated imaging. Images of rat arteries show that the contrast agent is indeed localized on the specific regions of the tissues. We currently have a tool that allows us to understand and optimize the MR contrast agent.

  8. Macroscopic and Microscopic Investigation of Densification Behavior for Gadolinium-doped Ceria upon Sintering

    NASA Astrophysics Data System (ADS)

    Kosaka, T.; Sato, K.

    2011-10-01

    The densification behaviour of Gadolinium-doped ceria (GDC) upon sintering is investigated from macroscopic and microscopic points of view. The time-resolved length-change measurement with high-resolution dilatometry and positron lifetime spectroscopy are conducted. Positron lifetime spectroscopy reveals the presence of nanovoids at grain boundaries in GDC. Time-dependent length-change measurement reveals that particle rearrangement occurs at the initial stage of sintering. Densifications at the sintering neck and inside the particle grain are discussed.

  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. 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.

  11. 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.

  12. 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.

  13. Highly absorbing gadolinium test device to characterize the performance of neutron imaging detector systems

    SciTech Connect

    Gruenzweig, C.; Frei, G.; Lehmann, E.; Kuehne, G.; David, C.

    2007-05-15

    We report on the fabrication and application of a novel neutron imaging test device made of gadolinium. It is designed for a real time evaluation of the spatial resolution, resolution direction, and distortions of a neutron imaging detector system. Measurements of the spatial resolution of {sup 6}LiF doped ZnS scintillator screens with different thicknesses and of imaging plates were performed. The obtained results are in good agreement with comparison measurements using the standard knife edge detection method.

  14. Hearing function after intratympanic application of gadolinium-based contrast agent: A long-term evaluation.

    PubMed

    Louza, Julia; Krause, Eike; Gürkov, Robert

    2015-10-01

    The aim of this study was to evaluate the long-term influence of intratympanic gadolinium-based contrast agent on hearing function in patients with possible Ménière's disease and normal auditory thresholds who were undergoing locally enhanced magnetic resonance imaging scans. Prospective observational cohort study in a tertiary referral university hospital ear, nose, and throat department. Between 2009 and 2012, 17 patients with possible or probable Ménière's disease and a four-tone pure-tone average baseline of <25 dB were recruited for our study. Before undergoing intratympanic injection of gadolinium-based contrast agent, all patients underwent a complete audiological evaluation. The study population was then invited back after at least 6 months postinjection for a follow-up auditory evaluation. This consisted of comprehensive clinical and audiological tests on both sides and were evaluated according to the ototoxicity guidelines. A long-term evaluation of our study group revealed no significant difference in the air-conduction pure-tone average. Furthermore, no statistical difference at individual frequencies compared to baseline was found. There was no evidence of ototoxicity in the injected ear. Long-term hearing function assessment after intratympanic application of gadolinium-based agent showed no evidence of ototoxicity. The use of intratympanic gadolinium-based agent in the diagnosis of Ménièrés disease is currently a helpful tool, and seems to be a safe method, especially with regard to auditory function. 4. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

  15. Nanoamplifiers synthesized from gadolinium and gold nanocomposites for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Tian, Xiumei; Shao, Yuanzhi; He, Haoqiang; Liu, Huan; Shen, Yingying; Huang, Wenlin; Li, Li

    2013-03-01

    We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential.We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential. Electronic supplementary information

  16. Gadolinium thin films as benchmark for magneto-caloric thin films

    NASA Astrophysics Data System (ADS)

    Helmich, Lars; Bartke, Marianne; Teichert, Niclas; Schleicher, Benjamin; Fähler, Sebastian; Hütten, Andreas

    2017-05-01

    We report on the preparation of Gadolinium thin films by means of sputter deposition on Silicon Oxide wafers. A series of samples with different buffer layers and various substrate temperatures has been produced. The film on an amorphous Tantalum buffer deposited at 773 K shows the highest increase of magnetization during the phase transition at the Curie temperature. Further detailed analysis of the magnetic properties has been conducted by VSM.

  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. 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.

  19. Pulmonary vein inflow artifact reduction for free-breathing left atrium late gadolinium enhancement.

    PubMed

    Moghari, Mehdi H; Peters, Dana C; Smink, Jouke; Goepfert, Lois; Kissinger, Kraig V; Goddu, Beth; Hauser, Thomas H; Josephson, Mark E; Manning, Warren J; Nezafat, Reza

    2011-07-01

    Two-dimensional "pencil-beam" navigator, placed on the right hemidiaphragm, is used for free-breathing late gadolinium enhancement of the left atrium in patients with atrial fibrillation. The pencil-beam navigator creates an inflow artifact in the right pulmonary veins and atrial wall that may obscure local pulmonary vein and left atrium scars. To reduce this artifact, we propose a large slab right hemidiaphragm projection navigator that measures the respiratory motion while reducing the associated inflow artifact. Eighteen subjects underwent pulmonary vein late gadolinium enhancement using the pencil-beam and projection navigator. Subjective inflow and respiratory motion artifact scores (1 = severe, 2 = moderate, 3 = mild, and 4 = none) from two blinded readers were compared. The artifact scores were 3.8 ± 0.4 and 2.1 ± 0.7 for the projection and pencil-beam navigators, respectively (P < 0.001). Respiratory motion artifact scores were similar between the two techniques (3.0 ± 0.5 vs. 3.1 ± 0.5 for projection vs. pencil-beam navigator). The proposed method greatly reduces the inflow artifact in free-breathing pulmonary vein late gadolinium enhancement while allowing adequate respiratory motion compensation. Copyright © 2011 Wiley-Liss, Inc.

  20. Specific lipase-responsive polymer-coated gadolinium nanoparticles for MR imaging of early acute pancreatitis.

    PubMed

    Zhang, Hong-Wu; Wang, Li-Qin; Xiang, Qing-Feng; Zhong, Qian; Chen, Lu-Ming; Xu, Cai-Xia; Xiang, Xian-Hong; Xu, Bo; Meng, Fei; Wan, Yi-Qian; Deng, David Y B

    2014-01-01

    Currently, available methods for diagnosis of acute pancreatitis (AP) are mainly dependent on serum enzyme analysis and imaging techniques that are too low in sensitivity and specificity to accurately and promptly diagnose AP. The lack of early diagnostic tools highlights the need to search for a highly effective and specific diagnostic method. In this study, we synthesized a conditionally activated, gadolinium-containing, nanoparticle-based MRI nanoprobe as a diagnostic tool for the early identification of AP. Gadolinium diethylenetriaminepentaacetic fatty acid (Gd-DTPA-FA) nanoparticles were synthesized by conjugation of DTPA-FA ligand and gadolinium acetate. Gd-DTPA-FA exhibited low cytotoxicity and excellent biocompatibility when characterized in vitro and in vivo studies. L-arginine induced a gradual increase in the intensity of the T1-weighted MRI signal from 1 h to 36 h in AP rat models. The increase in signal intensity was most significant at 1 h, 6 h and 12 h. These results suggest that the Gd-DTPA-FA as an MRI contrast agent is highly efficient and specific to detect early AP.

  1. Gadolinium prevents high airway pressure-induced permeability increases in isolated rat lungs.

    PubMed

    Parker, J C; Ivey, C L; Tucker, J A

    1998-04-01

    To determine the initial signaling event in the vascular permeability increase after high airway pressure injury, we compared groups of lungs ventilated at different peak inflation pressures (PIPs) with (gadolinium group) and without (control group) infusion of 20 microM gadolinium chloride, an inhibitor of endothelial stretch-activated cation channels. Microvascular permeability was assessed by using the capillary filtration coefficient (Kfc), a measure of capillary hydraulic conductivity. Kfc was measured after ventilation for 30-min periods with 7, 20, and 30 cmH2O PIP with 3 cmH2O positive end-expiratory pressure and with 35 cmH2O PIP with 8 cmH2O positive end-expiratory pressure. In control lungs, Kfc increased significantly to 1.8 and 3.7 times baseline after 30 and 35 cmH2O PIP, respectively. In the gadolinium group, Kfc was unchanged from baseline (0.060 +/- 0.010 ml . min-1 . cmH2O-1 . 100 g-1) after any PIP ventilation period. Pulmonary vascular resistance increased significantly from baseline in both groups before the last Kfc measurement but was not different between groups. These results suggest that microvascular permeability is actively modulated by a cellular response to mechanical injury and that stretch-activated cation channels may initiate this response through increases in intracellular calcium concentration.

  2. [Dixon's technic for fat suppression. Its potential applications in combination with gadolinium-DTPA].

    PubMed

    Mascalchi, M; Battolla, L; Zampa, V; Falaschi, F; Caramella, D; Bartolozzi, C

    1994-01-01

    Modification of the Dixon technique enables the reconstruction of water and fat images operating at midfield strength. The technique was combined with intravenous administration of gadolinium-DTPA in five patients with lumbosacral spine conditions, four patients with soft tissue neoplasms and three with skeletal neoplasms; all patients were examined at 0.5 T. Mean attenuation of fat signal in T1-weighted images was 85% and implied a redistribution of the gray-scale dynamic range. This allowed easier appreciation of normal and abnormal enhancement in both areas containing fat tissue and areas without it. This was useful in the evaluation of fresh scars in two patients recently submitted to lamino-discectomy and of the prevertebral extension of the inflammatory process in one patient with spondylodiscitis. In the patients with soft tissue neoplasms the combination of fat suppression and Gadolinium was helpful to assess lesion size. Finally, in the patients with skeletal neoplasms fat-suppressed images obviated for the lesion disappearance observed on conventional T1-weighted SE images after contrast administration. The combination of intravenous administration of gadolinium-DPTA with Dixon's fat-suppression technique is a new promising capability of midfield MRI.

  3. [Natural history of lumbar disc hernias: does gadolinium enhancement have any prognostic value?].

    PubMed

    Ramos Amador, A; Alcaraz Mexía, M; González Preciado, J L; Fernández Zapardiel, S; Salgado, R; Páez, A

    2013-09-01

    To evaluate the percentage of disc hernias that have disappeared after one year of follow-up and the time to disappearance. To determine whether gadolinium enhancement is useful for predicting whether the hernia will disappear. To analyze whether the pattern of enhancement can help predict whether the fragment will disappear. This prospective study included 118 patients with acute symptoms of lumbosciatica and a herniated disc diagnosed by CT. In 72 patients, we performed gadolinium-enhanced MRI every 6 months for one year or until the herniation disappeared; we related the findings of protrusion, extrusion, and the enhancement pattern with the disappearance or persistence of herniated disc material. We analyzed the results with univariate and multivariate statistics. The 59% of the hernias disappeared within 1 year of follow-up and 66% disappeared within the first 8 months of follow-up. The 83% of the extruded hernias disappeared, and this was significant in the multivariate analysis (P<.005). The absence of enhancement was significantly associated with the persistence of the hernia in the univariate analysis. The enhancement pattern was not useful for predicting whether the hernia would disappear. Five hernias disappeared within the first two months. A high percentage of disc hernias disappear. We found a significant association between extrusion and disappearance but no correlation between the pattern of gadolinium uptake and the disappearance of the hernia. Copyright © 2010 SERAM. Published by Elsevier Espana. All rights reserved.

  4. 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

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

    PubMed

    Jingu, Akiko; Fukuda, Junya; Taketomi-Takahashi, Ayako; Tsushima, Yoshito

    2014-10-06

    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. 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. 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. 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.

  6. 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.

  7. 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

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

    NASA Astrophysics Data System (ADS)

    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.; Krtička, M.; Bečvář, F.

    2009-03-01

    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.

  9. 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

  10. 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

  11. Does gadolinium-based contrast material improve diagnostic accuracy of local invasion in rectal cancer MRI? A multireader study.

    PubMed

    Gollub, Marc J; Lakhman, Yulia; McGinty, Katrina; Weiser, Martin R; Sohn, Michael; Zheng, Junting; Shia, Jinru

    2015-02-01

    OBJECTIVE. The purpose of this study was to compare reader accuracy and agreement on rectal MRI with and without gadolinium administration in the detection of T4 rectal cancer. MATERIALS AND METHODS. In this study, two radiologists and one fellow independently interpreted all posttreatment MRI studies for patients with locally advanced or recurrent rectal cancer using unenhanced images alone or combined with contrast-enhanced images, with a minimum interval of 4 weeks. Readers evaluated involvement of surrounding structures on a 5-point scale and were blinded to pathology and disease stage. Sensitivity, specificity, negative predictive value, positive predictive value, and AUC were calculated and kappa statistics were used to describe interreader agreement. RESULTS. Seventy-two patients (38 men and 34 women) with a mean age of 61 years (range, 32-86 years) were evaluated. Fifteen patients had 32 organs invaded. Global AUCs without and with gadolinium administration were 0.79 and 0.77, 0.91 and 0.86, and 0.83 and 0.78 for readers 1, 2, and 3, respectively. AUCs before and after gadolinium administration were similar. Kappa values before and after gadolinium administration for pairs of readers ranged from 0.5 to 0.7. CONCLUSION. On the basis of pathology as a reference standard, the use of gadolinium during rectal MRI did not significantly improve radiologists' agreement or ability to detect T4 disease.

  12. The Effect of gadolinium on the ESR response of alanine and ammonium tartrate exposed to thermal neutrons.

    PubMed

    Marrale, Maurizio; Brai, Maria; Gennaro, Gaetano; Bartolotta, Antonio; D'Oca, Maria Cristina

    2008-02-01

    Many efforts have been made to develop neutron capture therapy (NCT) for cancer treatment. Among the challenges in using NCT is the characterization of the features of the mixed radiation field and of its components. In this study, we examined the enhancement of the ESR response of pellets of alanine and ammonium tartrate with gadolinium oxide exposed to a thermal neutron beam. In particular, the ESR response of these dosimeters as a function of the gadolinium content inside the dosimeter was analyzed. We found that the addition of gadolinium improves the sensitivity of both alanine and ammonium tartrate. However, the use of gadolinium reduces or abolishes tissue equivalence because of its high atomic number (Z(Gd) = 64). Therefore, it is necessary to find the optimum compromise between the sensitivity to thermal neutrons and the reduction of tissue equivalence. Our analysis showed that a low concentration of gadolinium oxide (of the order of 5% of the total mass of the dosimeter) can enhance the thermal neutron sensitivity more than 13 times with an insignificant reduction of tissue equivalence.

  13. Characterization of the reaction products and precipitates at the interface of carbon fiber reinforced magnesium–gadolinium composite

    SciTech Connect

    Wang, Yaping; Jiang, Longtao; Chen, Guoqin; Lin, Xiu; Zhang, Shaofeng; Pei, Risheng; Wu, Gaohui

    2016-03-15

    In the present work, carbon fiber reinforced magnesium-gadolinium composite was fabricated by pressure infiltration method. The phase composition, micro-morphology, and crystal structure of reaction products and precipitates at the interface of the composite were investigated. Scanning electron microscopy and energy dispersive spectroscopy analysis revealed the segregation of gadolinium element at the interface between carbon fiber and matrix alloy. It was shown that block-shaped Gd4C5, GdC2 and nano-sized Gd2O3 were formed at the interface during the fabrication process due to the interfacial reaction. Furthermore, magnesium-gadolinium precipitates including needle-like Mg5Gd (or Mg24Gd5) and thin plate-shaped long period stacking-ordered phase, were also observed at the interface and in the matrix near the interface. The interfacial microstructure and bonding mode were influenced by these interfacial products, which were beneficial for the improvement of the interfacial bonding strength. - Highlights: • Gadolinium element segregated on the surface of carbon fibers. • Block-shaped Gd{sub 4}C{sub 5} and GdC{sub 2} were formed at the interface via chemical reaction. • Gadolinium and oxygen reacted at the interface and formed nano-scaled Gd{sub 2}O{sub 3}. • The precipitates formed in the interface were identified to be Mg{sub 5}Gd (or Mg{sub 24}Gd{sub 5}) and plate-shaped long period stacking-ordered phase.

  14. Positive gadolinium anomalies in wastewater treatment plant effluents and aquatic environment in the Hérault watershed (South France).

    PubMed

    Rabiet, M; Brissaud, F; Seidel, J L; Pistre, S; Elbaz-Poulichet, F

    2009-05-01

    Anthropogenic gadolinium (Gd), used as a contrast agent in magnetic resonance imaging, may enter rivers and groundwaters with the effluents of wastewater treatment plant (WWTP). Such contaminations, which are mainly found in densely populated areas with highly developed medical systems, induce positive gadolinium anomalies in waters. This study reports on the occurrence of positive Gd anomaly in wastewaters, surface and groundwaters in a slightly populated Mediterranean watershed. Water samples have been collected along the Hérault River, in its tributaries, in wells and springs supplying drinking water and in WWTP effluents during two sampling campaigns in February and July 2003. Systematically pronounced positive gadolinium anomalies (Gd/Gd( *)) were observed in WWTP effluents with values reaching 306. These observations have shown that Gd/Gd( *) can also be found in wastewater drained from rural communities, not equipped with MRI facilities. Positive gadolinium anomalies were detected in two tributaries of the Hérault River and in some wells supplying drinking water, corresponding to an excess of anthropogenic Gd in water up to 15.4pM. A monthly monitoring on one well has confirmed the persistence of gadolinium anomalies all along the year, suggesting a continual wastewater contamination on this site. A spatial monitoring on one tributary showed that wastewater contribution modifies completely the normalized REE pattern of river water, resulting in a decrease of REE amount correlated to the Gd anomaly appearance.

  15. 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.

  16. Nephrogenic systemic fibrosis: change in incidence following a switch in gadolinium agents and adoption of a gadolinium policy--report from two U.S. universities.

    PubMed

    Altun, Ersan; Martin, Diego R; Wertman, Rebecca; Lugo-Somolinos, Aida; Fuller, Edwin R; Semelka, Richard C

    2009-12-01

    To determine the incidence of nephrogenic systemic fibrosis (NSF) in tertiary care centers of two U.S. universities following the switch from the use of gadodiamide to gadobenate dimeglumine and gadopentetate dimeglumine, and the adoption of restrictive gadolinium-based contrast agent (GBCA) policies. Institutional review board approval with waiver of informed consent was obtained for this Health Insurance Portability and Accountability Act-compliant retrospective study. NSF patients were identified between January 2000 and December 2006 at center A and between October 2003 and February 2007 at center B (preadoption periods); and from June 2007 to June 2008 at both centers (postadoption period). The numbers of patients who underwent gadolinium-enhanced magnetic resonance at each center, patients at risk for NSF at center A, and dialysis patients at center B were identified in the pre- and postadoption periods. Gadodiamide was the only agent used in the preadoption period. Gadobenate dimeglumine and gadopentetate dimeglumine were the agents used in the postadoption period. A restrictive GBCA policy that limits the use and dose of GBCAs in patients with risk factors was adopted in the postadoption period. Follow-up lasted 9 months from July 2008 to March 2009. Corresponding incidences were determined and compared with the Fisher exact test. Respective total benchmark incidence of NSF at both centers, at-risk incidence of NSF at center A, and dialysis incidence of NSF at center B were 37 of 65 240, 28 of 925, and nine of 312 in the preadoption period and zero of 25 167, zero of 147, and zero of 402 in the postadoption period. All three incidences demonstrated significant differences (P < .0001, .024, and .001, respectively) between the pre- and postadoption periods. Following the switch from gadodiamide to gadobenate dimeglumine and gadopentetate dimeglumine, and the adoption of restrictive GBCA policies, no NSF cases were observed at either center.

  17. Relaxometric studies of gadolinium-functionalized perfluorocarbon nanoparticles for MR imaging.

    PubMed

    de Vries, Anke; Moonen, Rik; Yildirim, Muhammed; Langereis, Sander; Lamerichs, Rolf; Pikkemaat, Jeroen A; Baroni, Simona; Terreno, Enzo; Nicolay, Klaas; Strijkers, Gustav J; Grüll, Holger

    2014-01-01

    Fluorine MRI ((19) F MRI) is receiving an increasing attention as a viable alternative to proton-based MRI ((1) H MRI) for dedicated application in molecular imaging. The (19) F nucleus has a high gyromagnetic ratio, a 100% natural abundance and is furthermore hardly present in human tissues allowing for hot spot MR imaging. The applicability of (19) F MRI as a molecular and cellular imaging technique has been exploited, ranging from cell tracking to detection and imaging of tumors in preclinical studies. In addition to applications, developing new contrast materials with improved relaxation properties has also been a core research topic in the field, since the inherently low longitudinal relaxation rates of perfluorocarbon compounds result in relatively low imaging efficiency. Borrowed from (1) H MRI, the incorporation of lanthanides, specifically Gd(III) complexes, as signal modulating ingredients in the nanoparticle formulation has emerged as a promising approach to improvement of the fluorine signal. Three different perfluorocarbon emulsions were investigated at five different magnetic field strengths. Perfluoro-15-crown-5-ether was used as the core material and Gd(III)DOTA-DSPE, Gd(III)DOTA-C6-DSPE and Gd(III)DTPA-BSA as the relaxation altering components. While Gd(III)DOTA-DSPE and Gd(III)DOTA-C6-DSPE were favorable constructs for (1) H NMR, Gd(III)DTPA-BSA showed the strongest increase in (19F) R(1). These results show the potential of the use of paramagnetic lipids to increase (19F) R(1) at clinical field strengths (1.5-3 T). At higher field strengths (6.3-14 T), gadolinium does not lead to an increase in (19F) R(1) compared with emulsions without gadolinium, but leads to an significant increase in (19F) R(2). Our data therefore suggest that the most favorable situation for fluorine measurements is at high magnetic fields without the inclusion of gadolinium constructs.

  18. 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.

  19. Toward modeling phosphate tellurate glasses: the devitrification and addition of gadolinium ions behavior.

    PubMed

    Rada, S; Culea, M; Culea, E

    2008-11-06

    Glasses in the xGd2O3 x (100 - x)[7TeO2 x 3P2O5] system with 0 < or = x < or = 20 mol % have been prepared using the melt quenching method. The influence of gadolinium ions on structural behavior of the phosphate tellurate glass has been investigated using infrared spectroscopy and density functional theory (DFT) calculations. The addition of gadolinium ions into the host glass matrix leads to an increase of the glass network polymerization due to the replacement of P-O-P bonds by the more resistant P-O-Te bonds having as result the improvement of the chemical durability of the glass. The structural evolution of the studied glasses with the gradual increase of the gadolinium oxide content up to 20 mol % could be explained by considering that the excess of oxygen may be accommodated by the conversion of some orthophosphate structural units into metaphosphate or/and pyrophosphate units. X-ray diffraction and IR spectra revealed that heat treatment of the samples also causes an increase of the glass network polymerization for heat treatment times, t, up to 36 h, while for 36 h > t > or = 48 h showed a drastic structural modification which lead to the apparition of the Te4P2O13 crystalline phase. DFT calculations show that tellurium atoms occupy two different sites in the proposed model. In the first case the tellurium atom is coordinated with four oxygen atoms giving a trigonal bipyramide arrangement, while in the second case the tellurium atom is coordinated with three O atoms. The calculated IR absorption spectrum of the proposed model for phosphotellurite glasses is in good agreement with the experimental absorption data.

  20. Quantitative assessment of the rheumatoid synovial microvascular bed by gadolinium-DTPA enhanced magnetic resonance imaging

    PubMed Central

    Gaffney, K.; Cookson, J.; Blades, S.; Coumbe, A.; Blake, D.

    1998-01-01

    OBJECTIVE—To examine the relation between rate of synovial membrane enhancement, intra-articular pressure (IAP), and histologically determined synovial vascularity in rheumatoid arthritis, using gadolinium-DTPA enhanced magnetic resonance imaging (MRI).
METHODS—Dynamic gadolinium-DTPA enhanced MRI was performed in 31 patients with knee synovitis (10 patients IAP study, 21 patients vascular morphometry study). Rate of synovial membrane enhancement was quantified by line profile analysis using the image processing package ANALYZE. IAP was measured using an intra-compartmental pressure monitor system. Multiple synovial biopsy specimens were obtained by a blind biopsy technique. Blood vessels were identified immunohistochemically using the endothelial cell marker QBend30 and quantified (blood vessel numerical density and fractional area).
RESULTS—Median blood vessel numerical density and fractional area were 77.5/mm2 (IQR; 69.3-110.7) and 5.6% (IQR; 3.4-8.5) respectively. The rate of synovial membrane enhancement (median 2.74 signal intensity units/s, IQR 2.0-3.8) correlated with both blood vessel numerical density (r = 0.46, p < 0.05) and blood vessel fractional area (r = 0.55, p < 0.02). IAP did not influence the rate of enhancement.
CONCLUSIONS—Gadolinium-DTPA enhanced MRI may prove to be a valuable technique for evaluating drugs that influence angiogenesis.

 Keywords: magnetic resonance imaging; rheumatoid arthritis; synovitis; vascularity PMID:9640130

  1. Influence of acquired obesity on coronary vessel wall late gadolinium enhancement in discordant monozygote twins.

    PubMed

    Makowski, Marcus R; Jansen, Christian H P; Ebersberger, Ullrich; Schaeffter, Tobias; Razavi, Reza; Mangino, Massimo; Spector, Tim D; Botnar, Rene M; Greil, Gerald F

    2016-10-14

    The aim of this study was to investigate the impact of BMI on late gadolinium enhancement (LGE) of the coronary artery wall in identical monozygous twins discordant for BMI. Coronary LGE represents a useful parameter for the detection and quantification of atherosclerotic coronary vessel wall disease. Thirteen monozygote female twin pairs (n = 26) with significantly different BMIs (>1.6 kg/m2) were recruited out of >10,000 twin pairs (TwinsUK Registry). A coronary 3D-T2prep-TFE MR angiogram and 3D-IR-TFE vessel wall scan were performed prior to and following the administration of 0.2 mmol/kg of Gd-DTPA on a 1.5 T MR scanner. The number of enhancing coronary segments and contrast to noise ratios (CNRs) of the coronary wall were quantified. An increase in BMI was associated with an increased number of enhancing coronary segments (5.3 ± 1.5 vs. 3.5 ± 1.6, p < 0.0001) and increased coronary wall enhancement (6.1 ± 1.1 vs. 4.8 ± 0.9, p = 0.0027) compared to matched twins with lower BMI. This study in monozygous twins indicates that acquired factors predisposing to obesity, including lifestyle and environmental factors, result in increased LGE of the coronary arteries, potentially reflecting an increase in coronary atherosclerosis in this female study population. • BMI-discordant twins allow the investigation of the influence of lifestyle factors independent from genetic confounders. • Only thirteen obesity-discordant twins were identified underlining the strong genetic component of BMI. • In female twins, a BMI increase is associated with increased coronary late gadolinium enhancement. • Increased late gadolinium enhancement in the coronary vessel wall potentially reflects increased atherosclerosis.

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

    SciTech Connect

    Solovyov, V.F.; Gibert, M.; Puig, T.; Obradors, X.

    2010-12-06

    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.

  3. 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.

  4. Size-dependent strain in epitaxial (001) gadolinium-doped ceria nanoislands

    NASA Astrophysics Data System (ADS)

    Solovyov, Vyacheslav F.; Gibert, Marta; Puig, Teresa; Obradors, Xavier

    2010-12-01

    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.

  5. 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

  6. 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.

  7. 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.

  8. Safety Evaluation and Imaging Properties of Gadolinium-Based Nanoparticles in nonhuman primates

    PubMed Central

    Kotb, Shady; Piraquive, Joao; Lamberton, Franck; Lux, François; Verset, Michael; Di Cataldo, Vanessa; Contamin, Hugues; Tillement, Olivier; Canet-Soulas, Emmanuelle; Sancey, Lucie

    2016-01-01

    In this article, we report the safety evaluation of gadolinium-based nanoparticles in nonhuman primates (NHP) in the context of magnetic resonance imaging (MRI) studies in atherosclerosis bearing animals and healthy controls. In healthy NHP, the pharmacokinetics and toxicity profiles demonstrated the absence of dose, time, and sex-effects, as well as a suitable tolerance of intravenous administration of the nanoparticles. We investigated their imaging properties for arterial plaque imaging in a standard diet or a high cholesterol diet NHP, and compared their characteristics with clinically applied Gd-chelate. This preliminary investigation reports the efficient and safe imaging of atherosclerotic plaques. PMID:27725693

  9. The developmental history of the gadolinium chelates as intravenous contrast media for magnetic resonance.

    PubMed

    Runge, Val M; Ai, Tao; Hao, Dapeng; Hu, Xuemei

    2011-12-01

    The developmental history of the gadolinium chelates, which spans 30 years, is described, focusing, in part, on the seminal work with each of the major agents in use today. By examining this history, insight is gained into important issues of efficacy and safety, with valuable lessons to be learned from the mistakes made during this period. An overview of physicochemical characteristics and chemical structures is also provided. The review concludes with a discussion of current research directions involving this field, which is that of the intravenous contrast media for magnetic resonance, in the past 5 years.

  10. Gadolinium(III)-sensitized fluorescence of europium in its mixed-metal compounds with trifluroacetate

    NASA Astrophysics Data System (ADS)

    Kalinovskaya, I. V.; Zadorozhnaya, A. N.

    2017-04-01

    The fluorescence properties of mixed-metal compounds of Eu(III) and Gd(III) with trifluoroacetic acid, Eu1-xGdx(C2F3O2)3·yD·zH2O, where D - 1,10-phenanthroline, 2,2-dipyridil, diphenylguanidine, x = 0, 0.25, 0.5, or 0.7, were studied. Luminescence spectroscopic evidence and the examination of excitation spectra indicate the occurrence of efficient energy transfer from the gadolinium to the europium ion. The greatest promotion of Eu3+ photoluminescence at 615 nm is observed when Eu:Gd = 1:1.

  11. 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

  12. Controlled manipulation of gadolinium-coordinated supramolecules by low-temperature scanning tunneling microscopy.

    PubMed

    Urgel, José I; Ecija, David; Auwärter, Willi; Barth, Johannes V

    2014-03-12

    Coordination bonding between para-quarterphenyl-dicarbonitrile linkers and gadolinium on Ag(111) has been exploited to construct pentameric mononuclear supramolecules, consisting of a rare-earth center surrounded by five molecular linkers. By employing a scanning tunneling microscope tip, a manipulation protocol was developed to position individual pentamers on the surface. In addition, the tip was used to extract and replace individual linkers yielding tetrameric, pentameric, nonameric, and dodecameric metallosupramolecular arrangements. These results open new avenues toward advanced nanofabrication methods and rare-earth nanochemistry by combining the versatility of metal-ligand interactions and atomistic manipulation capabilities.

  13. 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. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 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.

  15. 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.

  16. Chest radiography with a large-area detector based on cesium-iodide/amorphous-silicon technology: image quality and dose requirement in comparison with an asymmetric screen-film system.

    PubMed

    Strotzer, M; Völk, M; Reiser, M; Lenhart, M; Manke, C; Gmeinwieser, J; Holzknecht, N; Link, J; Feuerbach, S

    2000-07-01

    The purpose of this study was to evaluate a large-area, flat-panel X-ray detector, which uses cesium-iodide (CsI) and amorphous silicon (a-Si). Conventional images were compared with digital images acquired with equal dose (2.5 microGy) and with 50% dose reduction. Fifteen consecutive patients were studied prospectively using an asymmetric screen-film system (detector dose, 2.5 microGy). Digital images were taken from the same patients in a posteroanterior view with detector doses of 2.5 and 1.25 microGy, respectively. The CsI/a-Si active-matrix imager had a panel-size of 43 x 43 cm, a matrix of 3 x 3k, and a pixel-pitch of 143 microm. Hard copies were presented in a random order to eight independent observers, who rated image quality according to six subjective quality criteria. Statistical significance of differences was evaluated with Student's t test for paired samples (confidence level, 95%). Digital radiographs with 2.5 and 1.25 microGy were superior to conventional images regarding all quality criteria. Statistically significant differences were observed for five of six criteria at a detector dose of 2.5 microGy and for only one quality feature at 1.25 microGy. Flat-panel digital imagers based on CsI/a-Si technique have the potential to replace conventional systems and might allow a reduction of radiation dose by 50% without loss of image quality.

  17. Microstructural Anisotropy of Magnetocaloric Gadolinium Cylinders: Effect on the Mechanical Properties of the Material.

    PubMed

    Petrovič, Darja Steiner; Šturm, Roman; Naglič, Iztok; Markoli, Boštjan; Pepelnjak, Tomaž

    2016-05-17

    The development of advanced materials and technologies based on magnetocaloric Gd and its compounds requires an understanding of the dependency of mechanical properties on their underlying microstructure. Therefore, the aim of the study was to characterize microstructural inhomogeneities in the gadolinium that can be used in magnetocaloric refrigeration systems. Microstructures of magnetocaloric gadolinium cylinders were investigated by light microscopy and FE-SEM (Field Emission Scanning Electron Microscopy), EDS (Energy-dispersive X-ray Spectroscopy), and BSE (Back-scattered Electrons) in both the extrusion and the extrusion-transversal directions. XRD (X-ray Diffraction) analyses were performed to reveal the presence of calcium- and fluorine-based compounds. Metallographic characterization showed an oxidized and inhomogeneous microstructure of the cross-sections. The edges and the outer parts of the cylinders were oxidized more intensively on the surfaces directly exposed to the processing tools. Moreover, a significant morphological anisotropy of the non-metallic inclusions was observed. CaF inclusions act as active nucleation sites for internal oxidation. The non-metallic, Ca- and F-containing inclusions can be classified as complex calciumoxyfluorides. The solubility of Er and Yb in the CaF was negligible compared to the Gd matrix and/or the oxide phase. Lower mechanical properties of the material are a consequence of the lower structural integrity due to selective oxidation of surfaces and interfaces.

