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Sample records for agents including gadolinium

  1. Extracellular gadolinium contrast agents: Differences in stability

    International Nuclear Information System (INIS)

    Extracellular gadolinium contrast agents (Gd-CA) are either linear or macrocyclic chelates available as ionic or non-ionic preparations. The molecular structure whether cyclic or linear and ionicity determines the stability of Gd-CA. Linear chelates are flexible open chains which do not offer a strong binding to Gd3+. In contrast, the macrocyclic chelates offer a strong binding to Gd3+ by the virtue of being preorganized rigid rings of almost optimal size to cage the gadolinium atom. Non-ionic preparations are also less stable in comparison to the ionic ones as the binding between Gd3+ with the negatively charged carboxyl groups is stronger in comparison to that with amides or alcohol in the non-ionic preparations. According to stability constants and kinetic measurements, the most stable Gd-CM is the ionic-macrocyclic chelate Gd-DOTA and the least stable agents are the non-ionic linear chelates gadodiamide and gadoversetamide. In vivo data confirmed the low stability of non-ionic linear chelates but no significant difference was observed amongst the macrocyclic agents whether ionic (Gd-DOTA) or non-ionic such as Gd-HP-DO3A and Gd-BT-DO3A. The stability of Gd-CA seems to be an important factor in the pathogenesis of the serious complication of nephrogenic systemic fibrosis. Gd-CA of low stability are likely to undergo transmetallation and release free Gd ions that deposit in tissue and attract circulating fibrocytes to initiate the process of fibrosis. No cases of NSF have been observed so far after the exclusive use of the stable macrocyclic Gd-CA

  2. Extracellular gadolinium contrast agents: Differences in stability

    Energy Technology Data Exchange (ETDEWEB)

    Morcos, S.K. [Department of Diagnostic Imaging, Sheffield Teaching Hospitals NHS Foundation Trust, Northern General Hospital, Sheffield S5 7AU (United Kingdom)], E-mail: sameh.morcos@sth.nhs.uk

    2008-05-15

    Extracellular gadolinium contrast agents (Gd-CA) are either linear or macrocyclic chelates available as ionic or non-ionic preparations. The molecular structure whether cyclic or linear and ionicity determines the stability of Gd-CA. Linear chelates are flexible open chains which do not offer a strong binding to Gd{sup 3+}. In contrast, the macrocyclic chelates offer a strong binding to Gd{sup 3+} by the virtue of being preorganized rigid rings of almost optimal size to cage the gadolinium atom. Non-ionic preparations are also less stable in comparison to the ionic ones as the binding between Gd{sup 3+} with the negatively charged carboxyl groups is stronger in comparison to that with amides or alcohol in the non-ionic preparations. According to stability constants and kinetic measurements, the most stable Gd-CM is the ionic-macrocyclic chelate Gd-DOTA and the least stable agents are the non-ionic linear chelates gadodiamide and gadoversetamide. In vivo data confirmed the low stability of non-ionic linear chelates but no significant difference was observed amongst the macrocyclic agents whether ionic (Gd-DOTA) or non-ionic such as Gd-HP-DO3A and Gd-BT-DO3A. The stability of Gd-CA seems to be an important factor in the pathogenesis of the serious complication of nephrogenic systemic fibrosis. Gd-CA of low stability are likely to undergo transmetallation and release free Gd ions that deposit in tissue and attract circulating fibrocytes to initiate the process of fibrosis. No cases of NSF have been observed so far after the exclusive use of the stable macrocyclic Gd-CA.

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

    Science.gov (United States)

    Rogosnitzky, Moshe; Branch, Stacy

    2016-06-01

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

  4. New Dual Mode Gadolinium Nanoparticle Contrast Agent for Magnetic Resonance Imaging

    OpenAIRE

    Ghaghada, Ketan B.; Ravoori, Murali; Sabapathy, Divya; Bankson, James; Kundra, Vikas; ANNAPRAGADA, ANANTH

    2009-01-01

    Background Liposomal-based gadolinium (Gd) nanoparticles have elicited significant interest for use as blood pool and molecular magnetic resonance imaging (MRI) contrast agents. Previous generations of liposomal MR agents contained gadolinium-chelates either within the interior of liposomes (core-encapsulated gadolinium liposomes) or presented on the surface of liposomes (surface-conjugated gadolinium liposomes). We hypothesized that a liposomal agent that contained both core-encapsulated gad...

  5. Gadolinium deposition within the dentate nucleus and globus pallidus after repeated administrations of gadolinium-based contrast agents - current status

    Energy Technology Data Exchange (ETDEWEB)

    Stojanov, Dragan [University of Nis, Faculty of Medicine, Nis (Serbia); Center for Radiology, Nis (Serbia); Aracki-Trenkic, Aleksandra [Center for Radiology, Nis (Serbia); Benedeto-Stojanov, Daniela [University of Nis, Faculty of Medicine, Nis (Serbia)

    2016-05-15

    Gadolinium-based contrast agents (GBCAs) have been used clinically since 1988 for contrast-enhanced magnetic resonance imaging (CE-MRI). Generally, GBCAs are considered to have an excellent safety profile. However, GBCA administration has been associated with increased occurrence of nephrogenic systemic fibrosis (NSF) in patients with severely compromised renal function, and several studies have shown evidence of gadolinium deposition in specific brain structures, the globus pallidus and dentate nucleus, in patients with normal renal function. Gadolinium deposition in the brain following repeated CE-MRI scans has been demonstrated in patients using T1-weighted unenhanced MRI and inductively coupled plasma mass spectroscopy. Additionally, rodent studies with controlled GBCA administration also resulted in neural gadolinium deposits. Repeated GBCA use is associated with gadolinium deposition in the brain. This is especially true with the use of less-stable, linear GBCAs. In spite of increasing evidence of gadolinium deposits in the brains of patients after multiple GBCA administrations, the clinical significance of these deposits continues to be unclear. Here, we discuss the current state of scientific evidence surrounding gadolinium deposition in the brain following GBCA use, and the potential clinical significance of gadolinium deposition. There is considerable need for further research, both to understand the mechanism by which gadolinium deposition in the brain occurs and how it affects the patients in which it occurs. (orig.)

  6. Gadolinium as a Neutron Capture Therapy Agent

    Science.gov (United States)

    Shih, Jing-Luen Allen

    The clinical results of treating brain tumors with boron neutron capture therapy are very encouraging and researchers around the world are once again making efforts to develop this therapeutic modality. Boron-10 is the agent receiving the most attention for neutron capture therapy but ^{157}Gd is a nuclide that also holds interesting properties of being a neutron capture therapy agent. The objective of this study is to evaluate ^{157}Gd as a neutron capture therapy agent. In this study it is determined that tumor concentrations of about 300 mug ^{157}Gd/g tumor can be achieved in brain tumors with some FDA approved MRI contrast agents such as Gd-DTPA and Gd-DOTA, and up to 628 mug ^{157 }Gd/g tumor can be established in bone tumors with Gd-EDTMP. Monte Carlo calculations show that with only 250 ppm of ^{157}Gd in tumor, neutron capture therapy can deliver 2,000 cGy to a tumor of 2 cm diameter or larger with 5 times 10^{12} n/cm ^2 fluence at the tumor. Dose measurements which were made with films and TLD's in phantoms verified these calculations. More extended Monte Carlo calculations demonstrate that neutron capture therapy with Gd possesses comparable dose distribution to B neutron capture therapy. With 5 times 10^{12 } n/cm^2 thermal neutrons at the tumor, Auger electrons from the Gd produced an optical density enhancement on the films that is similar to the effect caused by about 300 cGy of Gd prompt gamma dose which will further enhance the therapeutic effects. A technique that combines brachytherapy with Gd neutron capture therapy has been evaluated. Monte Carlo calculations show that 5,000 cGy of prompt gamma dose can be delivered to a treatment volume of 40 cm^3 with a 3-plane implant of a total of 9 Gd needles. The tumor to normal tissue advantage of this method is as good as ^{60} Co brachytherapy. Measurements of prompt gamma dose with films and TLD-700's in a lucite phantom verify the Monte Carlo evaluation. A technique which displays the Gd

  7. Gadolinium Contrast Agent-Induced CD163+ Ferroportin+ Osteogenic Cells in Nephrogenic Systemic Fibrosis

    OpenAIRE

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

    2013-01-01

    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 o...

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

    Science.gov (United States)

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

    2016-06-01

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

  9. The effect of a gadolinium-based contrast agent on diffusion tensor imaging

    International Nuclear Information System (INIS)

    Objective: The aim of this study was to investigate in detail the effect of gadolinium contrast on diffusion tensor imaging scans. As the present literature offers conflicting results, we have included a large selection of indices in the analysis. Materials and methods: Sixteen patients harboring an intra-axial contrast enhancing brain tumor were included in this study. Two diffusion tensor imaging scans were performed—one natively, and the second following a gadolinium contrast agent application. Maps of the invariant indices fractional anisotropy (FA), linear, planar, and spherical indices, trace, eigenvalues λ1, λ2, λ3 as well as of the components of the diffusion tensor matrix Dxx, Dyy, Dzz, Dxy, Dxz and Dyz were co-registered and compared statistically with matching ROI pairs in the contrast enhancing areas, peritumoral edema and the normal appearing white matter. Results: We have observed a significant increase in the FA and disproportional decrease of the eigenvalues in the post-contrast scans. In accordance with these findings, the spherical index was decreased and the linear and planar indices were increased. There was a significant decrease of all diagonal components of the diffusion tensor matrix. These changes have been strongest in the contrast enhancing areas, but there were also significant changes in the peritumoral edema and the normal appearing white matter. Conclusion: Diffusion tensor imaging scans performed after gadolinium contrast agent administration may display artificially increased FA values due to disproportional changes of the measured eigenvalues. The distortion of the diffusion measurement is strongest in, but not limited to the contrasting areas.

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

    International Nuclear Information System (INIS)

    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 LD50 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

  11. Determination of gadolinium-based MRI contrast agents in biological and environmental samples: A review

    Energy Technology Data Exchange (ETDEWEB)

    Telgmann, Lena [University of Münster, Institute of Inorganic and Analytical Chemistry, Münster (Germany); Sperling, Michael [University of Münster, Institute of Inorganic and Analytical Chemistry, Münster (Germany); European Virtual Institute for Speciation Analysis (EVISA), Münster (Germany); Karst, Uwe, E-mail: uk@uni-muenster.de [University of Münster, Institute of Inorganic and Analytical Chemistry, Münster (Germany)

    2013-02-18

    Highlights: ► All major methods for the analysis of Gd-based MRI contrast agents are discussed. ► Biological and environmental samples are covered. ► Pharmacokinetics and species transformation can be investigated. ► The figures of merit as limit of detection and analysis time are described. -- Abstract: The development of analytical methods and strategies to determine gadolinium and its complexes in biological and environmental matrices is evaluated in this review. Gadolinium (Gd) chelates are employed as contrast agents for magnetic resonance imaging (MRI) since the 1980s. In general they were considered as safe and well-tolerated, when in 2006, the disease nephrogenic systemic fibrosis (NSF) was connected to the administration of MRI contrast agents based on Gd. Pathogenesis and etiology of NSF are yet unclear and called for the development of several analytical methods to obtain elucidation in this field. Determination of Gd complex stability in vitro and in vivo, as well as the quantification of Gd in body fluids like blood and urine was carried out. Separation of the Gd chelates was achieved with high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). For detection, various methods were employed, including UV–vis absorbance and fluorescence spectroscopy, electrospray ionization mass spectrometry (ESI-MS) and inductively coupled plasma mass spectrometry (ICP-MS). A second challenge for analysts was the discovery of high concentrations of anthropogenic Gd in surface waters draining populated areas. The source could soon be determined to be the increasing administration of Gd complexes during MRI examinations. Identification and quantification of the contrast agents was carried out in various surface and groundwater samples to determine the behavior and fate of the Gd chelates in the environment. The improvement of limits of detection (LOD) and limits of quantification (LOQ) was and still is the goal of past and ongoing