  18. Microstructural Anisotropy of Magnetocaloric Gadolinium Cylinders: Effect on the Mechanical Properties of the Material

    PubMed Central

    Petrovič, Darja Steiner; Šturm, Roman; Naglič, Iztok; Markoli, Boštjan; Pepelnjak, Tomaž

    2016-01-01

    The development of advanced materials and technologies based on magnetocaloric Gd and its compounds requires an understanding of the dependency of mechanical properties on their underlying microstructure. Therefore, the aim of the study was to characterize microstructural inhomogeneities in the gadolinium that can be used in magnetocaloric refrigeration systems. Microstructures of magnetocaloric gadolinium cylinders were investigated by light microscopy and FE-SEM (Field Emission Scanning Electron Microscopy), EDS (Energy-dispersive X-ray Spectroscopy), and BSE (Back-scattered Electrons) in both the extrusion and the extrusion-transversal directions. XRD (X-ray Diffraction) analyses were performed to reveal the presence of calcium- and fluorine-based compounds. Metallographic characterization showed an oxidized and inhomogeneous microstructure of the cross-sections. The edges and the outer parts of the cylinders were oxidized more intensively on the surfaces directly exposed to the processing tools. Moreover, a significant morphological anisotropy of the non-metallic inclusions was observed. CaF inclusions act as active nucleation sites for internal oxidation. The non-metallic, Ca- and F-containing inclusions can be classified as complex calciumoxyfluorides. The solubility of Er and Yb in the CaF was negligible compared to the Gd matrix and/or the oxide phase. Lower mechanical properties of the material are a consequence of the lower structural integrity due to selective oxidation of surfaces and interfaces. PMID:28773502

  19. Microemulsion-made gadolinium carbonate hollow nanospheres showing magnetothermal heating and drug release.

    PubMed

    Jung-König, J; Sanhaji, M; Popescu, R; Seidl, C; Zittel, E; Schepers, U; Gerthsen, D; Hilger, I; Feldmann, C

    2017-06-22

    Gadolinium carbonate (Gd2(CO3)3) hollow nanospheres and their suitability for drug transport and magnetothermally-induced drug release are presented. The hollow nanospheres are prepared via a microemulsion-based synthesis using tris(tetramethylcyclopentadienyl)gadolinium(iii) and CO2 as the starting materials. Size, structure and composition of the as-prepared Gd2(CO3)3 hollow nanospheres are comprehensively validated by several independent analytical methods (HRTEM, HAADF-STEM, DLS, EDXS, XRD, FT-IR, DTA-TG). Accordingly, they exhibit an outer diameter of 26 ± 4 nm, an inner cavity of 7 ± 2 nm, and a wall thickness of 9 ± 3 nm. As a conceptual study, the nanocontainer-functionality of the Gd2(CO3)3 hollow nanospheres is validated upon filling with the anti-cancerogenic agent doxorubicin (DOX), which is straightforward via the microemulsion (ME) strategy. The resulting DOX@Gd2(CO3)3 nanocontainers provide the option of multimodal imaging including optical and magnetic resonance imaging (OI, MRI) as well as magnetothermal heating and drug release. As a proof-of-concept, we could already prove the intrinsic DOX-based fluorescence, a low systemic toxicity according to in vitro studies as well as the magnetothermal effect and a magnetothermally-induced DOX release. In particular, the latter is new for Gd-containing nanoparticles and highly promising in view of theranostic nanocontainers and synergistic physical and chemical tumor treatment.

  20. 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.

  1. Modulation of channel activity and gadolinium block of MscL by static magnetic fields.

    PubMed

    Petrov, Evgeny; Martinac, Boris

    2007-02-01

    The magnetic field of the Earth has for long been known to influence the behaviour and orientation of a variety of living organisms. Experimental studies of the magnetic sense have, however, been impaired by the lack of a plausible cellular and/or molecular mechanism providing meaningful explanation for detection of magnetic fields by these organisms. Recently, mechanosensitive (MS) ion channels have been implied to play a role in magnetoreception. In this study we have investigated the effect of static magnetic fields (SMFs) of moderate intensity on the activity and gadolinium block of MscL, the bacterial MS channel of large conductance, which has served as a model channel to study the basic physical principles of mechanosensory transduction in living cells. In addition to showing that direct application of the magnetic field decreased the activity of the MscL channel, our study demonstrates for the first time that SMFs can reverse the effect of gadolinium, a well-known blocker of MS channels. The results of our study are consistent with a notion that (1) the effects of SMFs on the MscL channels may result from changes in physical properties of the lipid bilayer due to diamagnetic anisotropy of phospholipid molecules and consequently (2) cooperative superdiamagnetism of phospholipid molecules under influence of SMFs could cause displacement of Gd(3+) ions from the membrane bilayer and thus remove the MscL channel block.

  2. Effects of Polyethyleneimine on the Sonochemical Synthesis of Gadolinium Ion-Modified ZnO Nanorods.

    PubMed

    Choi, Seok Cheol; Yun, Won Suk; Sohn, Sang Ho

    2015-01-01

    We prepared gadolinium (Gd) ion-modified ZnO nanorods by a sonochemical decomposition of zinc acetate dehydrate and gadolinium acetate hydrate precursor solutions with and without polyethyleneimine (PEI). We investigated the effects of PEI on the sonochemical synthesis of ZnO nanorods with and without Gd ion modifications. In the case of nascent ZnO nanorods, PEI in the precursor solutions can prohibit radial growth but allow axial growth, resulting in changes in the degree of preferred crystal orientations, and in the PL properties of the resulting nanorods. In the case of Gd ion-modified ZnO nanorods, we observed that the ZnO nanorods, fabricated sonochemically in the precursor solutions with PEI, exhibited a peak broadening of the ZnO(002) crystal plane and decreasing crystal orientation with respect to the c plane. We note that PEI can negatively affect the crystal orientation and crystallinity of Gd ion-modified ZnO nanorods, even though it cannot affect the lattice constant.

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

    PubMed

    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

    2012-09-07

    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.

  4. Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T(1) contrast ability.

    PubMed

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

    2016-02-14

    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.

  5. 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.

  6. Density functional calculations for structural, electronic, and magnetic properties of gadolinium-oxide clusters

    SciTech Connect

    Yuan, H. K.; Chen, H. Tian, C. L.; Kuang, A. L.; Wang, J. Z.

    2014-04-21

    Gadolinium-oxide clusters in various sizes and stoichiometries have been systematically studied by employing the density functional theory with the generalized gradient approximation. The clusters in bulk stoichiometry are relatively more stable and their binding energies increase with the increasing size. Stoichiometric (Gd{sub 2}O{sub 3}){sub n} clusters of n = 1–3 prefer cage-like structures, whereas the clusters of n = 4–30 prefer compact structures layered by wedge-like units and exhibit a rough feature toward the bulk-like arrangement with small disorders of atomic positions. The polyhedral-cages analogous to carbon-fullerenes are stable isomers yet not the minimum energy configurations. Their stabilities can be improved by embedding one oxygen atom or a suitable cage to form core-shell configurations. The mostly favored antiferromagnetic couplings between adjacent Gd atoms are nearly degenerated in energy with their ferromagnetic couplings, resulting in super-paramagnetic characters of gadolinium-oxide clusters. The Ruderman-Kittel-Kasuya-Yosida (RKKY)-type mechanism together with the superexchange-type mechanism plays cooperation role for the magnetic interactions in clusters. We present, as a function of n, calculated binding energies, ionization potential, electron affinity, and electronic dipole moment.

  7. 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.

  8. 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.

  9. Energy-Discriminating Gadolinium K-Edge X-ray Computed Tomography System

    NASA Astrophysics Data System (ADS)

    Matsukiyo, Hiroshi; Watanabe, Manabu; Sato, Eiichi; Osawa, Akihiro; Enomoto, Toshiyuki; Nagao, Jiro; Abderyim, Purkhet; AIzawa, Katsuo; Hitomi, Keitaro; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Ogawa, Akira; Takahashi, Kiyomi; Sato, Shigehiro; Onagawa, Jun

    2010-02-01

    An energy-discriminating K-edge X-ray computed tomography (CT) system is useful for increasing the contrast resolution of a target region utilizing contrast media and for reducing the absorbed dose for patients. The CT system is of the first-generation type of detector using cadmium telluride (CdTe). CT is performed by repeated translations and rotations of an object. Penetrating X-ray photons from the object are detected by a CdTe detector, and event signals of X-ray photons are produced using charge-sensitive and shaping amplifiers. Both photon energy and energy width are selected out using a multichannel analyzer, and the number of photons is counted by a countercard. To perform energy discrimination, a low-dose-rate X-ray generator for photon counting was developed. Its maximum tube voltage and minimum tube current were 110 kV and 1 µA, respectively. In energy-discriminating CT, the tube voltage and tube current were 100 kV and 20 µA, respectively, and the X-ray intensity was 2.98 µGy/s at a distance of 1.0 m from the source and a tube voltage of 100 kV. The demonstration of enhanced gadolinium K-edge X-ray CT was carried out by selecting photons with energies just beyond the gadolinium K-edge energy of 50.3 keV.

  10. Energy-Discriminating Gadolinium K-Edge X-ray Computed Tomography System

    NASA Astrophysics Data System (ADS)

    Hiroshi Matsukiyo,; Manabu Watanabe,; Eiichi Sato,; Akihiro Osawa,; Toshiyuki Enomoto,; Jiro Nagao,; Purkhet Abderyim,; Katsuo AIzawa,; Keitaro Hitomi,; Etsuro Tanaka,; Hidezo Mori,; Toshiaki Kawai,; Akira Ogawa,; Kiyomi Takahashi,; Shigehiro Sato,; Jun Onagawa,

    2010-02-01

    An energy-discriminating K-edge X-ray computed tomography (CT) system is useful for increasing the contrast resolution of a target region utilizing contrast media and for reducing the absorbed dose for patients. The CT system is of the first-generation type of detector using cadmium telluride (CdTe). CT is performed by repeated translations and rotations of an object. Penetrating X-ray photons from the object are detected by a CdTe detector, and event signals of X-ray photons are produced using charge-sensitive and shaping amplifiers. Both photon energy and energy width are selected out using a multichannel analyzer, and the number of photons is counted by a countercard. To perform energy discrimination, a low-dose-rate X-ray generator for photon counting was developed. Its maximum tube voltage and minimum tube current were 110 kV and 1 μA, respectively. In energy-discriminating CT, the tube voltage and tube current were 100 kV and 20 μA, respectively, and the X-ray intensity was 2.98 μGy/s at a distance of 1.0 m from the source and a tube voltage of 100 kV. The demonstration of enhanced gadolinium K-edge X-ray CT was carried out by selecting photons with energies just beyond the gadolinium K-edge energy of 50.3 keV.

  11. Gadolinium-Based Contrast Agents for Vessel Wall Magnetic Resonance Imaging (MRI) of Atherosclerosis

    PubMed Central

    Calcagno, Claudia; Ramachandran, Sarayu; Millon, Antoine; Robson, Philip M.; Mani, Venkatesh

    2012-01-01

    Cardiovascular disease due to atherosclerosis is the number one killer in the Western world, and threatens to become the major cause of morbidity and mortality worldwide. It is therefore paramount to develop non-invasive methods for the detection of high-risk, asymptomatic individuals before the onset of clinical symptoms or events. In the recent past, great strides have been made in the understanding of the pathological mechanisms involved in the atherosclerotic cascade down to the molecular details. This has allowed the development of contrast agents that can aid in the in vivo characterization of these processes. Gadolinium chelates are among the contrast media most commonly used in MR imaging. Originally used for MR angiography for the detection and quantification of vascular stenosis, more recently they have been applied to improve characterization of atherosclerotic plaques. In this manuscript, we will briefly review gadolinium-chelates (Gd) based contrast agents for non-invasive MR imaging of atherosclerosis. We will first describe Gd-based non-targeted FDA approved agents, used routinely in clinical practice for the evaluation of neovascularization in other diseases. Secondly, we will describe non-specific and specific targeted contrast agents, which have great potential for dissecting specific biological processes in the atherosclerotic cascade. Lastly, we will briefly compare Gd-based agents to others commonly used in MRI and to other imaging modalities. PMID:23539505

  12. Gadolinium-Based Contrast Agents for Vessel Wall Magnetic Resonance Imaging (MRI) of Atherosclerosis.

    PubMed

    Calcagno, Claudia; Ramachandran, Sarayu; Millon, Antoine; Robson, Philip M; Mani, Venkatesh; Fayad, Zahi

    2013-02-01

    Cardiovascular disease due to atherosclerosis is the number one killer in the Western world, and threatens to become the major cause of morbidity and mortality worldwide. It is therefore paramount to develop non-invasive methods for the detection of high-risk, asymptomatic individuals before the onset of clinical symptoms or events. In the recent past, great strides have been made in the understanding of the pathological mechanisms involved in the atherosclerotic cascade down to the molecular details. This has allowed the development of contrast agents that can aid in the in vivo characterization of these processes. Gadolinium chelates are among the contrast media most commonly used in MR imaging. Originally used for MR angiography for the detection and quantification of vascular stenosis, more recently they have been applied to improve characterization of atherosclerotic plaques. In this manuscript, we will briefly review gadolinium-chelates (Gd) based contrast agents for non-invasive MR imaging of atherosclerosis. We will first describe Gd-based non-targeted FDA approved agents, used routinely in clinical practice for the evaluation of neovascularization in other diseases. Secondly, we will describe non-specific and specific targeted contrast agents, which have great potential for dissecting specific biological processes in the atherosclerotic cascade. Lastly, we will briefly compare Gd-based agents to others commonly used in MRI and to other imaging modalities.

  13. Chemical and magnetic structure of uranium/gadolinium multilayers studied by transmission

    SciTech Connect

    Wilkins, S.B.; Springell, R.; Langridge, S.; Wildes, A.; Sanchez-Hanke, C.; Moore, K.T.; Butterfield, M.; Chivall, J.; Ward, R.C.C.; Wells, M.R.; Lander, G.H.

    2010-04-29

    We present a multitechnique approach to study the detailed chemical and magnetic structure of uranium/gadolinium multilayers. At low temperature the saturation magnetization is found to be {approx}60% of that of bulk gadolinium. We address this problem, which is found in many other multilayers and suggest a model that may have wider applications. Transmission electron microscopy images indicate a microstructure, consistent with a columnar growth of Gd with crystallites of the order 20 {yields} 100{angstrom}. Off-specular neutron scattering is most strongly visible at saturation field, indicating that Gd moments are not aligned with the applied field. X-ray resonant magnetic scattering provides proof of coupled in-plane length scales for both the structural and the magnetic roughness. A detailed x-ray scattering study of both the specular and off-specular reflectivities has been used to investigate the in-plane structure of the multilayers. We calculate the roughness and transverse correlation cut-off length, {zeta}{sub x} = 120 {+-} 30{angstrom}, and present a simple model to determine an average column size of 27 {+-} 6{angstrom} and a reduction in the magnetic saturation of {approx}40%.

  14. Order-disorder transitions in gadolinium zirconate: A potential electrolyte material in solid oxide fuel cells

    SciTech Connect

    Meilicke, S.; Haile, S.

    1995-12-31

    Rare-earth, yttrium, and calcium doped zirconates are the materials of choice for electrolytes in solid oxide fuel cells. The dopant in these materials serves not only to stabilized the cubic phase of zirconia, but also to introduce anion defects that presumably increase the ionic conductivity. In order to understand the relationships between anion defect distribution, thermal history and ionic conductivity, the structural properties of gadolinium zirconate, Gd{sub 2}Zr{sub 2}O{sub 7}, have been examined via high-temperature x-ray powder diffraction. Gadolinium zirconate is an ideal material for such a structure-property-processing study: it shows ordering of defects at low temperatures, taking on a pyrochlore structure, and disordering at elevated temperature, taking on a defect fluorite structure. Diffraction experiments, performed as functions of time and temperature, confirmed the transition temperature to lie between 1,500 and 1,550 C. They also revealed that the transformation takes place most rapidly just below the transition temperature, indicating that the ordering process is kinetically constrained at low temperatures. Moreover, x-ray data collected at room temperature from quenched samples were found to be as useful, if not more so, than those collected in situ at high temperature. The latter are affected by thermal scattering, severely compromising data quality.

  15. 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.

  16. Geometrical confinement of gadolinium-based contrast agents in nanoporous particles enhances T1 contrast

    PubMed Central

    Ananta, Jeyarama S.; Godin, Biana; Sethi, Richa; Moriggi, Loick; Liu, Xuewu; Serda, Rita E.; Krishnamurthy, Ramkumar; Muthupillai, Raja; Bolskar, Robert D.; Helm, Lothar; Ferrari, Mauro; Wilson, Lon J.; Decuzzi, Paolo

    2010-01-01

    Magnetic resonance imaging contrast agents are currently designed by modifying their structural and physiochemical properties in order to improve relaxivity and to enhance image contrast. Here we show a general method for increasing relaxivity by confining contrast agents inside the nanoporous structure of silicon particles. Magnevist, gadofullerenes and gadonanotubes were loaded inside the pores of quasi-hemispherical and discoidal particles. For all combinations of nanoconstructs, a boost in longitudinal proton relaxivity r1 was observed: for Magnevist, r1~14 mM-1s-1/Gd3+ion (~8.15×10+7 mM-1s-1/construct); for gadofullerenes, r1~200 mM-1s-1/Gd3+ion (~7×10+9 mM-1s-1/construct); for gadonanotubes, r1~150 mM-1s-1/Gd3+ion (~2×10+9 mM-1s-1/construct). These relaxivity values are about 4 to 50 times larger than that of clinically-available gadolinium-based agents (~4 mM-1s-1 /Gd3+ion). The enhancement in contrast is attributed to the geometrical confinement of the agents, which influences the paramagnetic behavior of the Gd3+ions. Thus, nanoscale confinement offers a new and general strategy for enhancing the contrast of gadolinium-based contrast agents. PMID:20972435

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

    PubMed Central

    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

  18. Thermal neutron capture cross section of gadolinium by pile-oscillation measurements in MINERVE

    SciTech Connect

    Leconte, P.; Di-Salvo, J.; Antony, M.; Pepino, A.; Hentati, A.

    2012-07-01

    Natural gadolinium is used as a burnable poison in most LWR to account for the excess of reactivity of fresh fuels. For an accurate prediction of the cycle length, its nuclear data and especially its neutron capture cross section needs to be known with a high precision. Recent microscopic measurements at Rensselaer Polytechnic Inst. (RPI) suggest a 11% smaller value for the thermal capture cross section of {sup 157}Gd, compared with most of evaluated nuclear data libraries. To solve this inconsistency, we have analyzed several pile-oscillation experiments, performed in the MINERVE reactor. They consist in the measurement of the reactivity variation involved by the introduction in the reactor of small-samples, containing different mass amounts of natural gadolinium. The analysis of these experiments is done through the exact perturbation theory, using the PIMS calculation tool, in order to link the reactivity effect to the thermal capture cross section. The measurement of reactivity effects is used to deduce the 2200 m.s-1 capture cross section of {sup nat}Gd which is (49360 {+-} 790) b. This result is in good agreement with the JEFF3.1.1 value (48630 b), within 1.6% uncertainty at 1{sigma}, but is strongly inconsistent with the microscopic measurements at RPI which give (44200 {+-} 500) b. (authors)

  19. [Important of magnetic resonance angiography with gadolinium injection in pulmonary vein diseases].

    PubMed

    Godart, F; Cocheteux, B; Willoteaux, S; Francart, Ch; Brevière, G M; Jaillard, S; Beregi, J P; Rey, Ch

    2002-05-01

    The study of the pulmonary veins by echocardiography is sometimes difficult especially when the ultrasonic window is restricted. Conventional angiography is the classic reference examination but it exposes the patient to ionising radiation and requires the injection of an iodine contrast product. Another technique that can provide the essential information is magnetic resonance angiography (MRA) with injection of gadolinium. It was performed in 9 patients for suspected congenital or acquired anomalies of the pulmonary veins between June 1999 and December 2001. The patient's ages varied from 1 month to 10 years. The examinations were carried out on a 1.5 T Vision machine (Siemens, Erlangen, Germany) without "cardiac gating" or apnoea after parental consent. MRA with gadolinium injection showed 5 drainage anomalies (3 partial pulmonary venous refluxes in the superior vena cava, 2 scimitar syndromes) and 3 stenoses (one due to compression by an aneurysm of the left pulmonary artery, a second secondary to pericardial agenesis, and a third secondary to hypoplasia of an isolated vein). MRA allowed three dimensional visualisation of these anomalies. This is a rapid, non-invasive and certain imaging technique which does not expose the patient to ionising radiation. It is therefore of significance in the investigation of anomalies of the pulmonary veins complementing echocardiography, and could in future replace cardiac catheterisation.

  20. Nanodiamond-Gadolinium(III) Aggregates for Tracking Cancer Growth In Vivo at High Field.

    PubMed

    Rammohan, Nikhil; MacRenaris, Keith W; Moore, Laura K; Parigi, Giacomo; Mastarone, Daniel J; Manus, Lisa M; Lilley, Laura M; Preslar, Adam T; Waters, Emily A; Filicko, Abigail; Luchinat, Claudio; Ho, Dean; Meade, Thomas J

    2016-12-14

    The ability to track labeled cancer cells in vivo would allow researchers to study their distribution, growth, and metastatic potential within the intact organism. Magnetic resonance (MR) imaging is invaluable for tracking cancer cells in vivo as it benefits from high spatial resolution and the absence of ionizing radiation. However, many MR contrast agents (CAs) required to label cells either do not significantly accumulate in cells or are not biologically compatible for translational studies. We have developed carbon-based nanodiamond-gadolinium(III) aggregates (NDG) for MR imaging that demonstrated remarkable properties for cell tracking in vivo. First, NDG had high relaxivity independent of field strength, a finding unprecedented for gadolinium(III) [Gd(III)]-nanoparticle conjugates. Second, NDG demonstrated a 300-fold increase in the cellular delivery of Gd(III) compared to that of clinical Gd(III) chelates without sacrificing biocompatibility. Further, we were able to monitor the tumor growth of NDG-labeled flank tumors by T1- and T2-weighted MR imaging for 26 days in vivo, longer than was reported for other MR CAs or nuclear agents. Finally, by utilizing quantitative maps of relaxation times, we were able to describe tumor morphology and heterogeneity (corroborated by histological analysis), which would not be possible with competing molecular imaging modalities.

  1. 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.

  2. Pediatric Patients Demonstrate Progressive T1-Weighted Hyperintensity in the Dentate Nucleus following Multiple Doses of Gadolinium-Based Contrast Agent.

    PubMed

    Roberts, D R; Chatterjee, A R; Yazdani, M; Marebwa, B; Brown, T; Collins, H; Bolles, G; Jenrette, J M; Nietert, P J; Zhu, X

    2016-12-01

    While there have been recent reports of brain retention of gadolinium following gadolinium-based contrast agent administration in adults, a retrospective series of pediatric patients has not previously been reported, to our knowledge. We investigated the relationship between the number of prior gadolinium-based contrast agent doses and increasing T1 signal in the dentate nucleus on unenhanced T1-weighted MR imaging. We hypothesized that despite differences in pediatric physiology and the smaller gadolinium-based contrast agent doses that pediatric patients are typically administered based on weighted-adjusted dosing, the pediatric brain would also demonstrate dose-dependent increasing T1 signal in the dentate nucleus. We included children with multiple gadolinium-based contrast agent administrations at our institution. A blinded reader placed ROIs within the dentate nucleus and adjacent cerebellar white matter. To eliminate reader bias, we also performed automated ROI delineation of the dentate nucleus, cerebellar white matter, and pons. Dentate-to-cerebellar white matter and dentate-to pons ratios were compared with the number of gadolinium-based contrast agent administrations. During 20 years at our institution, 280 patients received at least 5 gadolinium-based contrast agent doses, with 1 patient receiving 38 doses. Sixteen patients met the inclusion/exclusion criteria for ROI analysis. Blinded reader dentate-to-cerebellar white matter ratios were significantly associated with gadolinium-based contrast agent doses (rs = 0.77, P = .001). The dentate-to-pons ratio and dentate-to-cerebellar white matter ratios based on automated ROI placement were also significantly correlated with gadolinium-based contrast agent doses (t = 4.98, P < .0001 and t = 2.73, P < .02, respectively). In pediatric patients, the number of prior gadolinium-based contrast agent doses is significantly correlated with progressive T1-weighted dentate hyperintensity. Definitive confirmation of

  3. The determination of samarium, europium, gadolinium and dysprosium in uranium products by direct-current plasma emission spectrometry.

    PubMed

    Flavelle, F; Westland, A D

    1986-05-01

    Samarium, europium, gadolinium and dysprosium were separated from uranium-containing materials by means of solvent extraction with Alamine 336, followed by cation-exchange. The elements were determined in the sub-ppm range by means of direct-current plasma atomic-emission spectrometry.

  4. Neutron and Charged-Particle Induced Cross Sections for Radiochemistry in the Region of Samarium, Europium, and Gadolinium

    SciTech Connect

    Hoffman, R D; Kelley, K; Dietrich, F S; Bauer, R; Mustafa, M

    2004-11-30

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron and proton induced nuclear reaction cross sections in the mass region of samarium, europium and gadolinium (62 {le} Z {le} 64, 82 {le} N {le} 96).

  5. Hybrid gold-gadolinium nanoclusters for tumor-targeted NIRF/CT/MRI triple-modal imaging in vivo

    NASA Astrophysics Data System (ADS)

    Hu, De-Hong; Sheng, Zong-Hai; Zhang, Peng-Fei; Yang, Da-Zhi; Liu, Shu-Hui; Gong, Ping; Gao, Du-Yang; Fang, Sheng-Tao; Ma, Yi-Fan; Cai, Lin-Tao

    2013-01-01

    Multimodal imaging is highly desirable for accurate diagnosis because it can provide complementary information from each imaging modality. In this study, we prepared hybrid gold-gadolinium nanoclusters (NCs), which are ultrasmall, stable, biocompatible, and suitable for triple-modal NIRF/CT/MRI imaging. Upon intravenously injected, the hybrid NCs are effectively accumulated in tumor tissues and quickly clear by renal excretion, indicating their capacity of tumor targeting and low body residues. Notably, the ultrasmall hybrid NCs would penetrate into the solid tumor for capturing its heterostructure and do not induce potential toxicity in vivo. Hence, the well-defined hybrid gold-gadolinium NCs provide a versatile nanoprobe for cancer targeted imaging and diagnosis in vivo.Multimodal imaging is highly desirable for accurate diagnosis because it can provide complementary information from each imaging modality. In this study, we prepared hybrid gold-gadolinium nanoclusters (NCs), which are ultrasmall, stable, biocompatible, and suitable for triple-modal NIRF/CT/MRI imaging. Upon intravenously injected, the hybrid NCs are effectively accumulated in tumor tissues and quickly clear by renal excretion, indicating their capacity of tumor targeting and low body residues. Notably, the ultrasmall hybrid NCs would penetrate into the solid tumor for capturing its heterostructure and do not induce potential toxicity in vivo. Hence, the well-defined hybrid gold-gadolinium NCs provide a versatile nanoprobe for cancer targeted imaging and diagnosis in vivo. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr33543c

  6. Endolymphatic hydrops in Meniere's disease detected by MRI after intratympanic administration of gadolinium: comparison with sudden deafness.

    PubMed

    Horii, Arata; Osaki, Yasuhiro; Kitahara, Tadashi; Imai, Takao; Uno, Atsuhiko; Nishiike, Suetaka; Fujita, Norihiko; Inohara, Hidenori

    2011-06-01

    The detection rate of endolymphatic hydrops was significantly higher in patients with Meniere's disease compared with those with sudden deafness, indicating that 3 T magnetic resonance imaging (MRI) with intratympanic gadolinium injection was effective in diagnosing endolymphatic hydrops. To compare the detection rate of endolymphatic hydrops between patients with Meniere's disease and sudden deafness as controls by 3 T MRI after intratympanic gadolinium injection with conventional pulse sequence such as two-dimensional fluid-attenuated inversion recovery. Ten patients with unilateral Meniere's disease and eight with sudden deafness underwent inner ear MRI 24 h after intratympanic gadolinium injection. The endolymphatic space was detected as a low signal intensity area, while the perilymphatic space showed high intensity by gadolinium enhancement. Due to faint enhancement, images could not be evaluated in 1 of 10 patients with Meniere's disease. However, the other nine patients together with two of the eight with sudden deafness were diagnosed as having hydrops. The difference in detection rates between the two diseases was statistically significant. Two hydrops-positive cases with sudden deafness were considered to be of the secondary type of hydrops, because images were taken after partial recovery from hearing loss several months after the onset of the disease.

  7. The feasibility of in vivo quantification of bone-gadolinium in humans by prompt gamma neutron activation analysis (PGNAA) following gadolinium-based contrast-enhanced MRI

    NASA Astrophysics Data System (ADS)

    Mostafaei, F.; McNeill, F. E.; Chettle, D. R.; Noseworthy, M. D.; Prestwich, W. V.

    2015-11-01

    The feasibility of using a 238Pu/Be-based in vivo prompt γ-ray neutron activation analysis (IVNAA) system, previously successfully used for measurements of muscle, for the detection of gadolinium (Gd) in bone was presented. Gd is extensively used in contrast agents in MR imaging. We present phantom measurement data for the measurement of Gd in the tibia. Gd has seven naturally occurring isotopes, of which two have extremely large neutron capture cross sections; 155Gd (14.8% natural abundance (NA), σ= 60,900 barns) and 157Gd (15.65% NA, σ= 254,000 barns). Our previous work focused on muscle but this only informs about the short term kinetics of Gd. We studied the possibility of measuring bone, as it may be a long term storage site for Gd. A human simulating bone phantom set was developed. The phantoms were doped with seven concentrations of Gd of concentrations 0.0, 25, 50, 75, 100, 120 and 150 ppm. Additional elements important for neutron activation analysis, Na, Cl and Ca, were also included to create an overall elemental composition consistent with Reference Man. The overall conclusion is that the potential application of this Pu-Be-based prompt in vivo NAA for the monitoring of the storage and retention of Gd in bone is not feasible.

  8. Magnetic resonance knee arthrography. Enhanced contrast by gadolinium complex in the rabbit and in humans.

    PubMed

    Engel, A

    1990-01-01

    This study contains the fundamentals and the technique of the intraarticular application of an MRI contrast agent in connection with magnetic resonance imaging (MRI arthrography). It also presents the resulting clinical relevance for knee joint diagnostics. The significance of MRI arthrography is linked above all to the central question of whether or not it is possible to depict the hyaline cartilage, its surface and its thickness with the help of MRI arthrography. MRI arthrography was used for in vitro examinations of rabbit knee joint cartilage and human joint cartilage. The in vivo application was carried out in 73 patients. Apart from the metric evaluation and the assessment of the information content of the MRI image, the corresponding histologic sections were made in 20 knee joints in order to compare the cartilage surface and the thickness of the cartilage with the results in the MRI image. The optimum amount of contrast agent for visualization was determined, the uptake and clearance of the contrast agent from the cartilage were assessed, and trace elements from the cartilage were also analyzed. The examination showed that the molecular structure of the contrast agent (gadolinium-DTPA) does not prevent the uptake of the contrast agent into the matrix of the hyaline cartilage. But this process is reversible. Thus, 14 hours after the intraarticular application of the contrast agent no measurable traces of gadolinium-DTPA could be established. The intraarticular application of the contrast agent also made it possible to achieve a constant and reproducible visualization of all joint structures. This affected mainly the surface of the hyaline cartilage. The best imaging quality was achieved with intraarticular application of 30 to 40 mL of a 2 mmolar solution of gadolinium-DTPA. The technique used for the intraarticular application is the same as for the common procedures of knee joint aspiration. The clinical importance of MRI arthrography lies in the fact that

  9. Ligand basicity and rigidity control formation of macrocyclic polyamino carboxylate complexes of gadolinium(III)

    SciTech Connect

    Kumar, K.; Tweedle, M.F. )

    1993-09-29

    The formation reaction rates of some macrocyclic polyamino carboxylate complexes of gadolinium, GdL (where L is DO3A = 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid, H[sub 3]L, HP-DO3A = 10-(hydroxyproyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid, H[sub 3]L, and DO3MA = (1R,4R,7R)-[alpha],[alpha][prime],[alpha][double prime]-trimethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-triacetic acid, H[sub 3]L), have been measured at 25.0 [+-] 0.1 [degrees]C and at a constant ionic strength of 1.0 (NaCl) by an indicator method. The formation reactions are first order in the limiting reagent (ligand) and nearly independent of the excess reagent (gadolinium ion). A mechanism of the formation of the gadolinium complexes involves the formation of a precursor (intermediate) complex, Gd(*HL), in an equilibrium step followed by its deprotonation and reorganization to the final product in the rate-determining step. The stability constants (log K[sub Gd(*HL)]) of the intermediate have been determined from the kinetic data and the values are 8.9 (DO3A), 9.0(HP-DO3A), and 10.7 (DO3MA). The nature of the intermediate is proposed in which the metal is coordinated to oxygens and at least one nitrogen of the ligand. Deprotonation and reorganization of the intermediate are specific-base assisted. The second-order rate constants (k[sub OH], M[sup [minus]1]s[sup [minus]1]) for the reorganization of the intermediate, Gd(*HL) (L are given in the parentheses), are (2.1 [+-] 0.1) x 10[sup 7] (DO3A), (1.23 [+-] 0.04) x 10[sup 7] (HP-DO3A), and (7.2 [+-] 0.3) x 10[sup 4] (DO3MA), compared to the literature data (7.1 [+-] 1) x 10[sup 7] (NOTA) and (5.9 [+-] 0.2) x 10[sup 6] (DOTA). The specific-base assisted rate of reorganization of the intermediate, Gd(*HL), is correlated with the ligand strain energy and its first protonation constant.

  10. Effect of gadolinium on the ryanodine receptor/sarcoplasmic reticulum calcium release channel of skeletal muscle.

    PubMed

    Sárközi, Sándor; Szegedi, Csaba; Lukács, Balázs; Ronjat, Michel; Jóna, István

    2005-01-01

    The effect of gadolinium ions on the sarcoplasmic reticulum (SR) calcium release channel/ryanodine receptor (RyR1) was studied using heavy SR (HSR) vesicles and RyR1 isolated from rabbit fast twitch muscle. In the [(3)H]ryanodine binding assay, 5 microM Gd(3+) increased the K(d) of the [(3)H]ryanodine binding of the vesicles from 33.8 nM to 45.6 nM while B(max), referring to the binding capacity, was not affected significantly. In the presence of 18 nM[(3)H]ryanodine and 100 microM free Ca(2+), Gd(3+) inhibited the binding of the radiolabeled ryanodine with an apparent K(d) value of 14.7 microM and a Hill coefficient of 3.17. In (45)Ca(2+) experiments the time constant of (45)Ca(2+) efflux from HSR vesicles increased from 90.9 (+/- 11.1) ms to 187.7 (+/- 24.9) ms in the presence of 20 microM gadolinium. In single channel experiments gadolinium inhibited the channel activity from both the cytoplasmic (cis) (IC(50) = 5.65 +/- 0.33 microM, n(Hill) = 4.71) and the luminal (trans) side (IC(50) = 5.47 +/- 0.24 microM, n(Hill) = 4.31). The degree of inhibition on the cis side didn't show calcium dependency in the 100 microM to 1 mM Ca(2+) concentration range which indicates no competition with calcium on its regulatory binding sites. When Gd(3+) was applied at the trans side, EGTA was present at the cis side to prevent the binding of Gd(+3) to the cytoplasmic calcium binding regulatory sites of the RyR1 if Gd(3+) accidentally passed through the channel. The inhibition of the channel did not show any voltage dependence, which would be the case if Gd(3+) exerted its effect after getting to the cis side. Our results suggest the presence of inhibitory binding sites for Gd(3+) on both sides of the RyR1 with similar Hill coefficients and IC(50) values.