  12. A small MRI contrast agent library of gadolinium(III)-encapsulated supramolecular nanoparticles for improved relaxivity and sensitivity**

    OpenAIRE

    Chen, Kuan-Ju; Wolahan, Stephanie M.; Wang, Hao; Hsu, Chao-Hsiung; Chang, Hsing-Wei; Durazo, Armando; Hwang, Lian-Pin; Garcia, Mitch A.; Jiang, Ziyue Karen; Wu, Lily; Lin, Yung-Ya; Tseng, Hsian-Rong

    2010-01-01

    We introduce a new category of nanoparticle-based T1 MRI contrast agents (CAs) by encapsulating paramagnetic chelated gadolinium(III), i.e., Gd3+·DOTA, through supramolecular assembly of molecular building blocks that carry complementary molecular recognition motifs, including adamantane (Ad) and β-cyclodextrin (CD). A small library of Gd3+·DOTA-encapsulated supramolecular nanoparticles (Gd3+·DOTA⊂SNPs) was produced by systematically altering the molecular building block mixing ratios. A broa...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2016-05-19

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

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

    Science.gov (United States)

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

    2016-05-01

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

  16. Complications from the use of intravenous gadolinium-based contrast agents for magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Elias Junior, Jorge; Santos, Antonio Carlos dos; Nogueira-Barbosa, Marcello Henrique; Muglia, Valdair Francisco; Koenigkam-Santos, Marcel [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Hospital das Clinicas. Centro de Ciencias das Imagens e Fisica Medica]. E-mail: jejunior@fmrp.usp.br

    2008-07-15

    Gadolinium-based contrast agents are much safer than the iodinated ones; however complications may occur and should be recognized for appropriate orientation and management. The total incidence of adverse reactions to contrast agents in magnetic resonance imaging ranges between 2% and 4%. Cases of severe acute reactions to gadolinium, such as laryngospasm and anaphylactic shock, are rare. Chronic complications secondary to the use of gadolinium also can occur and, recently an association between its use and a rare dermatologic disease occurring in patients with renal failure has been reported. Nephrogenic systemic fibrosis was the subject of an official health notification issued by the American Food and Drug Administration. This progressive disease is characterized by hardened skin with fibrotic nodules and plaques which may involve other parts of the body. Patients who have been affected by this disorder presented chronic renal failure, with metabolic acidosis and had been submitted to magnetic resonance angiography, probably involving exposure to large amounts of intravenous paramagnetic contrast. This review is aimed at presenting a succinct description of the gadolinium-based contrast agent types, possible secondary complications, their preventive measures and management. (author)

  17. Field strength and dose dependence of contrast enhancement by gadolinium-based MR contrast agents

    International Nuclear Information System (INIS)

    The relaxivities r1 and r2 of magnetic resonance contrast agents and the T1 relaxation time values of tissues are strongly field dependent. We present quantitative data and simulations of different gadolinium-based extracellular fluid contrast agents and the modulation of their contrast enhancement by the magnetic field to be able to answer the following questions: How are the dose and field dependences of their contrast enhancement? Is there an interrelationship between dose and field dependence? Should one increase or decrease doses at specific fields? Nuclear magnetic relaxation dispersion data were acquired for the following contrast agents: gadopentetate dimeglumine, gadoterate meglumine, gadodiamide injection, and gadoteridol injection, as well as for several normal and pathological human tissue samples. The magnetic field range stretched from 0.0002 to 4.7 T, including the entire clinical imaging range. The data acquired were then fitted with the appropriate theoretical models. The combination of the diamagnetic relaxation rates (R1 = 1/T1 and R2 = 1/T2) of tissues with the respective paramagnetic contributions of the contrast agents allowed the prediction of image contrast at any magnetic field. The results revealed a nearly identical field and dose-dependent increase of contrast enhancement induced by these contrast agents within a certain dose range. The target tissue concentration (TTC) was an important though nonlinear factor for enhancement. The currently recommended dose of 0.1 mmol/kg body weight seems to be a compromise close to the lower limits of diagnostically sufficient contrast enhancement for clinical imaging at all field strengths. At low field contrast enhancement might be insufficient. Adjustment of dose or concentration, or a new class of contrast agents with optimized relaxivity, would be a valuable contribution to a better diagnostic yield of contrast enhancement at all fields. (orig.)

  18. Re-evaluating gadolinium(III) texaphyrin as a radiosensitizing agent.

    Science.gov (United States)

    Bernhard, E J; Mitchell, J B; Deen, D; Cardell, M; Rosenthal, D I; Brown, J M

    2000-01-01

    Gadolinium(III) texaphyrin (Gd-tex) was recently proposed as a radiosensitizing agent that combines preferential tumor uptake with detection of drug localization by magnetic resonance imaging (S. W. Young et al., Proc. Natl. Acad. Sci. USA, 93: 6610-6615, 1996). In view of the initial report on this compound, four radiobiology laboratories undertook independent efforts to further study radiosensitization by Gd-tex. In addition to repeating the previously reported studies on Gd-tex in HT-29 cells, we tested five other human tumor cell lines (U-87 MG, U251-NCI, SW480, A549, and MCF-7). These studies included a Gd-tex treatment period of 24 h before irradiation (as in the original publication), with concentrations of Gd-tex ranging from 20-500 microM. In neither the HT-29 cells nor any of the other five human cell lines did we see radiation sensitization by Gd-tex. Two cell lines (MCF-7 and U-87 MG) were further tested for radiosensitization by Gd-tex under hypoxic conditions. No radiosensitization was observed in either case. Finally, the radiation response of two tumor lines were assessed in vivo. Neither HT-29 xenografts in severe combined immunodeficient (SCID) mice nor RIF-1 tumors growing in C3H mice demonstrated radiosensitization after Gd-tex treatment before single or fractionated doses of radiation. Our results raise questions about the efficacy of Gd-tex as a radiosensitizing agent. PMID:10646858

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

    Directory of Open Access Journals (Sweden)

    Kim Hyo Jeong

    2010-01-01

    Full Text Available Abstract 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.

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

    Science.gov (United States)

    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.

  1. Preparation and initial characterization of biodegradable particles containing gadolinium-DTPA contrast agent for enhanced MRI

    OpenAIRE

    Doiron, Amber L.; Chu, Kevin; Ali, Adeel; Brannon-Peppas, Lisa

    2008-01-01

    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-c...

  2. Accumulation of MRI contrast agents in malignant fibrous histiocytoma for gadolinium neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, T. [Department of Orthopaedic Surgery, Hyogo Cancer Center, Akashi 673-0021 (Japan)], E-mail: fujitaku@hp.pref.hyogo.jp; Ichikawa, H. [Faculty of Pharmaceutical Sciences and Cooperative Research Center of Life Sciences, Kobe Gakuin University, Kobe 650-8586 (Japan); Akisue, T. [Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Fujita, I. [Department of Orthopaedic Surgery, Hyogo Cancer Center, Akashi 673-0021 (Japan); Kishimoto, K.; Hara, H. [Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Imabori, M. [Department of Orthopaedic Surgery, Hyogo Cancer Center, Akashi 673-0021 (Japan); Kawamitsu, H. [Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Sharma, P.; Brown, S.C.; Moudgil, B.M. [Particle Engineering Research Center, University of Florida, Gainesville, FL32611 (United States); Fujii, M. [Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Yamamoto, T. [Department of Orthopaedic Surgery, Kagawa University, Kagawa 761-0793 (Japan); Kurosaka, M. [Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe 650-0017 (Japan); Fukumori, Y. [Faculty of Pharmaceutical Sciences and Cooperative Research Center of Life Sciences, Kobe Gakuin University, Kobe 650-8586 (Japan)

    2009-07-15

    Neutron-capture therapy with gadolinium (Gd-NCT) has therapeutic potential, especially that gadolinium is generally used as a contrast medium in magnetic resonance imaging (MRI). The accumulation of gadolinium in a human sarcoma cell line, malignant fibrosis histiocytoma (MFH) Nara-H, was visualized by the MRI system. The commercially available MRI contrast medium Gd-DTPA (Magnevist, dimeglumine gadopentetate aqueous solution) and the biodegradable and highly gadopentetic acid (Gd-DTPA)-loaded chitosan nanoparticles (Gd-nanoCPs) were prepared as MRI contrast agents. The MFH cells were cultured and collected into three falcon tubes that were set into the 3-tesra MRI system to acquire signal intensities from each pellet by the spin echo method, and the longitudinal relaxation time (T1) was calculated. The amount of Gd in the sample was measured by inductively coupled plasma atomic emission spectrography (ICP-AES). The accumulation of gadolinium in cells treated with Gd-nanoCPs was larger than that in cells treated with Gd-DTPA. In contrast, and compared with the control, Gd-DTPA was more effective than Gd-nanoCPs in reducing T1, suggesting that the larger accumulation exerted the adverse effect of lowering the enhancement of MRI. Further studies are warranted to gain insight into the therapeutic potential of Gd-NCT.

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

    Science.gov (United States)

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

    2016-04-01

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

  4. Comparison of gadolinium Cy2DOTA, a new hepatobiliary agent, and gadolinium HP-DO3A, an extracellular agent, in healthy liver and metastatic disease

    International Nuclear Information System (INIS)

    A new gadolinium (Gd) chelate with preferential hepatobiliary uptake, Gd Cy2DOTA, 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 Cy2DOTA. Two minutes after contrast, liver SI was 1.94 ± 0.05 with Gd Cy2DOTA 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 2DOTA but not with Gd HP-DO3A. The maximum improvement in lesion conspicuity (rabbit) occurred 45 minutes after injection of Gd Cy2DOTA and 5 minutes after injection of Gd HP-DO3A. 22 refs., 12 figs

  5. Gadolinium MRI Contrast Agents Based on Triazine Dendrimers: Relaxivity and In Vivo Pharmacokinetics

    OpenAIRE

    Lim, Jongdoo; Turkbey, Baris; Bernardo, Marcelino; Bryant, L. Henry; Garzoni, Matteo; Pavan, Giovanni M.; Nakajima, Takahito; Choyke, Peter L; Simanek, Eric E; Kobayashi, Hisataka

    2012-01-01

    Four gadolinium (Gd)-based macromolecular contrast agents, G3-(Gd-DOTA)24, G5-(Gd-DOTA)96, G3-(Gd-DTPA)24, and G5-(Gd-DTPA)96, were prepared that varied in the size of dendrimer (generation three and five), the type of chelate group (DTPA or DOTA), and the theoretical number of metallated chelates (24 and 96). Synthesis relied on a dichlorotriazine derivatized with a DOTA or DTPA ligand that was incorporated into the dendrimer and ultimately metallated with Gd ions. Paramagnetic characteristi...

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

    OpenAIRE

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

    2010-01-01

    Abstract 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 ...

  7. Safety of the Gadolinium-Based Contrast Agents for Magnetic Resonance Imaging, Focusing in Part on Their Accumulation in the Brain and Especially the Dentate Nucleus.

    Science.gov (United States)

    Runge, Val M

    2016-05-01

    The established class of intravenous contrast media for magnetic resonance imaging is the gadolinium chelates, more generally referred to as the gadolinium-based contrast agents (GBCAs). These can be differentiated on the basis of stability in vivo, with safety and tolerability of the GBCAs dependent upon chemical and biologic inertness. This review discusses first the background in terms of development of these agents and safety discussions therein, and second their relative stability based both on in vitro studies and clinical observations before and including the advent of nephrogenic systemic fibrosis. This sets the stage for the subsequent focus of the review, the current knowledge regarding accumulation of gadolinium in the brain and specifically the dentate nucleus after intravenous administration of the GBCAs and differentiation among agents on this basis. The information available to date, from the initial conception of these agents in 1981 to the latest reports concerning safety, demonstrates a significant difference between the macrocyclic and linear chelates. The review concludes with a discussion of the predictable future, which includes, importantly, a reassessment of the use of the linear GBCAs or a subset thereof. PMID:26945278

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

    Science.gov (United States)

    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.

  9. Investigating the stability of gadolinium based contrast agents towards UV radiation.

    Science.gov (United States)

    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. PMID:26802476

  10. Graphene oxide-gadolinium (III) oxide nanoparticle composite: a novel MR contrast agent with high longitudinal and transverse relaxivity

    International Nuclear Information System (INIS)

    Production of bio-compatible contrast agent materials to enhance the sensitivity of the magnetic resonance imaging (MRI) technique is a highly active area in MRI related research. This work illustrates the potential of a new material: graphene oxide-gadolinium (III) oxide nanoparticle (GO-Gd2O3) composite in yielding both transverse (16.3 mM−1 s−1) and longitudinal relaxivity (40 mM−1 s−1) values which are significantly higher than the proton relaxivity values achieved using the gadolinium based contrast agents currently used in MRI. Such high proton relaxivity values can facilitate low dosage of GO-Gd2O3 composite for obtaining both T1 and T2 weighted high signal-to-noise ratio images in MRI. (paper)

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

    Science.gov (United States)

    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

  12. Gadolinium-Hematoporphyrin: new potential MRI contrast agent for detection of breast cancer cell line (MCF-7

    Directory of Open Access Journals (Sweden)

    D Shahbazi Gahrouei

    2005-09-01

    Full Text Available Background: Gadolinium-porphyrins have been synthesized and are currently being investigated as magnetic resonance imaging (MRI contrast agents. This study aimed to synthesize Gd-hematoporphyrin and applicate it for in vitro detection of breast cancer cell line (MCF-7. Methods: The naturally occurring porphyrin (hematoporphyrin was inserted with gadolinium (III nitrate hexahydrate to yield Gd-H. T1 relaxation times and signal enhancement of the contrast agents were presented, and the results were compared. UV spectrophotometer measured the attachment of Gd to the cell membrane of MCF-7. Results: Most of gadolinium chloride (GdCl3 was found in the washing solution, indicate that it didn`t fixed to the breast cell membranes during incubation. Gd-DTPA showed some uptake into the MCF-7 cell membranes with incubation, however, its uptake was significantly lower than Gd-H. Conclusion: Good cell memberan uptake of Gd-porphyrin is comparable to controls, indicating selective delivery it to the breast cell line and considerable potency in diagnostic MR imaging for detection of breast cancer. Key Words: Porphyrin, Contrast agent, MRI, Hematoporphyrin, Breast cancer cell (MCF-7

  13. High prevalence of nephrogenic systemic fibrosis in chronic renal failure patients exposed to gadodiamide, a gadolinium-containing magnetic resonance contrast agent

    DEFF Research Database (Denmark)

    Rydahl, Casper; Thomsen, Henrik S; Marckmann, Peter

    2008-01-01

    OBJECTIVE: Nephrogenic systemic fibrosis (NSF) is a serious disease affecting renal failure patients. It may be caused by some gadolinium (Gd)-containing contrast agents, including gadodiamide. The study aimed at estimating the prevalence of NSF after gadodiamide exposure for patients with chronic......%, 95% CI: 6%-15%) were diagnosed with NSF within a mean follow-up period of 29 months (range 16-43 months). All 18 cases had stage 5 CKD (ie, estimated glomerular filtration rate less than 15 mL/min/1.73 m2 or in dialysis therapy) at the time of their gadodiamide exposure. The prevalence of NSF among...

  14. Gadolinium(III-DOTA Complex Functionalized with BODIPY as a Potential Bimodal Contrast Agent for MRI and Optical Imaging

    Directory of Open Access Journals (Sweden)

    Matthias Ceulemans

    2015-11-01

    Full Text Available The synthesis and characterization of a novel gadolinium(III DOTA complex functionalized with a boron-dipyrromethene derivative (BODIPY is described. The assembly of the complex relies on azide diazotransfer chemistry in a copper tube flow reactor. The azide thus formed is coupled directly with an alkyne via click chemistry, resulting into a paramagnetic and luminescent gadolinium(III complex. Luminescent data and relaxometric properties of the complex have been evaluated, suggesting the potential applicability of the complexes as a bimodal contrast agent for magnetic resonance and optical imaging. The complex displays a bright emission at 523 nm with an absorption maximum of 507 nm and high quantum yields of up to 83% in water. The proton relaxivity of the complex measured at 310 K and at frequencies of 20 and 60 MHz had the values of 3.9 and 3.6 s−1·mM−1, respectively.

  15. Effects of iodinated contrast agent, xylocaine and gadolinium concentration on the signal emitted in magnetic resonance arthrography: a samples study*

    Science.gov (United States)

    da Silva, Yvana Lopes Pinheiro; Costa, Rita Zanlorensi Visneck; Pinho, Kátia Elisa Prus; Ferreira, Ricardo Rabello; Schuindt, Sueliton Miyamoto

    2015-01-01

    Objective To investigate the effects of dilution of paramagnetic contrast agent with iodinated contrast and xylocaine on the signal intensity during magnetic resonance arthrography, and to improve the paramagnetic contrast agent concentration utilized in this imaging modality. Materials and Methods Samples specially prepared for the study with three different concentrations of paramagnetic contrast agent diluted in saline, iodinated contrast agent and xylocaine were imaged with fast spin echo T1-weighted sequences with fat saturation. The samples were placed into flasks and graphical analysis of the signal intensity was performed as a function of the paramagnetic contrast concentration. Results As compared with samples of equal concentrations diluted only with saline, the authors have observed an average signal intensity decrease of 20.67% for iodinated contrast agent, and of 28.34% for xylocaine. However, the increased gadolinium concentration in the samples caused decrease in signal intensity with all the dilutions. Conclusion Minimizing the use of iodinated contrast media and xylocaine and/or the use of a gadolinium concentration of 2.5 mmol/L diluted in saline will improve the sensitivity of magnetic resonance arthrography. PMID:25987746

  16. Effects of iodinated contrast agent, xylocaine and gadolinium concentration on the signal emitted in magnetic resonance arthrography: a samples study

    Directory of Open Access Journals (Sweden)

    Yvana Lopes Pinheiro da Silva

    2015-04-01

    Full Text Available Objective: To investigate the effects of dilution of paramagnetic contrast agent with iodinated contrast and xylocaine on the signal intensity during magnetic resonance arthrography, and to improve the paramagnetic contrast agent concentration utilized in this imaging modality. Materials and Methods: Samples specially prepared for the study with three different concentrations of paramagnetic contrast agent diluted in saline, iodinated contrast agent and xylocaine were imaged with fast spin echo T1-weighted sequences with fat saturation. The samples were placed into flasks and graphical analysis of the signal intensity was performed as a function of the paramagnetic contrast concentration. Results: As compared with samples of equal concentrations diluted only with saline, the authors have observed an average signal intensity decrease of 20.67% for iodinated contrast agent, and of 28.34% for xylocaine. However, the increased gadolinium concentration in the samples caused decrease in signal intensity with all the dilutions. Conclusion: Minimizing the use of iodinated contrast media and xylocaine and/or the use of a gadolinium concentration of 2.5 mmol/L diluted in saline will improve the sensitivity of magnetic resonance arthrography.

  17. Dark Blood Magnetic Resonance Lymphangiography Using Dual-Agent Relaxivity Contrast (DARC-MRL): A Novel Method Combining Gadolinium and Iron Contrast Agents.

    Science.gov (United States)

    Maki, Jeffrey H; Neligan, Peter C; Briller, Noah; Mitsumori, Lee M; Wilson, Gregory J

    2016-01-01

    The objective of this study was to develop and demonstrate a technique to eliminate venous enhancement in contrast-enhanced magnetic resonance lymphangiography through shortening T2(⁎) in the blood pool, thus allowing for a lymphatic-only map. Administration of the blood-pool iron agent ferumoxtyol in addition to intracutaneous gadolinium during contrast-enhanced magnetic resonance lymphangiography allows for suppression of vascular structures to achieve venous-free lymphatic mapping. PMID:26460054

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

    International Nuclear Information System (INIS)

    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. (paper)

  19. 13 CFR 107.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent. 107.1620 Section 107.1620 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance...

  20. Vibrational dynamics of zero-field-splitting hamiltonian in gadolinium-based MRI contrast agents from ab initio molecular dynamics

    International Nuclear Information System (INIS)

    The electronic relaxation of gadolinium complexes used as MRI contrast agents was studied theoretically by following the short time evolution of zero-field-splitting parameters. The statistical analysis of ab initio molecular dynamics trajectories provided a clear separation between static and transient contributions to the zero-field-splitting. For the latter, the correlation time was estimated at approximately 0.1 ps. The influence of the ligand was also probed by replacing one pendant arm of our reference macrocyclic complex by a bulkier phosphonate arm. In contrast to the transient contribution, the static zero-field-splitting was significantly influenced by this substitution

  1. New gadolinium-containing contrast agent based on N-(2-hydroxypropyl)methacrylamide copolymer

    Czech Academy of Sciences Publication Activity Database

    Šubr, Vladimír; Heilmann, M.; Kiessling, F.; Peschke, P.; Ulbrich, Karel

    Miami Beach : Controlled Release Society, 2005, #339/1-#339/2. [Annual Meeting and Exposition of the Controlled Release Society /32./. Miami Beach (US), 18.06.2005-22.06.2005] R&D Projects: GA AV ČR(CZ) IAA4050201 Keywords : N-(2-hydroxypropyl)methacrylamide copolymers * gadolinium * MRI Subject RIV: CD - Macromolecular Chemistry

  2. Study on the uptake and distribution of gadolinium based contrast agents in biological samples using laser ablation with inductively coupled plasma mass spectroscopy

    International Nuclear Information System (INIS)

    Gadolinium based contrast agents are used for magnetic resonance imaging. After their excretion by medicated patients they reach surface water passing waste water treatment plants where they are not removed sufficiently. The behavior of the contrast agents in the environment and the interaction with organisms was investigated in this work due to the toxicity of the free Gd3+ ion and the associated risks, such as accumulation in the human food chain. In this work, the two elemental analytical imaging methods laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and synchrotron radiation X-ray fluorescence analysis (SRXRF) have been used to investigate the uptake, distribution, and excretion of Gd-based contrast agents by various biological systems. Both methods were analytically characterized and compared for this application. The detection limits of gadolinium were determined under optimized conditions by LA-ICP-MS and SRXRF. With calibration by remains of dried elemental standard droplets detection limits of 0.78 pg absolute amount of gadolinium (LA-ICP-MS), respectively 89 pg (SRXRF) were reached. Based on filamentous algae as water plants the uptake and the excretion of Gd-based contrast agents were revealed. The dependence on concentration of the contrast agent in the exposition solution and the independence of temporal uptake within one to seven days were studied for duckweed. By LA-ICP-MS gadolinium was quantified in a leaf of cress plant. The verification of the results was performed by SRXRF and ICP-MS after digestion. Furthermore, the uptake and distribution of Gd-based contrast agents in higher organisms (water flea) were observed. The exact location of gadolinium was resolved by three-dimensional μ-computed tomography by the comparison of an exposed with a Gd-free water flea. In all studies, gadolinium was detected in the investigated exposed model organisms. It can be concluded that the contrast agents were taken from the environment.