  11. Effect of the mineralizer solution in the hydrothermal synthesis of gadolinium-doped (10% mol Gd) ceria nanopowders.

    PubMed

    Dell'Agli, Gianfranco; Spiridigliozzi, Luca; Marocco, Antonello; Accardo, Grazia; Ferone, Claudio; Cioffi, Raffaele

    2016-05-18

    Gadolinium-doped ceria is an attractive electrolyte material for potential application in solid oxide fuel cells (SOFCs) operating at intermediate temperatures typically with 10%-20% substitution of Ce+4 by Gd+3. In particular, 10% gadolinium-doped ceria seems to have the highest values of conductivities among the other dopant compositions. Nanosized powders of gadolinium-doped ceria were prepared by hydrothermal treatment using coprecipitate as a precursor and in the presence of 3 different mineralizer solutions. The powders obtained were characterized by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy and thermal analysis, while the electrical behavior of the corresponding pellets were ascertained by AC impedance spectroscopy. Nanocrystalline gadolinium-doped ceria powders with fluorite cubic crystal structure were obtained by hydrothermal treatment. Independent of the mineralizer used, these powders were able to produce very dense ceramics, especially when selecting an optimized sintering cycle. In contrast, the electrical behavior of the samples was influenced by the mineralizer solution, and the samples synthesized in the neutral and alkaline solutions showed higher values of electrical conductivity, in the range of temperatures of interest. By the coprecipitation method, it has been possible to synthesize nanosized gadolinium-doped cerium oxide in a fluorite structure, stable in a wide range of temperatures. Hydrothermal treatment directly on the as-synthesized coprecipitates, without any drying step, had a very positive effect on the powders, which can be sintered with a high degree of densification, especially with an optimized sintering cycle. Furthermore, the electrical behavior of these samples was very interesting, especially for the samples synthesized using neutral mineralizer solution and basic mineralizer solution.

  12. Late gadolinium enhancement and adverse outcomes in a contemporary cohort of adult survivors of tetralogy of Fallot.

    PubMed

    Dobson, Richard J; Mordi, Ify; Danton, Mark H; Walker, Niki L; Walker, Hamish A; Tzemos, Nikolaos

    2017-01-01

    Myocardial fibrosis has been associated with poorer outcomes in tetralogy of Fallot, however only a handful of studies have assessed its significance in the current era. Our aim was to quantify the amount of late gadolinium enhancement in both the LV and RV in a contemporary cohort of adults with surgically repaired tetralogy of Fallot, and assess the relationship with adverse clinical outcomes. Single centre cohort study SETTING: National tertiary referral center Patients: One hundred fourteen patients with surgically repaired tetralogy of Fallot with median age 29.5 years (range 17.5-64.2). Prospective follow-up for mean 2.4 years (SD 1.29). Cardiovascular magnetic resonance was performed, and late gadolinium enhancement mass was estimated for the LV using the 5-SD remote myocardium method, and for the RV using a segmental scoring system. Cohort characterization was determined through the use of a computerized database. Survival analysis from time of scan to first adverse event, defined as an episode of atrial arrhythmia, sustained ventricular arrhythmia, hospitalization with heart failure, or implantable cardioverter-defibrillator insertion. Eleven patients experienced an adverse outcome in the follow-up period, although there were no deaths. LV late gadolinium enhancement was associated with adverse outcomes in a univariate model (P = .027). However, when adjusted for age at scan the significant variables included NYHA class (P = .006), peak oxygen uptake (P = .028), number of prior sternotomies (P = .044), and higher indexed RV and LV end diastolic volumes (P = .002 and P < .001), but not RV or LV late gadolinium enhancement. Formal quantification of late gadolinium enhancement is not currently as helpful in ascertaining prognosis compared to other, more easily assessed parameters in a contemporary cohort of tetralogy of Fallot survivors, however assessment particularly of the LV holds promise for the future. © 2016 Wiley Periodicals

  13. Hepatic Gadolinium Deposition and Reversibility after Contrast Agent-enhanced MR Imaging of Pediatric Hematopoietic Stem Cell Transplant Recipients.

    PubMed

    Maximova, Natalia; Gregori, Massimo; Zennaro, Floriana; Sonzogni, Aurelio; Simeone, Roberto; Zanon, Davide

    2016-11-01

    Purpose To determine if hepatic gadolinium deposition occurs in pediatric patients with iron overload but normal renal and hepatic function who undergo gadolinium-based contrast agent (GBCA)-enhanced magnetic resonance (MR) imaging. Materials and Methods Design and execution of this study was approved by the Ethical Committee of Institute for Research in Maternal and Child Health Burlo Garofolo of Trieste (reference no. 1105/2015). Because of the retrospective nature of the study, the requirement to obtain informed consent was waived. Twenty-one recipients of allogeneic hematopoietic stem cell transplants who underwent GBCA-enhanced MR imaging for suspected infection or relapse followed by liver biopsy comprised the study group. The number of GBCA-enhanced MR examinations and cumulative gadolinium dose for each patient was analyzed by comparing liver histologic analysis and iron and gadolinium liver concentration (GLC). Eight patients had siderosis and underwent chelation therapy. The study group was compared with four control patients who were never exposed to GBCA. Statistical analysis was performed with Spearman rank coefficient for correlation. Results All 21 patients had positive correlations between GLC and total GBCA dose (r = 0.4486; P < .05) and between GLC and liver iron concentration (r = 0.56; P < .05). Patients who underwent deferoxamine therapy had a significant reduction of GLC (from 0.64 μg/g ± 0.29 to 0.20 μg/g ± 0.17 [standard deviation]; P < .05). Conclusion In the presence of siderosis, a transmetallation mechanism may be set off between ferric ion and gadoterate meglumine. Deferoxamine appears capable of binding to gadolinium ion. Further studies of the safety of GBCAs in severe siderosis are needed. Chelation should be considered in patients with iron overload and a history of GBCA exposure. (©) RSNA, 2016.

  14. Tolerance and Long-Term MRI Imaging of Gadolinium-Modified Meshes Used in Soft Organ Repair

    PubMed Central

    Letouzey, Vincent; Huberlant, Stéphanie; Cornille, Arnaud; Blanquer, Sébastien; Guillaume, Olivier; Lemaire, Laurent; Garric, Xavier; de Tayrac, Renaud

    2015-01-01

    Background Synthetic meshes are frequently used to reinforce soft tissues. The aim of this translational study is to evaluate tolerance and long-term MRI visibility of two recently developed Gadolinium-modified meshes in a rat animal model. Materials and Methods Gadolinium-poly-ε-caprolactone (Gd-PCL) and Gadolinium-polymethylacrylate (Gd-PMA) modified meshes were implanted in Wistar rats and their tolerance was assessed daily. Inflammation and biocompatibility of the implants were assessed by histology and immunohistochemistry after 30 days post implantation. Implants were visualised by 7T and 3T MRI at day 30 and at day 90. Diffusion of Gadolinium in the tissues of the implanted animals was assessed by Inductively Coupled Plasma Mass Spectrometry. Results Overall Gd-PMA coated implants were better tolerated as compared to those coated with Gd-PCL. In fact, Gd-PMA implants were characterised by a high ratio collagen I/III and good vascularisation of the integration tissues. High resolution images of the coated mesh were obtained in vivo with experimental 7T as well as 3T clinical MRI. Mass spectrometry analyses showed that levels of Gadolinium in animals implanted with coated mesh were similar to those of the control group. Conclusions Meshes coated with Gd-PMA are better tolerated as compared to those coated with Gd-PCL as no signs of erosion or significant inflammation were detected at 30 days post implantation. Also, Gd-PMA coated meshes were clearly visualised with both 7T and 3T MRI devices. This new technique of mesh optimisation may represent a valuable tool in soft tissue repair and management. PMID:25811855

  15. Influence of gadolinium doping on the structure and defects of ceria under fuel cell operating temperature

    NASA Astrophysics Data System (ADS)

    Acharya, S. A.; Gaikwad, V. M.; Sathe, V.; Kulkarni, S. K.

    2014-03-01

    Correlation between atomic positional shift, oxygen vacancy defects, and oxide ion conductivity in doped ceria system has been established in the gadolinium doped ceria system from X-ray diffraction (XRD) and Raman spectroscopy study at operating temperature (300-600 °C) of Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC). High temperature XRD data are used to quantify atomic positional shift from mean position with temperature. The Raman spectroscopy study shows additional vibration modes related to ordering of defect spaces (GdCe'-Vo••)* and (2GdCe'-Vo••)x generated due to association of oxygen vacancies and reduced cerium or dopant cations site (Gd3+), which disappear at 450 °C; indicating oxygen vacancies dissociation from the defect complex. The experimental evidences of cation-anion positional shifting and oxygen vacancies dissociation from defect complex in the IT-SOFC operating temperature are discussed to correlate with activation energy for ionic conductivity.

  16. Novel structured gadolinium doped ceria based electrolytes for intermediate temperature solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Timurkutluk, Bora; Timurkutluk, Cigdem; Mat, Mahmut D.; Kaplan, Yuksel

    Novel three-layered intermediate temperature solid oxide fuel cell (SOFC) electrolytes based on gadolinium doped ceria (GDC) are developed to suppress the electronic conductivity of GDC, to improve the mechanical properties of the cell and to minimize power loss due to mixed conductive nature of GDC. Three different electrolytes are fabricated by sandwiching thin YSZ, ScSZ and ScCeSZ between two relatively thick GDC layers. An electrolyte composed of pure GDC is also manufactured for comparison. NiO/GDC and LSCF/GDC electrodes are then coated on the electrolytes by a screen printing route. SEM results show that it is possible to obtain dense and crack free thin layers of YSZ, ScSZ and ScCeSZ between two GDC layers without delamination. Performance measurements indicate that interlayered thin electrolytes act as an electronic conduction barrier and improve open circuit voltages (OCVs) of GDC based cells.

  17. Synthesis of bulk-size transparent gadolinium oxide-polymer nanocomposites for gamma ray spectroscopy.

    PubMed

    Cai, Wen; Chen, Qi; Cherepy, Nerine; Dooraghi, Alex; Kishpaugh, David; Chatziioannou, Arion; Payne, Stephen; Xiang, Weidong; Pei, Qibing

    2013-03-14

    Heavy element loaded polymer composites have long been proposed to detect high energy X- and γ-rays upon scintillation. The previously reported bulk composite scintillators have achieved limited success because of the diminished light output resulting from fluorescence quenching and opacity. We demonstrate the synthesis of a transparent nanocomposite comprising gadolinium oxide nanocrystals uniformly dispersed in bulk-size samples at a high loading content. The strategy to avoid luminescence quenching and opacity in the nanocomposite was successfully deployed, which led to the radioluminescence light yield of up to 27 000/MeV, about twice as much as standard commercial plastic scintillators. Nanocomposites monoliths (14 mm diameter by 3 mm thickness) with 31 wt% loading of nanocrystals generated a photoelectric peak for Cs-137 gamma (662 keV) with 11.4% energy resolution.

  18. Characterization of PAH matrix with monazite stream containing uranium, gadolinium and iron

    NASA Astrophysics Data System (ADS)

    Pal, Sangita; Meena, Sher Singh; Goswami, D.

    2016-05-01

    Uranium (U) gadolinium(Gd) and iron (Fe) containing alkaline waste simulated effluent (relevant to alkaline effluent of monazite ore) has been treated with a novel amphoteric resin viz, Polyamidehydroxamate (PAH) containing amide and hydroxamic acid groups. The resin has been synthesized in an eco-friendly manner by polymerization nad conversion to functional groups characterized by FT-IR spectra and architectural overview by SEM. Coloration of the loaded matrix and de-coloration after extraction of uranium is the special characteristic of the matrix. Effluent streams have been analyzed by ICP-AES, U loaded PAH has been characterized by FT-IR, EXAFS, Gd and Fe by X-ray energy values of EDXRF at 6.053 Kev and 6.405 Kev respectively. The remarkable change has been observed in Mössbauer spectrum of Fe-loaded PAH samples.

  19. Luminescence properties of Eu3+-doped Lanthanum gadolinium hafnates transparent ceramics

    NASA Astrophysics Data System (ADS)

    Wang, Zhengjuan; Zhou, Guohong; Zhang, Jian; Qin, Xianpeng; Wang, Shiwei

    2017-09-01

    Eu3+-doped Lanthanum gadolinium hafnates (La0.8Gd1.2Hf2O7) transparent ceramics with different Eu3+ concentration were fabricated by vacuum sintering. XRD results showed all the ceramics are cubic pyrochlore structure. The effects of annealing process on in-line transmittance and luminescence behavior of the Eu3+-doped La0.8Gd1.2Hf2O7 transparent ceramics were investigated. Before annealing, the in-line transmittance of the ceramics was low and the luminescence intensity was weak. As Eu3+ doping content increased, the transmittance as well as the luminescence intensity decreased. This was ascribed to oxygen vacancy and other defects in the ceramics resulted from the vacuum sintering. After annealing, the transmittance and luminescence intensity were raised, indicating the elimination of oxygen vacancy. Moreover, with the increase of Eu3+ doping content from 1 at% to 10 at%, the luminescence intensity increased without concentration quenching.

  20. Gadolinium-free MR in coarctation-can contrast-enhanced MR angiography be replaced?

    PubMed

    Kalmar, Peter I; Koestenberger, Martin; Marterer, Robert; Tschauner, Sebastian; Sorantin, Erich

    2016-01-01

    To determine the difference in vessel measurements, signal-to-noise ratio (SNR), and voxel size between contrast-enhanced and noncontrast magnetic resonance techniques in patients with coarctation of the aorta (CoA). In 39 patients, vessel size, SNR, and voxel size were compared in cine magnetic resonance imaging (MRI), gadolinium-free magnetic resonance angiography (Gd-free MRA), and contrast-enhanced MRA (ce-MRA). There was no significant difference in measurement and SNR, but there was a significant difference in voxel size (P<.001). Our results show that, in CoA patients, monitoring of vessel size using cine MRI and Gd-free MRA is equivalent to ce-MRA while being less invasive. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Radioluminescence and optical studies of gadolinium calcium phosphate oxyfluoride glasses doped with Sm3+

    NASA Astrophysics Data System (ADS)

    Meejitpaisan, P.; Insiripong, S.; Kedkaew, C.; Kim, H. J.; Kaewkhao, J.

    2017-08-01

    Sm3+-doped gadolinium calcium phosphate oxyfluoride glasses have been synthesized and investigated their optical, photo and radioluminescence properties. The glasses were prepared by melt quenching technique at 1400 °C. The characteristic absorption bands of Sm3+ ions originating from the 6H5/2 ground state and occurring absorbed photon in visible light (VIS) and near-infrared (NIR) region with clearly observed from absorption spectra. From the photoluminescence (PL), the glasses showed the emission at 561 (4G5/2→6H5/2), 598 (4G5/2→6H7/2), 644 (4G5/2→6H9/2) and 705 nm (4G5/2→6H11/2). The radioluminescence (RL), emission spectra were corresponding to those from PL measurements. From RL measurement, the integral scintillation efficiency of developed glass was determined at 43% when compared with BGO crystal.

  2. Analysis of Blood Gadolinium in an Isotope Geochemist Following Contrast MRI

    NASA Astrophysics Data System (ADS)

    Wasylenki, L. E.

    2011-12-01

    Normal brain tissue does not have blood flowing throughout it; instead oxygen diffuses across a blood-brain barrier in order to oxygenate brain cells. Brain tumors, however, do grow blood supplies, so an abnormal distribution of blood in the brain is a key indicator of abnormal cell growth. But how is the distribution of blood in inside the brain observed? The lanthanide ion gadolinium(III) has unpaired 5f-shell electrons and is thus paramagnetic. As such, the presence of Gd causes the nuclei of nearby atoms to relax more quickly when excited to high-energy spin states by pulses of radio-frequency energy than they would without Gd nearby. The signal in magnetic resonance imaging correlates with this nuclear spin relaxation time, so gadolinium's presence in certain body tissues makes those tissues appear as bright areas on MRI images. Gadolinium is therefore commonly injected intravenously just prior to MRI imaging, so that the distribution of blood in and around the brain can be mapped. Gadolinium as a free ion is toxic, so it is injected in a relatively inert form, often as gadoversetamide, in which Gd is tightly bound in nine-fold coordination with N, C, and O. This compound is removed from the blood by the kidneys at a rate that is fast compared to the rate of breakdown of this compound in the blood, thus preventing release of toxic Gd in the bloodstream. But how quickly can the kidneys of an isotope geochemist remove Gd from blood? In this experiment, a single isotope geochemist's wristwatch was synchronized with that of the MRI technician and then left in a dressing room with all other magnetically susceptible objects until after the MRI. The time of intravenous injection of gadoversetamide into the isotopist was recorded by the technician and later transmitted verbally to the isotopist. Following the MRI session, blood samples were collected by self-fingerprick, in a Class 100 trace metal clean lab, from 47 to 281 minutes after intravenous injection. For each

  3. Modeling of gadolinium recovery from nitrate medium with 8-hydroxyquinoline by emulsion liquid membrane.

    PubMed

    Hasan, M A; Aglan, R F; El-Reefy, S A

    2009-07-30

    The extraction equilibrium of Gd(III) from nitrate medium by 8-hydroxyquinoline (HOX) in toluene was studied. Liquid-liquid investigations were first carried out. Based on the equilibrium results, the extraction of Gd(III) from aqueous nitrate medium into an emulsion liquid membrane system (ELM) containing 8-hydroxyquinoline in toluene as extractant, HNO(3) as stripping solution, Span-80 as surfactant was studied. The stability of the prepared ELM was studied in terms of the degree of membrane breakage. The different parameters affecting the permeation of gadolinium (III) were also studied. A general permeation model for the recovery of Gd(III) by the selected membrane is presented. The internal mass transfer in the water in oil (W/O) emulsion drop, the external mass transfer around the drop, the rates of formation and decomposition of the complex at the external aqueous-organic interface were considered.

  4. X-ray Absorption Improvement of Single Wall Carbon Nanotube through Gadolinium Encapsulation

    NASA Astrophysics Data System (ADS)

    Alimin; Narsito, I.; Kartini; Santosa, S. J.

    2016-02-01

    X-ray absorption improvement of single-wall carbon nanotube (SWCNT) through gadolinium (Gd) encapsulation has been studied. The liquid phase adsorption using ethanol has been performed for the doping treatment. The Gd-doped SWCNT (Gd@SWCNT) was characterized by nitrogen adsorption isotherms, Raman spectroscopy, Transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA) techniques. A relatively high residual weight of Gd@SWCNT compared to non-doped SWCNT (n-SWCNT) indicated that Gd has been doped in the nanotube. Even though Gd nanoparticles could not be observed clearly by TEM image, however, a significant decrease of nitrogen uptakes at low pressure and RBM (Radial Breathing Mode) upshift of Raman spectra of Gd@SWCNT specimen suggest that the metal nanoparticles might be encapsulated in the internal tube spaces of the nanotube. It was found that Gd-doped in the SWCNT increased significantly mass attenuation coefficient of the nanotube.

  5. Characterization of PAH matrix with monazite stream containing uranium, gadolinium and iron

    SciTech Connect

    Pal, Sangita Goswami, D.; Meena, Sher Singh

    2016-05-23

    Uranium (U) gadolinium (Gd) and iron (Fe) containing alkaline waste simulated effluent (relevant to alkaline effluent of monazite ore) has been treated with a novel amphoteric resin viz, Polyamidehydroxamate (PAH) containing amide and hydroxamic acid groups. The resin has been synthesized in an eco-friendly manner by polymerization nad conversion to functional groups characterized by FT-IR spectra and architectural overview by SEM. Coloration of the loaded matrix and de-coloration after extraction of uranium is the special characteristic of the matrix. Effluent streams have been analyzed by ICP-AES, U loaded PAH has been characterized by FT-IR, EXAFS, Gd and Fe by X-ray energy values of EDXRF at 6.053 KeVand 6.405 KeV respectively. The remarkable change has been observed in Mössbauer spectrum of Fe-loaded PAH samples.

  6. Obtaining gadolinium nanoparticles and studying their properties in a helium flow

    NASA Astrophysics Data System (ADS)

    Petinov, V. I.

    2016-07-01

    A method for obtaining Gd nanoparticles with diameters of 89 to 18 nm upon metal evaporation both in a flow of pure helium and with the addition of 0.5% of oxygen is described. It is found that the addition of O2 does not affect the size of the particles, their structure, or the Curie temperature, though the magnetization is reduced. Particles with sizes of 18 nm have cubic lattice symmetry (fcc) and remain paramagnetic below T c; with an increase in the size of nanoparticles, the proportion of the hexagonal (hcp) phase, which coincides with the gadolinium structure, also grows, and below T c such particles become ferromagnetic. Oxygen impurities seem to have no effect on magnetic and structural transitions in nanoparticles.

  7. Effect of Gadolinium Doping on the Air Oxidation of Uranium Dioxide

    SciTech Connect

    Scheele, Randall D.; Hanson, Brady D.; Cumblidge, Stephen E.; Jenson, Evan D.; Kozelisky, Anne E.; Sell, Rachel L.; MacFarlan, Paul J.; Snow, Lanee A.

    2004-12-04

    Researchers at the Pacific Northwest National Laboratory (PNNL) investigated the effects of gadolinia concentration on the air oxidization of gadolinia-doped uranium dioxide using thermogravimetry and differential scanning calorimetry to determine if such doping could improve uranium dioxide's stability as a nuclear fuel during potential accident scenarios in a nuclear reactor or during long-term disposal. We undertook this study to determine whether the resistance of the uranium dioxide to oxidation to the orthorhombic U3O8 with its attendant crystal expansion could be prevented by addition of gadolinia. Our studies found that gadolinium has little effect on the thermal initiation of the first step of the reported two-step air oxidation of UO2; however, increasing gadolinia content does stabilize the initial tetragonal or cubic product allowing significant oxidation before the second expansive step to U3O8 begins.

  8. Feasibility study of a gadolinium-loaded DIN-based liquid scintillator

    NASA Astrophysics Data System (ADS)

    Song, Sook Hyung; Joo, Kyung Kwang; So, Sun Heang; Yeo, In Sung

    2013-09-01

    DIN (di-isopropylnaphthalene) has a high flashpoint and can be used as a base solvent in liquid scintillators. It reduces safety concerns to humans and the environment. (PPO, 3 g/ ℓ) and (bis-MSB, 30 mg/ ℓ) were dissolved to formulate a DIN-based liquid scintillator (LS). A gadolinium (Gd) complex with carboxylic acid was synthesized using a neutralized chemical reaction. Then, 0.1% Gd was loaded into the LS. This Gd-loaded DIN-based LS using a solvent-solvent extraction method is the first attempt at a LS. In this study, we investigated the physical and the optical properties of this LS, and we will summarize all the characteristics of the Gd-loaded DIN-based LS.

  9. Synthesis of bulk-size transparent gadolinium oxide–polymer nanocomposites for gamma ray spectroscopy

    PubMed Central

    Cai, Wen; Chen, Qi; Cherepy, Nerine; Dooraghi, Alex; Kishpaugh, David; Chatziioannou, Arion; Payne, Stephen; Xiang, Weidong

    2015-01-01

    Heavy element loaded polymer composites have long been proposed to detect high energy X- and γ-rays upon scintillation. The previously reported bulk composite scintillators have achieved limited success because of the diminished light output resulting from fluorescence quenching and opacity. We demonstrate the synthesis of a transparent nanocomposite comprising gadolinium oxide nanocrystals uniformly dispersed in bulk-size samples at a high loading content. The strategy to avoid luminescence quenching and opacity in the nanocomposite was successfully deployed, which led to the radioluminescence light yield of up to 27 000/MeV, about twice as much as standard commercial plastic scintillators. Nanocomposites monoliths (14 mm diameter by 3 mm thickness) with 31 wt% loading of nanocrystals generated a photoelectric peak for Cs-137 gamma (662 keV) with 11.4% energy resolution. PMID:26478816

  10. Transient band structures in the ultrafast demagnetization of ferromagnetic gadolinium and terbium

    NASA Astrophysics Data System (ADS)

    Teichmann, Martin; Frietsch, Björn; Döbrich, Kristian; Carley, Robert; Weinelt, Martin

    2015-01-01

    We compare the laser-driven demagnetization dynamics of the rare earths gadolinium and terbium by mapping their transient valance band structures with time- and angle-resolved photoelectron spectroscopy. In both metals, the minority and majority spin valence bands evolve independently with different time constants after optical excitation. The ultrafast shift of the partially unoccupied minority spin bulk band to higher binding energy and of the majority spin surface state to lower binding energy suggests spin transport between surface and bulk. The slower response of the fully occupied majority spin band follows the lattice temperature and is attributed to Elliott-Yafet type spin-flip scattering. Terbium shows a stronger and faster decay of the exchange splitting, pointing to ultrafast magnon emission via 4 f spin-to-lattice coupling.

  11. Dielectric and conducting behavior of gadolinium-terbium fumarate heptahydrate crystals

    NASA Astrophysics Data System (ADS)

    Shah, M. D.; Want, B.

    2015-07-01

    Gadolinium-terbium fumarate heptahydrate crystals were grown in silica gel by using single gel diffusion technique. The crystals were characterized by different physico-chemical techniques of characterization. Powder X-ray diffraction results showed that the grown material is purely crystalline in nature. Elemental analyses suggested the chemical formula of the compound to be Gd Tb (C4H2O4)3ṡ7H2O. Energy dispersive X-ray analysis confirmed the presence of Gd and Tb in the title compound. The dielectric and conductivity studies of the grown compound were carried as function of frequency of applied field and the temperature. The grown material showed a dielectric anomaly which was correlated with its thermal behavior. The ac conductivity of the material showed Jonscher's power law behavior: σ(ω)=σo+Aωs, with a temperature-dependent power exponent s(<1). The conductivity was found to be a function of temperature and frequency.

  12. Controllable Fabrication and Optical Properties of Uniform Gadolinium Oxysulfate Hollow Spheres

    PubMed Central

    Chen, Fashen; Chen, Gen; Liu, Tao; Zhang, Ning; Liu, Xiaohe; Luo, Hongmei; Li, Junhui; Chen, Limiao; Ma, Renzhi; Qiu, Guanzhou

    2015-01-01

    Uniform gadolinium oxysulfate (Gd2O2SO4) hollow spheres were successfully fabricated by calcination of corresponding Gd-organic precursor obtained via a facile hydrothermal process. The Gd2O2SO4 hollow spheres have a mean diameter of approximately 550 nm and shell thickness in the range of 30–70 nm. The sizes and morphologies of as-prepared Gd2O2SO4 hollow spheres could be deliberately controlled by adjusting the experimental parameters. Eu-doped Gd2O2SO4 hollow spheres have also been prepared for the property modification and practical applications. The structure, morphology, and properties of as-prepared products were characterized by XRD, TEM, HRTEM, SEM and fluorescence spectrophotometer. Excited with ultraviolet (UV) pump laser, successful downconversion (DC) could be achieved for Eu-doped Gd2O2SO4 hollow spheres. PMID:26671661

  13. In vivo selective cancer-tracking gadolinium eradicator as new-generation photodynamic therapy agent

    PubMed Central

    Zhang, Tao; Lan, Rongfeng; Chan, Chi-Fai; Law, Ga-Lai; Wong, Wai-Kwok; Wong, Ka-Leung

    2014-01-01

    In this work, we demonstrate a modality of photodynamic therapy (PDT) through the design of our truly dual-functional—PDT and imaging—gadolinium complex (Gd-N), which can target cancer cells specifically. In the light of our design, the PDT drug can specifically localize on the anionic cell membrane of cancer cells in which its laser-excited photoemission signal can be monitored without triggering the phototoxic generation of reactive oxygen species—singlet oxygen—before due excitation. Comprehensive in vitro and in vivo studies had been conducted for the substantiation of the effectiveness of Gd-N as such a tumor-selective PDT photosensitizer. This treatment modality does initiate a new direction in the development of “precision medicine” in line with stem cell and gene therapies as tools in cancer therapy. PMID:25453097

  14. Predictors of mesorectal fascia invasion after gadolinium injection in rectal carcinoma after neoadjuvant therapy.

    PubMed

    Quaia, Emilio; Gennari, Antonio Giulio; De Paoli, Luca; Angileri, Roberta; Ukmar, Maja; Cova, Maria Assunta

    2014-01-01

    To assess spectral presaturation inversion-recovery MRI sequence with gadolinium to identify predictors of mesorectal fascia (MRF) invasion in patients with locally advanced rectal carcinoma after neoadjuvant therapy. Sixty-five patients underwent neoadjuvant concomitant radiation and chemotherapy and surgery. Magnetic resonance images were assessed by two radiologists. Linear (odds ratio, 95% confidence intervals: 19.33, 1.98-188.6) and reticular strands (odds ratio, 95% confidence intervals: 9.75, 1.45-67.77) reaching the MRF are predictors of MRF invasion. Linear or reticular mesorectal strands reaching the MRF detected at contrast-enhanced MRI represent a predictor of MRF invasion. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Effects of exposure to gadolinium on the development of geographically and phylogenetically distant sea urchins species.

    PubMed

    Martino, Chiara; Bonaventura, Rosa; Byrne, Maria; Roccheri, Maria; Matranga, Valeria

    2016-06-02

    Gadolinium (Gd), a metal of the lanthanide series used as contrast agent for magnetic resonance imaging, is released into the aquatic environment. We investigated the effects of Gd on the development of four sea urchin species: two from Europe, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Exposure to Gd from fertilization resulted in inhibition or alteration of skeleton growth in the plutei. The similar morphological response to Gd in the four species indicates a similar mechanism underlying abnormal skeletogenesis. Sensitivity to Gd greatly varied, with the EC50 ranging from 56 nM to 132 μM across the four species. These different sensitivities highlight the importance of testing toxicity in several species for risk assessment. The strong negative effects of Gd on calcification in plutei, together with the plethora of marine species that have calcifying larvae, indicates that Gd pollution is urgent issue that needs to be addressed.

  16. Nanosystem composed with MSNs, gadolinium, liposome and cytotoxic peptides for tumor theranostics.

    PubMed

    Jin, Yaqing; Zhang, Nengpan; Li, Chunlin; Pu, Kefeng; Ding, Chen; Zhu, Yimin

    2017-03-01

    A dual-functional delivery system, based on mesoporous silica nanoparticles (MSNs) with the integration of Magnetic Resonance (MR) imaging and therapeutic peptide delivery, is reported in this paper. A lipid bilayer is attached onto the surface of the nanoparticles, following the doping of Gadolinium (Gd), a paramagnetic lanthanide ion. The liposome-coated GdMSNs exhibit improved colloidal stability, better biocompatibility and more efficient cellular uptake. The Gd renders the nano carrier a potential T1 contrast agent, confirmed by the MR imaging. A pro-apoptotic peptide, KLA (HGGKLAKLAKKLAKLAK), is encapsulated into the GdMSNs-LP and enters into the cells successfully to induce mitochondrial swelling and apoptosis, while it is nontoxic outside the cells. The synthesis procedure is convenient and free of toxic organic reagents. The nanosystem we construct may contribute to a promising theranostic platform for therapeutic peptide delivery in cancer treatment.

  17. Gadolinium(III) complexes as MRI contrast agents: ligand design and properties of the complexes.

    PubMed

    Hermann, Petr; Kotek, Jan; Kubícek, Vojtech; Lukes, Ivan

    2008-06-21

    Magnetic resonance imaging is a commonly used diagnostic method in medicinal practice as well as in biological and preclinical research. Contrast agents (CAs), which are often applied are mostly based on Gd(III) complexes. In this paper, the ligand types and structures of their complexes on one side and a set of the physico-chemical parameters governing properties of the CAs on the other side are discussed. The solid-state structures of lanthanide(III) complexes of open-chain and macrocyclic ligands and their structural features are compared. Examples of tuning of ligand structures to alter the relaxometric properties of gadolinium(III) complexes as a number of coordinated water molecules, their residence time (exchange rate) or reorientation time of the complexes are given. Influence of the structural changes of the ligands on thermodynamic stability and kinetic inertness/lability of their lanthanide(III) complexes is discussed.

  18. Redox-Triggered Self-Assembly of Gadolinium-Based MRI Probes for Sensing Reducing Environment

    PubMed Central

    2014-01-01

    Controlled self-assembly of small molecule gadolinium (Gd) complexes into nanoparticles (GdNPs) is emerging as an effective approach to design activatable magnetic resonance imaging (MRI) probes and amplify the r1 relaxivity. Herein, we employ a reduction-controlled macrocyclization reaction and self-assembly to develop a redox activated Gd-based MRI probe for sensing a reducing environment. Upon disulfide reduction at physiological conditions, an acyclic contrast agent 1 containing dual Gd-chelates undergoes intramolecular macrocyclization to form rigid and hydrophobic macrocycles, which subsequently self-assemble into GdNPs, resulting in a ∼60% increase in r1 relaxivity at 0.5 T. Probe 1 has high r1 relaxivity (up to 34.2 mM–1 s–1 per molecule at 0.5 T) upon activation, and also shows a high sensitivity and specificity for MR detection of thiol-containing biomolecules. PMID:24992373

  19. General synthesis route to fabricate uniform upconversion luminescent gadolinium oxide hollow spheres.

    PubMed

    Jia, Guang; Zhang, Cuimiao; Ding, Shiwen; Wang, Liyong

    2011-08-01

    Uniform upconversion luminescent gadolinium oxide hollow spheres were successfully synthesized via a homogeneous precipitation method with carbon spheres as template followed by a calcination process. During the annealing process, the carbon spheres template can be effectively removed and the amorphous precursor has converted to crystalline Gd2O3, which can be confirmed by the XRD and TG-DSC analysis. SEM and TEM images indicate that the Gd2O3 hollow spheres with diameters of 300-400 nm are uniform in size and distribution. The rare earth activator ions Ln3+-doped Gd2O3 hollow spheres exhibit intense upconversion luminescence with different colors under 980 nm light excitation, which may find potential applications in the fields such as drug delivery or biological labeling. Moreover, the upconversion luminescent mechanisms of the hollow spherical phosphors were investigated in detail.

  20. Coherent spin dynamics in a gadolinium-doped CaW O4 crystal

    NASA Astrophysics Data System (ADS)

    Baibekov, E. I.; Gafurov, M. R.; Zverev, D. G.; Kurkin, I. N.; Rodionov, A. A.; Malkin, B. Z.; Barbara, B.

    2017-02-01

    We report the first observation of Rabi oscillations in the spin-7/2 ensemble of trivalent gadolinium ions hosted in CaW O4 single crystal. A number of transitions within the lowest electronic multiplet 8S7 /7 2 2 of G d3 + ion are studied using a combination of continuous-wave and pulsed electron paramagnetic resonance spectroscopy. The corresponding Rabi damping curves and the spin coherence times are detected at varying strengths of the microwave field. These data are well reproduced by a theoretical model which accounts for the intrinsic inhomogeneity of the microwave field within the microwave resonator and the magnetic dipole interactions in the diluted spin ensemble. The results indicate that the studied 8-level ground manifold of G d3 + ion can represent an effective three-qubit quantum system.

  1. Magnetically induced optical activity and dichroism of gadolinium oxide nanoparticle-based ferrofluids

    SciTech Connect

    Paul, Nibedita; Devi, Manasi; Mohanta, Dambarudhar; Saha, Abhijit

    2012-02-15

    The present work reports on magnetically induced optical activity (such as Faraday rotation and linear dichroism) of pristine and gamma-irradiated gadolinium oxide (Gd{sub 2}O{sub 3}) nanoparticle-based ferrofluids. The ferrofluids were produced by dispersing N-cetyl-N,N,N-trimethyl ammonium bromide (CTAB)-coated {approx}9-nm-sized Gd{sub 2}O{sub 3} particles in a carrier fluid of ethanol. The ferrofluids were then irradiated with 1.25 MeV energetic gamma rays (dose: 868 Gy and 2.635 kGy). Irradiation-led formation of a number of point defects was revealed through high resolution electron microscopy. The interaction of light with the ionized point defects is believed to have caused substantial improvement in the magneto-optic response of irradiated magnetic fluids.

  2. Induction of skeletal abnormalities and autophagy in Paracentrotus lividus sea urchin embryos exposed to gadolinium.

    PubMed

    Martino, Chiara; Chiarelli, Roberto; Bosco, Liana; Roccheri, Maria Carmela

    2017-07-06

    Gadolinium (Gd) concentration is constantly increasing in the aquatic environment, becoming an emergent environmental pollutant. We investigated the effects of Gd on Paracentrotus lividus sea urchin embryos, focusing on skeletogenesis and autophagy. We observed a delay of biomineral deposition at 24 hours post fertilization (hpf), and a strong impairment of skeleton growth at 48 hpf, frequently displayed by an asymmetrical pattern. Skeleton growth was found partially resumed in recovery experiments. The mesodermal cells designated to biomineralization were found correctly migrated at 24 hpf, but not at 48 hpf. Western blot analysis showed an increase of the LC3-II autophagic marker at 24 and 48 hpf. Confocal microscopy studies confirmed the increased number of autophagolysosomes and autophagosomes. Results show the hazard of Gd in the marine environment, indicating that Gd is able to affect different aspects of sea urchin development: morphogenesis, biomineralization, and stress response through autophagy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Quantitative imaging of proteoglycan in cartilage using a gadolinium probe and microCT.

    PubMed

    Cockman, M D; Blanton, C A; Chmielewski, P A; Dong, L; Dufresne, T E; Hookfin, E B; Karb, M J; Liu, S; Wehmeyer, K R

    2006-03-01

    Micro-computed tomography (microCT) imaging has the potential to allow the three-dimensional (3D) visualization of cartilage morphology. However, cartilage intensity on a microCT image is weak because cartilage does not strongly attenuate X-rays. This work was designed to demonstrate that exposure of cartilage to charged gadolinium compounds modifies the intensity to allow an improved visualization of cartilage morphology and the determination of proteoglycan content. Trypsin was used to deplete proteoglycan in bovine nasal cartilage disks. Disks were then exposed to Gd(3+), gadopentetate (Gd-DTPA(2-)), or gadoteridol (Gd-HP-DO3A), and imaged with microCT. The intensities of the disks were measured from the images and compared to the actual proteoglycan content determined with a dimethylmethylene blue assay. Treatment of naïve disks with 200 mM Gd(3+) for 24h at room temperature produced a 2.8-fold increase in intensity on microCT images. Similar treatment with 200 mM Gd-DTPA(2-) produced a 1.4-fold increase. After 2h of trypsin treatment at room temperature, the intensities of cartilage disks exposed to 20 0mM Gd(3+) decreased by 12%. Conversely, the intensities of trypsin-treated disks exposed to 200 mM Gd-DPTA(2-) increased by 15%. Trypsin treatment caused a 4% increase in the intensities of disks exposed to neutral Gd-HP-DO3A. The correlation between proteoglycan content and the microCT intensity of cartilage treated with Gd(3+) was very good (r(2)=0.81). Gadolinium and microCT allow an improved 3D visualization of cartilage and quantification of its proteoglycan content.

  4. Aqueous stability of gadolinium in surface waters receiving sewage treatment plant effluent Boulder Creek, Colorado

    USGS Publications Warehouse

    Verplanck, P.L.; Taylor, H.E.; Nordstrom, D.K.; Barber, L.B.

    2005-01-01

    In many surface waters, sewage treatment plant (STP) effluent is a substantial source of both regulated and unregulated contaminants, including a suite of complex organic compounds derived from household chemicals, pharmaceutical, and industrial and medical byproducts. In addition, STP effluents in some urban areas have also been shown to have a positive gadolinium (Gd) anomaly in the rare earth element (REE) pattern, with the Gd derived from its use in medical facilities. REE concentrations are relatively easy to measure compared to many organic wastewater compounds and may provide a more widely utilized tracer of STP effluents. To evaluate whether sewage treatment plant-associated Gd is a useful tracer of treatment plant effluent, an investigation of the occurrence, fate, and transport of rare earth elements was undertaken. The rare earth element patterns of four of five STP effluents sampled display positive Gd anomalies. The one site that did not have a Gd anomaly serves a small community, population 1200, with no medical facilities. Biosolids from a large metropolitan STP are not enriched in Gd even though the effluent is, suggesting that a substantial fraction of Gd remains in the aqueous phase through routine treatment plant operation. To evaluate whether STP-derived Gd persists in the fluvial environment, a 14-km study reach downstream of an STP was sampled. Gadolinium anomalies were present at all five downstream sites, but the magnitude of the anomaly decreased. Effluent from STPs is a complex mixture of organic and inorganic constituents, and to better understand the chemical interactions and their effect on REEs, the aqueous speciation was modeled using comprehensive chemical analyses of water samples collected downstream of STP input. These calculations suggest that the REEs will likely remain dissolved because phosphate and carbonate complexes dominate over free REE ions. This study supports the application of Gd anomalies as a useful tracer of urban

  5. Biocompatible nanotemplate-engineered nanoparticles containing gadolinium: stability and relaxivity of a potential MRI contrast agent.

    PubMed

    Zhu, Donghua; White, R D; Hardy, Peter A; Weerapreeyakul, Natthida; Sutthanut, Khaetthareeya; Jay, Michael

    2006-04-01

    In this article, we use a nanotemplate engineering approach to prepare biodegradable nanoparticles composed of FDA-approved materials and possessing accessible gadolinium (Gd) atoms and demonstrate their potential as a Magnetic Resonance Imaging (MRI) contrast agent. Nanoparticles containing dimyristoyl phosphoethanolamine diethylene triamine penta acetate (PE-DTPA) were prepared using 3.5 mg of Brij 78, 2.0 mg of emulsifying wax and 0.5 mg of PE-DTPA/ml from a microemulsion precursor. After the addition of GdCl3, the presence of Gd on the surface of nanoparticles was characterized using inductively coupled plasma atomic emission spectroscopy and Scanning Transmission Electron Microscopy (STEM). The in vitro relaxivities of the PE-DTPA-Gd nanoparticles in different media were assessed at different field strengths. The conditional stability constant of Gd binding to the nanoparticles was determined using competitive spectrophotometric titration. Transmetallation kinetics of the gadolinium ion from PE-DTPA-Gd nanoparticles with zinc as the competing ionic was measured using the relaxivity evolution method. Nanoparticles with a diameter of approximately 130 nm possessing surface chelating functions were made from GRAS (Generally Regarded As Safe) materials. STEM demonstrated the uniform distribution of Gd3+ on the surface of the nanoparticles. The thermodynamic binding constant for Gd3+ to the nanoparticles was approximately 10(18) M(-1) and transmetallation studies with Zn2+ yielded kinetic constants K1 and K(-1) of 0.033 and 0.022 1/h, respectively, with an equilibrium constant of 1.5. A payload of approximately 10(5) Gd/nanoparticle was achieved; enhanced relaxivities were observed, including a pH dependence of the transverse relaxivity (r2). Nanoparticles composed of materials that have been demonstrated to be hemocompatible and enzymatically metabolized and possessing accessible Gd ions on their surface induce relaxivities in the bulk water signal that make them

  6. The use of theranostic gadolinium-based nanoprobes to improve radiotherapy efficacy

    PubMed Central

    Sancey, L; Kotb, S; Roux, S; Dufort, S; Bianchi, A; Crémillieux, Y; Fries, P; Coll, J-L; Rodriguez-Lafrasse, C; Janier, M; Dutreix, M; Barberi-Heyob, M; Boschetti, F; Denat, F; Louis, C; Porcel, E; Lacombe, S; Le Duc, G; Deutsch, E; Perfettini, J-L; Detappe, A; Verry, C; Berbeco, R; Butterworth, K T; McMahon, S J; Prise, K M; Perriat, P; Tillement, O

    2014-01-01

    A new efficient type of gadolinium-based theranostic agent (AGuIX®) has recently been developed for MRI-guided radiotherapy (RT). These new particles consist of a polysiloxane network surrounded by a number of gadolinium chelates, usually 10. Owing to their small size (<5 nm), AGuIX typically exhibit biodistributions that are almost ideal for diagnostic and therapeutic purposes. For example, although a significant proportion of these particles accumulate in tumours, the remainder is rapidly eliminated by the renal route. In addition, in the absence of irradiation, the nanoparticles are well tolerated even at very high dose (10 times more than the dose used for mouse treatment). AGuIX particles have been proven to act as efficient radiosensitizers in a large variety of experimental in vitro scenarios, including different radioresistant cell lines, irradiation energies and radiation sources (sensitizing enhancement ratio ranging from 1.1 to 2.5). Pre-clinical studies have also demonstrated the impact of these particles on different heterotopic and orthotopic tumours, with both intratumoural or intravenous injection routes. A significant therapeutical effect has been observed in all contexts. Furthermore, MRI monitoring was proven to efficiently aid in determining a RT protocol and assessing tumour evolution following treatment. The usual theoretical models, based on energy attenuation and macroscopic dose enhancement, cannot account for all the results that have been obtained. Only theoretical models, which take into account the Auger electron cascades that occur between the different atoms constituting the particle and the related high radical concentrations in the vicinity of the particle, provide an explanation for the complex cell damage and death observed. PMID:24990037

  7. Gadolinium Enhanced MR Coronary Vessel Wall Imaging at 3.0 Tesla.

    PubMed

    Kelle, Sebastian; Schlendorf, Kelly; Hirsch, Glenn A; Gerstenblith, Gary; Fleck, Eckart; Weiss, Robert G; Stuber, Matthias

    2010-10-11

    Purpose. We evaluated the influence of the time between low-dose gadolinium (Gd) contrast administration and coronary vessel wall enhancement (LGE) detected by 3T magnetic resonance imaging (MRI) in healthy subjects and patients with coronary artery disease (CAD). Materials and Methods. Four healthy subjects (4 men, mean age 29 ± 3 years and eleven CAD patients (6 women, mean age 61 ± 10 years) were studied on a commercial 3.0 Tesla (T) whole-body MR imaging system (Achieva 3.0 T; Philips, Best, The Netherlands). T1-weighted inversion-recovery coronary magnetic resonance imaging (MRI) was repeated up to 75 minutes after administration of low-dose Gadolinium (Gd) (0.1 mmol/kg Gd-DTPA). Results. LGE was seen in none of the healthy subjects, however in all of the CAD patients. In CAD patients, fifty-six of 62 (90.3%) segments showed LGE of the coronary artery vessel wall at time-interval 1 after contrast. At time-interval 2, 34 of 42 (81.0%) and at time-interval 3, 29 of 39 evaluable segments (74.4%) were enhanced. Conclusion. In this work, we demonstrate LGE of the coronary artery vessel wall using 3.0 T MRI after a single, low-dose Gd contrast injection in CAD patients but not in healthy subjects. In the majority of the evaluated coronary segments in CAD patients, LGE of the coronary vessel wall was already detectable 30-45 minutes after administration of the contrast agent.

  8. Gadolinium-based Compounds Induce NLRP3-dependent IL-1β Production and Peritoneal Inflammation

    PubMed Central

    Schmidt-Lauber, Christian; Bossaller, Lukas; Abujudeh, Hani H.; Vladimer, Gregory I.; Christ, Anette; Fitzgerald, Katherine A.; Latz, Eicke; Gravallese, Ellen M.; Marshak-Rothstein, Ann; Kay, Jonathan

    2015-01-01

    Objective Nephrogenic systemic fibrosis (NSF) is a progressive fibrosing disorder that may develop in patients with chronic kidney disease (CKD) after administration of gadolinium-based contrast agents (GBCAs). In the setting of impaired renal clearance of GBCAs, gadolinium (Gd) deposits in various tissues and fibrosis subsequently develops. However, the precise mechanism by which fibrosis occurs in NSF is incompletely understood. Because other profibrotic agents, such silica or asbestos, activate the NOD-like receptor protein 3 (NLRP3) inflammasome and initiate IL-1β release with the subsequent development of fibrosis, we evaluated the effects of GBCAs on inflammasome activation. Methods Bone marrow derived macrophages (BMDM) from C57BL/6, Nlrp3−/− and Asc−/− mice were incubated with three Gd-containing compounds and IL-1β activation and secretion was detected by ELISA and Western blot analysis. Inflammasome activation and regulation was investigated in IL-4- and IFNγ-polarized macrophages by ELISA, qRT-PCR and NanoString nCounter analysis. Furthermore, C57BL/6 and Nlrp3−/− mice were injected i.p. with GBCA and recruitment of inflammatory cells to the peritoneum was analyzed by FACS. Results Both free Gd and GBCAs activate the NLRP3 inflammasome and induce IL-1β secretion in vitro. Gd-DTPA also induces the recruitment of neutrophils and inflammatory monocytes to the peritoneum in vivo. Gd activated IL-4-polarized macrophages more effectively than IFNγ-polarized macrophages, which preferentially expressed genes known to downregulate inflammasome activity. Conclusion These data suggest that Gd released from GBCAs triggers a NLRP3 inflammasome-dependent inflammatory response that leads to fibrosis in an appropriate clinical setting. The preferential activation of IL-4-differentiated macrophages is consistent with the predominantly fibrotic presentation of NSF. PMID:24914072

  9. Gadolinium detection via in vivo prompt gamma neutron activation analysis following gadolinium-based contrast agent injection: a pilot study in 10 human participants.

    PubMed

    Gräfe, J L; McNeill, F E; Noseworthy, M D; Chettle, D R

    2014-09-01

    Gadolinium (Gd) based contrast agents are routinely used as part of many magnetic resonance imaging (MRI) procedures. The widespread use of these agents and concerns about Gd toxicity, motivated us to develop a monitoring procedure that could non-invasively measure quantitatively potential retention of toxic free Gd in tissues after use of the agent. We have been developing a method to measure Gd painlessly and non-invasively by prompt gamma neutron activation analysis. In this paper we present the results of a pilot study where we show that we can measure Gd, quantitatively in vivo, in the lower leg muscle of 10 participants. A series of three neutron leg scans were performed. The effective radiation dose for a single neutron leg scan was very low, 0.6 µSv, so multiple scans were possible. Calibration phantom and in vivo detection limits were determined to be identical: 0.58 ppm. Gd was not detectable in muscle prior to exposure to the contrast agent Gadovist(®). Gd was detected, at greater than 99% confidence, in 9 participants within 1 h of contrast administration and in 1 participant approximately 3.3 h post-contrast administration. The measured concentrations of Gd ranged from 2.0 to 17.3 ppm (6.9 to 56 uncertainties different from zero). No detectable Gd was measured in any participant in the third neutron scan (conducted 0.7 to 5.9 d post-contrast). The results of this study validate our new measurement technology. This technique could be used as a non-invasive monitoring procedure for exposure and retention of Gd from Gd-based chelates used in MRI.

  10. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) of cadaveric shoulders: comparison of contrast dynamics in hyaline and fibrous cartilage after intraarticular gadolinium injection.

    PubMed

    Wiener, E; Hodler, J; Pfirrmann, C W A

    2009-01-01

    Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a novel method to investigate cartilaginous and fibrocartilaginous structures. To investigate the contrast dynamics in hyaline and fibrous cartilage of the glenohumeral joint after intraarticular injection of gadopentetate dimeglumine. Transverse T(1) maps were acquired on a 1.5T scanner before and after intraarticular injection of 2.0 mmol/l gadopentetate dimeglumine in five cadaveric shoulders using a dual flip angle three-dimensional gradient echo (3D-GRE) sequence. The acquisition time for the T(1) maps was 5 min 5 s for the whole shoulder. Measurements were repeated every 15 min over 2.5 hours. Regions of interest (ROIs) covering the glenoid cartilage and the labrum were drawn to assess the temporal evolution of the relaxation parameters. T(1) of unenhanced hyaline cartilage of the glenoid was 568+/-34 ms. T(1) of unenhanced fibrous cartilage of the labrum was 552+/-38 ms. Significant differences (P=0.002 and 0.03) in the relaxation parameters were already measurable after 15 min. After 2 to 2.5 hours, hyaline and fibrous cartilage still demonstrated decreasing relaxation parameters, with a larger range of the T(1)(Gd) values in fibrous cartilage. T(1) and triangle Delta R(1) values of hyaline and fibrous cartilage after 2.5 hours were 351+/-16 ms and 1.1+/-0.09 s(-1), and 332+/-31 ms and 1.2+/-0.1 s(-1), respectively. A significant decrease in T(1)(Gd) was found 15 min after intraarticular contrast injection. Contrast accumulation was faster in hyaline than in fibrous cartilage. After 2.5 hours, contrast accumulation showed a higher rate of decrease in hyaline cartilage, but neither hyaline nor fibrous cartilage had reached equilibrium.

  11. Bioinspired synthesis and characterization of gadolinium-labeled magnetite nanoparticles for dual contrast t1- and T2-weighted magnetic resonance imaging.

    PubMed

    Bae, Ki Hyun; Kim, Young Beom; Lee, Yuhan; Hwang, Jinyoung; Park, Hyunwook; Park, Tae Gwan

    2010-03-17

    Gadolinium-labeled magnetite nanoparticles (GMNPs) were synthesized via a bioinspired manner to use as dual contrast agents for T1- and T2-weighted magnetic resonance imaging. A mussel-derived adhesive moiety, 3,4-dihydroxy-l-phenylalanine (DOPA), was utilized as a robust anchor to form a mixed layer of poly(ethylene glycol) (PEG) chains and dopamine molecules on the surface of iron oxide nanoparticles. Gadolinium ions were subsequently complexed at the distal end of the dopamine molecules that were prefunctionalized with a chelating ligand for gadolinium. The resultant GMNPs exhibited high dispersion stability in aqueous solution. Crystal structure and superparamagnetic properties of magnetite nanocrystals were also maintained after the complexation of gadolinium. The potential of GMNPs as dual contrast agents for T1 and T2-weighted magnetic resonance imaging was demonstrated by conducting in vitro and in vivo imaging and relaxivity measurements.

  12. Comparison between (99m)Tc-diphosphonate imaging and MRI with late gadolinium enhancement in evaluating cardiac involvement in patients with transthyretin familial amyloid polyneuropathy.

    PubMed

    Minutoli, Fabio; Di Bella, Gianluca; Mazzeo, Anna; Donato, Rocco; Russo, Massimo; Scribano, Emanuele; Baldari, Sergio

    2013-03-01

    Cardiac involvement is not rare in systemic amyloidosis and is associated with poor prognosis. Both (99m)Tc-diphosphonate imaging and cardiac MRI with late gadolinium enhancement are considered valuable tools in revealing amyloid deposition in the myocardium; however, to our knowledge, no comparative study between the two techniques exists. We compared findings of these two techniques in patients with transthyretin-familial amyloid polyneuropathy (FAP). Eighteen patients with transthyretin-FAP underwent (99m)Tc-diphosphonate imaging and MRI with late gadolinium enhancement. Images were visually evaluated by independent readers to determine the presence of radiotracer accumulation or late gadolinium enhancement-positive areas at the level of cardiac chambers. Interobserver agreement ranged from moderate to very good for (99m)Tc-diphosphonate imaging findings and was very good for findings of MRI with late gadolinium enhancement. Left ventricle (LV) radiotracer uptake was found in 10 of 18 patients, whereas LV late gadolinium enhancement-positive areas were found in eight of 18 patients (χ(2) = 0.9; p = 0.343). One hundred fifty-nine LV segments showed (99m)Tc-diphosphonate accumulation, and 57 LV segments were late gadolinium enhancement positive (p < 0.0001). Radiotracer uptake was found in the right ventricle (RV) in eight patients and in both atria in five patients, whereas MRI showed that RV was involved in three patients and both atria in six patients; the differences were not statistically significant (RV, p = 0.07; atria, p = 1). Intermodality agreement between (99m)Tc-diphosphonate imaging and MRI ranged from fair to good. Our study shows that, although (99m)Tc-diphosphonate imaging and MRI with late gadolinium enhancement have similar capabilities to identify patients with myocardial amyloid deposition, cardiac amyloid infiltration burden can be significantly underestimated by visual analysis of MRI with late gadolinium enhancement compared with (99m

  13. Helium defectoscopy of cerium gadolinium ceramics Ce0.8Gd0.2O1.9 with a submicrocrystalline structure in the impurity disorder region

    NASA Astrophysics Data System (ADS)

    Koromyslov, A. V.; Zhiganov, A. N.; Kovalenko, M. A.; Kupryazhkin, A. Ya.

    2013-12-01

    The concentration of impurity anion vacancies formed upon the dissociation of gadolinium-vacancy complexes has been determined using helium defectoscopy of the cerium gadolinium ceramics Ce0.8Gd0.2O1.9 with a submicrocrystalline structure in the temperature range T = 740-1123 K and at saturation pressures ranging from 0.05 to 15 MPa. It has been found that the energy of dissociation of gadoliniumvacancy complexes is E {eff/ D }= 0.26 ± 0.06 eV, and the energy of dissolution of helium in anion vacancies in the impurity disorder region is E P = -0.31 ± 0.09 eV. The proposed mechanism of dissolution has been confirmed by the investigation of the electrical conductivity of the cerium gadolinium ceramics, as well as by the high-speed molecular dynamics simulation of the dissociation of gadolinium-vacancy complexes. It has been assumed that a decrease in the effective dissolution energy in comparison with the results of the previously performed low-temperature investigations is caused by the mutual repulsion of vacancies formed upon the dissociation of gadolinium-vacancy complexes in highly concentrated solutions of gadolinium in CeO2 with increasing temperature.

  14. The Effect of Pressure and Temperature on Separation of Free Gadolinium(III) From Gd-DTPA Complex by Nanofiltration-Complexation Method

    NASA Astrophysics Data System (ADS)

    Rahayu, Iman; Anggraeni, Anni; Ukun, MSS; Bahti, Husein H.

    2017-05-01

    Nowdays, the utilization of rare earth elements has been carried out widely in industry and medicine, one of them is gadolinium in Gd-DTPA complex is used as a contrast agent in a magnetic resonance imaging (MRI) diagnostic to increase the visual contrast between normal tissue and diseased. Although the stability of a given complex may be high enough, the complexation step couldnot have been completed, so there is possible to gadolinium(III) in the complex compound. Therefore, the function of that compounds should be dangerous because of the toxicity of gadolinium(III) in human body. So, it is necessarry to separate free gadolinium(III) from Gd-DTPA complex by nanofiltration-complexation. The method of this study is complexing of Gd2O3 with DTPA ligand by reflux and separation of Gd-DTPA complex from gadolinium(III) with a nanofiltration membrane on the variation of pressures(2, 3, 4, 5, 6 bars) and temperature (25, 30, 35, 40 °C) and determined the flux and rejection. The results of this study are the higher of pressures and temperatures, permeation flux are increasing and ion rejections are decreasing and gave the free gadolinium(III) rejection until 86.26%.

  15. Effects of rare-earth filters on patient exposure and image contrast

    SciTech Connect

    Mauriello, S.M.; Washburn, D.B.; Matteson, S.R.

    1987-08-01

    Minimizing patient exposure while maintaining a diagnostically acceptable radiograph is a major goal in diagnostic radiography. Rare-earth filters may be the means to achieve this goal due to their band-pass effect. The purpose of this study was to examine the image contrast effects and exposure reductions for various thicknesses of aluminum, samarium, gadolinium, gadolinium oxysulfide, and gadolinium oxysulfide added to 2.5 mm of aluminum. Trials were conducted on an intra-oral dental x-ray unit (range, 65 to 90 kVp). When compared with conventional aluminum, all of the rare-earth filters provided lower radiation exposures, with gadolinium in the metallic or oxysulfide form providing the lowest exposures. Samarium, at a thickness of 0.127 mm, yielded the highest image contrast. Gadolinium or gadolinium oxysulfide added to 2.5 mm of aluminum resulted in a slight loss of contrast when compared with conventional aluminum filtration. This loss may not be clinically significant, and when coupled with the reduced exposure afforded by these filters, they become viable as acceptable alternatives to aluminum filtration.

  16. Dramatic impact of the giant local magnetic fields on spin-dependent recombination processes in gadolinium based garnets

    SciTech Connect

    Romanov, N. G. Tolmachev, D. O.; Gurin, A. S.; Uspenskaya, Yu. A.; Asatryan, H. R.; Badalyan, A. G.; Baranov, P. G.; Wieczorek, H.; Ronda, C.

    2015-06-29

    A giant magnetic field effect on spin-dependent recombination of the radiation-induced defects has been found in cerium doped gadolinium based garnet crystals and ceramics, promising materials for scintillator applications. A sharp and strong increase in the afterglow intensity stimulated by external magnetic field and an evidence of the magnetic field memory have been discovered. The effect was ascribed to huge Gd-induced internal magnetic fields, which suppress the recombination, and cross-relaxation with Gd{sup 3+} ions leading to reorientation of the spins of the electron and hole centers. Thus, the spin system of radiation-induced defects in gadolinium garnet based scintillator materials was shown to accumulate significant energy which can be released in external magnetic fields.

  17. Properties of high k gate dielectric gadolinium oxide deposited on Si (1 0 0) by dual ion beam deposition (DIBD)

    NASA Astrophysics Data System (ADS)

    Zhou, Jian-Ping; Chai, Chun-Lin; Yang, Shao-Yan; Liu, Zhi-Kai; Song, Shu-Lin; Li, Yan-Li; Chen, Nuo-Fu

    2004-09-01

    Gadolinium oxide thin films have been prepared on silicon (1 0 0) substrates with a low-energy dual ion-beam epitaxial technique. Substrate temperature was an important factor to affect the crystal structures and textures in an ion energy range of 100-500 eV. The films had a monoclinic Gd2O3 structure with preferred orientation (4 bar 0 2) at low substrate temperatures. When the substrate temperature was increased, the orientation turned to (2 0 2), and finally, the cubic structure appeared at the substrate temperature of 700 °C, which disagreed with the previous report because of the ion energy. The AES studies found that Gadolinium oxide shared Gd2O3 structures, although there were a lot of oxygen deficiencies in the films, and the XPS results confirmed this. AFM was also used to investigate the surface images of the samples. Finally, the electrical properties were presented.

  18. Gadolinium(III) Complexes with N-Alkyl-N-methylglucamine Surfactants Incorporated into Liposomes as Potential MRI Contrast Agents

    PubMed Central

    Silva, Simone Rodrigues; Duarte, Érica Correia; Ramos, Guilherme Santos; Kock, Flávio Vinícius Crizóstomo; Andrade, Fabiana Diuk; Frézard, Frédéric; Colnago, Luiz Alberto; Demicheli, Cynthia

    2015-01-01

    Complexes of gadolinium(III) with N-octanoyl-N-methylglucamine (L8) and N-decanoyl-N-methylglucamine (L10) with 1 : 2 stoichiometry were synthesized and characterized by elemental analysis, electrospray ionization-tandem mass spectrometry (ESI-MS), infrared (IR) spectroscopy, and molar conductivity measurements. The transverse (r2) and longitudinal (r1) relaxivity protons were measured at 20 MHz and compared with those of the commercial contrasts. These complexes were incorporated in liposomes, resulting in the increase of the vesicle zeta potential. Both the free and liposome-incorporated gadolinium complexes showed high relaxation effectiveness, compared to commercial contrast agent gadopentetate dimeglumine (Magnevist). The high relaxivity of these complexes was attributed to the molecular rotation that occurs more slowly, because of the elevated molecular weight and incorporation in liposomes. The results establish that these paramagnetic complexes are highly potent contrast agents, making them excellent candidates for various applications in molecular MR imaging. PMID:26347596

  19. The use of innovative gadolinium-based contrast agent for MR-diagnosis of cancer in the experiment

    NASA Astrophysics Data System (ADS)

    Chernov, V.; Medvedeva, A.; Sinilkin, I.; Zelchan, R.; Grigorev, E.; Frolova, I.; Nam, I.

    2016-02-01

    The present study of the functional suitability and specific activity of the contrast agent gadolinium-based for magnetic resonance imaging demonstrated that the investigated contrast agent intensively accumulates in organs and anatomical structures of the experimental animals. In the model of tumor lesions in animals, study have shown that investigational contrast agent accumulates in the tumor tissue and retained there in for a long enough time.

  20. Electrical and microstructural characterization of ceramic gadolinium-doped ceria electrolytes for ITSOFCs by sol-gel route.

    PubMed

    Accardo, Grazia; Ferone, Claudio; Cioffi, Raffaele; Frattini, Domenico; Spiridigliozzi, Luca; Dell'Agli, Gianfranco

    2016-04-06

    Gadolinium-doped ceria (GDC) is a promising alternative as a solid electrolyte for intermediate temperature solid oxide fuel cells (ITSOFCs) due to its low operating temperature and its high electrical conductivity. The traditional synthesis processes require extended time for powder preparation. Sol-gel methodology for electrolyte fabrication is more versatile and efficient. In this work, nanocrystalline ceria powders, with 10 and 20 mol% of gadolinium (Ce0.9Gd0.1O1.95 and Ce0.8Gd0.2O1.9) were synthesized by a modified sol-gel technique, featuring a nitrate-fuel exothermic reaction. GDC tablets were prepared from powders and sintered at 1500°C with a dwell time of 3 hours. The sintered pellets' microstructure (by SEM) and electrical conductivity (by EIS) were evaluated. The powder properties, such as crystalline structure (by XRD), thermal properties (TGA/DTA), particle size and morphology (TEM) and textural properties (BET method) were determined and, in addition, for the first time an accurate chemical structural evolution (FTIR) was studied. Sintered GDC0.8 samples exhibited the maximum theoretical density of 97% and an average grain size of 700 nm. The electrical conductivity vs. temperature showed values ranging from 1.9∙10(-2) to 5.5∙10(-2) S·cm(-1) at 600°C and 800°C for GDC with 20 mol% of gadolinium. The methodology investigated showed reduced reaction time, a better control of stoichiometry and low cost. Characterization results demonstrated that these materials can be applied in ITSOFCs due to high conductivity, even at 550°C-600°C. The increased conductivity is related to the improved mobility of gadolinium ions in a high-density structure, with nanometric grains.

  1. Steady-state Raman gain coefficients of potassium-gadolinium tungstate at the wavelength of 532 nm

    NASA Astrophysics Data System (ADS)

    Chulkov, R.; Markevich, V.; Orlovich, V.; El-Desouki, M.

    2015-12-01

    Stokes generation has been considered under the Fourier-limited nanosecond pulse excitation to find Raman gain coefficients in potassium-gadolinium tungstate. Data of numerical simulation under spontaneous Stokes initiation, light diffraction, and optical feedback have been compared with experimental results to reveal coefficient values of 14 ± 3 and 11 ± 3 cm/GW for the p[mm]p and p[gg]p sample orientations, respectively, at 532 nm wavelength.

  2. Gadolinium oxide nanoplates with high longitudinal relaxivity for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Cho, Minjung; Sethi, Richa; Ananta Narayanan, Jeyarama Subramanian; Lee, Seung Soo; Benoit, Denise N.; Taheri, Nasim; Decuzzi, Paolo; Colvin, Vicki L.