  3. Intercellular imaging by a polyarginine derived cell penetrating peptide labeled magnetic resonance contrast agent,diethylenetriamine pentaacetic acid gadolinium

    Institute of Scientific and Technical Information of China (English)

    GUO You-min; LIU Min; YANG Jun-le; GUO Xiao-juan; WANG Si-cen; DUAN Xiao-yi; WANG Peng

    2007-01-01

    Background The cellular plasma membrane represents a natural barrier to many exogenous molecules including magnetic resonance (MR) contrast agent. Cell penetrating peptide (CPP) is used to internalize proteins, peptides, and radionuclide. This study was undertaken to assess the value of a new intracellular MR contrast medium, CPP labeled diethylenetriamine pentaacetic acid gadolinium (Gd-DTPA) in molecular imaging in vitro. Methods Fluorescein-5-isothiocyanate (FITC) and Gd-DTPA respectively labeled with CPP (FITC-CPP, Gd-DTPA-CPP) were synthesized by the solid-phase method. Human hepatic cancer cell line-HepG2 was respectively stained by FITC-CPP and FITC to observe the uptake and intracellular distribution. HepG2 was respectively incubated with 100 nmol/ml Gd-DTPA-CPP for 0, 10, 30, 60 minutes, and imaged by MR for studying the relationship between the incubation time and T1WI signal. The cytotoxicity to NIH3T3 fibroblasts cells was measured by 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide reduction assay (MTT). Results The molecular weights of CPP labeled imaging agents, which were determined by MALDI mass spectrometry (FITC-CPP MW=2163.34, Gd-DTPA-CPP MW=2285.99), were similar to the calculated molecular weights. Confocal microscopy suggested HepG2 translocated FITC-CPP in cytoplasm and nucleus independent with the incubation temperature. MR images showed HepG2 uptaken Gd-DTPA-CPP had a higher T1 weighted imaging (T1WI) signal, and that the T1WI signal intensity was increasing in a time-dependent manner (r=0.972, P=0.001), while the signal intensity between the cells incubated by Gd-DTPA for 60 minutes and the controlled cells was not significantly different (P=0.225). By MTT, all concentrations from 50 nmol/ml to 200 nmol/ml had no significant (F=0.006, P=1.000) effect on cell viability of mouse NIH3T3 fibroblasts, compared with the control group. Conclusions The newly constructed CPP based on polyarginine can translocate cells by carrying FITC

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

    Directory of Open Access Journals (Sweden)

    Simone Rodrigues Silva

    2015-01-01

    Full Text Available 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.

  5. Adverse allergic reactions to linear ionic gadolinium-based contrast agents: experience with 194, 400 injections

    International Nuclear Information System (INIS)

    Aim: To report the authors' experience with the administration of four gadolinium-based contrast agents (GBCA; gadopentetate dimeglumine, gadofosveset trisodium, gadoxetate disodium and gadobenate dimeglumine) in a large study population at a single, large academic medical centre. Materials and methods: The institutional review board approved this retrospective study in which data in the electronic incident reporting system were searched. A total of 194, 400 intravenous administrations of linear ionic GBCAs were assessed for the incidence of adverse reactions and risk factors from 1 January 2007 to 14 January 2014. The severity of reactions (mild, moderate, and severe), patient type (outpatients, inpatients, and emergency), examination type, and treatment options were also investigated. Results: In total, 204/194400 (0.1%) patients (mean age 45.7 ± 14.9) showed adverse reactions, consisting of 6/746 (0.80%), 10/3200 (0.31%), 14/6236 (0.22%) and 174/184218 (0.09%), for gadofosveset trisodium, gadoxetate disodium, gadobenate dimeglumine, and gadopentetate dimeglumine, respectively. An overall significant difference was found between different GBCAs regarding the total number of reactions (p < 0.0001). When comparing the GBCAs together, significant differences were found between gadofosveset trisodium versus gadopentetate dimeglumine (p < 0.0001), gadofosveset trisodium versus gadobenate dimeglumine (p = 0.0051), gadoxetate disodium versus gadopentetate dimeglumine (p < 0.0001) and gadopentetate dimeglumine versus gadobenate dimeglumine (p = 0.0013). Rate of reaction was higher in females (F: 146/113187, 0.13%/M: 58/81213, 0.07%; p < 0.0001). Rate of reactions was higher in outpatient (180/158885, 0.11%), emergency (10/10413, 0.10%), and inpatients (14/25102, 0.05%), respectively (p < 0.0001). Most of the patients had mild symptoms 171/204 (83.8%). Abdomen–pelvis, liver, and thoracic examinations had highest rates of reactions (0.17 versus 0

  6. Gallium-67/stable gadolinium antagonism: MRI contrast agent markedly alters the normal biodistribution of gallium-67

    International Nuclear Information System (INIS)

    An 11-yr-old patient was scanned 96 hr after the administration of gallium-67 (67Ga). The scan emulated the biodistribution of a typical bone-seeking radipharmaceutical-rather than that of 67Ga. None of the factors previously identified with alteration of the biodistribution of 67Ga were found. However, the patient had been injected with gadopentetate in conjunction with magnetic resonance imaging 4 hr before receiving the 67Ga. Gadolinium appears to cause a strong carrier-like effect in 67Ga scans

  7. Four Gadolinium(III) Complexes Appended to a Porphyrin: A Water-Soluble Molecular Theranostic Agent with Remarkable Relaxivity Suited for MRI Tracking of the Photosensitizer.

    Science.gov (United States)

    Sour, Angélique; Jenni, Sébastien; Ortí-Suárez, Ana; Schmitt, Julie; Heitz, Valérie; Bolze, Frédéric; Loureiro de Sousa, Paulo; Po, Chrystelle; Bonnet, Célia S; Pallier, Agnès; Tóth, Éva; Ventura, Barbara

    2016-05-01

    A molecular theranostic agent for magnetic resonance imaging (MRI) and photodynamic therapy (PDT) consisting of four [GdDTTA](-) complexes (DTTA(4-) = diethylenetriamine-N,N,N″,N″-tetraacetate) linked to a meso-tetraphenylporphyrin core, as well as its yttrium(III) analogue, was synthesized. A variety of physicochemical methods were used to characterize the gadolinium(III) conjugate 1 both as an MRI contrast agent and as a photosensitizer. The proton relaxivity measured in H2O at 20 MHz and 25 °C, r1 = 43.7 mmol(-1) s(-1) per gadolinium center, is the highest reported for a bishydrated gadolinium(III)-based contrast agent of medium size and can be related to the rigidity of the molecule. The complex displays also a remarkable singlet oxygen quantum yield of ϕΔ = 0.45 in H2O, similar to that of a meso-tetrasulfonated porphyrin. We also evidenced the ability of the gadolinium(III) conjugate to penetrate in cancer cells with low cytotoxicity. Its phototoxicity on Hela cells was evaluated following incubation at low micromolar concentration and moderate light irradiation (21 J cm(-2)) induced 50% of cell death. Altogether, these results demonstrate the high potential of this conjugate as a theranostic agent for MRI and PDT. PMID:27074089

  8. Gadolinium- and manganite-based contrast agents with fluorescent probes for both magnetic resonance and fluorescence imaging of pancreatic islets: a comparative study

    Czech Academy of Sciences Publication Activity Database

    Berková, Z.; Jirák, D.; Zacharovová, K.; Lukeš, I.; Kotková, Z.; Kotek, J.; Kačenka, M.; Kaman, Ondřej; Řehoř, I.; Hájek, M.; Saudek, F.

    2013-01-01

    Roč. 8, č. 4 (2013), s. 614-621. ISSN 1860-7179 Institutional support: RVO:68378271 Keywords : contrast agents * gadolinium * magnetic resonance imaging * manganite * pancreatic islets Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.046, year: 2013

  9. Nephrogenic systemic fibrosis after application of gadolinium-based contrast agents - a status paper; Nephrogene systemische Fibrose nach Anwendung gadoliniumhaltiger Kontrastmittel - ein Statuspapier zum aktuellen Stand des Wissens

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, M.; Uder, M. [Erlangen-Nuernberg Univ., Erlangen (Germany). Inst. fuer Radiologie

    2007-06-15

    Recently the association of a rare disease named ''nephrogenic systemic fibrosis'' (NSF) with the administration of gadolinium-containing contrast media, especially gadodiamide (Omniscan, GE-Healthcare), was described. NSF is a scleroderma-like disease characterised by widespread tissue fibrosis. Until now, NSF cases were observed only in patients with kidney disease. Almost all patients were suffering from chronic renal insufficiency, 90 % of them required renal replacement therapy. The true incidence of the disease is unknown. First retrospective analyses of selected collectives of patients with end-stage renal disease showed 2 - 5 % cases of NSF after administration of Gadolinium-containing contrast agents with an odds ratio of 20 - 50 in comparison to non-exposed controls. NSF is a serious adverse reaction, which may result in severe disabilities and even death. Therefore all radiologists applying gadolinium-based contrast agents should be informed about this disease and the recent recommendations for its prevention. On the basis of the published data, Omniscan should not be used in patients with severe renal impairment (GFR < 30 ml/min/1.73 m{sup 2}) and those who have had or are undergoing liver transplantation. In neonates and infants up to 1 year of age, Omniscan should only be used after careful consideration. Also the other gadolinium-based contrast agents should be used in high-risk patients only after careful consideration using the lowest dose possible.

  10. GADOLINIUM(Gd)-BASED and Ion Oxide Nanoparticle Contrast Agents for Pre-Clinical and Clinical Magnetic Resonance Imaging (mri) Research

    Science.gov (United States)

    Ng, Thian C.

    2012-06-01

    It is known that one strength of MRI is its excellent soft tissue discrimination. It naturally provides sufficient contrast between the structural differences of normal and pathological tissues, their spatial extent and progression. However, to further extend its applications and enhance even more contrast for clinical studies, various Gadolinium (Gd)-based contrast agents have been developed for different organs (brain strokes, cancer, cardio-MRI, etc). These Gd-based contrast agents are paramagnetic compounds that have strong T1-effect for enhancing the contrast between tissue types. Gd-contrast can also enhance magnetic resonance angiography (CE-MRA) for studying stenosis and for measuring perfusion, vascular susceptibility, interstitial space, etc. Another class of contrast agents makes use of ferrite iron oxide nanoparticles (including Superparamagnetic Ion Oxide (SPIO) and Ultrasmall Superparamagnetic Iron Oxide (USPIO)). These nanoparticles have superior magnetic susceptibility effect and produce a drop in signal, namely in T2*-weighted images, useful for the determination of lymph nodes metastases, angiogenesis and arteriosclerosis plaques.