    2014-10-01

    Molecular-based contrast agents for magnetic resonance imaging (MRI) are often characterized by insufficient relaxivity, thus requiring the systemic injection of high doses to induce sufficient contrast enhancement at the target site. In this work, gadolinium oxide (Gd2O3) nanoplates are produced via a thermal decomposition method. The nanoplates have a core diameter varying from 2 to 22 nm, a thickness of 1 to 2 nm and are coated with either an oleic acid bilayer or an octylamine modified poly(acrylic acid) (PAA-OA) polymer layer. For the smaller nanoplates, longitudinal relaxivities (r1) of 7.96 and 47.2 (mM s)-1 were measured at 1.41 T for the oleic acid bilayer and PAA-OA coating, respectively. These values moderately reduce as the size of the Gd2O3 nanoplates increases, and are always larger for the PAA-OA coating. Cytotoxicity studies on human dermal fibroblast cells documented no significant toxicity, with 100% cell viability preserved up to 250 μM for the PAA-OA coated Gd2O3 nanoplates. Given the 10 times increase in longitudinal relaxivity over the commercially available Gd-based molecular agents and the favorable toxicity profile, the 2 nm PAA-OA coated Gd2O3 nanoplates could represent a new class of highly effective T1 MRI contrast agents.Molecular-based contrast agents for magnetic resonance imaging (MRI) are often characterized by insufficient relaxivity, thus requiring the systemic injection of high doses to induce sufficient contrast enhancement at the target site. In this work, gadolinium oxide (Gd2O3) nanoplates are produced via a thermal decomposition method. The nanoplates have a core diameter varying from 2 to 22 nm, a thickness of 1 to 2 nm and are coated with either an oleic acid bilayer or an octylamine modified poly(acrylic acid) (PAA-OA) polymer layer. For the smaller nanoplates, longitudinal relaxivities (r1) of 7.96 and 47.2 (mM s)-1 were measured at 1.41 T for the oleic acid bilayer and PAA-OA coating, respectively. These values

  3. Comparison of gadolinium Cy{sub 2}DOTA, a new hepatobiliary agent, and gadolinium HP-DO3A, an extracellular agent, in healthy liver and metastatic disease

    SciTech Connect

    Runge, V.M.; Wells, J.W.; Williams, N.M.

    1995-02-01

    A new gadolinium (Gd) chelate with preferential hepatobiliary uptake, Gd Cy{sub 2}DOTA, was compared in two animal species with Gd HP-DO3A (gadoteridol), a clinically approved contrast agent with extracellular distribution. Liver enhancement was evaluated for these two contrast agents using magnetic resonance imaging, whereas an experimental model of metastatic disease was used to evaluate the agents` efficacy for liver-lesion delineation. The two agents were compared in four healthy Rhesus monkeys (eight studies) and five New Zealand White rabbits with implanted VX-2 liver tumors (ten studies). The contrast dose was 0.1 mmol/kg, with the agents given in random order and at least 72 hours between contrast injections. Breathhold T1-weighted spin echo scans were obtained at 1.5 tesla (T) before and after contrast was administered. Postcontrast scans were obtained 1 to 90 minutes after injection in the monkeys and 1 to 240 minutes after injection in the rabbits. Prolonged hepatic enhancement, superior in degree to that with Gd HP-DO3A, was noted to both monkeys and rabbits after injection of Gd Cy{sub 2}DOTA. Two minutes after contrast, liver SI was 1.94 {+-} 0.05 with Gd Cy{sub 2}DOTA compared with 1.5 {+-} 0.05 with Gd HP-DO3A in monkeys. Sixty minutes after contrast, liver SI was 1.60 {+-} 0.09 compared with 1.20 {+-} 0.02. The difference between agents was significant at all times from 2 to 60 minutes after contrast injection (P < 0.01). Excretion of contrast into the gall bladder was observed in both animal species with Gd Cy{sub 2}DOTA but not with Gd HP-DO3A. The maximum improvement in lesion conspicuity (rabbit) occurred 45 minutes after injection of Gd Cy{sub 2}DOTA and 5 minutes after injection of Gd HP-DO3A. 22 refs., 12 figs.

  4. Nanoparticles for multi-modality cancer diagnosis: Simple protocol for self-assembly of gold nanoclusters mediated by gadolinium ions.

    PubMed

    Hou, Wenxiu; Xia, Fangfang; Alfranca, Gabriel; Yan, Hao; Zhi, Xiao; Liu, Yanlei; Peng, Chen; Zhang, Chunlei; de la Fuente, Jesus Martinez; Cui, Daxiang

    2017-03-01

    It is essential to develop a simple synthetic strategy to improve the quality of multifunctional contrast agents for cancer diagnosis. Herein, we report a time-saving method for gadolinium (Gd(3+)) ions-mediated self-assembly of gold nanoclusters (GNCs) into monodisperse spherical nanoparticles (GNCNs) under mild conditions. The monodisperse, regular and colloidal stable GNCNs were formed via selectively inducing electrostatic interactions between negatively-charged carboxylic groups of gold nanoclusters and trivalent cations of gadolinium in aqueous solution. In this way, the Gd(3+) ions were chelated into GNCNs without the use of molecular gadolinium chelates. With the co-existence of GNCs and Gd(3+) ions, the formed GNCNs exhibit significant luminescence intensity enhancement for near-infrared fluorescence (NIRF) imaging, high X-ray attenuation for computed tomography (CT) imaging and reasonable r1 relaxivity for magnetic resonance (MR) imaging. The excellent biocompatibility of the GNCNs was proved both in vitro and in vivo. Meanwhile, the GNCNs also possess unique NIRF/CT/MR imaging ability in A549 tumor-bearing mice. In a nutshell, the simple and safe GNCNs hold great potential for tumor multi-modality clinical diagnosis.

  5. Neuroprotective effect of gadolinium: a stretch-activated calcium channel blocker in mouse model of ischemia-reperfusion injury.

    PubMed

    Gulati, Puja; Muthuraman, Arunachalam; Jaggi, Amteshwar S; Singh, Nirmal

    2013-03-01

    The present study was designed to investigate the potential of gadolinium, a stretch-activated calcium channel blocker in ischemic reperfusion (I/R)-induced brain injury in mice. Bilateral carotid artery occlusion of 12 min followed by reperfusion for 24 h was given to induce cerebral injury in male Swiss mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was assessed using Morris water maze test and motor incoordination was evaluated using rota-rod, lateral push, and inclined beam walking tests. In addition, total calcium, thiobarbituric acid reactive substance (TBARS), reduced glutathione (GSH), and acetylcholinesterase (AChE) activity were also estimated in brain tissue. I/R injury produced a significant increase in cerebral infarct size. A significant loss of memory along with impairment of motor performance was also noted. Furthermore, I/R injury also produced a significant increase in levels of TBARS, total calcium, AChE activity, and a decrease in GSH levels. Pretreatment of gadolinium significantly attenuated I/R-induced infarct size, behavioral and biochemical changes. On the basis of the present findings, we can suggest that opening of stretch-activated calcium channel may play a critical role in ischemic reperfusion-induced brain injury and that gadolinium has neuroprotective potential in I/R-induced injury.

  6. Relaxivity enhancement of aquated Tris(β-diketonate)gadolinium(III) chelates by confinement within ultrashort single-walled carbon nanotubes.

    PubMed

    Law, Justin J; Guven, Adem; Wilson, Lon J

    2014-01-01

    Ultrashort single-walled carbon nanotubes loaded with gadolinium ions (gadonanotubes) have been previously shown to exhibit extremely high T1 -weighted relaxivities (>100 mm(-1) s(-1) ). To further examine the effect of nanoconfinement on the relaxivity of gadolinium-based contrast agents for magnetic resonance imaging, a series of ultrashort single-walled carbon nanotube (US-tube) materials internally loaded with gadolinium chelates have been prepared and studied. US-tubes were loaded with Gd(acac)3  · 2H2 O, Gd(hfac)3  · 2H2 O, and Gd(thd)3 (acac = acetylacetone, hfac = hexafluoroacetylacetone, thd = tetramethylheptanedione). The longitudinal relaxivities of the prepared materials determined at 25°C in a 1.5 T field were 103 mm(-1) s(-1) for Gd(acac)3  · 2H2 O@US-tubes, 105 mm(-1) s(-1) for Gd(hfac)3  · 2H2 O@US-tubes and 26 mm(-1) s(-1) for Gd(thd)3 @US-tubes. Compared with the relaxivities obtained for the unloaded chelates (<10 mm(-1) s(-1) ) as well as accounting for the T1 reduction observed for the empty US-tubes, the boost in relaxivity for chelate-loaded US-tubes is attributed to confinement within the nanotube and depends on the number of coordinated water molecules.

  7. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    SciTech Connect

    Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; Vohra, Y. K.

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8 GPa and 600 K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially-grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high pressure area on the order of a few tens of seconds. This device is then used to scan the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in the experiment the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp→αSm transition proceeds in discontinuous steps at points along the expected phase boundary. Additionally, the unit cell volumes of each phase deviate from the expected thermal expansion behavior just before each transition is observed from the diffraction data. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0 - 10 GPa and 300 - 650 K.

  8. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    SciTech Connect

    Montgomery, J. M.; Samudrala, G. K.; Vohra, Y. K.; Velisavljevic, N.

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8 GPa and 600 K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0–10 GPa and 300–650 K.

  9. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    SciTech Connect

    Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; Vohra, Y. K.

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8GPa and 600K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0–10GPa and 300–650K

  10. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    DOE PAGES

    Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; ...

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8GPa and 600K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phasemore » diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0–10GPa and 300–650K« less

  11. Gadolinium enhanced cardiovascular magnetic resonance in Anderson-Fabry disease. Evidence for a disease specific abnormality of the myocardial interstitium.

    PubMed

    Moon, James C C; Sachdev, Bhavesh; Elkington, Andrew G; McKenna, William J; Mehta, Atul; Pennell, Dudley J; Leed, Philip J; Elliott, Perry M

    2003-12-01

    Anderson-Fabry Disease (AFD), an X-linked disorder of sphingolipid metabolism, is a cause of idiopathic left ventricular hypertrophy but the mechanism of hypertrophy is poorly understood. Gadolinium enhanced cardiovascular magnetic resonance can detect focal myocardial fibrosis. We hypothesised that hyperenhancement would be present in AFD. Eighteen males (mean 43+/-14 years) and eight female heterozygotes (mean 48+/-12 years) with AFD underwent cine and late gadolinium cardiovascular magnetic resonance. Nine male (50%) had myocardial hyperenhancement ranging from 3.4% to 20.6% (mean 7.7+/-5.7%) of total myocardium; in males, percentage hyperenhancement related to LV mass index (r=0.78, P=0.0002) but not to ejection fraction or left ventricular volumes. Lesser hyperenhancement was also found in four (50%) heterozygous females (mean 4.6%). In 12 (92%) patients with abnormal gadolinium uptake, hyperenhancement occurred in the basal infero-lateral wall where, unlike myocardial infarction, it was not sub-endocardial. In two male patients with severe LVH (left ventricular hypertrophy) and systolic impairment there was additional hyperenhancement in other myocardial segments. These observations suggests that myocardial fibrosis occurs in AFD and may contribute to the hypertrophy and the natural history of the disease.

  12. Gadolinium based contrast agents in current practice: Risks of accumulation and toxicity in patients with normal renal function

    PubMed Central

    Ranga, Anju; Agarwal, Yatish; Garg, Kanika J

    2017-01-01

    Despite being decked as the most prized compounds in the nugget box of contrast agents for clinical radiologists, and carrying an indisputable tag of safety of the US Food and Drug Administration for close to three decades, all may not be seemingly well with the family of gadolinium compounds. If the first signs of violations of primum non nocere in relation to gadolinium-based contrast agents (GBCAs) appeared in the millennium year with the first published report of skin fibrosis in patients with compromised renal function, the causal relationship between the development of nephrogenic systemic fibrosis (NSF) and GBCAs, first proposed by two European groups in 2006, further precluded their use in renocompromised patients. The toxicity, pharmacokinetics, and pharmacodynamics of GBCAs, however, has come under hawk-eyed scrutiny with recent reports that gadolinium tends to deposit cumulatively in the brain of patients with normal hepatobiliary function and intact blood–brain barrier. While the jury on the long-term hazard significance of this critical scientific finding is still out, the use of GBCAs must be guided by due clinical diligence, avoidance of repeated doses, and preferring GBCAs with the best safety profiles. PMID:28744073

  13. Gadolinium-148 production cross section measurements for 600-and 800-MEV protons.

    SciTech Connect

    Kelley, K. C.; Devlin, M. J.; Pitcher, E. J.; Mashnik, S. G.; Hertel, N. E.

    2004-01-01

    In a series of experiments at LANSCE's WNR facility, {sup 148}Gd production was measured for 600- and 800-MeV protons on tungsten, tantalum, and gold. These experiments used 3 {mu}m thin W, Ta, and Au foils and 10 {mu}m thin Al activation foils. Gadolinium spallation yields were determined from these foils using alpha spectroscopy and compared with the LANL codes CEM2k+GEM2 and MCNPX. When heavy metal targets, such as tungsten, are bombarded with protons greater than a few hundred MeV many different nuclides are produced. These nuclides are both stable and radioactive and are created by spallation, proton activation, or secondary reactions with neutrons and other nuclear particles made in the target. These products are distributed somewhat heterogeneously throughout a thick target because of the energy dependence of the cross sections and energy loss of the proton beam within the target. From this standpoint, it is difficult to measure nuclide production cross sections for a given energy proton in a thick target. At the Los Alamos Neutron Science Center (LANSCE) accelerator complex, protons are accelerated to 800 MeV and directed to two tungsten targets, Target 4 at the Weapons Neutron Research (WNR) facility and 1L target at the Manuel Lujan Jr. Neutron Scattering Center. DOE requires hazard classification analyses to be performed on these targets and places limits on radionuclide inventories in the target as a means of determining the 'nuclear facility' category level. Presently, WNR's Target 4 is a non-nuclear facility while the Lujan 1L target is classified as a Category 3 nuclear facility. Gadolinium-148 is a radionuclide created from the spallation of tungsten and other heavy elements. Allowable 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 {sup 148}Gd is generally low, but it encompasses almost two-thirds of the total inhalation dose burden in an accident

  14. Luminescence properties and electronic structure of Ce{sup 3+}-doped gadolinium aluminum garnet

    SciTech Connect

    Dotsenko, V.P.; Berezovskaya, I.V.; Voloshinovskii, A.S.; Zadneprovski, B.I.; Efryushina, N.P.

    2015-04-15

    Highlights: • The luminescence properties of Ce{sup 3+} ions in (Y, Gd){sub 3}Al{sub 5}O{sub 12} are analyzed. • The Gd{sup 3+} → Y{sup 3+} substitution leads to increasing of Ce{sup 3+} noncubic crystal field splitting parameter. • The excitation spectra for the Ce{sup 3+} emission in GdAG contain bands at 6.67, 7.75, and 9.76 eV. • These features are due to the Ce{sup 3+}-bound exciton formation and O 2p → Al 3s, 3p transitions. • Contributions from Al atoms to the conduction-band density of states are quite essential. - Abstract: Yttrium-gadolinium aluminum garnets (YGdAG) doped with Ce{sup 3+} ions have been prepared by co-precipitation method. The luminescent properties of Ce{sup 3+} ions in Gd{sub 3(1−x)}Ce{sub 3x}Al{sub 5}O{sub 12} (x = 0.01) have been studied upon excitation in the 2–20 eV region. The substitution of Gd{sup 3+} for Y{sup 3+} in the garnet structure results in broadening the emission band and shifting its maximum towards the longer wavelengths. It was found that in addition to the 4f → 5d excitation bands of Ce{sup 3+} ions, the excitation spectra for the Ce{sup 3+} emission contain bands at 6.67, 7.75, and 9.76 eV. These bands are attributed to the Ce{sup 3+}-bound exciton formation and O 2p → Al 3s, 3p transitions, respectively. Although gadolinium states dominate near the bottom of the conduction band of Gd{sub 3}Al{sub 5}O{sub 12}, contributions from Al{sub tetr} and Al{sub oct} atoms to the conduction-band density of states are evaluated as quite essential.

  15. Synergistic enhancement of iron oxide nanoparticle and gadolinium for dual-contrast MRI

    SciTech Connect

    Zhang, Fan; Huang, Xinglu; Qian, Chunqi; Zhu, Lei; Hida, Naoki; Niu, Gang; Chen, Xiaoyuan

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer MR contrast agents exert influence on T{sub 1} or T{sub 2} relaxation time of the surrounding tissue. Black-Right-Pointing-Pointer Combined use of iron oxide and Gd-DTPA can improve the sensitivity/specificity of lesion detection. Black-Right-Pointing-Pointer Dual contrast MRI enhances the delineation of tumor borders and small lesions. Black-Right-Pointing-Pointer The effect of DC-MRI can come from the high paramagnetic susceptibility of Gd{sup 3+}. Black-Right-Pointing-Pointer The effect of DC-MRI can also come from the distinct pharmacokinetic distribution of SPIO and Gd-DTPA. -- Abstract: Purpose: The use of MR contrast agents allows accurate diagnosis by exerting an influence on the longitudinal (T{sub 1}) or transverse (T{sub 2}) relaxation time of the surrounding tissue. In this study, we combined the use of iron oxide (IO) particles and nonspecific extracellular gadolinium chelate (Gd) in order to further improve the sensitivity and specificity of lesion detection. Procedures: With a 7-Tesla scanner, pre-contrasted, IO-enhanced and dual contrast agent enhanced MRIs were performed in phantom, normal animals, and animal models of lymph node tumor metastases and orthotopic brain tumor. For the dual-contrast (DC) MRI, we focused on the evaluation of T{sub 2} weighted DC MRI with IO administered first, then followed by the injection of a bolus of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Results: Based on the C/N ratios and MRI relaxometry, the synergistic effect of coordinated administration of Gd-DTPA and IO was observed and confirmed in phantom, normal liver and tumor models. At 30 min after administration of Feridex, Gd-DTPA further decreased T{sub 2} relaxation in liver immediately after the injection. Additional administration of Gd-DTPA also immediately increased the signal contrast between tumor and brain parenchyma and maximized the C/N ratio to -4.12 {+-} 0.71. Dual contrast MRI also enhanced the

  16. Monte Carlo Study of Radiation Dose Enhancement by Gadolinium in Megavoltage and High Dose Rate Radiotherapy

    PubMed Central

    Zhang, Daniel G.; Feygelman, Vladimir; Moros, Eduardo G.; Latifi, Kujtim; Zhang, Geoffrey G.

    2014-01-01

    MRI is often used in tumor localization for radiotherapy treatment planning, with gadolinium (Gd)-containing materials often introduced as a contrast agent. Motexafin gadolinium is a novel radiosensitizer currently being studied in clinical trials. The nanoparticle technologies can target tumors with high concentration of high-Z materials. This Monte Carlo study is the first detailed quantitative investigation of high-Z material Gd-induced dose enhancement in megavoltage external beam photon therapy. BEAMnrc, a radiotherapy Monte Carlo simulation package, was used to calculate dose enhancement as a function of Gd concentration. Published phase space files for the TrueBeam flattening filter free (FFF) and conventional flattened 6MV photon beams were used. High dose rate (HDR) brachytherapy with Ir-192 source was also investigated as a reference. The energy spectra difference caused a dose enhancement difference between the two beams. Since the Ir-192 photons have lower energy yet, the photoelectric effect in the presence of Gd leads to even higher dose enhancement in HDR. At depth of 1.8 cm, the percent mean dose enhancement for the FFF beam was 0.38±0.12, 1.39±0.21, 2.51±0.34, 3.59±0.26, and 4.59±0.34 for Gd concentrations of 1, 5, 10, 15, and 20 mg/mL, respectively. The corresponding values for the flattened beam were 0.09±0.14, 0.50±0.28, 1.19±0.29, 1.68±0.39, and 2.34±0.24. For Ir-192 with direct contact, the enhanced were 0.50±0.14, 2.79±0.17, 5.49±0.12, 8.19±0.14, and 10.80±0.13. Gd-containing materials used in MRI as contrast agents can also potentially serve as radiosensitizers in radiotherapy. This study demonstrates that Gd can be used to enhance radiation dose in target volumes not only in HDR brachytherapy, but also in 6 MV FFF external beam radiotherapy, but higher than the currently used clinical concentration (>5 mg/mL) would be needed. PMID:25275550

  17. LATE GADOLINIUM ENHANCEMENT BY CARDIOVASCULAR MAGNETIC RESONANCE HERALDS AN ADVERSE PROGNOSIS IN NONISCHEMIC CARDIOMYOPATHY

    PubMed Central

    Wu, Katherine C.; Weiss, Robert G.; Thiemann, David R.; Kitagawa, Kakuya; Schmidt, André; Dalal, Darshan; Lai, Shenghan; Bluemke, David A.; Gerstenblith, Gary; Marbán, Eduardo; Tomaselli, Gordon F.; Lima, João A.C.

    2008-01-01

    Structured Abstract Objectives We examined whether the presence and extent of late gadolinium enhancement (LGE) by CMR predict adverse outcomes in nonischemic cardiomyopathy (NICM) patients. Background Morbidity and mortality is high in NICM patients. However, the clinical course of an individual patient is unpredictable and current risk stratification approaches are limited. Cardiovascular magnetic resonance (CMR) detects myocardial fibrosis, which appears as LGE after contrast administration and may convey prognostic importance. Methods In a prospective cohort study, 65 NICM patients with LVEF ≤35% underwent CMR before placement of an internal cardioverter defibrillator (ICD) for primary prevention of sudden cardiac death. CMRs were analyzed for the presence and extent of LGE, and for LV function, volumes, and mass. Patients were followed for an index composite endpoint of three cardiac events: hospitalization for heart failure, appropriate ICD firing, and cardiac death. Results 42% (n=27) of patients had CMR LGE, averaging 10±13% of LV mass. During a 17 month median follow-up, 44% (n=12) of patients with LGE had an index composite outcome event, versus only 8% (n=3) of those without LGE (p<0.001 for Kaplan-Meier survival curves). After adjustment for LV volume index and functional class, patients with LGE had an eight-fold higher risk of experiencing the primary outcome (hazard ratio 8.2, 95% CI 2.2–30.9, p=0.002). Conclusions CMR LGE in NICM patients strongly predicts adverse cardiac outcomes. CMR LGE may represent the end-organ consequences of sustained adrenergic activation and adverse LV remodeling, and its identification may significantly improve risk stratification strategies in this high risk population. Condensed Abstract Predicting prognosis in nonischemic cardiomyopathy patients is challenging and current risk stratification approaches are limited. Cardiovascular magnetic resonance (CMR) detects myocardial fibrosis, which appears as late

  18. A Method for Simulating Mammograms

    DTIC Science & Technology

    2004-08-01

    fluence is attenuated to 1%, 5%, and 10% of the original intensity inside Gadolinium Oxysulfide and Cesium Iodide . The distance values in Table 1 are...50x 50/tm 2 and 17 x 17/UM2 for Gadolinium Oxysulfide and Cesium Iodide . With this table, we can choose the size of a cut-off window. For example, if...absorption on the imaging performance of the detector or intensifying screen. The calculation to a cesium iodide layer with pixel size 17x1 7 microns shows

  19. Evaluation of thermomechanical properties of non-stoichiometric gadolinium doped ceria using atomistic simulations

    NASA Astrophysics Data System (ADS)

    Swaminathan, N.; Qu, J.

    2009-06-01

    It is well known that gadolinium doped ceria (GDC), when subjected to reducing conditions, undergoes significant volumetric expansion and changes its elastic stiffness. In this paper, a methodology based on a semi-analytical formulation in conjunction with molecular dynamic (MD) simulation is presented to determine the coefficient of compositional expansion (CCE) and the complete elastic stiffness tensor of two common forms of GDC at various levels of non-stoichiometry and temperatures. The CCE is determined by comparing the volumes of the MD simulation cell before and after the reduction at a given temperature. To compute the elastic constants, MD simulations are first conducted to determine the equilibrium (relaxed) positions of each atom. Then, the constants are obtained through an analytical method that uses the relaxed positions of the atoms in the simulation cell. It is found that the elastic stiffness tensor of the non-stoichiometric structures remain cubic. The elastic constant C11 decreases with increasing vacancy concentration, while the changes in C12 and C66 were found to be negligible. In addition, both the elastic constants and the CCE are found to be insensitive to temperature.

  20. A density functional study of defect migration in gadolinium doped ceria.

    PubMed

    Dholabhai, Pratik P; Adams, James B; Crozier, Peter; Sharma, Renu

    2010-07-28

    Oxygen ion conductivity of doped ceria is observed to be two-three orders of magnitude higher than yttria stabilized zirconia, the most widely used solid electrolyte material at temperatures below 600 degrees C. Gadolinium doped ceria (GDC) is known to be one of the most promising solid electrolyte materials for operation of solid oxide fuel cells below 600 degrees C. To understand the atomic defect migration in GDC, we have used total energy calculations within the framework of density functional theory to follow oxygen vacancy migration in GDC. We report activation energies for various oxygen vacancy migration pathways in GDC. Oxygen vacancy formation and migration were evaluated for first, second, and third nearest neighbor positions to a Gd(3+) ion. Due to the comparable ionic radii of Gd(3+) and host Ce(4+) ions, the first nearest neighbor site with respect to the dopant cation is found to be the most favorable oxygen vacancy formation site. The migration pathway where the vacancy migrates from a second to first nearest neighbor is found to be most favorable. The calculated activation energies for oxygen vacancy migration in GDC are compared against the reported measured and calculated values from the literature. This work will provide a foundation for the development of a kinetic lattice Monte Carlo model for vacancy diffusion in GDC, which will improve the understanding of oxygen ion conductivity in doped ceria.

  1. Predicting the optimal dopant concentration in gadolinium doped ceria: a kinetic lattice Monte Carlo approach

    NASA Astrophysics Data System (ADS)

    Dholabhai, Pratik P.; Anwar, Shahriar; Adams, James B.; Crozier, Peter A.; Sharma, Renu

    2012-01-01

    Gadolinium doped ceria (GDC) is a promising alternative electrolyte material for solid oxide fuel cells that offers the possibility of operation in the intermediate temperature range (773-1073 K). To determine the optimal dopant concentration in GDC, we have employed a systematic approach of applying a 3D kinetic lattice Monte Carlo (KLMC) model of vacancy diffusion in conjunction with previously calculated activation energies for vacancy migration in GDC as inputs. KLMC simulations were performed including the vacancy repelling effects in GDC. Increasing the dopant concentration increases the vacancy concentration, which increases the ionic conductivity. However, at higher concentrations, vacancy-vacancy repulsion impedes vacancy diffusion, and together with vacancy trapping by dopants decreases the ionic conductivity. The maximum ionic conductivity is predicted to occur at ≈20% to 25% mole fraction of Gd dopant. Placing Gd dopants in pairs, instead of randomly, was found to decrease the conductivity by ≈50%. Overall, the trends in ionic conductivity results obtained using the KLMC model developed in this work are in reasonable agreement with the available experimental data. This KLMC model can be applied to a variety of ceria-based electrolyte materials for predicting the optimum dopant concentration.

  2. Efficient potassium gadolinium tungstate Raman lasers generating single or multiple wavelengths spanning the green to red

    NASA Astrophysics Data System (ADS)

    Mildren, Richard P.; Pask, H. M.; McKay, T.; Piper, J. A.

    2005-01-01

    We review our recent studies into external cavity and intracavity potassium gadolinium tungstate Raman lasers generating output wavelengths in the range 555 nm to 669 nm. We have characterised the performance external cavity Raman lasers pumped by Q-switched 532 nm pump lasers at 5-10 kHz pulse repetition rates generating either single output wavelengths or multiple wavelengths simultaneously. Single output wavelengths are obtained with slope efficiencies up to 68% and maximum output powers ~0.5 W. Simultaneous output at 5 wavelengths (eg., 532 nm, 559 nm, 589 nm, 622 nm and 658 nm) is demonstrated with ~100 mW output power for at least 3 lines. Using the intracavity Raman laser scheme, we demonstrate a 0.3-1.8 W laser that is "user switchable" amongst wavelengths spanning the green to red eg., 532 nm - 555 nm - 579 nm - 606 nm, the wavelengths corresponding to frequency sums and mixing of Stokes and fundamental intra-cavity fields.

  3. Enhancement of cell performance using a gadolinium strontium cobaltite coated cathode in molten carbonate fuel cells

    NASA Astrophysics Data System (ADS)

    Song, Shin Ae; Jang, Seong-Cheol; Han, Jonghee; Yoon, Sung Pil; Nam, Suk Woo; Oh, In-Hwan; Lim, Tae-Hoon

    To enhance cathode performance, gadolinium strontium cobaltite (Gd 0.6Sr 0.4CoO 3, GSC) is coated onto a porous Ni plate by a vacuum suction method, for use as the cathode in molten carbonate fuel cells (MCFCs). GSC is a mixed ionic and electronic conductor (MIEC) material, and thus has high electronic conductivity and catalytic activity at low temperatures. The electrode performance of the GSC-coated cathode is examined by various methods, such as single cell operation and electrochemical impedance spectroscopy (EIS). At 600 °C, the performance of a single cell using a GSC-coated cathode is 0.813 V. This result is very surprising given that the performance of an uncoated conventional cathode is 0.69 V. Impedance analysis confirms that a dramatic decrease in the charge transfer resistance after GSC coating is primarily responsible for the cell enhancement at low temperature. The reaction orders for O 2 and CO 2 at uncoated and GSC-coated cathodes are also examined via a symmetric cell test, to identify the reaction mechanism of oxygen reduction. The peroxide mechanism, which is known to be a fast reaction, is predominant for the GSC-coated cathode at low temperatures, whereas the superoxide mechanism is predominant for the uncoated cathode.

  4. High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

    NASA Astrophysics Data System (ADS)

    Zairov, Rustem; Mustafina, Asiya; Shamsutdinova, Nataliya; Nizameev, Irek; Moreira, Beatriz; Sudakova, Svetlana; Podyachev, Sergey; Fattakhova, Alfia; Safina, Gulnara; Lundstrom, Ingemar; Gubaidullin, Aidar; Vomiero, Alberto

    2017-01-01

    Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging.

  5. Hybrid mercuric iodide (HgI/sub 2/): gadolinium orthosilicate (GSO) detector for PET

    SciTech Connect

    Dahlbom, M.; Barton, J.B.; Hoffman, E.J.; Mandelkern, M.; Ricci, A.R.

    1985-02-01

    Gadolinium orthosilicate (GSO), a high density (6.71 g/cm/sup 3/), high effective Z (59) scintillation detector with faster decay time (60 ns) and higher light yield than bismuth germanate (BGO), was evaluated as a replacement for BGO for a hybrid detection system for high resolution Positron Emission Tomography (PET). The detection system consists of multiple GSO detectors attached to a single photomultiplier tube (PMT) and a HgI/sub 2/ photodetector attached to each GSO crystal. The PMT signal provides coincidence timing and energy discrimination and the photodetector signal identifies the crystal of interaction. GSO light yield was 1.7 times that of BGO with energy resolution consistent with improved photon statistics (17.8 to 13.8% FWHM). Resolution of GSO coupled to a HgI/sub 2/ photodetector was 13.6% FWHM. Coincidence timing was 2.3 ns FWHM. Timing between PMT and HgI/sub 2/ was 136 ns FWHM.

  6. The influence of gadolinium and yttrium on biomass production and nutrient balance of maize plants.

    PubMed

    Saatz, Jessica; Vetterlein, Doris; Mattusch, Jürgen; Otto, Matthias; Daus, Birgit

    2015-09-01

    Rare earth elements (REE) are expected to become pollutants by enriching in the environment due to their wide applications nowadays. The uptake and distribution of gadolinium and yttrium and its influence on biomass production and nutrient balance was investigated in hydroponic solution experiments with maize plants using increasing application doses of 0.1, 1 and 10 mg L(-1). It could be shown that concentrations of up to 1 mg L(-1) of Gd and Y did not reduce or enhance the plant growth or alter the nutrient balance. 10 mg L(-1) Gd or Y resulted in REE concentrations of up to 1.2 weight-% in the roots and severe phosphate deficiency symptoms. Transfer rates showed that there was only little transport of Gd and Y from roots to shoots. Significant correlations were found between the concentration of Gd and Y in the nutrient solution and the root tissue concentration of Ca, Mg and P.

  7. Polydisulfide Manganese(II) Complexes as Non-Gadolinium Biodegradable Macromolecular MRI Contrast Agents

    PubMed Central

    Ye, Zhen; Jeong, Eun-Kee; Wu, Xueming; Tan, Mingqian; Yin, Shouyu; Lu, Zheng-Rong

    2011-01-01

    Purpose To develop safe and effective manganese(II) based biodegradable macromolecular MRI contrast agents. Materials and Methods In this study, we synthesized and characterized two polydisulfide manganese(II) complexes, Mn-DTPA cystamine copolymers and Mn-EDTA cystamine copolymers, as new biodegradable macromolecular MRI contrast agents. The contrast enhancement of the two manganese based contrast agents were evaluated in mice bearing MDA-MB-231 human breast carcinoma xenografts, in comparison with MnCl2. Results The T1 and T2 relaxivities were 4.74 and 10.38 mM−1s−1 per manganese at 3T for Mn-DTPA cystamine copolymers (Mn=30.50 kDa) and 6.41 and 9.72 mM−1s−1 for Mn-EDTA cystamine copolymers (Mn= 61.80 kDa). Both polydisulfide Mn(II) complexes showed significant liver, myocardium and tumor enhancement. Conclusion The manganese based polydisulfide contrast agents have a potential to be developed as alternative non-gadolinium contrast agents for MR cancer and myocardium imaging. PMID:22031457

  8. Comparison of MRI properties between derivatized DTPA and DOTA gadolinium-dendrimer conjugates

    PubMed Central

    Nwe, K.; Bernardo, M; Regino, C. A. S.; Williams, M; Brechbiel, M. W.

    2010-01-01

    In this report we directly compare the in vivo and in vitro MRI properties of gadolinium-dendrimer conjugates of derivatized acyclic diethylenetriamine-N,N’,N’,N’’, N’’-pentaacetic acid (1B4M-DTPA) and macrocyclic 1,4,7,10-tetraazacyclododecane-N,N’,N’’,N’’’-tetraacetic acid (C-DOTA). The metal-ligand chelates were pre-formed in alcohol prior to conjugation to the generation 4 PAMAM dendrimer (G4D), and the dendrimer-based agents were purified by Sephadex® G-25 column. The analysis and SE-HPLC data indicated chelate to dendrimer ratios of 30:1 and 28:1 respectively. Molar relaxivity measured at pH 7.4, 22°C, and 3T are comparable (29.5 vs. 26.9 mM−1s−1), and both conjugates are equally viable as MRI contrast agents based on the images obtained. The macrocyclic agent however exhibits a faster rate of clearance in vivo (t1/2 = 16 vs. 29 min.). Our conclusion is that the macrocyclic-based agent is the more suitable agent for in vivo use for these reasons combined with kinetic inertness associated with the Gd(III) DOTA complex stability properties. PMID:20663676

  9. Purificaiton of Lanthanides for Large Neutrino Detectors: Thorium Removal from Gadolinium Chloride

    SciTech Connect

    Yeh, M.; Cumming, J.B.; Hans, S.; Hahn, R.L.