  11. Gadolinium-porphyrins: new potential magnetic resonance imaging contrast agents for melanoma detection

    Directory of Open Access Journals (Sweden)

    Daryoush Shahbazi-Gahrouei

    2006-11-01

    Full Text Available BACKGROUND: Two new porphyrin-based magnetic resonance imaging (MRI contrast agents, Gd-hematoporphyrin (Gd-H and Gd-tetra-carboranylmethoxyphenyl-porphyrin (Gd-TCP were synthesized and tested in nude mice with human melanoma (MM-138 xenografts as new melanoma contrast agents. METHODS: Subcutaneous xenografts of human melanoma cells (MM-138 were studied in 30 (five groups of six nude mice. The effect of different contrast agents (Gd-TCP, Gd-H, GdCl3 and Gd-DTPA on proton relaxation times was measured in tumors and other organs. T1 values, signal enhancement and the Gd concentration for different contrast agent solutions were also investigated. RESULTS: The porphyrin agents showed higher relaxivity compared to the clincal agent, Gd-DTPA. A significant 16% and 21% modification in T1 relaxation time of the water in human melanoma tumors grafted in the nude mice was revealed 24 hours after injection of Gd-TCP and Gd-H, respectively. The percentage of injected Gd localized to the tumor measured by inductively coupled plasma atomic emission spectrometry (ICP-AES was approximately 21% for Gd-TCP and 28% for Gd-H which were higher than that of Gd-DTPA (10%. CONCLUSIONS: The high concentration of Gd in the tumor is indicative of a selective retention of the compounds and indicates that Gd-TCP and Gd-H are promising MR imaging contrast agents for melanoma detection. Gd-porphyrins have considerable promise for further diagnostic applications in magnetic resonance imaging. KEY WORDS: MRI, porphyrin-based contrast agent, hematoporphyrin, melanoma.

  12. Dermal inorganic gadolinium concentrations: evidence for in vivo transmetallation and long-term persistence in nephrogenic systemic fibrosis

    DEFF Research Database (Denmark)

    Abraham, J L; Thakral, C; Skov, L;

    2008-01-01

    BACKGROUND: Gadolinium (Gd)-based magnetic resonance contrast agents (GBMCA), including gadodiamide, have been identified as the probable causative agents of the serious disease, nephrogenic systemic fibrosis (NSF). OBJECTIVES: To investigate retained Gd-containing deposits in skin biopsies from...

  13. Gadolinium-enhanced inner ear magnetic resonance imaging for evaluation of delayed endolymphatic hydrops, including a bilateral case.

    Science.gov (United States)

    Fukushima, Munehisa; Oya, Ryohei; Akazawa, Hitoshi; Tsuruta, Yukinori; Inohara, Hidenori

    2016-05-01

    Conclusion The data suggests that gadolinium-enhanced inner ear MR imaging is useful for diagnosis of delayed endolymphatic hydrops (DEH) because it is independent of inner ear function, and the size of the affected endolymphatic space is clearly enlarged. Objective This study was performed to semi-quantitatively evaluate the endolymphatic space in patients with all types of DEH using gadolinium-enhanced inner ear magnetic resonance (MR) imaging. Patients and methods Seven patients (age range = 21-77 years; five female, two male) with ipsilateral DEH (n = 5), contralateral DEH (n = 1), and bilateral DEH (n = 1). All patients underwent 3T MR imaging 4 h after intravenous injection of gadolinium. Software was used to determine the size of the endolymphatic space. Pure tone audiometry and caloric testing using an electronystagmogram were carried out. Results One side of the endolymphatic space was dominantly extended in patients with ipsilateral DEH, and both sides of the space were extended in patients with contralateral and bilateral DEH. In patients with ipsilateral DEH, the volume ratio of endolymph to vestibule was 2.5-4.3-times that in the unaffected ear. The volume ratio of endolymph to vestibule was nearly equal in patients with contralateral and bilateral DEH. PMID:26799493

  14. Diffusion weighted MR imaging in patients with HCC and liver cirrhosis after administration of different gadolinium contrast agents: Is it still reliable?

    International Nuclear Information System (INIS)

    Purpose: Diffusion weighted imaging (DWI) is an emerging technique for abdominal MR and usually performed before intravenous contrast injection. Recent studies performed in patients with normal liver function have shown that DWI can be performed after gadolinium administration. Aim of this study was to compare DWI before and after administration of different gadolinium compounds in patients with HCC and liver cirrhosis. Materials and methods: 15 patients with known HCC and liver cirrhosis underwent liver MRI at 1.5 T (Magnetom Avanto, Siemens) including DWI on day 1 before and after administration of gadobutrol (Gadovist®) and on day 2 after administration of EOB-Gadolinium-DTPA (Primovist®). Signal to noise ratios (SNR) and contrast to noise ratios (CNR) of HCC lesions were determined for all DWI data sets. Furthermore, ADC values were compared using a Wilcoxon test. A p-value 2). Similarly, no significant differences were found for CNR (average values:34.4 vs. 32.3 vs. 30.7; b = 50 s/mm2) nor for ADC-values (mean: 1.5 vs. 1.4 vs. 1.5 × 10−3 mm2/s) of HCC. Conclusion: There is no significant difference regarding DWI in patients with cirrhosis before and after contrast injection. Hence, it is reliable to run DWI after gadolinium either as an alternative for unsuccessful pre-contrast DWI or as a gap filler to spare time in EOB-Gadolinium-DTPA imaging.

  15. Evaluation of Visibility of Celiac and Renal Arteries on Digital Subtraction Angiography Using Iodine, Gadolinium and Carbon dioxide Contrast Agents: A Porcine Experimental Study

    OpenAIRE

    SHINMURA, Kohei; Baba, Yasutaka; HAYASHI, SADAO; Ikeda, Shunichiro; MOTOMURA, Eriko; KIYAO, Yutaro; NAKAJO, Masayuki; 新村, 耕平; 馬場, 康貴; 林, 完勇; 池田, 俊一郎; 本村, 江利子; 木屋尾, 祐太郎; 中條, 政敬

    2014-01-01

    Purpose: To examine the differences in visibility of celiac, renal arteries and nephrogram on digital subtraction angiography (DSA)among 3 different contrast agents in a porcine model.Methods: Six swine underwent percutaneous catheterization and DSA. Celiac and bilateral renal DSA angiograms with iodine,gadolinium and CO2 were obtained by the same injection protocols for each swine. The arterial diameter, contrast enhancement andrenal density were measured using the Image-J software. Assessme...

  16. Study of suspending agents for gadolinium(III)-exchanged hectorite. An oral magnetic resonance imaging contrast agent

    International Nuclear Information System (INIS)

    Clays modified with paramagnetic ions have been shown to be effective magnetic resonance imaging contrast agents. The efficacy in part relies on the suspension of the small clay particles in aqueous solution. In this study a series of macromolecules were eveluated as suspending agents for Gd(III) ion exchanged hectorite clay in water. The room temperature relaxivities for the Gd-hectorite clays were enhanced by the addition of poly(ethylene oxide), poly(ethylene glycol), cyclodextrins, and cholic acid to aqueous suspensions. Additionally, there was no evidence of free Gd(III) in solution in the presence of these suspending agents. In contrast the combination of alginic acid or poly(sodium 4-styrenesulfonate) with the clays resulted in release of the Gd(III) into solution. Xanthan gum, which is often used as an emulsifier and stabilizer in food products, forms a viscous suspension but also reacts with free Gd(III) ions. 25 refs., 10 figs., 2 tabs

  17. Preclinical animal acute toxicity studies of new developed MRI contrast agent based on gadolinium

    Science.gov (United States)

    Nam, I. F.; Zhuk, V. V.

    2015-04-01

    Acute toxicity test of new developed MRI contrast agent based on disodium salt of gadopentetic acid complex were carried out on Mus musculus and Sprague Dawley rats according to guidelines of preclinical studies [1]. Groups of six animals each were selected for experiment. Death and clinical symptoms of animals were recorded during 14 days. As a result the maximum tolerated dose (MTD) for female mice is 2.8 mM/kg of body weight, male mice - 1.4 mM/kg, female rats - 2.8 mM/kg, male rats - 5.6 mM/kg of body weight. No Observed Adverse Effect Dose (NOAEL) for female mice is 1.4 mM/kg, male mice - 0.7 mM/kg, male and female rats - 0.7 mM/kg. According to experimental data new developed MRI contrast agent based on Gd-DTPA complex is low-toxic.

  18. Contrast-enhanced voiding urosonography phantom study: intravenous iodinated and gadolinium-based contrast agents may cause false-negative results in assessment of vesicoureteral reflux in children

    International Nuclear Information System (INIS)

    Contrast-enhanced voiding urosonography (ce-VUS) is commonly requested simultaneously to other diagnostic imaging necessitating intravenous contrast agents. To date there is limited knowldedge about intravesical interactions between different types of contrast agents. To assess the effect of excreted intravenous iodinated and gadolinium-based contrast agents on the intravesical distribution of ultrasound contrast within contrast-enhanced voiding urosonography. Iodinated (iomeprol, iopamidol) and gadolinium-based (gadoterate meglumine) contrast agents were diluted to bladder concentration and injected into balloons filled with saline solution. CT scans were performed to assess the contrast distribution in these phantoms. Regions of interest were placed at the top and bottom side of each balloon and Hounsfield units (HU) were measured. Three other balloons were filled with saline solution and contrast media likewise. The ultrasound contrast agent sulphur hexafluoride was added and its distribution was assessed using sonography. MDCT scans showed a separation of two liquid layers in all bladder phantoms with the contrast layers located at the bottom and the saline solution at the top. Significant differences of the HU measurements at the top and bottom side were observed (P < 0.001-0.007). Following injection of ultrasound contrast agent, US showed its distribution exclusively among the saline solution. False-negative results of contrast-enhanced voiding urosonography may occur if it is performed shortly after imaging procedures requiring intravenous contrast. (orig.)

  19. Contrast-enhanced voiding urosonography phantom study: intravenous iodinated and gadolinium-based contrast agents may cause false-negative results in assessment of vesicoureteral reflux in children

    Energy Technology Data Exchange (ETDEWEB)

    Veldhoen, Simon; Sauer, Alexander; Gassenmaier, Tobias; Petritsch, Bernhard; Herz, Stefan; Blanke, Philipp; Bley, Thorsten A.; Wirth, Clemens [University Hospital Wuerzburg, Department of Diagnostic and Interventional Radiology, Wuerzburg (Germany); Derlin, Thorsten [University Hospital Wuerzburg, Department of Diagnostic and Interventional Radiology, Wuerzburg (Germany); Hannover Medical School, Department of Nuclear Medicine, Hannover (Germany)

    2015-06-15

    Contrast-enhanced voiding urosonography (ce-VUS) is commonly requested simultaneously to other diagnostic imaging necessitating intravenous contrast agents. To date there is limited knowldedge about intravesical interactions between different types of contrast agents. To assess the effect of excreted intravenous iodinated and gadolinium-based contrast agents on the intravesical distribution of ultrasound contrast within contrast-enhanced voiding urosonography. Iodinated (iomeprol, iopamidol) and gadolinium-based (gadoterate meglumine) contrast agents were diluted to bladder concentration and injected into balloons filled with saline solution. CT scans were performed to assess the contrast distribution in these phantoms. Regions of interest were placed at the top and bottom side of each balloon and Hounsfield units (HU) were measured. Three other balloons were filled with saline solution and contrast media likewise. The ultrasound contrast agent sulphur hexafluoride was added and its distribution was assessed using sonography. MDCT scans showed a separation of two liquid layers in all bladder phantoms with the contrast layers located at the bottom and the saline solution at the top. Significant differences of the HU measurements at the top and bottom side were observed (P < 0.001-0.007). Following injection of ultrasound contrast agent, US showed its distribution exclusively among the saline solution. False-negative results of contrast-enhanced voiding urosonography may occur if it is performed shortly after imaging procedures requiring intravenous contrast. (orig.)