    2010-06-01

    Metal-loaded liquid scintillators are the detectors of choice for various neutrino experiments. Procedures have been developed to transfer metals into organic liquids by solvent extraction or direct dissolution of a metallic compound. Traces of natural radioactivity introduced into the scintillator with the metal may produce undesirable backgrounds. Measurements using a {sup 229}Th tracer indicate that the inclusion of a pH-controlled partial hydrolysis and filtration prior to the preparation of a gadolinium-loading compound can reduce thorium by a factor of {approx}100. This 'self-scavenging' procedure has the advantage that it uses only reagents encountered in the production process. Addition of non-elemental scavengers such as iron, or the use of solvent extraction or ion exchange procedures can be avoided. It also improves the optical transmission in the blue region by removing traces of iron. This purification method has potential applications to the large-scale production of other metal-loaded liquid scintillators and for the removal of traces of thorium in the industrial production of lanthanides.

  10. Ammonia gas sensing property of gadolinium oxide using fiber optic gas sensor

    NASA Astrophysics Data System (ADS)

    Kumar, J. Santhosh; Ranganathan, B.; Sastikumar, D.

    2017-05-01

    The design of fiber optic sensor is based on a cladding modification methodology. A fiber-optic chemical sensor is developed by replacing a certain portion of the original cladding with a chemically sensitive material, specifically, calcinated gadolinium oxide (Gd2O3).Both the light absorption co-efficient and refractive index change upon exposure to chemical vapours of volatile organic compounds (VOCs) such as ammonia (NH3), ethanol (CH3CH2OH), and methanol (CH3OH). The spectral characteristics of the sensor were studied for different concentrations ranging from 0-500 ppm. These changes induced the optical intensity modulation of the transmitted optical signal. During interaction between the sensing material and VOCs, the output intensity is taken into account to detect the toxic VOCs present in the environment. This was systematically investigated by X-ray diffractometer (XRD) and SEM. The XRD analysis indicated that the calcinated Gd2O3 was formed in cubic structure with the crystallite size of 13 nm. The Gd2O3 nanorods with thickness ranging from 80 to 120 nm were confirmed from SEM. The ammonia gas response of the Gd2O3 sensor is presented. A model is proposed for understanding the spectral intensity variations.

  11. Layered gadolinium-based nanoparticle as a novel delivery platform for microRNA therapeutics

    NASA Astrophysics Data System (ADS)

    Yoo, Shannon S.; Razzak, Rene; Bédard, Eric; Guo, Linghong; Shaw, Andrew R.; Moore, Ronald B.; Roa, Wilson H.

    2014-10-01

    Specific expression patterns of microRNA (miRNA) molecules have been linked to cancer initiation, progression, and metastasis. The accumulating evidence for the role of oncogenic or tumor-suppressing miRNAs identified the need for nano-scaled platform that can help deliver nucleotides to modulate miRNAs. Here we report the synthesis of novel layered gadolinium hydroxychloride (LGdH) nanoparticles, a member of the layered double hydroxide (LDH) family, with physiochemical properties suitable for cell uptake and tracing via magnetic resonance (MR) imaging. As a proof of concept, we demonstrate the inhibition of mature miRNA-10b in metastatic breast cancer cell line using LGdH nanoparticle as a delivery platform. Through characterization analysis, we show that nanoparticles are easily and stably loaded with anti-miRNA oligonucleotides (AMO) and efficiently penetrate cell membranes. We demonstrate that AMOs delivered by LGdH nanoparticles remain functional by inducing changes in the expression of its downstream effector and by curbing the invasive properties. Furthermore, we demonstrate the traceability of LGdH nanoparticles via T1 weighted MR imaging. LGdH nanoparticles, which are biocompatible with cells in vitro, provide a promising multifunctional platform for microRNA therapeutics through their diagnostic, imaging, and therapeutic potentials.

  12. Acute Respiratory Distress Syndrome after the Use of Gadolinium Contrast Media.

    PubMed

    Park, Jihye; Byun, Il Hwan; Park, Kyung Hee; Lee, Jae-Hyun; Nam, Eun Ji; Park, Jung-Won

    2015-07-01

    Acute respiratory distress syndrome (ARDS) is a medical emergency that threatens life. To this day, ARDS is very rarely reported by iodine contrast media, and there is no reported case of ARDS induced by gadolinium contrast media. Here, we present a case with ARDS after the use of gadobutrol (Gadovist) as a magnetic resonance imaging (MRI) contrast medium. A 26 years old female without any medical history, including allergic diseases and without current use of drugs, visited the emergency room for abdominal pain. Her abdominopelvic computed tomography with iodine contrast media showed a right ovarian cyst and possible infective colitis. Eighty-three hours later, she underwent pelvis MRI after injection of 7.5 mL (0.1 mL/kg body weight) of gadobutrol (Gadovist) to evaluate the ovarian cyst. She soon presented respiratory difficulty, edema of the lips, nausea, and vomiting, and we could hear wheezing upon auscultation. She was treated with dexamethasone, epinephrine, and norepinephrine. Her chest X-ray showed bilateral central bat-wing consolidative appearance. Managed with mechanical ventilation, she was extubated 3 days later and discharged without complications.

  13. Thermal-Diffusivity Dependence on Temperature of Gadolinium Calcium Oxoborate Single Crystals

    NASA Astrophysics Data System (ADS)

    Trefon-Radziejewska, D.; Bodzenta, J.; Łukasiewicz, T.

    2013-05-01

    Thermal diffusivities of pure and doped gadolinium calcium oxoborate (GdCOB) single crystals were measured as a function of the temperature along optical indicatrix axes X, Y, and Z. Three GdCOB samples were investigated, chemically pure single crystal, the one doped with 4 at% of Nd and the next one doped with 7 at% of Yb. Measurements were carried out for temperature range 40 °C to 300 °C. Determination of the thermal diffusivity based on an analysis of thermal wave propagation in the sample. For a detection of temperature disturbance propagating in the sample the mirage effect was used. Obtained results show that the thermal diffusivity decreases with the increase of sample temperature for all investigated crystals. The GdCOB single crystals reveal a strong anisotropy. The thermal diffusivity along Y direction has the highest value while values obtained in X and Z axes are much lower. Dopants cause decrease in the thermal diffusivity for all investigated directions.

  14. A comparison of homogeneous and inhomogeneous absorption broadening in Nd doped Gadolinium Gallium Garnet

    NASA Astrophysics Data System (ADS)

    Ferri, Christopher; Ghosh, Sayantani

    2015-03-01

    We perform a temperature dependent optical absorption study of the 4I9 / 2-->4F3 / 2 (Zn -->Rn)transition of the Neodymium dopant in Neodymium(III) doped Gadolinium Gallium Garnet. Absorption spectra are acquired for these transitions as a function of temperature from 12K to 300K. The absorption peaks are subsequently fit with Voigt profiles to measure the homogeneous and inhomogeneous broadening for each transition. We find that for the Z1 -->R2 transition the homogeneous and inhomogeneous broadening are of the same order. Below 80K, for the Z1 -->R1 transition, the homogeneous broadening is below the resolution of our spectrometer (1.85 cm-1) resulting in a lower bound of ~ 18 ps for the excited state lifetime which is likely much slower. Furthermore, because of the resolution limit, the ratio of inhomogeneous broadening to homogeneous broadening for this transition has a lower bound of ~ 6 . This work was funded by NSF Grant DMR-1056860.

  15. Influence of gadolinium doping on the structure and defects of ceria under fuel cell operating temperature

    SciTech Connect

    Acharya, S. A. Gaikwad, V. M.; Sathe, V.; Kulkarni, S. K.

    2014-03-17

    Correlation between atomic positional shift, oxygen vacancy defects, and oxide ion conductivity in doped ceria system has been established in the gadolinium doped ceria system from X-ray diffraction (XRD) and Raman spectroscopy study at operating temperature (300–600 °C) of Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC). High temperature XRD data are used to quantify atomic positional shift from mean position with temperature. The Raman spectroscopy study shows additional vibration modes related to ordering of defect spaces (Gd{sub Ce}{sup ′}−V{sub o}{sup ••}){sup *} and (2Gd{sub Ce}{sup ′}−V{sub o}{sup ••}){sup x} generated due to association of oxygen vacancies and reduced cerium or dopant cations site (Gd{sup 3+}), which disappear at 450 °C; indicating oxygen vacancies dissociation from the defect complex. The experimental evidences of cation-anion positional shifting and oxygen vacancies dissociation from defect complex in the IT-SOFC operating temperature are discussed to correlate with activation energy for ionic conductivity.

  16. Performance improvement of gadolinium oxide resistive random access memory treated by hydrogen plasma immersion ion implantation

    SciTech Connect

    Wang, Jer-Chyi Hsu, Chih-Hsien; Ye, Yu-Ren; Ai, Chi-Fong; Tsai, Wen-Fa

    2014-03-15

    Characteristics improvement of gadolinium oxide (Gd{sub x}O{sub y}) resistive random access memories (RRAMs) treated by hydrogen plasma immersion ion implantation (PIII) was investigated. With the hydrogen PIII treatment, the Gd{sub x}O{sub y} RRAMs exhibited low set/reset voltages and a high resistance ratio, which were attributed to the enhanced movement of oxygen ions within the Gd{sub x}O{sub y} films and the increased Schottky barrier height at Pt/Gd{sub x}O{sub y} interface, respectively. The resistive switching mechanism of Gd{sub x}O{sub y} RRAMs was dominated by Schottky emission, as proved by the area dependence of the resistance in the low resistance state. After the hydrogen PIII treatment, a retention time of more than 10{sup 4} s was achieved at an elevated measurement temperature. In addition, a stable cycling endurance with the resistance ratio of more than three orders of magnitude of the Gd{sub x}O{sub y} RRAMs can be obtained.

  17. Sorafenib and gadolinium co-loaded liposomes for drug delivery and MRI-guided HCC treatment.

    PubMed

    Xiao, Yanan; Liu, Yongjun; Yang, Shaomei; Zhang, Bo; Wang, Tianqi; Jiang, Dandan; Zhang, Jing; Yu, Dexin; Zhang, Na

    2016-05-01

    To improve the poor water solubility of sorafenib and to monitor its distribution and the early feedback effects on its in vivo treatment efficacy in a precise manner, sorafenib (SF) and gadolinium (Gd) co-loaded liposomes (SF/Gd-liposomes) were prepared. The simultaneous imaging and therapy efficacies of the SF/Gd-liposomes were tested. The solubility of SF in SF/Gd-liposomes was significantly increased from 0.21 μg/mL to 250 μg/mL. The imaging capability of SF/Gd-liposomes were tested by in-vitro and the in-vivo imaging ability tests and the results confirmed that SF/Gd-liposomes could be served as an effective contrast agent. The design of SF/Gd-liposomes allowed the MRI-guided in vivo visualization of the delivery and biodistribution of liposome. In the in vivo antitumor studies, SF/Gd-liposomes had better antitumor effects in H22 tumor-bearing mice than SF solution (oral or i.v. administration) (P<0.05). These findings indicated that the SF/Gd-liposomes could be used as the promising nano-carriers for the MRI-guided in vivo visualization of the delivery and HCC treatment.

  18. [Studies of three-dimensional cardiac late gadolinium enhancement MRI at 3.0 Tesla].

    PubMed

    Ishimoto, Takeshi; Ishihara, Masaru; Ikeda, Takayuki; Kawakami, Momoe

    2008-12-20

    Cardiac late Gadolinium enhancement MR imaging has been shown to allow assessment of myocardial viability in patients with ischemic heart disease. The current standard approach is a 3D inversion recovery sequence at 1.5 Tesla. The aims of this study were to evaluate the technique feasibility and clinical utility of MR viability imaging at 3.0 Tesla in patients with myocardial infarction and cardiomyopathy. In phantom and volunteer studies, the inversion time required to suppress the signal of interests and tissues was prolonged at 3.0 Tesla. In the clinical study, the average inversion time to suppress the signal of myocardium at 3.0 Tesla with respect to MR viability imaging at 1.5 Tesla was at 15 min after the administration of contrast agent (304.0+/-29.2 at 3.0 Tesla vs. 283.9+/-20.9 at 1.5 Tesla). The contrast between infarction and viable myocardium was equal at both field strengths (4.06+/-1.30 at 3.0 Tesla vs. 4.42+/-1.85 at 1.5 Tesla). Even at this early stage, MR viability imaging at 3.0 Tesla provides high quality images in patients with myocardial infarction. The inversion time is significantly prolonged at 3.0 Tesla. The contrast between infarction and viable myocardium at 3.0 Tesla are equal to 1.5 Tesla. Further investigation is needed for this technical improvement, for clinical evaluation, and for limitations.

  19. Random lasing in Nd{sup 3+} doped potassium gadolinium tungstate crystal powder

    SciTech Connect

    Moura, André L.; Fewo, Serge I.; Carvalho, Mariana T.; Gomes, Anderson S. L.; Araújo, Cid B. de; Kuzmin, Andrey N.; Prasad, Paras N.

    2015-02-28

    Random laser (RL) emission in Nd{sup 3+} doped potassium gadolinium tungstate—KGd(WO{sub 4}){sub 2}:Nd{sup 3+}—crystal powder is demonstrated. The powder was excited at 813 nm in resonance with the Nd{sup 3+} transition {sup 4}I{sub 9/2}→{sup 4}F{sub 5/2}. RL emission at 1067 nm due to the {sup 4}F{sub 3/2}→{sup 4}I{sub 11/2} transition was observed and characterized. An intensity threshold dependent on the laser spot area and bandwidth narrowing from ≈2.20 nm to ≈0.40 nm were observed and measured. For a beam spot area of 0.4 mm{sup 2}, a RL threshold of 6.5 mJ/mm{sup 2} (90 MW/cm{sup 2}) was determined. For excitation intensity smaller than the RL threshold, only spontaneous emission from level {sup 4}F{sub 3/2} with decay time in the tens microsecond range was observed, but for excitation above the RL threshold, significant shortening of excited level lifetime, characteristic of a stimulated process was found. The overall characteristics measured show that KGd(WO{sub 4}){sub 2}:Nd{sup 3+} is an efficient material for operation of solid state RLs in the near-infrared.

  20. Co-Precipitation Synthesis of Gadolinium Aluminum Gallium Oxide (GAGG) via Different Precipitants

    NASA Astrophysics Data System (ADS)

    Sun, Yan; Yang, Shenghui; Zhang, Ye; Jiang, Jun; Jiang, Haochuan

    2014-02-01

    In order to obtain a uniform transparent ceramic scintillator, well-dispersed fine starting powders with high-purity, small grain size, spherical morphology and high sinter-ability are necessary. In this study, Ce3+ doped gadolinium aluminum gallium garnet Gd3Al3Ga2O12 (GAGG) powders were synthesized by the co-precipitation method. NH4OH, NH4HCO3 and the mixed solution of NH4OH and NH4HCO3 were used as precipitants, respectively. The precursor composition, phase formation process, microstructure, morphology, particle size distribution and luminescent properties of obtained GAGG powders were measured. The results show that powders prepared using the mixed precipitant exhibit the best microstructural morphology, good sinter-ability and highest luminescent intensity. Pure GAGG polycrystalline powders could be obtained at about 950°C for 1.5 h and the average size of the particles is about 50 nm. The photoluminescence spectrum shows a strong green-yellow emission near 540 nm.

  1. Modelling of the Gadolinium Fuel Test IFA-681 using the BISON Code

    SciTech Connect

    Pastore, Giovanni; Hales, Jason Dean; Novascone, Stephen Rhead; Spencer, Benjamin Whiting; Williamson, Richard L

    2016-05-01

    In this work, application of Idaho National Laboratory’s fuel performance code BISON to modelling of fuel rods from the Halden IFA-681 gadolinium fuel test is presented. First, an overview is given of BISON models, focusing on UO2/UO2-Gd2O3 fuel and Zircaloy cladding. Then, BISON analyses of selected fuel rods from the IFA-681 test are performed. For the first time in a BISON application to integral fuel rod simulations, the analysis is informed by detailed neutronics calculations in order to accurately capture the radial power profile throughout the fuel, which is strongly affected by the complex evolution of absorber Gd isotopes. In particular, radial power profiles calculated at IFE–Halden Reactor Project with the HELIOS code are used. The work has been carried out in the frame of the collaboration between Idaho National Laboratory and Halden Reactor Project. Some slide have been added as an Appendix to present the newly developed PolyPole-1 algorithm for modeling of intra-granular fission gas release.

  2. Preparation and initial characterization of biodegradable particles containing gadolinium-DTPA contrast agent for enhanced MRI.

    PubMed

    Doiron, Amber L; Chu, Kevin; Ali, Adeel; Brannon-Peppas, Lisa

    2008-11-11

    Accurate imaging of atherosclerosis is a growing necessity for timely treatment of the disease. Magnetic resonance imaging (MRI) is a promising technique for plaque imaging. The goal of this study was to create polymeric particles of a small size with high loading of diethylenetriaminepentaacetic acid gadolinium (III) (Gd-DTPA) and demonstrate their usefulness for MRI. A water-in-oil-in-oil double emulsion solvent evaporation technique was used to encapsulate the MRI agent in a poly(lactide-co-glycolide) (PLGA) or polylactide-poly(ethylene glycol) (PLA-PEG) particle for the purpose of concentrating the agent at an imaging site. PLGA particles with two separate average sizes of 1.83 microm and 920 nm, and PLA-PEG particles with a mean diameter of 952 nm were created. Loading of up to 30 wt % Gd-DTPA was achieved, and in vitro release occurred over 5 h. PLGA particles had highly negative zeta potentials, whereas the particles incorporating PEG had zeta potentials closer to neutral. Cytotoxicity of the particles on human umbilical vein endothelial cells (HUVEC) was shown to be minimal. The ability of the polymeric contrast agent formulation to create contrast was similar to that of Gd-DTPA alone. These results demonstrate the possible utility of the contrast agent-loaded polymeric particles for plaque detection with MRI.

  3. Concurrent Dual Contrast for Cellular Magnetic Resonance Imaging Using Gadolinium Oxide and Iron Oxide Nanoparticles

    PubMed Central

    Loai, Yasir; Ganesh, Tameshwar; Margaret Cheng, Hai-Ling

    2012-01-01

    Rationale and Objectives. Concurrent visualization of differential targets in cellular and molecular imaging is valuable for resolving processes spatially and temporally, as in monitoring different cell subtypes. The purpose of this study was to demonstrate concurrent, dual (positive and negative) contrast visualization on magnetic resonance imaging (MRI) of two colocalized cell populations labeled with Gadolinium “Gd” oxide and iron “Fe” oxide nanoparticles. Materials and Methods. Human aortic endothelial cells (EC) and smooth muscle cells (SMC) were labeled with various concentrations of Gd oxide and Fe oxide, respectively. MRI on single- or mixed-cell samples was performed at 7 tesla. Proper cell phenotype expressions, cell uptake of contrast agents, and the effect of labeling on cell viability and proliferation were also determined. Results. Both contrast agents were efficiently taken up by cells, with viability and proliferation largely unaffected. On MRI, the positive contrast associated with Gd oxide-labeled EC and negative contrast associated with Fe oxide-labeled SMC discriminated the presence of each cell type, whether it existed alone or colocalized in a mixed-cell sample. Conclusion. It is feasible to use Gd oxide and Fe oxide for dual contrast and concurrent discrimination of two colocalized cell populations on MRI at 7 tesla. PMID:22919479

  4. Heavy-ion beam induced effects in enriched gadolinium target films prepared by molecular plating

    NASA Astrophysics Data System (ADS)

    Mayorov, D. A.; Tereshatov, E. E.; Werke, T. A.; Frey, M. M.; Folden, C. M.

    2017-09-01

    A series of enriched gadolinium (Gd, Z = 64) targets was prepared using the molecular plating process for nuclear physics experiments at the Cyclotron Institute at Texas A&M University. After irradiation with 48Ca and 45Sc projectiles at center-of-target energies of Ecot = 3.8-4.7 MeV/u, the molecular films displayed visible discoloration. The morphology of the films was examined and compared to the intact target surface. The thin films underwent a heavy-ion beam-induced density change as identified by scanning electron microscopy and α-particle energy loss measurements. The films became thinner and more homogenous, with the transformation occurring early on in the irradiation. This transformation is best described as a crystalline-to-amorphous phase transition induced by atomic displacement and destruction of structural order of the original film. The chemical composition of the thin films was surveyed using energy dispersive spectroscopy and X-ray diffraction, with the results confirming the complex chemistry of the molecular films previously noted in other publications.

  5. Synthesis, Characterization, and Thermal Kinetics of Mixed Gadolinium: Calcium Heptamolybdate System

    PubMed Central

    Koul, R. K.; Suri, Shivani; Singh, Vishal; Bamzai, K. K.

    2014-01-01

    Synthesis of mixed gadolinium calcium heptamolybdate (GdCaHM) system in silica gel medium using single gel single tube technique has been successfully achieved. The grown crystal exhibits various morphologies, which includes spherulites, multifaceted, and square platelets. The nature of the grown material was established by X-ray diffraction (XRD) studies. Fourier transform infrared spectroscopy (FTIR) study signifies the presence of heptamolybdate (Mo7O24) and water symmetry structure, whereas energy dispersive X-ray analysis (EDAX) establishes the stoichiometric of the grown crystal as GdCaMo7O24·8H2O. The thermal behaviour was studied using the thermoanalytical techniques, which include thermogravimetry (TG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). Results obtained on the application of TG based models, namely, Horowitz-Metzger, Coats-Redfern, and Piloyan-Novikova, suggest the contracting cylindrical model as the relevant model for the thermal decomposition of the material. The kinetic parameters, namely, the order of reaction (n), activation energy (Ea), frequency factor (Z), and entropy (ΔS∗), were also calculated using these three models. PMID:27350973

  6. Manufacturing and in vivo inner ear visualization of MRI traceable liposome nanoparticles encapsulating gadolinium

    PubMed Central

    2010-01-01

    Background Treatment of inner ear diseases remains a problem because of limited passage through the blood-inner ear barriers and lack of control with the delivery of treatment agents by intravenous or oral administration. As a minimally-invasive approach, intratympanic delivery of multifunctional nanoparticles (MFNPs) carrying genes or drugs to the inner ear is a future therapy for treating inner ear diseases, including sensorineural hearing loss (SNHL) and Meniere's disease. In an attempt to track the dynamics and distribution of nanoparticles in vivo, here we describe manufacturing MRI traceable liposome nanoparticles by encapsulating gadolinium-tetra-azacyclo-dodecane-tetra-acetic acid (Gd-DOTA) (abbreviated as LPS+Gd-DOTA) and their distribution in the inner ear after either intratympanic or intracochlear administration. Results Measurements of relaxivities (r1 and r2) showed that LPS+Gd-DOTA had efficient visible signal characteristics for MRI. In vivo studies demonstrated that LPS+Gd-DOTA with 130 nm size were efficiently taken up by the inner ear at 3 h after transtympanic injection and disappeared after 24 h. With intracochlear injection, LPS+Gd-DOTA were visualized to distribute throughout the inner ear, including the cochlea and vestibule with fast dynamics depending on the status of the perilymph circulation. Conclusion Novel LPS+Gd-DOTA were visible by MRI in the inner ear in vivo demonstrating transport from the middle ear to the inner ear and with dynamics that correlated to the status of the perilymph circulation. PMID:21167059

  7. Inactivation of Kupffer Cells by Gadolinium Chloride Protects Murine Liver From Radiation-Induced Apoptosis

    SciTech Connect

    Du Shisuo; Qiang Min; Zeng Zhaochong; Ke Aiwu; Ji Yuan; Zhang Zhengyu; Zeng Haiying; Liu Zhongshan

    2010-03-15

    Purpose: To determine whether the inhibition of Kupffer cells before radiotherapy (RT) would protect hepatocytes from radiation-induced apoptosis. Materials and Methods: A single 30-Gy fraction was administered to the upper abdomen of Sprague-Dawley rats. The Kupffer cell inhibitor gadolinium chloride (GdCl3; 10 mg/kg body weight) was intravenously injected 24 h before RT. The rats were divided into four groups: group 1, sham RT plus saline (control group); group 2, sham RT plus GdCl3; group 3, RT plus saline; and group 4, RT plus GdCl3. Liver tissue was collected for measurement of apoptotic cytokine expression and evaluation of radiation-induced liver toxicity by analysis of liver enzyme activities, hepatocyte micronucleus formation, apoptosis, and histologic staining. Results: The expression of interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha was significantly attenuated in group 4 compared with group 3 at 2, 6, 24, and 48 h after injection (p <0.05). At early points after RT, the rats in group 4 exhibited significantly lower levels of liver enzyme activity, apoptotic response, and hepatocyte micronucleus formation compared with those in group 3. Conclusion: Selective inactivation of Kupffer cells with GdCl3 reduced radiation-induced cytokine production and protected the liver against acute radiation-induced damage.

  8. Late gadolinium enhanced cardiovascular magnetic resonance of lamin A/C gene mutation related dilated cardiomyopathy

    PubMed Central

    2011-01-01

    Background The purpose of this study was to identify early features of lamin A/C gene mutation related dilated cardiomyopathy (DCM) with cardiovascular magnetic resonance (CMR). We characterise myocardial and functional findings in carriers of lamin A/C mutation to facilitate the recognition of these patients using this method. We also investigated the connection between myocardial fibrosis and conduction abnormalities. Methods Seventeen lamin A/C mutation carriers underwent CMR. Late gadolinium enhancement (LGE) and cine images were performed to evaluate myocardial fibrosis, regional wall motion, longitudinal myocardial function, global function and volumetry of both ventricles. The location, pattern and extent of enhancement in the left ventricle (LV) myocardium were visually estimated. Results Patients had LV myocardial fibrosis in 88% of cases. Segmental wall motion abnormalities correlated strongly with the degree of enhancement. Myocardial enhancement was associated with conduction abnormalities. Sixty-nine percent of our asymptomatic or mildly symptomatic patients showed mild ventricular dilatation, systolic failure or both in global ventricular analysis. Decreased longitudinal systolic LV function was observed in 53% of patients. Conclusions Cardiac conduction abnormalities, mildly dilated LV and depressed systolic dysfunction are common in DCM caused by a lamin A/C gene mutation. However, other cardiac diseases may produce similar symptoms. CMR is an accurate tool to determine the typical cardiac involvement in lamin A/C cardiomyopathy and may help to initiate early treatment in this malignant familiar form of DCM. PMID:21689390

  9. Lunar prospector measurements of the distribution of incompatible elements gadolinium, samarium and thorium

    SciTech Connect

    Elphic, R.C.; Lawrence, D.J.; Feldman, W.C.; Barraclough, B.L.; Maurice, S.; Binder, A.B.; Lucey, P.G.

    1999-04-01

    Lunar Prospector neutron spectrometer (NS) and gamma ray spectrometer (GRS) observations have been used to map out the distribution of incompatible elements on the lunar surface. Specifically, the GRS data provide maps of the distribution of thorium and potassium while the NS data provide information on the distribution of iron and titanium, and the rare earth elements gadolinium and samarium. Using results of analysis of Celementine spectral reflectance (CSR) data, the Fe- and Ti-contributions to the NS data can be removed, leaving primarily rare earth element contributions from Gd and Sm. The Th and K maps correlate with the inferred Gd and Sm maps (r {approximately} 0.93), but there are regions of significant disagreement. One of these is in the KREEP-rich circum-Imbrium ring. No clear explanation has emerged for this disagreement, though Th, K, Gd and Sm have differing degrees of incompatibility. These results clearly are important to discussions of the geochemistry of the Procellarum-Imbrium Th-rich Terrane and the South-Pole-Aitken Terrane.

  10. Optical constants determination of neodymium and gadolinium in the 3-nm to 100-nm wavelength range

    NASA Astrophysics Data System (ADS)

    Kjornrattanawanich, B.; Windt, D. L.; Uspenskii, Y. A.; Seely, J. F.

    2006-08-01

    The optical constants (n, k) of the wavelength-dependent index of refraction N = n+ik = 1-δ+ik of Nd (Neodymium) and Gd (Gadolinium) are determined in the wavelength range of 3 nm to 100 nm by the transmittance method using synchrotron radiation. Nd and Gd films with thicknesses ranging from 5 nm to 180 nm were fabricated on Si photodiodes (which served as the coating substrates as well as the detectors) and capped with Si layers to protect these reactive rare earth elements from oxidation. The imaginary part (k) obtained directly from the transmittance measurement is used in the derivation of the real part (δ) of the complex index of refraction N through the Kramers- Kronig integral. The measured optical constants are used in the design of currently developed Nd- and Gd-based multilayers for solar imaging applications. Our results on Nd and Gd optical constants and the reflectance of some Nd- and Gd-based multilayers are presented.

  11. Whole-core comet solutions to a 3-dimensional PWR benchmark problem with gadolinium

    SciTech Connect

    Zhang, D.; Rahnema, F.

    2012-07-01

    A pressurized water reactor (PWR) benchmark problem with gadolinium was used to determine the accuracy and computational efficiency of the coarse mesh radiation transport method COMET. The benchmark problem contains 193 square fuel assemblies. The COMET solution (eigenvalue, assembly averaged and fuel pin averaged fission density distributions) was compared with those obtained from the corresponding Monte Carlo reference solution using the same 2-group material cross section library. The comparison showed that both the core eigenvalue and fission density distribution averaged over each assembly and fuel pin predicated by COMET agree very well with the corresponding MCNP reference solution if the incident flux response expansion used in COMET is truncated at 2nd order in the two spatial and the two angular variables. The benchmark calculations indicate that COMET has Monte Carlo accuracy. In, particular, the eigenvalue difference between the codes ranged from 17 pcm to 35 pcm, being within 2 standard deviations of the calculational uncertainty. The mean flux weighted relative differences in the assembly and fuel pin fission densities were 0.47% and 0.65%, respectively. It was also found that COMET's full (whole) core computational speed is 30,000 times faster than MCNP in which only 1/8 of the core is modeled. It is estimated that COMET would have been about over 6 orders of magnitude faster than MCNP if the full core were also modeled in MCNP. (authors)

  12. A complement to the modern crystallographer's toolbox: caged gadolinium complexes with versatile binding modes.

    PubMed

    Stelter, Meike; Molina, Rafael; Jeudy, Sandra; Kahn, Richard; Abergel, Chantal; Hermoso, Juan A

    2014-06-01

    A set of seven caged gadolinium complexes were used as vectors for introducing the chelated Gd(3+) ion into protein crystals in order to provide strong anomalous scattering for de novo phasing. The complexes contained multidentate ligand molecules with different functional groups to provide a panel of possible interactions with the protein. An exhaustive crystallographic analysis showed them to be nondisruptive to the diffraction quality of the prepared derivative crystals, and as many as 50% of the derivatives allowed the determination of accurate phases, leading to high-quality experimental electron-density maps. At least two successful derivatives were identified for all tested proteins. Structure refinement showed that the complexes bind to the protein surface or solvent-accessible cavities, involving hydrogen bonds, electrostatic and CH-π interactions, explaining their versatile binding modes. Their high phasing power, complementary binding modes and ease of use make them highly suitable as a heavy-atom screen for high-throughput de novo structure determination, in combination with the SAD method. They can also provide a reliable tool for the development of new methods such as serial femtosecond crystallography.

  13. Acute Respiratory Distress Syndrome after the Use of Gadolinium Contrast Media

    PubMed Central

    Park, Jihye; Byun, Il Hwan; Park, Kyung Hee; Lee, Jae-Hyun; Nam, Eun Ji

    2015-01-01

    Acute respiratory distress syndrome (ARDS) is a medical emergency that threatens life. To this day, ARDS is very rarely reported by iodine contrast media, and there is no reported case of ARDS induced by gadolinium contrast media. Here, we present a case with ARDS after the use of gadobutrol (Gadovist) as a magnetic resonance imaging (MRI) contrast medium. A 26 years old female without any medical history, including allergic diseases and without current use of drugs, visited the emergency room for abdominal pain. Her abdominopelvic computed tomography with iodine contrast media showed a right ovarian cyst and possible infective colitis. Eighty-three hours later, she underwent pelvis MRI after injection of 7.5 mL (0.1 mL/kg body weight) of gadobutrol (Gadovist) to evaluate the ovarian cyst. She soon presented respiratory difficulty, edema of the lips, nausea, and vomiting, and we could hear wheezing upon auscultation. She was treated with dexamethasone, epinephrine, and norepinephrine. Her chest X-ray showed bilateral central bat-wing consolidative appearance. Managed with mechanical ventilation, she was extubated 3 days later and discharged without complications. PMID:26069143

  14. MR of intracranial tumors: Combined use of gadolinium and magnetization transfer

    SciTech Connect

    Kurki, T.; Niemi, P.; Valtonen, S.

    1994-10-01

    To study the potential combined application of gadolinium and magnetization transfer in the MR imaging of intracranial tumors. Twenty-two patients were imaged at low field strength (0.1 T). Corresponding gradient-echo partial saturation images without and with magnetization transfer pulse were produced. Images with intermediate repetition times were obtained in 18 cases; five different sequences were produced in 4 cases. Gadopentetate dimeglumine was used at a dose of 0.1 mmol/kg. Magnetization transfer effect increased the contrast between enhancing lesion and normal brain and the contrast between edema and normal brain; the contrast between enhancing lesion and edema was not significantly changed. On intermediate-repetition-time magnetization transfer images the contrast between enhancing tumor and normal brain and the contrast between edema and normal brain were superior to short-repetition-time magnetization transfer images, but the differentiation between enhancing tumor and edema was poorer. Magnetization transfer can be used to improve contrast in Gd-enhanced MR imaging. Combining magnetization transfer with an intermediate-repetition-time image provides the possibility for displaying both enhancing and nonehancing lesions on a single MR image. 20 refs., 7 figs., 2 tabs.