  20. Gadolinium-labeled dendronized gold nanoparticles as new targeted MRI contrast agent

    Science.gov (United States)

    Pan, Hongmu; Daniel, Marie-Christine

    2010-04-01

    Early diagnosis is critical for positive outcome of cancer treatments. In many cases, lives would be saved if the tumor could be detected at a very early stage. Nanoparticles have the property of passively targeting tumor sites due to their enhanced permeation and retention (EPR) effect. Thus they can play a critical role in improving the ability to find cancer in its earliest and most treatable stages. Furthermore magnetic resonance imaging is one of the most precise techniques for cancer screening since it can show 3D images of the tumors. For a better enhancement of the sensitivity of this method, MRI contrast agent (DOTA)Gd was attached to poly(propylene imine) dendrons of third generation and the obtained dendrons were used for modification of gold nanoparticles.

  1. Gadolinium Nanoparticles Conjugated with Therapeutic Bifunctional Chelate as a Potential T1 Theranostic Magnetic Resonance Imaging Agent.

    Science.gov (United States)

    Kang, Min-Kyoung; Lee, Gang Ho; Jung, Ki-Hye; Jung, Jae-Chang; Kim, Hee-Kyung; Kim, Yeon-Hee; Lee, Jongmin; Ryeom, Hun-Kyu; Kim, Tae-Jeong; Chang, Yongmin

    2016-05-01

    This work is directed toward the synthesis of two types of gadolinium oxide nanoparticles (Gd-oxide NPs), abbreviated as Gd@SiO2-DO3A and Gd@SiO2-DO2A-BTA, with diameters of 50-60 nm. The synthesis involves sequential coating of Gd-oxide NPs with tetraethyl orthosilicate (TEOS) and (3-aminopropyl) triethoxysilane (APTES), followed by functionalization of the aminopropylsilane group with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) or 1,4,7,10-tetraazacyclododecane-1,4,7-trisacetic acid conjugates of benzothiazoles (DO3A-BTA). Gd@SiO2-DO3A and Gd@SiO2-DO2A-BTA exhibit high water solubility and colloidal stability. The r1 relaxivities of both Gd@SiO2-DO3A and Gd@SiO2-DO2A-BTA are higher than those of the corresponding low-molecular-weight magnetic resonance imaging contrast agents (MRI CAs), and their r2/r1 ratios are close to 1, indicating that both can be used as potential T1 MRI CAs. Biodistribution studies demonstrated that Gd@SiO2-DO2A-BTA was excreted via both hepatobiliary and renal pathways. Gd@SiO2-DO2A-BTA exhibits a strong intracellular uptake property in a series of tumor cell lines, and has significant anticancer characteristics against cell lines such as SK-HEP-1, MDA-MB-231, HeLa, and Hep-3B. PMID:27305813

  2. Evaluation of absorbed dose in Gadolinium neutron capture therapy

    OpenAIRE

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

    2015-01-01

    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 i...

  3. A Reactive Behavior Agent: Including Emotions into a Video Game

    Directory of Open Access Journals (Sweden)

    A. L. Laureano-Cruces

    2012-10-01

    Full Text Available Why we have emotions and how they influence human behavior are two questions we constantly ask ourselves.According to researchers in the field, there are two kinds of information that the person receives to make a decision.This information is integrated to generate a whole. One comes from ourselves it is proprioceptive and refers toemotions; the other one is external, it comes from the environment. Thus, emotions are immersed in different areas ofa person’s life, including social, functional, and cognitive aspects. It has an important role in the decision-makingprocess. It is on this last point that this paper focuses its approach, which consists of including a cognitive structure ofemotions in a reactive behavior in order to enrich behavior, including the information generated through internalevaluation of the external physical stimuli. Our work is based on the OCC theory (named after the name of its authors:Ortony, Collins and Clore. This theory proposes that a decision-making process is affected through differentperspectives: a goals and events, b agents and their actions, and c objects and their capacity for attraction. Thecase study is situated within a scenario that represents an approach that seeks to include a module of emotions withinthe design of the architecture of a videogame.

  4. Radioprotection: mechanism and radioprotective agents including honeybee venom

    International Nuclear Information System (INIS)

    Since 1949, a great deal of research has been carried on the radioprotective action of chemical substances. These substances have shown to reduce mortality when administered to animals prior to exposure to a lethal dose of radiation. This fact is of considerable importance since it permits reduction of radiation-induced damage and provides prophylactic treatment for the damaging effects produced by radiotherapy. The following radioprotection mechanisms were proposed: free radical scavenger, repair by hydrogen donation to target molecules formation of mixed disulfides, delay of cellular division and induction of hypoxia in the tissues. Radioprotective agents have been divided into four major groups: the thiol compounds, other sulfur compounds, pharmacological agents (anesthetic drugs, analgesics, tranquilizers, etc.) and other radioprotective agents (WR-1065, WR-2721, vitamins C and E, glutathione, etc.). Several studies revealed the radioprotective action of Apis mellifera honeybee venom as well as that of its components mellitin and histamine. Radioprotective activity of bee venom involves mainly the stimulation of the hematopoietic system. In addition, release of histamine and reduction in oxygen tension also contribute to the radioprotective action of bee venom. (author)

  5. Radioprotection: mechanism and radioprotective agents including honeybee venom

    Energy Technology Data Exchange (ETDEWEB)

    Varanda, E.A.; Tavares, D.C. [UNESP, Araraquara, SP (Brazil). Escola de Ciencias Farmaceuticas. Dept. de Ciencias Biologicas

    1998-07-01

    Since 1949, a great deal of research has been carried on the radioprotective action of chemical substances. These substances have shown to reduce mortality when administered to animals prior to exposure to a lethal dose of radiation. This fact is of considerable importance since it permits reduction of radiation-induced damage and provides prophylactic treatment for the damaging effects produced by radiotherapy. The following radioprotection mechanisms were proposed: free radical scavenger, repair by hydrogen donation to target molecules formation of mixed disulfides, delay of cellular division and induction of hypoxia in the tissues. Radioprotective agents have been divided into four major groups: the thiol compounds, other sulfur compounds, pharmacological agents (anesthetic drugs, analgesics, tranquilizers, etc.) and other radioprotective agents (WR-1065, WR-2721, vitamins C and E, glutathione, etc.). Several studies revealed the radioprotective action of Apis mellifera honeybee venom as well as that of its components mellitin and histamine. Radioprotective activity of bee venom involves mainly the stimulation of the hematopoietic system. In addition, release of histamine and reduction in oxygen tension also contribute to the radioprotective action of bee venom. (author)

  6. Cellular uptake and imaging studies of gadolinium-loaded single-walled carbon nanotubes as MRI contrast agents.

    Science.gov (United States)

    Tang, Annie M; Ananta, Jeyarama S; Zhao, Hong; Cisneros, Brandon T; Lam, Edmund Y; Wong, Stephen T; Wilson, Lon J; Wong, Kelvin K

    2011-01-01

    We quantify here, for the first time, the intracellular uptake (J774A.1 murine macrophage cells) of gadolinium-loaded ultra-short single-walled carbon nanotubes (gadonanotubes or GNTs) in a 3 T MRI scanner using R(2) and R(2)* mapping in vitro. GNT-labeled cells exhibited high and linear changes in net transverse relaxations (ΔR(2) and ΔR 2*) with increasing cell concentration. The measured ΔR(2)* were about three to four times greater than the respective ΔR(2) for each cell concentration. The intracellular uptake of GNTs was validated with inductively coupled plasma optical emission spectrometry (ICP-OES), indicating an average cellular uptake of 0.44 ± 0.09 pg Gd per cell or 1.69 × 10(9) Gd(3+) ions per cell. Cell proliferation MTS assays demonstrated that the cells were effectively labeled, without cytotoxicity, for GNTs concentrations ≤28 µM Gd. In vivo relaxometry of a subcutaneously-injected GNT-labeled cell pellet in a mouse was also demonstrated at 3 T. Finally, the pronounced R(2)* effect of GNT-labeled cells enabled successful in vitro visualization of labeled cells at 9.4 T. PMID:21504063

  7. The influence of collagen network integrity on the accumulation of gadolinium-based MR contrast agents in articular cartilage

    International Nuclear Information System (INIS)

    Delayed gadolinium-enhanced MR imaging of cartilage is used to quantify the proteoglycan loss in early osteoarthritis. It is assumed that T 1 after Gd-DTPA administration in the near equilibrium state reflects selective proteoglycan loss from cartilage. To investigate the influence of the collagen network integrity on contrast accumulation, the relaxation rates ΔR1 and ΔR2 were compared after Gd-DTPA administration in a well established model of osteoarthritis. Collagen or proteoglycan depletion was induced by the proteolytic enzymes papain and collagenase in healthy bovine patellar cartilage. Using a dedicated MRI sequence, T1 and T2 maps were simultaneously acquired before and 11 h after Gd-DTPA administration. Depth-dependent profiles of ΔR1 and ΔR2 were calculated in healthy, proteoglycan and collagen-depleted articular cartilage and the mean values of different cartilage layers were compared using the Mann-Whitney-U test. In superficial layers (1 mm) there was no significant difference (p > 0.05) in either ΔR1 or ΔR2 between proteoglycan-depleted (16.6 ± 1.2 s-1, 15.9 ± 1.0 s-1) and collagen-depleted articular cartilage (15.3 ± 0.9 s-1, 15.5 ± 0.9 s-1). In deep layers (3 mm) both parameters were significantly higher (p = 0.005, 0.03) in proteoglycan-depleted articular cartilage (12.3 ± 1.1 s-1, 9.8 ± 0.8 s-1) than in collagen-depleted articular cartilage (9.1 ± 1.1 s-1, 8.7 ± 0.7 s-1). Both proteoglycan loss and alterations in the collagen network influence the accumulation of Gd-DTPA in articular cartilage with significant differences between superficial and deep cartilage layers. (orig.)

  8. The influence of collagen network integrity on the accumulation of gadolinium-based MR contrast agents in articular cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Wiener, Edzard; Schmidt, C.; Diederichs, G. [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Radiologie; Settles, M. [Klinikum rechts der Isar, Muenchen (Germany). Inst. fuer Roentgendiagnostik; Weirich, G. [Klinikum Rechts der Isar, Muenchen (Germany). Inst. fuer Pathologie und Pathologische Anatomie

    2011-03-15

    Delayed gadolinium-enhanced MR imaging of cartilage is used to quantify the proteoglycan loss in early osteoarthritis. It is assumed that T 1 after Gd-DTPA administration in the near equilibrium state reflects selective proteoglycan loss from cartilage. To investigate the influence of the collagen network integrity on contrast accumulation, the relaxation rates {delta}R1 and {delta}R2 were compared after Gd-DTPA administration in a well established model of osteoarthritis. Collagen or proteoglycan depletion was induced by the proteolytic enzymes papain and collagenase in healthy bovine patellar cartilage. Using a dedicated MRI sequence, T{sub 1} and T{sub 2} maps were simultaneously acquired before and 11 h after Gd-DTPA administration. Depth-dependent profiles of {delta}R1 and {delta}R2 were calculated in healthy, proteoglycan and collagen-depleted articular cartilage and the mean values of different cartilage layers were compared using the Mann-Whitney-U test. In superficial layers (1 mm) there was no significant difference (p > 0.05) in either {delta}R1 or {delta}R2 between proteoglycan-depleted (16.6 {+-} 1.2 s{sup -1}, 15.9 {+-} 1.0 s{sup -1}) and collagen-depleted articular cartilage (15.3 {+-} 0.9 s{sup -1}, 15.5 {+-} 0.9 s{sup -1}). In deep layers (3 mm) both parameters were significantly higher (p = 0.005, 0.03) in proteoglycan-depleted articular cartilage (12.3 {+-} 1.1 s{sup -1}, 9.8 {+-} 0.8 s{sup -1}) than in collagen-depleted articular cartilage (9.1 {+-} 1.1 s{sup -1}, 8.7 {+-} 0.7 s{sup -1}). Both proteoglycan loss and alterations in the collagen network influence the accumulation of Gd-DTPA in articular cartilage with significant differences between superficial and deep cartilage layers. (orig.)

  9. In an animal model nephrogenic systemic fibrosis cannot be induced by intraperitoneal injection of high-dose gadolinium based contrast agents

    Energy Technology Data Exchange (ETDEWEB)

    Langer, R.D., E-mail: rlanger@uaeu.ac.ae [Faculty of Medicine and Health Sciences (FMHS), United Arab Emirates University, Al Ain (United Arab Emirates); Lorke, D.E. [Florida International University, Miami, FL (United States); Neidl van Gorkom, K.F. [Faculty of Medicine and Health Sciences (FMHS), United Arab Emirates University, Al Ain (United Arab Emirates); Petroianu, G. [Florida International University, Miami, FL (United States); Azimullah, S.; Nurulain, S.M.; Singh, S. [Faculty of Medicine and Health Sciences (FMHS), United Arab Emirates University, Al Ain (United Arab Emirates); Fuchsjäger, M. [Al Ain Hospital, MUV-VAMED, Al Ain (United Arab Emirates)

    2012-10-15

    Aim and objective: Nephrogenic systemic fibrosis (NSF) has been reported in humans to be most likely induced by gadolinium based contrast agents (GBCA), namely by gadodiamide, gadopentetate dimeglumine, and gadoversetamide, rarely by other GBCA. The pathogenesis of NSF remains unclear; different hypotheses are under discussion. The objective of the study is to assess if in the animal model human-like NSF changes can be induced by high-dose, intraperitoneal GBCA injections over four weeks. Materials and methods: After approval by the institutional animal ethics committee, six rats each were randomly assigned to groups, and treated with seven different GBCA. Intraperitoneal (IP) injections – proven in the animal model to be effective – were chosen to prolong the animals’ exposure to the respective GBCA. GBCA doses of previous intravenous (IV) animal studies were applied. After five weeks all rats were sacrificed. Sham controls were treated with IP saline injections, employing the same regimen. Results: No findings comparable with human NSF were observed in all animals after IP treatment with all seven GBCA at daily doses of 2.5 and 5.0 mmol/kg body weight (BW). No histopathological abnormalities of all examined organs were noted. Weight loss was stated in weeks three and four with GBCA injections at doses of 5.0 mmol/kg BW, but rats regained weight after cessation of GBCA treatment. Conclusions: NSF-comparable pathological findings could not be induced by high dose intraperitoneal injection of seven GBCA.

  10. In an animal model nephrogenic systemic fibrosis cannot be induced by intraperitoneal injection of high-dose gadolinium based contrast agents

    International Nuclear Information System (INIS)

    Aim and objective: Nephrogenic systemic fibrosis (NSF) has been reported in humans to be most likely induced by gadolinium based contrast agents (GBCA), namely by gadodiamide, gadopentetate dimeglumine, and gadoversetamide, rarely by other GBCA. The pathogenesis of NSF remains unclear; different hypotheses are under discussion. The objective of the study is to assess if in the animal model human-like NSF changes can be induced by high-dose, intraperitoneal GBCA injections over four weeks. Materials and methods: After approval by the institutional animal ethics committee, six rats each were randomly assigned to groups, and treated with seven different GBCA. Intraperitoneal (IP) injections – proven in the animal model to be effective – were chosen to prolong the animals’ exposure to the respective GBCA. GBCA doses of previous intravenous (IV) animal studies were applied. After five weeks all rats were sacrificed. Sham controls were treated with IP saline injections, employing the same regimen. Results: No findings comparable with human NSF were observed in all animals after IP treatment with all seven GBCA at daily doses of 2.5 and 5.0 mmol/kg body weight (BW). No histopathological abnormalities of all examined organs were noted. Weight loss was stated in weeks three and four with GBCA injections at doses of 5.0 mmol/kg BW, but rats regained weight after cessation of GBCA treatment. Conclusions: NSF-comparable pathological findings could not be induced by high dose intraperitoneal injection of seven GBCA

  11. A gadolinium complex confined in silica nanoparticles as a highly efficient T1/T2 MRI contrast agent

    International Nuclear Information System (INIS)

    From the previous theoretical discussion, silica NPs with confined Gd chelates are particularly attractive because they are nontoxic, with sizes smaller than 100 nm, meeting the requirements of in vivo applications. Such NPs can be used to store and deliver drugs and their surface can be easily derivatized with biomolecules to yield targeting contrast agents. Here, we present mono-aqua Gd chelates embedded in silica nanoparticles which show exceptionally high relaxivities r1 (up to 84 s-1 mM-1 at 0.8 T) and r2 (larger than 227 s-1 mM-1 above 11.5 T) at 298 K. These NPs containing water-accessible Gd(III) complexes were prepared by the simple noncovalent incorporation of the mono-aqua complex [Gd(ebpatcn)(H2O)] into silica through a sol-gel method. (authors)

  12. A relaxometric method for the assessment of intestinal permeability based on the oral administration of gadolinium-based MRI contrast agents.

    Science.gov (United States)

    Gianolio, Eliana; Boffa, Cinzia; Orecchia, Valeria; Bardini, Paola; Catanzaro, Valeria; Poli, Valeria; Aime, Silvio

    2016-04-01

    Herein, a new relaxometric method for the assessment of intestinal permeability based on the oral administration of clinically approved gadolinium (Gd)-based MRI contrast agents (CAs) is proposed. The fast, easily performed and cheap measurement of the longitudinal water proton relaxation rate (R1 ) in urine reports the amount of paramagnetic probe that has escaped the gastrointestinal tract. The proposed method appears to be a compelling alternative to the available methods for the assessment of intestinal permeability. The method was tested on the murine model of dextran sulfate sodium (DSS)-induced colitis in comparison with healthy mice. Three CAs were tested, namely ProHance®, MultiHance® and Magnevist®. Urine was collected for 24 h after the oral ingestion of the Gd-containing CA at day 3-4 (severe damage stage) and day 8-9 (recovery stage) after treatment with DSS. The Gd content in urine measured by (1) H relaxometry was confirmed by inductively coupled plasma-mass spectrometry (ICP-MS). The extent of urinary excretion was given as a percentage of excreted Gd over the total ingested dose. The method was validated by comparing the results obtained with the established methodology based on the lactulose/mannitol and sucralose tests. For ProHance and Magnevist, the excreted amounts in the severe stage of damage were 2.5-3 times higher than in control mice. At the recovery stage, no significant differences were observed with respect to healthy mice. Overall, a very good correlation with the lactulose/mannitol and sucralose results was obtained. In the case of MultiHance, the percentage of excreted Gd complex was not significantly different from that of control mice in either the severe or recovery stages. The difference from ProHance and Magnevist was explained on the basis of the (known) partial biliary excretion of MultiHance in mice. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26866929

  13. Isotope effects in the gadolinium amalgam system

    International Nuclear Information System (INIS)

    Gadolinium is a good neutron absorbent used in uranium oxide nuclear fuel for LWR. The157 Gd has a very large cross section for neutron absorption, namely 254000 barn. One of the isotope separation method for gadolinium is the isotopic exchange in the Gd3+ - GdHg system. In this work, the separation elemental factors for this isotopic exchange reaction, determined experimentally, are presented. Gadolinium amalgam was prepared by electrolysis of aqueous solution of gadolinium acetate with lithium citrate as complexing agent ([Li+]/[Gd3+] = 12), in a glass electrolyzer with a Hg cathode and a Pt anode. The gadolinium amalgam was treated with HCl 1-2N and the extracted Gd3+ was precipitated as oxalate and converted in Gd2O3. Gadolinium in acetic solution was precipitated as oxalate and converted in Gd2O3. The isotopic ratios 154 Gd/160 Gd, 155 Gd/160 Gd, 156 Gd/160 Gd, 157 Gd/160 Gd and 158 Gd/160 Gd were determined in Gd2O3 samples by a mass spectrometer MAT 261 equipped with thermoionization ion source. After the isotopic exchange, GdHg enriches with the light Gd isotopes and the solution (Gd3+) enriches with 160 Gd. The dependence of separation elemental factor on mass difference between gadolinium isotopes is presented. (authors)

  14. Gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    Gadolinium neutron capture therapy makes use of photons and electrons produced by nuclear reactions between gadolinium and lower-energy neutrons which occur within the tumor. The results of our studies have shown that its radiation effect is mostly of low LET and that the electrons are the significant component in the over-all dose. The dose from gadolinium neutron capture reactions does not seem to increase in proportion to the gadolinium concentration, and the Gd-157 concentration of about 100 μg/ml appears most optimal for therapy. Close contact between gadolinium and the cell is not necessarily required for cell inactivation, however, the effect of electrons released from intracellular gadolinium may be significant. Experimental studies on tumor-bearing mice and rabbits have shown that this is a very promising modality though further improvements in gadolinium delivery to tumors are needed. (author)

  15. Emerging Concepts for Myocardial Late Gadolinium Enhancement MRI

    OpenAIRE

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

    2013-01-01

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

  16. Study on the uptake and distribution of gadolinium based contrast agents in biological samples using laser ablation with inductively coupled plasma mass spectroscopy; Untersuchungen zur Aufnahme und Verteilung von gadoliniumbasierten Kontrastmitteln in biologischen Proben mittels Laserablation mit induktiv gekoppelter Plasma-Massenspektrometrie

    Energy Technology Data Exchange (ETDEWEB)

    Lingott, Jana

    2016-01-05

    Gadolinium based contrast agents are used for magnetic resonance imaging. After their excretion by medicated patients they reach surface water passing waste water treatment plants where they are not removed sufficiently. The behavior of the contrast agents in the environment and the interaction with organisms was investigated in this work due to the toxicity of the free Gd{sup 3+} ion and the associated risks, such as accumulation in the human food chain. In this work, the two elemental analytical imaging methods laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and synchrotron radiation X-ray fluorescence analysis (SRXRF) have been used to investigate the uptake, distribution, and excretion of Gd-based contrast agents by various biological systems. Both methods were analytically characterized and compared for this application. The detection limits of gadolinium were determined under optimized conditions by LA-ICP-MS and SRXRF. With calibration by remains of dried elemental standard droplets detection limits of 0.78 pg absolute amount of gadolinium (LA-ICP-MS), respectively 89 pg (SRXRF) were reached. Based on filamentous algae as water plants the uptake and the excretion of Gd-based contrast agents were revealed. The dependence on concentration of the contrast agent in the exposition solution and the independence of temporal uptake within one to seven days were studied for duckweed. By LA-ICP-MS gadolinium was quantified in a leaf of cress plant. The verification of the results was performed by SRXRF and ICP-MS after digestion. Furthermore, the uptake and distribution of Gd-based contrast agents in higher organisms (water flea) were observed. The exact location of gadolinium was resolved by three-dimensional μ-computed tomography by the comparison of an exposed with a Gd-free water flea. In all studies, gadolinium was detected in the investigated exposed model organisms. It can be concluded that the contrast agents were taken from the

  17. Emerging concepts for myocardial late gadolinium enhancement MRI.

    Science.gov (United States)

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

    2013-08-01

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

  18. Intracranial neoplasms: MR imaging with gadolinium - DOTA

    International Nuclear Information System (INIS)

    After a review of the capabilities of magnetic resonance without contrast in the diagnostic assessment of intracranial tumors, the authors report the literature and their own experience concerning the use of the paramagnetic contrast agent gadolinium-DOTA in MR imaging. A 0.5 T superconducting system (Toshiba MRT-50A) was used in the evaluation of these tumors. The intravenous administration of gadolinium-DOTA does not substantially increase the sensitivity of MR to primary intra-axial tumors. However, it may provide better delineation of tumor macroscopic extension and separation of the nidus from the surrounding edema. The presence of enhancement reflects areas of alteration of the blood brain barrier and may anticipate malignant changes at the histopathological examination. The role of gadolinium-DOTA administration for differentiation of intra-axial tumor recurrence from parenchyma changes induced by surgery or radiotherapy remains to be established. On the other hand, gadolinium-DOTA dramatically increases the sensitivity and specificity of MR in the investigation of extra-axial primary tumors (meningiomas, neurinomas), sellar tumors and secondary neoplastic lesions as well as in the investigation of their recurrence. Gadolinium-DOTA may be indirectly useful in the identification of the dysontogenetic tumors do not show enhancement as the low grade tumors do. (author)

  19. Gadolinium photoionization process

    Science.gov (United States)

    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.