  15. A Versatile and Clearable Nanocarbon Theranostic Based on Carbon Dots and Gadolinium Metallofullerene Nanocrystals.

    PubMed

    Guan, Mirong; Li, Jie; Jia, Qingyan; Ge, Jiechao; Chen, Daiqin; Zhou, Yue; Wang, Pengfei; Zou, Toujun; Zhen, Mingming; Wang, Chunru; Shu, Chunying

    2016-09-01

    Nanocarbons such as carbon nanotubes, graphene derivatives, and carbon nanohorns have illustrated their potential uses as cancer theranostics owing to their intrinsic fluorescence or NIR absorbance as well as superior cargo loading capacity. However, some problems still need to be addressed, such as the fates and long-term toxicology of different nanocarbons in vivo and the improvement of their performance in various biomedical imaging-guided cancer therapy systems. Herein, a versatile and clearable nanocarbon theranostic based on carbon dots (CDs) and gadolinium metallofullerene nanocrystals (GFNCs) is first developed, in which GFNCs enhance the tumor accumulation of CDs, and CDs enhance the relaxivity of GFNCs, leading to an efficient multimodal imaging-guided photodynamic therapy in vivo without obvious long-term toxicity. Furthermore, biochemical analysis reveals that the novel nanotheranostic can harmlessly eliminate from the body in a reasonable period of time after exerting diagnostic and therapeutic function. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Metabolomic profiles delineate potential roles for gadolinium chloride in the proliferation or inhibition of Hela cells.

    PubMed

    Long, Xiao-Hui; Yang, Peng-Yuan; Liu, Qiong; Yao, Jun; Wang, Yi; He, Guo-Hua; Hong, Guang-Yan; Ni, Jia-Zuan

    2011-08-01

    Lanthanides (Lns) compounds have been reported to possess contrary effects on cell activity, i.e., promoting cell cycle progression and cell growth by lower concentration treatment, but suppressing cell proliferation and inducing cell apoptosis at higher dosing. However, the cellular processes during the intervention and the possible underlying mechanisms are still not well clarified. Using a combination of high-throughput liquid chromatography (LC) with mass spectrometry (MS), we have investigated the metabolomic profiles of Hela cells following gadolinium chloride (GdCl(3)) treatment in time- and concentration- dependent manners. A total of 48 metabolites released by Hela cells are identified to be differentially expressed (P < 0.05) in different states. Metabolic pathways analyses reveal that the differential metabolites are mainly characterized by increased lipid and amino acid metabolisms and by decreased lipid, amino acid, and carbohydrate metabolisms for cells treated with GdCl(3) at lower and higher concentrations, respectively. Notably, in the higher level GdCl(3) case, the down-expressions of metabolites are predominantly in the glycolytic and the redox pathways. The above results, obtained by using a metabolomic strategy for the first time, disclose that different cell signaling pathways are activated by GdCl(3) treatment with different concentrations, leading to inhibitory or promotional effect on Hela cells.

  17. Optical properties of color centers in calcium-stabilized gadolinium gallium garnets

    SciTech Connect

    Pogatshnik, G.J. ); Cain, L.S. ); Chen, Y. ); Evans, B.D. )

    1991-01-15

    The addition of small amounts of calcium during the crystal growth of large-diameter, gadolinium gallium garnet (GGG) crystals creates color centers that absorb in the near-uv region of the spectrum. Ultraviolet and {gamma}-ray irradiation of the crystals produced changes in the intensities of the uv color-center bands along with a broad absorption throughout the visible spectrum. The color center that gives rise to an absorption band at 350 nm serves as a photoionizable donor center so that uv excitation results in a visible coloration of the crystals. The effects of oxidation and reduction treatments on the strength of the color-center bands and on the radiation response of the material were examined. Photoluminescence bands were observed in both reduced GGG crystals as well as crystals that were irradiated with neutrons. Visible coloration is likely to occur during flashlamp pumping of laser rods that utilize large-diameter GGG crystals as the laser host. The changes in the optical properties of the material under uv excitation indicate that the addition of small amounts of calcium to assist in the growth of large-diameter crystals is likely to result in the degradation of laser performance.

  18. High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

    PubMed Central

    Zairov, Rustem; Mustafina, Asiya; Shamsutdinova, Nataliya; Nizameev, Irek; Moreira, Beatriz; Sudakova, Svetlana; Podyachev, Sergey; Fattakhova, Alfia; Safina, Gulnara; Lundstrom, Ingemar; Gubaidullin, Aidar; Vomiero, Alberto

    2017-01-01

    Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging. PMID:28091590

  19. Internalization pathways into cancer cells of gadolinium-based radiosensitizing nanoparticles.

    PubMed

    Rima, Wael; Sancey, Lucie; Aloy, Marie-Thérèse; Armandy, Emma; Alcantara, Gustavo B; Epicier, Thierry; Malchère, Annie; Joly-Pottuz, Lucile; Mowat, Pierre; Lux, François; Tillement, Olivier; Burdin, Béatrice; Rivoire, Annie; Boulé, Christelle; Anselme-Bertrand, Isabelle; Pourchez, Jérémie; Cottier, Michèle; Roux, Stéphane; Rodriguez-Lafrasse, Claire; Perriat, Pascal

    2013-01-01

    Over the last few decades, nanoparticles have been studied in theranostic field with the objective of exhibiting a long circulation time through the body coupled to major accumulation in tumor tissues, rapid elimination, therapeutic potential and contrast properties. In this context, we developed sub-5 nm gadolinium-based nanoparticles that possess in vitro efficient radiosensitizing effects at moderate concentration when incubated with head and neck squamous cell carcinoma cells (SQ20B). Two main cellular internalization mechanisms were evidenced and quantified: passive diffusion and macropinocytosis. Whereas the amount of particles internalized by passive diffusion is not sufficient to induce in vitro a significant radiosensitizing effect, the cellular uptake by macropinocytosis leads to a successful radiotherapy in a limited range of particles incubation concentration. Macropinocytosis processes in two steps: formation of agglomerates at vicinity of the cell followed by their collect via the lamellipodia (i.e. the "arms") of the cell. The first step is strongly dependent on the physicochemical characteristics of the particles, especially their zeta potential that determines the size of the agglomerates and their distance from the cell. These results should permit to control the quantity of particles internalized in the cell cytoplasm, promising ambitious opportunities towards a particle-assisted radiotherapy using lower radiation doses.

  20. Caustic Precipitation of Plutonium and Uranium with Gadolinium as a Neutron Poison

    SciTech Connect

    VISSER, ANN E.; BRONIKOWSKI, MICHAEL G.; RUDISILL, TRACY S.

    2005-10-18

    The caustic precipitation of plutonium (Pu) and uranium (U) from Pu and U-containing waste solutions has been investigated to determine whether gadolinium (Gd) could be used as a neutron poison for precipitation with greater than a fissile mass containing both Pu and enriched U. Precipitation experiments were performed using both process solution samples and simulant solutions with a range of 2.6-5.16 g/L U and 0-4.3:1 U:Pu. Analyses were performed on solutions at intermediate pH to determine the partitioning of elements for accident scenarios. When both Pu and U were present in the solution, precipitation began at pH 4.5 and by pH 7, 99% of Pu and U had precipitated. When complete neutralization was achieved at pH > 14 with 1.2 M excess OH{sup -}, greater than 99% of Pu, U, and Gd had precipitated. At pH > 14, the particles sizes were larger and the distribution was a single mode. The ratio of hydrogen:fissile atoms in the precipitate was determined after both settling and centrifuging and indicates that sufficient water was associated with the precipitates to provide the needed neutron moderation for Gd to prevent a criticality in solutions containing up to 4.3:1 U:Pu and up to 5.16 g/L U.

  1. Caustic Precipitation of Plutonium and Uranium with Gadolinium as a Neutron Poison

    SciTech Connect

    ANN, VISSER

    2005-04-14

    The caustic precipitation of plutonium (Pu) and uranium (U) from Pu and U containing waste solutions has been investigated to determine whether gadolinium (Gd) could be used as a neutron poison for precipitation with greater than a fissile mass containing both Pu and enriched U. Precipitation experiments were performed using both actual samples and simulant solutions with a range of 2.6-5.16 g/L U and 0-4.3 to 1 U to Pu. Analyses were performed on solutions at intermediate pH to determine the partitioning of elements for accident scenarios. When both Pu and U were present in the solution, precipitation began at pH 4.5 and by pH 7, 99 percent of Pu and U had precipitated. When complete neutralization was achieved at pH greater than 14 with 1.2 M excess OH-, greater than 99 percent of Pu, U, and Gd had precipitated. At pH greater than 14, the particles sizes were larger and the distribution was a single mode. The ratio of hydrogen to fissile atoms in the precipitate was determined after both settling and centrifuging and indicates that sufficient water was associated with the precipitates to provide the needed neutron moderation for Gd to prevent a criticality in solutions containing up to 4.3 to 1 U to Pu and up to 5.16 g/L U.

  2. Utility of gadolinium-enhanced MR urography in detection of bladder carcinoma.

    PubMed

    Niederhauser, Blake D; Kawashima, Akira; King, Bernard F; Takahashi, Naoki

    2013-03-01

    To evaluate the diagnostic accuracy of MR urography (MRU) in detecting bladder carcinoma. A retrospective review of 107 MRU exams obtained to evaluate for possible upper urinary tract urothelial carcinoma from 5/2005 to 5/2009 was performed by two experienced abdominal radiologists. Interpretation of the presence or absence of bladder carcinoma and lesion conspicuity in each imaging phase was made using 5-point confidence grading scales. Exams included 3D T1-weighted spoiled gradient-recalled echo images through the kidneys, ureters and bladder in the coronal plane during parenchymal phases and in both coronal and axial planes during pyelographic phases after intravenous administration of gadolinium and furosemide. Standard of reference was cystoscopy or cystectomy within 30 days of MRU. Statistical measures of performance, including receiver operating characteristics area under the curve (Az) values were calculated. Bladder carcinoma was present in 26/107 patients (24%). Sensitivity, specificity, accuracy, positive predictive value, negative predictive value and Az value were 73.1%, 91.4%, 86.9%, 73.1%, 91.4%, 0.89 for the first reviewer, and 84.6%, 75.3%, 77.6%, 52.4%, 93.8%, 0.86 for the second. Lesion conspicuity was superior on the parenchymal phase compared to the pyelographic phase (p=0.04). MRU obtained for suspicion of upper urinary tract TCC has a moderate accuracy in detecting bladder carcinoma. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Phase-Sensitive Inversion Recovery for Detecting Myocardial Infarction Using Gadolinium-Delayed Hyperenhancement

    PubMed Central

    Kellman, Peter; Arai, Andrew E.; McVeigh, Elliot R.; Aletras, Anthony H.

    2007-01-01

    After administration of gadolinium, infarcted myocardium exhibits delayed hyperenhancement and can be imaged using an inversion recovery (IR) sequence. The performance of such a method when using magnitude-reconstructed images is highly sensitive to the inversion recovery time (TI) selected. Using phase-sensitive reconstruction, it is possible to use a nominal value of TI, eliminate several breath-holds otherwise needed to find the precise null time for normal myocardium, and achieve a consistent contrast. Phase-sensitive detection is used to remove the background phase while preserving the sign of the desired magnetization during IR. Experimental results are presented which demonstrate the benefits of both phase-sensitive IR image reconstruction and surface coil intensity normalization for detecting myocardial infarction (MI). The phase-sensitive reconstruction method reduces the variation in apparent infarct size that is observed in the magnitude images as TI is changed. Phase-sensitive detection also has the advantage of decreasing the sensitivity to changes in tissue T1 with increasing delay from contrast agent injection. PMID:11810682

  4. Poly(lactic-co-glycolic acid) encapsulated gadolinium oxide nanoparticles for MRI-based cell tracking.

    PubMed

    Bennewitz, Margaret F; Williams, Simone S; Nkansah, Michael K; Shapiro, Erik M

    2013-06-01

    Superparamagnetic iron oxide particles have proven useful for cell tracking applications by monitoring cell transplantation and migration in living organisms. However, one perceived drawback is that these particles cause dark contrast in MRI, sometimes yielding confusion with other biological phenomena, which also yield dark contrast. To that end, researchers have investigated the use of gadolinium oxide (Gd2O3) based contrast agents for MRI-based cell tracking, as Gd2O3 has favorable r1 molar relaxivity. We synthesized Gd2O3 nanocrystals and encapsulated them within PLGA matrices to form approximatley to 150 nm nanoparticles. r1 was 1.9 mM(-1) sec(-1) and r2 was 8.4 mM(-1) sec(-1). Cell labeling with particles was well tolerated by cells except at very high doses. MRI of labeled cells showed that labeled cells could achieve both R1 and R2 enhancements due to the internalized particles. R2 enhancements were approximately to twice that of R1 enhancements suggesting the use of very short echo times when using Gd2O3 based contrast agents for MRI-based cell tracking.

  5. Cathodoluminescence properties of gadolinium-doped CaMoO4:Eu nanoparticles.

    PubMed

    Ramakrishna, P V

    2015-10-05

    Gadolinium (Gd(3+)) doped CaMoO4:Eu nanoparticles were prepared via facile auto-combustion route and annealed at 900 °C for ∼4 h. X-ray diffraction study confirms the tetragonal scheelite type of CaMoO4 phase. Low voltage cathodoluminescent (CL) measurement were performed for Gd(3+) (0 and 10 at.%) co-doped CaMoO4:Eu as a function of accelerating voltage and filament current. CL studies confirm that Gd(3+) co-doped CaMoO4:Eu has a visible emission peak centered at ∼615 nm and a broad host emission band in the range 380-550 nm. Commission Internationale de L'Eclairage chromaticity diagram co-ordinates of Gd(3+) co-doped CaMoO4:Eu are found to be in reddish orange region as was observed through photoluminescence and CL spectra. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Gadolinium dosimetry, a problematic issue in the neutron capture therapy. Comparison between experiments and computational simulations.

    NASA Astrophysics Data System (ADS)

    Bufalino, D.; Cerullo, N.; Colli, V.; Gambarini, G.; Rosi, G.

    2006-05-01

    In GdNCT the interested isotope is 157Gd that captures neutrons with (n, ) reaction and also emits internal conversion and Auger electrons. These electrons have an important effect on DNA strands, mainly due to the property of gadolinium to link to DNA. The emitted gamma rays partially interacts with tumours but mainly diffuse in the body damaging healthy tissues. Therefore in the study of Gd therapeutical effect both dosimetric and microdosimetric analyses must be performed. At Pisa University, in the last years some works were performed by NCT group. At the present these researches are continued on these topics carrying out also a PhD thesis. In this frame some simulations, using MC code, were performed in order to evaluate the dose distribution due to Gd reactions. It is however necessary to calibrate the calculations on experimental results, though they are scarce in GdNCT. Some experiments with 157Gd were performed by Milan group using gel dosimetry [1, 2, 3]. Therefore some computational comparisons were done. In these article the results of this comparisons are shown and discussed.

  7. Process-Property Relationship for Air Plasma-Sprayed Gadolinium Zirconate Coatings

    NASA Astrophysics Data System (ADS)

    Dwivedi, Gopal; Tan, Yang; Viswanathan, Vaishak; Sampath, Sanjay

    2015-02-01

    The continuous need of elevating operating temperature of gas turbine engines has introduced several challenges with the current state-of-the-art yttria-stabilized zirconia (YSZ)-based thermal barrier coatings (TBCs), requiring examination of new TBC material with high temperature phase stability, lower thermal conductivity, and resistance to environmental ash particles. Gadolinium zirconate (Gd2Zr2O7) (GDZ) has been shown to meet many of these requirements, and has, in fact, been successfully implemented in to engine components. However, several fundamental issues related to the process-ability, toughness, and microstructural differences for GDZ when compared to equivalent YSZ coating. This study seeks to critically address the process-structure-property correlations for plasma-sprayed GDZ coating subjected to controlled parametric exploration. Use of in-flight diagnostics coupled with in situ and ex situ coating property monitoring allows examination and comparison of the process-property interplay and the resultant differences between the two TBC compositions. The results indicate that it is feasible to retain material chemistry and fabricate relevant microstructures of interest with GDZ with concomitant performance advantages such as low conductivity, mechanical compliance, sintering resistance, and suppression of environmentally induced damage from ash particles. This study provides a framework for optimal design and manufacturing of emergent multi-layer and multi-material TBCs.

  8. Gadolinium-enhanced MR imaging of epiphyseal and metaphyseal marrow in normal piglets.

    PubMed

    Li, Xiaoming; Wang, Renfa; Qi, Jianpin; Tang, Lihua

    2005-01-01

    The purpose of this study is to define the appearance of normal epiphyseal and metaphyseal marrow and normal changes of marrow due to fatty conversion on Gadolinium (Gd)-enhanced MR Imaging. Unenhanced and enhanced T1-weighted MR imaging were performed in proximal and distal femoral ends of 8 healthy piglets at the ages of 2, 4, 6 and 8 weeks, respectively. The changes with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow with age were examined. The correlation of MRI characteristics with histological findings was studied. Our study showed that marrow of the metaphysis and of periphery of the 2nd ossification center were well vascularized hematopoietic marrow and had great enhancements. The enhancement ratio of metaphysis was greater than that of epiphyseal marrow and both enhancement ratios degraded gradually with age. The central regions of the epiphyseal ossification center and of the diaphysis were of fatty marrow and had little enhancement. It is concluded that on Gd-enhanced MR imaging the hematopoietic marrow of metaphysis and of periphery of the 2nd ossification center had greater enhancement than that of fatty marrow of central region of the 2nd ossification center. All of their enhancements decreased gradually with age.

  9. Magnetic properties of gadolinium and carbon co-doped gallium nitride

    NASA Astrophysics Data System (ADS)

    Syed Kaleemullah, N.; Ramsubramanian, S.; Mohankumar, R.; Munawar Basha, S.; Rajagopalan, M.; Kumar, J.

    2017-01-01

    Investigations have been carried out to study the ferromagnetic properties of Gadolinium (Gd) Carbon (C) co-doped wurtzite Gallium Nitride (GaN) using full-potential linear augmented plane wave (FP-LAPW) method within the density functional theory. The system shows half-metallic nature when single Gd is substituted in Ga36N36 supercell. The presence of carbon in GaN supercell is found to generate weak magnetic moment (Ms) in the neighbouring atoms. When Carbon is codoped in the Gd-GaN, it increased the total magnetic moment of the system (Mtot). The cause of ferromagnetism in the Gd and C co-doped GaN has been explained by Zener's p-d exchange mechanism. The role of defects in the magnetic property of this system is also investigated. The results indicate the gallium vacancy influences the magnetic moment of the Gd and C codoped GaN more than the nitrogen vacancy. The presence of holes is effective than electrons in achieving the ferromagnetism in the considered system.

  10. Design of a novel optical sensor for determination of trace gadolinium.

    PubMed

    Zare-Dorabei, R; Norouzi, P; Ganjali, M R

    2009-11-15

    In this work, a highly selective and sensitive gadolinium (Gd) optical sensor based on immobilization of bis(thiophenal) pyridine-2,6-diamine (BPD), on a triacetylcellulose membrane has been reported. This optode exhibits a linear range of the Gd(III) ion concentration of 2.5 x 10(-6)M with a detection limit of 0.93 x 10(-8) M. Response time of the newly designed optode was within 1-2 min, depending on the Gd(III) ion concentration. Response of the sensor is independent of solution pH in the range of 2.0-9.0. It manifests advantages of: low detection limit, fast response time, and most significantly, very good selectivity with respect to a number of lanthanide ions (La, Ce, Sm, Tm, Ho, and Eu ions). The sensor was successfully regenerated with thiourea solutions and its response was reversible and reproducible (R.S.D. less than 1.4%). This optode was applied to determine Gd(III) in synthetic and water samples, and validated with certified reference materials (CRMs).

  11. Removal of gadolinium-based contrast agents: adsorption on activated carbon.

    PubMed

    Elizalde-González, María P; García-Díaz, Esmeralda; González-Perea, Mario; Mattusch, Jürgen

    2017-01-31

    Three carbon samples were employed in this work, including commercial (1690 m(2) g(-1)), activated carbon prepared from guava seeds (637 m(2) g(-1)), and activated carbon prepared from avocado kernel (1068 m(2) g(-1)), to study the adsorption of the following gadolinium-based contrast agents (GBCAs): gadoterate meglumine Dotarem®, gadopentetate dimeglumine Magnevist®, and gadoxetate disodium Primovist®. The activation conditions with H3PO4 were optimized using a Taguchi methodology to obtain mesoporous materials. The best removal efficiency by square meter in a batch system in aqueous solution and model urine was achieved by avocado kernel carbon, in which mesoporosity prevails over microporosity. The kinetic adsorption curves were described by a pseudo-second-order equation, and the adsorption isotherms in the concentration range 0.5-6 mM fit the Freundlich equation. The chemical characterization of the surfaces shows that materials with a greater amount of phenolic functional groups adsorb the GBCA better. Adsorption strongly depends on the pH due to the combination of the following factors: contrast agent protonated forms and carbon surface charge. The tested carbon samples were able to adsorb 70-90% of GBCA in aqueous solution and less in model urine. This research proposes a method for the elimination of GBCA from patient urine before its discharge into wastewater.

  12. Response of a lithium gadolinium borate scintillator in monoenergetic neutron fields.

    PubMed

    Williams, A M; Beeley, P A; Spyrou, N M

    2004-01-01

    Accurate estimation of neutron dose requires knowledge of the neutron energy distribution in the working environment. Existing neutron spectrometry systems, Bonner spheres for example, are large and bulky, and require long data acquisition times. A portable system that could indicate the approximate neutron energy spectrum in a short time would be extremely useful in radiation protection. A composite scintillator, consisting of lithium gadolinium borate crystals in a plastic scintillator matrix, produced by Photogenics is being tested for this purpose. A prototype device based on this scintillator and digital pulse processing electronics has been calibrated using quasi-monoenergetic neutron fields at the low-scatter facility of the UK National Physical Laboratory (NPL). Energies selected were 144, 250, 565, 1400, 2500 and 5000 keV, with correction for scattered neutrons being made using the shadow cone technique. Measurements were also made in the NPL thermal neutron field. Pulse distributions collected with the digitiser in capture-gated mode are presented, and detection efficiency and energy resolution derived. For comparison, neutron spectra were also collected using the commercially available Microspec N-Probe from Bubble Technology Industries, which consists of an NE213 scintillator and a 3He proportional counter.

  13. Dual photon absorptiometry using a gadolinium-153 source applied to measure equine bone mineral content

    NASA Astrophysics Data System (ADS)

    Moure, Alessandro; Reichmann, Peter; Remigio Gamba, Humberto

    2003-12-01

    The application of the dual photon absorptiometry (DPA) technique, using gadolinium-153 as the photon source, to evaluate the bone mineral density (BMD) of the third metacarpal bone of horses is presented. The radiation detector was implemented with a NaI(TI) scintillator coupled to a 14 stage photomultiplier. A modular mechanical system allows the position of the prototype to be adjusted in relation to the animal. A moveable carrier makes it possible to scan the third metacarpal with a velocity adjustable between 1 and 12 mm s-1, in steps of 1 mm s-1, for a total distance of 250 mm. The prototype was evaluated with a phantom of the third metacarpal bone made of perspex and aluminium, and in vitro with a transverse slice of the third metacarpal bone of a horse. The tests showed that the prototype has an accuracy and precision of, approximately, 10% and 6%, respectively, for a 6 s acquisition time. Preliminary studies carried out in three foals from birth to one year of age indicated that the prototype is well suited to in vivo and in situ analysis of the BMD of the third metacarpal bones of horses, making it possible to evaluate the changes of BMD levels on a monthly basis. Also, results indicated an exponential behaviour of the BMD curve during the first year of life of the studied horses.

  14. Multifunctional gadolinium-based dendritic macromolecules as liver targeting imaging probes.

    PubMed

    Luo, Kui; Liu, Gang; He, Bin; Wu, Yao; Gong, Qingyong; Song, Bin; Ai, Hua; Gu, Zhongwei

    2011-04-01

    The quest for highly efficient and safe contrast agents has become the key factor for successful application of magnetic resonance imaging (MRI). The gadolinium (Gd) based dendritic macromolecules, with precise and tunable nanoscopic sizes, are excellent candidates as multivalent MRI probes. In this paper, a novel series of Gd-based multifunctional peptide dendritic probes (generation 2, 3, and 4) possessing highly controlled structures and single molecular weight were designed and prepared as liver MRI probes. These macromolecular Gd-ligand agents exhibited up to 3-fold increase in T(1) relaxivity comparing to Gd-DTPA complexes. No obvious in vitro cytotoxicity was observed from the measured concentrations. These dendritic probes were further functionalized with multiple galactosyl moieties and led to much higher cell uptake in vitro as demonstrated in T(1)-weighted scans. During in vivo animal studies, the probes provided better signal intensity (SI) enhancement in mouse liver, especially at 60 min post-injection, with the most efficient enhancement from the galactosyl moiety decorated third generation dendrimer. The imaging results were verified with analysis of Gd content in liver tissues. The design strategy of multifunctional Gd-ligand peptide dendritic macromolecules in this study may be used for developing other sensitive MRI probes with targeting capability. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Frequency and severity of acute allergic-like reactions to gadolinium-containing i.v. contrast media in children and adults.

    PubMed

    Dillman, Jonathan R; Ellis, James H; Cohan, Richard H; Strouse, Peter J; Jan, Sophia C

    2007-12-01

    The purpose of our study was to determine the frequency and severity of acute allergic-like reactions to i.v.-administered gadolinium-containing contrast media in children and adults. Pediatric (younger than 19 years) and adult department of radiology contrast material reaction forms involving patients who experienced acute allergic-like reactions to gadolinium-containing contrast media from January 1, 2001, through December 31, 2006, were retrospectively evaluated for the specific types of acute allergic-like reactions, reaction management, and patient outcomes. Relevant patient medical information, including documentation of prior gadolinium- or iodine-containing contrast material reaction, premedication before acute allergic-like reaction to i.v. gadolinium-containing contrast material, previous allergic reactions to substances other than contrast media, and history of asthma, was obtained by reviewing electronic medical records. Seventy-eight thousand three hundred fifty-three (65,009 adult and 13,344 pediatric) i.v. administrations of gadolinium-containing contrast material were performed during the study period. Acute allergic-like reactions were documented after 54 injections (reaction frequency, 0.07%). Forty-eight reactions involved adult patients (adult reaction frequency, 0.07%), and six reactions occurred in pediatric patients (pediatric reaction frequency, 0.04%). Forty (74%) acute allergic-like reactions were mild, 10 (19%) were moderate, and four (7%) were severe. No gadolinium-containing contrast material-related death occurred during the study period. Twenty-six (50%) of 52 patients had one or more presumed risk factors for contrast material reaction. Adult and pediatric acute allergic-like reactions to i.v.-administered gadolinium-containing contrast media are rare. Most of these reactions are mild; however, moderate and severe reactions that require immediate management do occur.

  16. Clearance of Gadolinium from the Brain with No Pathologic Effect after Repeated Administration of Gadodiamide in Healthy Rats: An Analytical and Histologic Study.

    PubMed

    Smith, Adrian P L; Marino, Michael; Roberts, Jeanette; Crowder, Janell M; Castle, Jason; Lowery, Lisa; Morton, Christine; Hibberd, Mark G; Evans, Paul M

    2017-03-01

    Purpose To measure the levels of gadolinium present in the rat brain 1 and 20 weeks after dosing with contrast agent and to determine if there are any histopathologic sequelae. Materials and Methods The study was approved by the GE Global Research Center Institutional Animal Care and Use Committee. Absolute gadolinium levels were quantified in the blood and brains of rats 1 week after dosing and 20 weeks after dosing with up to 20 repeat doses of gadodiamide (cumulative dose, 12 mmol per kilogram of body weight) by using inductively coupled plasma-mass spectrometry. Treatment groups (n = 6 rats per group) included low-dosage and high-dosage gadodiamide and osmolality-matched saline controls. Brain sections were submitted (blinded) for standard toxicology assessment per Registry of Industrial Toxicology Animal data guidelines. Analysis of variance and Mann-Whitney U tests with post hoc correction were used to assess differences in absolute gadolinium levels and percentage of injected dose, respectively. Results Dose-dependent low levels of gadolinium were detected in the brain, a mean ± standard deviation of 2.49 nmol per gram of brain tissue ± 0.30 or 0.00019% of the injected dose 1 week after dosing. This diminished by approximately 50% (to 1.38 nmol per gram of brain tissue ± 0.10 or 0.00011% of the injected dose) 20 weeks after dosing. As a percentage of injected dose, the levels of gadolinium measured were comparable between different doses, indicating that mechanisms of uptake and elimination were not saturated at the tested doses. There were no histopathologic findings associated with the levels of gadolinium measured. Conclusion Low levels of gadolinium are present in the brain after repeat dosing with gadodiamide, which is partially cleared over 20 weeks with no detectable neurotoxicity.

  17. In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging.

    PubMed

    Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

    2015-01-01

    Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N'-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor.

  18. Gadolinium, a mechano-sensitive channel blocker, inhibits osmosis-initiated motility of sea- and freshwater fish sperm, but does not affect human or ascidian sperm motility.

    PubMed

    Krasznai, Zoltán; Morisawa, Masaaki; Krasznai, Zoárd Tibor; Morisawa, Sachiko; Inaba, Kazuo; Bazsáné, Zsuzsa Kassai; Rubovszky, Bálint; Bodnár, Béla; Borsos, Antal; Márián, Teréz

    2003-08-01

    Exposure to hypo-osmotic or hyperosmotic environment triggers the initiation of fish sperm motility. In this article, we report that calcium and potassium channel blockers do not influence motility of puffer fish sperm but calmodulin antagonists reversibly decrease it, suggesting that calmodulin-Ca(2+) interactions are prerequisite for the initiation of sperm motility in this species. Gadolinium (a stretch activated ion channel blocker) decreased the motility of puffer fish sperm from 92 +/- 3% to 6 +/- 3% and that of carp sperm from 91 +/- 7% to 3.5 +/- 4.3% in a dose-dependent manner (10-40 micro M). The effect of gadolinium was reversible, suggesting that stretch activated ion channels participate in the initiation of sperm motility of the two species. Gadolinium inhibits changes in the isoelectric point of certain proteins of puffer fish sperm, which occur when sperm motility is initiated in a hypertonic solution. Anisotropy measurements showed that hypo-osmotic treatment, which initiates carp sperm motility, increased membrane fluidity. When hypo-osmotic treatment was given in the presence of gadolinium, the sperm membrane remained as rigid as in quiescent cells, while motility was blocked. By contrast, gadolinium did not influence the motility parameters of Ciona or human sperm. Based on these lines of evidence, we suggest that conformational changes of mechanosensitive membrane proteins are involved in osmolality-dependent but not osmolality-independent sperm.

  19. Gadolinium Enhanced MRI Assessment of Bone-Patellar Tendon-Bone Graft Harvest on Patellar Vascularity

    PubMed Central

    Jones, Kristofer J.; Lazaro, Lionel E.; Taylor, Samuel; Pardee, Nadine C.; Dyke, Jonathan P.; Hannafin, Jo A.; Warren, Russell F.; Lorich, Dean G.

    2013-01-01

    Objectives: Bone-patellar tendon-bone (BPTB) autograft remains a favored graft source for anterior cruciate ligament (ACL) reconstruction despite problems related to donor-site morbidity. Patellar devascularization has been proposed as a source of anterior knee pain following vascular disruption from traumatic injury (fracture) or surgical procedures involving the patella (total knee arthroplasty); however, no study has investigated the effect of BPTB harvest on patellar vascularity. Recent anatomic studies have suggested that the dominant arterial supply enters the patella through the inferior pole. We hypothesized that BPTB harvest can significantly diminish patellar vascularity following graft harvest. Methods: Nine matched pair cadaveric knee specimens (mean age 47.4 years) were dissected and cannulated at the superficial femoral, anterior tibialis, and posterior tibialis arteries. A single knee was randomly selected to undergo bone graft harvest. The contralateral knee was left intact to serve as a control. Gadolinium (Gd-DPTA) was injected into each knee and MRI signal enhancement was quantified to determine differences in osseous uptake between the two knees. Following MRI assessment, each matched pair was injected with a urethane polymer compound and dissected to correlate vessel disruption with MRI findings. Results: Graft harvest resulted in a mean 31% (range, 7.1-69.5%) decrease in signal enhancement when compared to the matched control. MRI assessment revealed two predominant patterns of vessel entry for the dominant inferior arterial supply. In one pattern, the vessel entered the inferomedial aspect (∼7 o’clock) of the distal patellar pole and was disrupted by bone graft harvest in two matched pairs (2/9, 22%). In the second pattern, the predominant vessel entered further medial (∼8 o’clock) and was not disrupted in 7 matched pairs. The mean decrease in gadolinium uptake following disruption of the predominant vessel measured 56% (range, 42

  20. Praseodymium and gadolinium doped ceria as a cathode material for low temperature solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Chockalingam, Rajalekshmi; Ganguli, Ashok Kumar; Basu, Suddhasatwa

    2014-03-01

    Mixed ionic electronic conducting praseodymium and gadolinium doped ceria (PrxCe0.95-xGd0.05O2-δ (0.15 ≤ x ≤ 0.40)) compositions have been studied as a cathode material for low temperature solid oxide fuel cells. Four compositions of PrxCe0.95-xGd0.05O2-δ (PCGO) have been prepared by varying the praseodymium content. Phase formation, thermal expansion, ionic conductivity, electronic conductivity, ionic transference number and electrochemical performance have been investigated. X-ray diffraction results indicate that PCGO samples crystallize in the fluorite structure, and the lattice volume decreases with increasing praseodymium content, x. The coefficient of thermal expansion increases with increasing x, and at x = 0.2 shows an optimum value of 12 × 10-6 K-1. Ionic transference number decrease while electronic conductivity increase with increasing x. It has been found that electronic contribution to the total conductivity is higher than ionic contribution for all compositions. The praseodymium doping with cerium dioxide introduces impurity bands within the ceria band gap and facilitates the electronic transition from valance band to conduction band through praseodymium impurity levels. The single cell with configuration, Pr0.2Ce0.75-xGd0.05O2-δ-Ce0.80Gd0.20O2-δ∥Ce0.80Gd0.20O2-δ∥NiO-Ce0.80Gd0.20O2-δ delivers a maximum power density of 98 mW cm-2 at 650 °C.

  1. Enhanced electron mobility at gadolinium oxide(100)/silicon(100) interface: Origin and applications

    NASA Astrophysics Data System (ADS)

    Sitaputra, Wattaka

    A growth of a gadolinium oxide (Gd2O3) layer with (100) orientation on a Si(100) substrate was obtained for the first time using molecular beam epitaxy deposition (MBE) with the growth temperature in the range of 150-200°C and the oxygen partial pressure in the range of 10 -7-10-6 Torr. The growth was performed on three type of Si(100) substrate; n-type, p-type, and intrinsic. Among the three major orientations, i.e. (111), (110) and (100), the Gd2O3(100) is known from energetic point of view to be least favorable. Nonetheless, an enhancement in electron mobility can only be found from the interface between Gd2O3(100) and Si(100). Although p-type Si(100) results in the best structural considerations from x-ray diffraction among the three types of substrate, the best feature was observed in the Gd2O 3(100)/n-type Si(100) because of its highest mobility enhancement and satisfactory structural stability. The mobility of 1670-1780 cm2/V˙s was observed at room temperature, for carrier concentration > 1018 cm-3. This amounts to a factor of four higher in electron mobility compared to a heavily doped n-type substrate with similar carrier concentration. This accumulation of electrons and mobility enhancement are attributed to two-dimensional confinement from charges transfer across the interface quite similar to modulation doping. Owing to these properties, the Gd2O3(100) becomes a promising candidate in promoting the scaling of logic devices.

  2. Microfabrication of a gadolinium-derived solid-state sensor for thermal neutrons

    PubMed Central

    Achyuthan, Komandoor E.; Allen, Matthew; Denton, Michele L. B.; Siegal, Michael P.; Manginell, Ronald P.

    2017-01-01

    Abstract Neutron sensing is critical in civilian and military applications. Conventional neutron sensors are limited by size, weight, cost, portability and helium supply. Here the microfabrication of gadolinium (Gd) conversion material–based heterojunction diodes for detecting thermal neutrons using electrical signals produced by internal conversion electrons (ICEs) is described. Films with negligible stress were produced at the tensile-compressive crossover point, enabling Gd coatings of any desired thickness by controlling the radiofrequency sputtering power and using the zero-point near p(Ar) of 50 mTorr at 100 W. Post-deposition Gd oxidation–induced spallation was eliminated by growing a residual stress-free 50 nm neodymium-doped aluminum cap layer atop Gd. The resultant coatings were stable for at least 6 years, demonstrating excellent stability and product shelf-life. Depositing Gd directly on the diode surface eliminated the air gap, leading to a 200-fold increase in electron capture efficiency and facilitating monolithic microfabrication. The conversion electron spectrum was dominated by ICEs with energies of 72, 132 and 174 keV. Results are reported for neutron reflection and moderation by polyethylene for enhanced sensitivity, and γ- and X-ray elimination for improved specificity. The optimal Gd thickness was 10.4 μm for a 300 μm-thick partially depleted diode of 300 mm2 active surface area. Fast detection (within 10 min) at a neutron source-to-diode distance of 11.7 cm was achieved with this configuration. All ICE energies along with γ-ray and Kα,β X-rays were modeled to emphasize correlations between experiment and theory. Semi-conductor thermal neutron detectors offer advantages for field-sensing of radioactive neutron sources. PMID:28369631

  3. Gadolinium Complex for the Catch and Release of Phosphate from Water.

    PubMed

    Harris, Sarah M; Nguyen, Jamie T; Pailloux, Sylvie L; Mansergh, Jarrett P; Dresel, Mark J; Swanholm, Tran B; Gao, Tuo; Pierre, Valérie C

    2017-04-18

    The ability of complexes of hard and labile metal ions with one or more open coordination sites to capture phosphates with high affinity and selectivity directly in water at neutral pH and release them under acidic conditions is evaluated with Gadolinium- 2,2',2''-(((nitrilotris(ethane-2,1-diyl))tris(azanediyl))tris(carbonyl))tris(4-oxo-4H-pyran-3-olate) (Gd-TREN-MAM). This model lanthanide complex has two open coordination sites that, at neutral pH, are filled with water molecules. In water at neutral pH, Gd-TREN-MAM binds phosphate with high affinity (Ka = 1.3 × 10(4)) via the formation of a ternary complex in which one phosphate replaces both inner-sphere water molecules. The formation of this complex is highly pH-dependent; the phosphate is completely released from Gd-TREN-MAM below pH 2. Because the Gd(III) ion remains complexed by its ligand, even under strong acidic conditions, Gd-TREN-MAM can be used at least 10 times in a pH-based recycling scheme that enables the catch and release of one phosphate per cycle. Gd-TREN-MAM is highly selective for phosphate over other anions of environmental concerns, including HCO3(-), HCO2(-), CH3CO2(-), SO4(2-), NO3(-), NO2(-), BrO3(-), AsO4(-), F(-), Cl(-), and Br(-) and, to a lesser extent, ClO3(-). The development of such receptors that bind phosphate reversibly in a pH-dependent manner opens the possibility to design catch-and-release systems for the purification of surface waters.

  4. Gadolinium inhibits prostate cancer PC3 cell migration and suppresses osteoclast differentiation in vitro.

    PubMed

    Wang, Peng; Zou, Xiao-Min; Huang, Jian; Zhang, Tian-Lan; Wang, Kui

    2011-11-01

    This study examined whether Gd (gadolinium) could suppress prostate cancer cell migration and prostate cancer cell-induced osteoclast differentiation. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] and colony forming assay showed that GdCl3 treatment inhibited both cell viability and colony forming ability in PC3 cells more significantly than that in DU145 cells. Annexin/PI (propidium iodide) staining showed an increase in apoptotic death of PC3 cells in the presence of GdCl3. Wound healing and adhesion assay indicated that GdCl3 suppressed PC3 cell migration. Western-blot analysis demonstrated that GdCl3 treatment inhibited phosphorylation of ERK (extracellular-signal-regulated kinase) and p38 MAPK (mitogen-activated protein kinase). Pretreatment with PTx (pertussis toxin), a Gi protein inhibitor, conferred resistance to GdCl3-induced colony formation, ERK and p38 phosphorylation in PC3 cells. Moreover, GdCl3 inhibited PC3 cell-induced osteoclast differentiation. RT-PCR (reverse transcription-PCR) indicated that GdCl3 decreased the expression of RANKL (receptor activator of nuclear factor-κB ligand) in PC3 cells, whereas it increased the expression of OPG (osteoprotegerin) in PC3 and DU145 cells. In conclusion, the present study indicated that GdCl3 inhibited PC3 cell migration mediated by the inactivation of both ERK and p38 MAPK pathways via PTx-sensitive G proteins, and also suppressed PC3 cell-induced osteoclast differentiation via regulating the mRNA expression of OPG and RANKL.

  5. [The protective role of gadolinium chloride in lung injury associated with acute necrotizing pancreatitis].

    PubMed

    Cheng, Shi; Song, Mao-Min; Li, Zhi-Hong; He, San-Guang

    2004-08-07

    To discuss the role of gadolinium chloride (GdCl(3)) in lung injury associated with acute necrotizing pancreatitis (ANP). Experimental animals were randomized into five groups (n = 18 for each group): normal control group, ANP group, GdCl(3) pretreatment group, ANP GdCl(3) pretreatment group, ANP GdCl(3) treatment group. Rat ANP model was induced by intraductal administration of 3% sodium taurocholate. Alveolar macrophages (AM) were obtained by bronchoalveolar lavage. The blood gas assay, the ratio of wet/dry tissue, protein content of bronchoalveolar lavage fluids (BALF), the myeloperoxidase (MPO) of lung tissue and generation of TNFalpha and NO by AM were evaluated. The apoptosis of AM was checked by agarose gel electrophoresis analysis, transmission electric microscopy observation and cytometry propidium iodide single stained method. The lung tissue was examined by histology. The parameter of GdCl(3) pretreatment group compared with normal control group had no statistical significance (P > 0.05). The indicators of ANP GdCl(3) pretreatment group and ANP GdCl(3) treatment group were elevated compared with the normal control group and had statistical significance (P < 0.05). But compared to the ANP group, they were all decreased and also had the statistical significance (P < 0.05). The 180 - 200 bp ladder pattern unique to apoptosis in agarose gel electrophoresis and the apoptotic typical morphologic feature in AM by transmission electric microscopy and typical subdiploid peak in DNA content figure could be observed in ANP GdCl(3) pretreatment group and ANP GdCl(3) treatment group, while the other three groups could not. Lung injury associated with ANP could be ameliorated by application of GdCl(3) through inducing apoptosis of AM of ANP.

  6. Effect of Gadolinium Chloride on Liver Regeneration Following Thioacetamide-Induced Necrosis in Rats

    PubMed Central

    Bautista, Mirandeli; Andres, David; Cascales, María; Morales-González, José A.; Sánchez-Reus, María Isabel

    2010-01-01

    Gadolinium chloride (GD) attenuates drug-induced hepatotoxicity by selectively inactivating Kupffer cells. The effect of GD was studied in reference to postnecrotic liver regeneration induced in rats by thioacetamide (TA). Rats, intravenously pretreated with a single dose of GD (0.1 mmol/Kg), were intraperitoneally injected with TA (6.6 mmol/Kg). Hepatocytes were isolated from rats at 0, 12, 24, 48, 72 and 96 h following TA intoxication, and samples of blood and liver were obtained. Parameters related to liver damage were determined in blood. In order to evaluate the mechanisms involved in the post-necrotic regenerative state, the time course of DNA distribution and ploidy were assayed in isolated hepatocytes. The levels of circulating cytokine TNFα was assayed in serum samples. TNFα was also determined by RT-PCR in liver extracts. The results showed that GD significantly reduced the extent of necrosis. The effect of GD induced noticeable changes in the post-necrotic regeneration, causing an increased percentage of hepatocytes in S phase of the cell cycle. Hepatocytes increased their proliferation as a result of these changes. TNFα expression and serum level were diminished in rats pretreated with GD. Thus, GD pre-treatment reduced TA-induced liver injury and accelerated postnecrotic liver regeneration. No evidence of TNFα implication in this enhancement of hepatocyte proliferation and liver regeneration was found. These results demonstrate that Kupffer cells are involved in TA-induced liver damage, as well as and also in the postnecrotic proliferative liver states. PMID:21151447

  7. Chelating DTPA amphiphiles: ion-tunable self-assembly structures and gadolinium complexes.

    PubMed

    Moghaddam, Minoo J; de Campo, Liliana; Kirby, Nigel; Drummond, Calum J

    2012-10-05

    A series of chelating amphiphiles and their gadolinium (Gd(III)) metal complexes have been synthesized and studied with respect to their neat and lyotropic liquid crystalline phase behavior. These amphiphiles have the ability to form ion-tunable self-assembly nanostructures and their associated Gd(III) complexes have potential as magnetic resonance imaging (MRI) contrast enhancement agents. The amphiphiles are composed of diethylenetriaminepentaacetic acid (DTPA) chelates conjugated to one or two oleyl chain(s) (DTPA-MO and DTPA-BO), or isoprenoid-type chain(s) of phytanyl (DTPA-MP and DTPA-BP). The thermal phase behavior of the neat amphiphiles was examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and cross polarizing optical microscopy (POM). Self-assembly of neat amphiphiles and their associated Gd complexes, as well as their lyotropic phase behavior in water and sodium acetate solutions of different ionic strengths, were examined by POM and small and wide angle X-ray scattering (SWAXS). All neat amphiphiles exhibited lamellar structures. The non-complexed amphiphiles showed a variety of lyotropic phases depending on the number and nature of the hydrophobic chain in addition to the ionic state of the hydration. Upon hydration with increased Na-acetate concentration and the subtle changes in the effective headgroup size, the interfacial curvature of the amphiphile increased, altering the lyotropic liquid crystalline structures towards higher order mesophases such as the gyroid (Ia3d) bicontinuous cubic phase. The chelation of Gd with the DTPA amphiphiles resulted in lamellar crystalline structures for all the neat amphiphiles. Upon hydration with water, the Gd-complexed mono-conjugates formed micellar or vesicular self-assemblies, whilst the bis-conjugates transformed only partially into lyotropic liquid crystalline mesophases.

  8. Respiratory bellows-gated late gadolinium enhancement of the left atrium.

    PubMed

    Peters, Dana C; Shaw, Jaime L; Knowles, Benjamin R; Moghari, Mehdi Hedjazi; Manning, Warren J

    2013-11-01

    To compare bellows-gated late gadolinium enhancement (LGE) with standard navigator-gated (NAV-gated) LGE for left atrial (LA) imaging, to eliminate the inflow artifacts associated with NAV-gating. Eleven subjects, including six patients with atrial fibrillation (AF), were imaged with a 3D free-breathing NAV-gated and bellows-gated LGE. Motion compensation was compared by blinded grading of image sharpness and motion ghosting (0 = worst, 2 = best). Inflow artifacts in the right inferior pulmonary vein (RIPV) and right superior PV (RSPV) were characterized on the same scale (0 = none, 2 = prominent). In patients, each PV was divided into four quadrants circumferentially in order to assess agreement about scar presence on both image sets. Respiratory compensation was not different (1.7 ± 0.5 vs. 1.6 ± 0.5, sharpness, 1.6 ± 0.5 vs. 1.6 ± 0.5, ghosting, P = NS) for bellows- and NAV-gated images. For NAV-gated LGE, inflow artifacts were more prominent in the RSPV than the RIPV (1.2 ± 0.8 vs. 0.7 ± 0.5, P = 0.046). Visually, inflow artifacts both obscured and mimicked the true scar. Disagreement on the presence of scar was found in 18% of the assessed quadrants, with 25% disagreement for RSPV quadrants (P = 0.01). Bellows-gated LGE provides similar respiratory compensation as NAV-gating, without inflow artifacts, leading to improved assessment of scar presence. Copyright © 2013 Wiley Periodicals, Inc.

  9. Microfabrication of a gadolinium-derived solid-state sensor for thermal neutrons

    DOE PAGES

    Pfeifer, Kent B.; Achyuthan, Komandoor E.; Allen, Matthew; ...

    2017-03-25

    Neutron sensing is critical in civilian and military applications. Conventional neutron sensors are limited by size, weight, cost, portability and helium supply. Here in this study, the microfabrication of gadolinium (Gd) conversion material–based heterojunction diodes for detecting thermal neutrons using electrical signals produced by internal conversion electrons (ICEs) is described. Films with negligible stress were produced at the tensile-compressive crossover point, enabling Gd coatings of any desired thickness by controlling the radiofrequency sputtering power and using the zero-point near p(Ar) of 50 mTorr at 100 W. Post-deposition Gd oxidation–induced spallation was eliminated by growing a residual stress-free 50 nm neodymium-dopedmore » aluminum cap layer atop Gd. The resultant coatings were stable for at least 6 years, demonstrating excellent stability and product shelf-life. Depositing Gd directly on the diode surface eliminated the air gap, leading to a 200-fold increase in electron capture efficiency and facilitating monolithic microfabrication. The conversion electron spectrum was dominated by ICEs with energies of 72, 132 and 174 keV. Results are reported for neutron reflection and moderation by polyethylene for enhanced sensitivity, and γ- and X-ray elimination for improved specificity. The optimal Gd thickness was 10.4 μm for a 300 μm-thick partially depleted diode of 300 mm2 active surface area. Fast detection (within 10 min) at a neutron source-to-diode distance of 11.7 cm was achieved with this configuration. All ICE energies along with γ-ray and Kα,β X-rays were modeled to emphasize correlations between experiment and theory. Semi-conductor thermal neutron detectors offer advantages for field-sensing of radioactive neutron sources.« less

  10. Modification of Mg{sub 2}Si in Mg–Si alloys with gadolinium

    SciTech Connect

    Ye, Lingying; Hu, Jilong Tang, Changping; Zhang, Xinming; Deng, Yunlai; Liu, Zhaoyang; Zhou, Zhile

    2013-05-15

    The modification effect of gadolinium (Gd) on Mg{sub 2}Si in the hypereutectic Mg–3 wt.% Si alloy has been investigated using optical microscope, scanning electron microscope, X-ray diffraction and hardness measurements. The results indicate that the morphology of the primary Mg{sub 2}Si is changed from coarse dendrite into fine polygon with the increasing Gd content. The average size of the primary Mg{sub 2}Si significantly decreases with increasing Gd content up to 1.0 wt.%, and then slowly increases. Interestingly, when the Gd content is increased to 4.0 and 8.0 wt.%, the primary and eutectic Mg{sub 2}Si evidently decrease and even disappear. The modification and refinement of the primary Mg{sub 2}Si is mainly attributed to the poisoning effect. The GdMg{sub 2} phase in the primary Mg{sub 2}Si is obviously coarsened as the Gd content exceeds 2.0 wt.%. While the decrease and disappearance of the primary and eutectic Mg{sub 2}Si are ascribed to the formation of vast GdSi compound. Therefore, it is reasonable to conclude that proper Gd (1.0 wt.%) addition can effectively modify and refine the primary Mg{sub 2}Si. - Highlights: ► Proper Gd (1.0 wt.%) addition can effectively modify and refine the primary Mg{sub 2}Si. ► We studied the reaction feasibility between Mg and Si, Gd and Si in Mg–Gd–Si system. ► We explored the modification mechanism of Gd modifier on Mg{sub 2}Si.

  11. Novel method of producing nanoparticles for gadolinium-scintillator-based digital radiography.

    PubMed

    Lee, Young Kyu; Park, Sung Kwang; Shin, Jung Wook; Oh, Kyung Min; Heo, Seung Uk; Cho, Gyu Seok; Kim, Jin Young; Nam, Sang Hee

    2013-10-01

    Radiation image sensor properties affect the dose of radiation that patients are exposed to in a clinical setting. Numerous radiation imaging systems use scintillators as materials that absorb radiation. Rare-earth scintillators produced from elements such as gadolinium, yttrium, lutetium, and lanthanum have been investigated to improve the properties of radiation imaging systems. Although such rare-earth scintillators are manufactured with a bulk structure, they exhibit low resolution and low efficiency when they are used as conversion devices. Nanoscintillators have been proposed and researched as a possible solution to these problems. According to the research, the optical properties and size of fine scintillators are affected by the sintering temperature used to produce nanoscintillators instead of the existing bulk-structured scintillators. Therefore, the main purpose of this research is to develop radiation-imaging sensors based on nanoscintillators in order to evaluate the quantitative properties of various scintillators produced under various conditions such as sintering temperature. This is accomplished by measuring acquired phantom images, and modulation transfer functions (MTFs) for complementary-symmetry metal-oxide-semiconductor (CMOS) image sensors under the same X-ray conditions. Low-temperature solution combustion was used to produce fine scintillators consisting of 5 wt% of europium as an activator dopant in a Gd2O3 scintillator host. Variations in the characteristics of the fine scintillators were investigated. The characteristics of fine scintillators produced at various sintering temperatures (i.e., 600, 800, or 1000 degrees C) and with a europium concentration of 0.5 wt% were also analyzed to determine the optimal conditions for synthesizing the fine scintillators.

  12. Strength and structural phase transitions of gadolinium at high pressure from radial X-ray diffraction

    SciTech Connect

    Xiong, Lun Liu, Jing; Bai, Ligang; Li, Xiaodong; Lin, Chuanlong; Lin, Jung-Fu

    2014-12-28

    Lattice strength and structural phase transitions of gadolinium (Gd) were determined under nonhydrostatic compression up to 55 GPa using an angle-dispersive radial x-ray diffraction technique in a diamond-anvil cell at room temperature. Three new phases of fcc structure, dfcc structure, and new monoclinic structure were observed at 25 GPa, 34 GPa, and 53 GPa, respectively. The radial x-ray diffraction data yield a bulk modulus K{sub 0} = 36(1) GPa with its pressure derivate K{sub 0}′ = 3.8(1) at the azimuthal angle between the diamond cell loading axis and the diffraction plane normal and diffraction plane ψ = 54.7°. With K{sub 0}′ fixed at 4, the derived K{sub 0} is 34(1) GPa. In addition, analysis of diffraction data with lattice strain theory indicates that the ratio of differential stress to shear modulus (t/G) ranges from 0.011 to 0.014 at pressures of 12–55 GPa. Together with estimated high-pressure shear moduli, our results show that Gd can support a maximum differential stress of 0.41 GPa, while it starts to yield to plastic deformation at 16 GPa under uniaxial compression. The yield strength of Gd remains approximately a constant with increasing pressure, and reaches 0.46 GPa at 55 GPa.

  13. Investigating the stability of gadolinium based contrast agents towards UV radiation.

    PubMed

    Birka, Marvin; Roscher, Jörg; Holtkamp, Michael; Sperling, Michael; Karst, Uwe

    2016-03-15

    Since the 1980s, the broad application of gadolinium(Gd)-based contrast agents for magnetic resonance imaging (MRI) has led to significantly increased concentrations of Gd in the aqueous environment. Little is known about the stability of these highly polar xenobiotics under environmental conditions, in wastewater and in drinking water treatment. Therefore, the stability of frequently applied Gd-based MRI contrast agents towards UV radiation was investigated. The hyphenation of hydrophilic interaction liquid chromatography (HILIC) with inductively coupled plasma mass spectrometry (ICP-MS) and of HILIC with electrospray ionization mass spectrometry (ESI-MS) provided quantitative elemental information as well as structural information. The contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A showed a high stability in irradiation experiments applying a wavelength range from 220 nm to 500 nm. Nevertheless, the degradation of Gd-BOPTA as well as the formation of Gd-containing transformation products was observed by means of HILIC-ICP-MS. Matrix-dependent irradiation experiments showed a degradation of Gd-BOPTA down to 3% of the initial amount in purified water after 300 min, whereas the degradation was slowed down in drinking water and surface water. Furthermore, it was observed that the sum of species continuously decreased with proceeding irradiation in all matrices. After irradiation in purified water for 300 min only 16% of the sum of species was left. This indicates a release of Gd(III) ions from the complex in course of irradiation. HILIC-ESI-MS measurements revealed that the transformation products mostly resulted from O-dealkylation and N-dealkylation reactions. In good correlation with retention times, the majority of transformation products were found to be more polar than Gd-BOPTA itself. Based on accurate masses, sum formulas were obtained and structures could be proposed.

  14. Activatable molecular MRI nanoprobe for tumor cell imaging based on gadolinium oxide and iron oxide nanoparticle.

    PubMed

    Li, Jingjing; Wang, Shan; Wu, Chen; Dai, Yue; Hou, Pingfu; Han, Cuiping; Xu, Kai

    2016-12-15

    Activatable molecular MRI nanoprobe for intracellular GSH sensing was designed. As an alternative to "always on" nanoprobe, activatable imaging nanoprobes which are designed to amplify or boost imaging signals only in response to the targets have attracted more and more attention. In this paper, we designed a novel activatable molecular magnetic resonance imaging (MRI) nanoprobe for tumor cell recognization based on a MRI signal variation induced by the distance change between T1 and T2 contrast agents (CAs) in the presence of glutathione (GSH). To achieve this aim, carboxyl group functionalized iron oxide nanoparticles (Fe3O4 NPs) and polyethylene glycol-coated gadolinium oxide (PEG-Gd2O3) NPs as T2 and T1 MRI CA were connected by cystamine which contains a disulfide linkage. Transmission electron microscopic (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometer (EDS), fourier transform infrared spectroscopy (FT-IR), mass spectra and (1)H nuclear magnetic resonance spectroscopy ((1)H NMR) were introduced for their characterizations. The formation of Fe3O4-cystamine-Gd2O3 (Fe3O4-SS-Gd2O3) nanocomplex resulted in a quenched T1 signal due to the near proximity of PEG-Gd2O3 NPs to Fe3O4 NPs and a "light-up" T1 signal with the cleavage of disulfide bond in the presence of GSH. These results provide not only an easy way to realize MRI of tumor cells based on the overexpressed intracellular GSH level, but also a new insight for the design of activatable MRI nanoprobe.

  15. Chronic inflammation and accelerated atherosclerosis as important cofactors in nephrogenic systemic fibrosis following intravenous gadolinium exposure.

    PubMed

    Grebe, Scott O; Borrmann, Marc; Altenburg, Alexander; Wesselman, Ulrich; Hein, Dietmar; Haage, Patrick

    2008-10-01

    Nephrogenic systemic fibrosis (NSF) is a rare disorder in patients with chronic kidney disease characterized by an increased tissue deposition of collagen. Its pathogenesis remains unclear. Prior studies indirectly suggested a possible impact of chronic inflammation and accelerated atherosclerosis--a common feature in kidney diseased patients--whereas recent data focused almost exclusively on gadolinium (Gd)-based MR contrast agents. Usually NSF develops a maximum of 2-3 months after Gd. Longer intervals have not yet been described. Therefore, we present the first case with an extraordinary long time course in terms of chronic inflammation. A 52-year-old Caucasian woman with end-stage renal disease was admitted to our hospital with progressive muscle weakness and skin induration resulting in growing immobility. Her past medical history revealed a secondary HPT, multiple vascular complications, a seronegative rheumatoid arthritis, and a pituitary gland adenoma. The latter conditions led to multiple MR examinations with Gd-based contrast agents, the last one more than 4 years ago. Numerous laboratory tests were performed including ESR, CRP, intact parathyroid hormone (iPTH), serum ferritin, cyclic-citrullinated peptide antibodies (CCP), ANA, ANCA, immunoelectrophoresis, and serology for hepatitis as well as human immunodeficiency virus. Eventually a skin biopsy of her left thigh was obtained. The laboratory investigation showed persistently elevated levels of CRP, ESR, serum ferritin, and iPTH, whereas all other parameters were inconspicuous. The hisology displayed typical signs of nephrogenic systemic fibrosis. NSF can occur at any time after Gd exposure in the long term. Gd is a necessary, but not the sole cause of NSF. Certain other cofactors such as chronic inflammation and accelerated atherosclerosis seem to be involved.

  16. Synchrotron X-ray Analyses Demonstrate Phosphate-Bound Gadolinium in Skin in Nephrogenic Systemic Fibrosis

    PubMed Central

    George, Simon J.; Webb, Samuel M.; Abraham, Jerrold L.; Cramer, Stephen P.

    2010-01-01

    Background Nephrogenic systemic fibrosis (NSF) is an incurable, debilitating disease found exclusively in patients with decreased kidney function and comprises a fibrosing disorder of the skin and systemic tissues. The disease is associated with exposure to Gadolinium based contrast agents (GBCA) used in magnetic resonance imaging (MRI). Tissue samples from many NSF patients contain micron-sized insoluble Gd-containing deposits. However, the precise composition and chemical nature of these particles is unclear. Objectives To clarify the precise chemical structure of the Gd-containing deposits in NSF tissues. Methods Autopsy skin tissues from a NSF patient are examined in situ using synchrotron x-ray fluorescence (SXRF) microscopy and extended absorption fine structure (EXAFS) spectroscopy and in correlation with light microscopy and the results of SEM/EDS analyses. Results The insoluble Gd deposits are shown to contain Gd no longer coordinated by GBCA chelator molecules but rather in a sodium calcium phosphate material. SXRF microscopy shows a clear correlation between Gd, Ca and P. EXAFS spectroscopy shows a very different spectrum from the GBCAs, with Gd-P distances at 3.11 Å and 3.72 Å as well as Gd-Gd distances at an average of 4.05 Å, consistent with a GdPO4 structure. Conclusions This is the first direct evidence for the chemical release of Gd from GBCA in human tissue. This supports the physical-chemical, clinical, and epidemiological data indicating a link between stability and dose of GBCA to the development of NSF. PMID:20560953

  17. Gadolinium cation (Gd+) reaction with O2: Potential energy surface mapped experimentally and with theory

    NASA Astrophysics Data System (ADS)

    Demireva, Maria; Armentrout, P. B.

    2017-05-01

    Guided ion beam tandem mass spectrometry is used to measure the kinetic energy dependent cross sections for reactions of the lanthanide metal gadolinium cation (Gd+) and GdO+ with O2 and for collision-induced dissociation (CID) of GdO2+ with Xe. Gd+ reacts with O2 in an exothermic and barrierless reaction to form GdO+ and O. GdO2+ is also formed in this reaction, but this product ion is formed in a sequential reaction, as verified by pressure dependent measurements and comparison with the results for the reaction of GdO+ with O2. The CID experiments of GdO2+ indicate the presence of two GdO2+ precursor ion populations, assigned to a weakly bound oxygen molecule adduct (Gd+-O2) and an inserted cyclic Gd+ dioxide species (O-Gd+-O). Analysis of the resulting product ion cross sections yields bond dissociation energies (BDEs, D0) for Gd+-O2 and OGd+-O, where the latter BDE is also independently measured in an exchange reaction between GdO+ and O2. The CID experiments also provide the energy of the barrier for the rearrangement of the Gd+-O2 adduct to the inserted O-Gd+-O structure (as identified by loss of a single oxygen atom). The thermochemistry measured here yields D0(OGd+-O) = 2.86 ± 0.08 eV, D0(Gd+-O2) = 0.75 ± 0.11 eV, and a barrier height relative to Gd+-O2 of 0.31 ± 0.07 eV. These data are sufficient to characterize in some detail the potential energy surface of the Gd+ reaction with O2 entirely from experiment. Theoretical calculations are performed for comparison with the experimental energetics and for further insight into the reaction mechanisms.

  18. The diagnostic role of gadolinium enhanced MRI in distinguishing between acute medullary bone infarct and osteomyelitis.

    PubMed

    Umans, H; Haramati, N; Flusser, G

    2000-04-01

    The objective of the study was to evaluate the diagnostic utility of contrast enhanced magnetic resonance imaging (MRI) for distinguishing between acute medullary bone infarct and osteomyelitis. There were 11 patients (age 6-34 years) presented to our institution between December 1994 and February 1998 with a clinical differential diagnosis of acute bone infarct versus osteomyelitis and inconclusive radiographs were imaged using MRI. All but one received i.v. gadolinium. Nine of the patients had homozygous Sickle Cell disease (SCD) and two had Systemic Lupus Erythematosus (SLE), the latter requiring chronic methylprednisolone. Osteomyelitis was confirmed either by biopsy alone or by the combination of Gallium(67) scan in conjunction with positive blood cultures and clinical resolution following antibiotics. Infarcts without osteomyelitis were confirmed either by biopsy or resolution of symptoms without antibiotic therapy. All patients had at least six months clinical follow-up. The results found that seven of nine patients with SCD had acute infarct only. One patient with SCD had osteomyelitis only. Three patients (two SLE and one SCD) had both acute-on-chronic infarcts and superimposed osteomyelitis, one with an adjacent soft tissue abscess. Accurate distinction between infarct and osteomyelitis was impossible for one patient with SLE who did not receive contrast. All other cases were correctly diagnosed prospectively based on distinct patterns of MRI contrast enhancement. In all adult patients, acute infarcts demonstrated thin, linear rim enhancement on MRI while osteomyelitis revealed more geographic and irregular marrow enhancement. Two of four cases of osteomyelitis also demonstrated subtle cortical defects with abnormal signal traversing marrow and soft tissue. The single pediatric patient demonstrated elongated, serpiginous central medullary enhancement with periostitis. We concluded that the pattern of MR contrast enhancement may allow accurate distinction

  19. Diagnostic performance of late gadolinium enhancement in the assessment of acute cellular rejection after heart transplantation

    PubMed Central

    Şimşek, Evrim; Nalbantgil, Sanem; Ceylan, Naim; Zoghi, Mehdi; Kemal, Hatice Soner; Engin, Çağatay; Yağdı, Tahir; Özbaran, Mustafa

    2016-01-01

    Objective: Allograft rejection is still an important cause of morbidity and mortality after heart transplantation (HTx). Many techniques in cardiac magnetic resonance imaging (CMR) were investigated to diagnose acute cellular rejection (ACR). However, there is not enough information about late gadolinium enhancement (LGE) in the myocardium and ACR. Methods: We prospectively analyzed our consecutive 41 heart transplant recipients who were admitted for routine endomyocardial biopsies. CMR was performed maximum 6 h before the scheduled endomyocardial biopsy. Correlation between LGE in the myocardium and ACR was investigated. Results: Twenty-seven patients showed no rejection, and nine of them had LGE in the myocardium. Fourteen patients had LGE in the left ventricle (LV), and two patients had LGE also in the right ventricle (RV). There was no correlation between LGE and ACR (p=0.879). There was no difference in the left ventricular ejection fraction (LVEF), right ventricular fractional area change (RVFAC), and cardiac ischemic time between the groups (p=0.825, p=0.370, and p=0.419, respectively). LGE in the myocardium could be due to previous rejection episodes; therefore, all patients were retrospectively searched for previous rejection grades and number of episodes. Thirty-eight of the 41 patients had a history of one ACR episode, but none of them had a statistically significant correlation with LGE (for grade 1R, p=0.964 and grade 3R, p=1) There was also no correlation between number of rejection episodes history and LGE. Conclusion: LGE is not suitable to detect ACR in heart transplant patients. LGE and the history of ACR have no correlation. PMID:26467370

  20. Convection enhanced delivery of different molecular weight tracers of gadolinium-tagged polylysine.

    PubMed

    Hardy, Peter A; Keeley, Dan; Schorn, Greg; Forman, Eric; Ai, Yi; Venugopalan, Ramakrishna; Zhang, Zhiming; Bradley, Luke H

    2013-09-30

    Convection enhanced delivery (CED) is a powerful method of circumventing the blood-brain barrier (BBB) to deliver therapeutic compounds directly to the CNS. While inferring the CED distribution of a therapeutic compound by imaging a magnetic resonance (MR)-sensitive tracer has many advantages, however how the compound distribution is affected by the features of the delivery system, its target tissue, and its molecular properties, such as its binding characteristics, charge, and molecular weight (MW) are not fully understood. We used MR imaging of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA)-tagged polylysine compounds of various MW, in vitro and in vivo, to measure the dependence of compounds MW on CED distribution. For the in vitro studies, the correlation between volume of distribution (Vd) as a function of MW was determined by measuring the T1 of the infused tracers, into 0.6% agarose gels through a multiport catheter. The compounds distributed in the gels inversely proportional to their MW, consistent with convection and unobstructed diffusion through a porous media. For the in vivo studies, Gd-DTPA tagged compounds were infused into the non-human primate putamen, via an implanted multiport catheter connected to a MedStream™ pump, programmed to deliver a predetermined volume with alternating on-off periods to take advantage of the convective and diffusive contributions to Vd. Unlike the gel studies, the higher MW polylysine-tracer infusions did not freely distribute from the multiport catheter in the putamen, suggesting that distribution was impeded by other properties that should also be considered in future tracer design and CED infusion protocols. Copyright © 2013 Elsevier B.V. All rights reserved.