  20. The isotope effect in gadolinium amalgam system

    International Nuclear Information System (INIS)

    Gadolinium is a neutron absorbing material and has been used as a burnable poison contained in the U fuel pellets for LWRs. Among the 7 isotopes of gadolinium, 157 Gd has a special large neutron absorption cross section of 254 000 barn (10 -24 cm2). In this paper gadolinium isotope separation factor for isotopic exchange between Gd 3+ (in solution) and gadolinium amalgam (GdHg) is determined. By electrolysis of aqueous solutions containing gadolinium acetate and lithium citrate, as complexing agent, using the ratio (Li +/Gd3+) = 12, gadolinium amalgam was prepared using a glass electrolyser with Hg as cathode and platinum as anode. The gadolinium amalgam was stirred with HCl solution 1-2N and Gd 3+ is precipitated as oxalate at weak acid pH and then converted to Gd2O3. The remained gadolinium in acetate solution (after electrolysis) was also precipitated as oxalate and converted to Gd2O3. On Gd2O3 samples the isotopic ratios 156 Gd/160 Gd were determined by mass spectrometry, using MAT 261 equipped with a thermal ionisation ion source. Between Gd3+ and Gadolinium amalgam there is an isotopic exchange, the heavy isotope 160 Gd was found to be enriched in Gd3+ while the lighter isotope, 156 Gd, was enriched in GdHg.. The single stage separation factor α (156 Gd/160 Gd) was determined in different experimental conditions: contact time between Gd3+ and GdHg, the yield of GdHg formation, current density. The range of the measured values of α was 1.0013 - 1.00456, average value being 1.0023 at 26 deg. C. The yield of GdHg formation has increased from 37-75.5% for the electrolyser of 40 mm i.d. (S = 12.56 cm2), to 89.6%, for electrolyser of 53 mm i.d. (S = 22 cm2).. After 30 minutes of contact (in electrolysis conditions) between Gd3+ and GdHg there is not an important passage of Gd between the two phases, in these conditions the isotopic exchange of Gd is studied. (authors)

  1. Gain of a 500-fold sensitivity on an intravital MR Contrast Agent based on an endohedral Gadolinium-Cluster-Fullerene-Conjugate: A new chance in cancer diagnostics

    OpenAIRE

    Braun, Klaus; Dunsch, Lothar; Pipkorn, Ruediger; Bock, Michael; Baeuerle, Tobias; Yang, Shangfeng; Waldeck, Waldemar; Wiessler, Manfred

    2010-01-01

    Among the applications of fullerene technology in health sciences the expanding field of magnetic resonance imaging (MRI) of molecular processes is most challenging. Here we present the synthesis and application of a GdxSc3-xN@C80-BioShuttle-conjugate referred to as Gd-cluster@-BioShuttle, which features high proton relaxation and, in comparison to the commonly used contrast agents, high signal enhancement at very low Gd concentrations. This modularly designed contrast agent represents a new ...

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

    International Nuclear Information System (INIS)

    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

  3. A Prototype for an Agent-based Secure Electronic Marketplace including Reputation Tracking Mechanisms

    OpenAIRE

    Padovan Boris; Sackmann Stefan; Eymann Thorsten; Pippow Ingo

    2002-01-01

    The future of electronic commerce will be shaped by open, heterogeneous and complex structures, consisting of networked marketplaces. Software agents will interact and negotiate on behalf of their human (or organizational) principals. Principals will be able to implement fraudulent strategies in their agents, which cannot be countered by technical security alone. In the absence of a single correctional institution, agents will have to rely on social mechanisms for assessing reliability and re...

  4. Gain of a 500-fold sensitivity on an intravital MR Contrast Agent based on an endohedral Gadolinium-Cluster-Fullerene-Conjugate: A new chance in cancer diagnostics

    Science.gov (United States)

    Braun, Klaus; Dunsch, Lothar; Pipkorn, Ruediger; Bock, Michael; Baeuerle, Tobias; Yang, Shangfeng; Waldeck, Waldemar; Wiessler, Manfred

    2010-01-01

    Among the applications of fullerene technology in health sciences the expanding field of magnetic resonance imaging (MRI) of molecular processes is most challenging. Here we present the synthesis and application of a GdxSc3-xN@C80-BioShuttle-conjugate referred to as Gd-cluster@-BioShuttle, which features high proton relaxation and, in comparison to the commonly used contrast agents, high signal enhancement at very low Gd concentrations. This modularly designed contrast agent represents a new tool for improved monitoring and evaluation of interventions at the gene transcription level. Also, a widespread monitoring to track individual cells is possible, as well as sensing of microenvironments. Furthermore, BioShuttle can also deliver constructs for transfection or active pharmaceutical ingredients, and scaffolding for incorporation with the host's body. Using the Gd-cluster@-BioShuttle as MRI contrast agent allows an improved evaluation of radio- or chemotherapy treated tissues. PMID:20567614

  5. Gain of a 500-fold sensitivity on an intravital MR Contrast Agent based on an endohedral Gadolinium-Cluster-Fullerene-Conjugate: A new chance in cancer diagnostics

    Directory of Open Access Journals (Sweden)

    Klaus Braun, Lothar Dunsch, Ruediger Pipkorn, Michael Bock, Tobias Baeuerle, Shangfeng Yang, Waldemar Waldeck, Manfred Wiessler

    2010-01-01

    Full Text Available Among the applications of fullerene technology in health sciences the expanding field of magnetic resonance imaging (MRI of molecular processes is most challenging. Here we present the synthesis and application of a GdxSc3-xN@C80-BioShuttle-conjugate referred to as Gd-cluster@-BioShuttle, which features high proton relaxation and, in comparison to the commonly used contrast agents, high signal enhancement at very low Gd concentrations. This modularly designed contrast agent represents a new tool for improved monitoring and evaluation of interventions at the gene transcription level. Also, a widespread monitoring to track individual cells is possible, as well as sensing of microenvironments. Furthermore, BioShuttle can also deliver constructs for transfection or active pharmaceutical ingredients, and scaffolding for incorporation with the host's body. Using the Gd-cluster@-BioShuttle as MRI contrast agent allows an improved evaluation of radio- or chemotherapy treated tissues.

  6. MR imaging of musculoskeletal tumors and tumor mimickers with intravenous gadolinium: experience with 242 patients

    International Nuclear Information System (INIS)

    Purpose. This pictorial essay reviews our experience with MR scans with gadolinium in patients with musculoskeletal tumors and tumor mimickers. Design. Review of 242 MR scans obtained in the initial evaluation of a possible primary musculoskeletal neoplasm. All scans included a T1-weighted, fat-suppressed sequence following intravenous administration of gadolinium. Results. MR scans with gadolinium did not contribute to differential diagnosis or patient management in 89% of the patients in this series. However, intravenous gadolinium did assist in guiding the biopsy of bulky lesions and evaluating treated tumor beds for possible recurrence. MR scans with gadolinium were sometimes helpful when the differential diagnosis included synovitis, Morton's neuroma or intramuscular myxoma, and when it was important to differentiate cystic from solid lesions. Conclusions. Routine use of gadolinium in every initial MR examination of a possible musculoskeletal mass is not warranted. However, there are appropriate selected indications for gadolinium administration as outlined above. (orig.). With 19 figs., 1 tab

  7. MR imaging of musculoskeletal tumors and tumor mimickers with intravenous gadolinium: experience with 242 patients

    Energy Technology Data Exchange (ETDEWEB)

    May, D.A. [Department of Radiology, Wilford Hall USAF Medical Center, San Antonio, TX (United States)]|[WHMC/PSRD, Lackland AFB, TX (United States); Good, R.B. [Department of Radiology, Wilford Hall USAF Medical Center, San Antonio, TX (United States); Smith, D.K. [Department of Radiology, Wilford Hall USAF Medical Center, San Antonio, TX (United States); Parsons, T.W. [Department of Orthopaedic Surgery, Wilford Hall USAF Medical Center, San Antonio, TX (United States)

    1997-01-01

    Purpose. This pictorial essay reviews our experience with MR scans with gadolinium in patients with musculoskeletal tumors and tumor mimickers. Design. Review of 242 MR scans obtained in the initial evaluation of a possible primary musculoskeletal neoplasm. All scans included a T1-weighted, fat-suppressed sequence following intravenous administration of gadolinium. Results. MR scans with gadolinium did not contribute to differential diagnosis or patient management in 89% of the patients in this series. However, intravenous gadolinium did assist in guiding the biopsy of bulky lesions and evaluating treated tumor beds for possible recurrence. MR scans with gadolinium were sometimes helpful when the differential diagnosis included synovitis, Morton`s neuroma or intramuscular myxoma, and when it was important to differentiate cystic from solid lesions. Conclusions. Routine use of gadolinium in every initial MR examination of a possible musculoskeletal mass is not warranted. However, there are appropriate selected indications for gadolinium administration as outlined above. (orig.). With 19 figs., 1 tab.

  8. Novel sorbents for removal of gadolinium-based contrast agents in sorbent dialysis and hemoperfusion: preventive approaches to nephrogenic systemic fibrosis

    Energy Technology Data Exchange (ETDEWEB)

    Yantasee, Wassana; Fryxell, Glen E.; Porter, George A.; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Chouyyok, Wilaiwan; Koonsiripaiboon, View; Xu, Jide; Raymond, Kenneth N.

    2010-02-01

    Gd based contrast agents in many forms of organocomplex have recently been linked to a debilitating and a potentially fatal skin disease called Nephrogenic Systemic Fibrosis (NSF) in patients with renal failures. Free Gd released from the complexes by transmetallation is believed to be the most important trigger for NSF. Removal of Gd complex from the patients immediately after the contrast study would prevent the dissociation of Gd and should eliminate NSF as a complication. Although removal of Gd based contrast agents may be accomplished with conventional hemodialysis, it requires three hemodialysis sessions at 3 hours each to remove 98% of the contrast agents. In this work, mesoporous silica material that are functionalized with 1-hydroxy-2-pyridinone (1,2-HOPO-SAMMS®) has been evaluated for effective removal of both free and chelated Gd (Magnevist, a brand of gadopentetate dimeglumine) from the dialysate and sodium chloride solution. The material has high affinity, rapid removal rate, and large sorption capacity for both free and chelated Gd, the properties that are far superior to those of activated carbon and zirconium phosphate currently used in the state-of-the-art sorbent dialysis systems. 99% of both free and chelated Gd would be removed in a single pass thru the sorbent bed of 1,2-HOPO-SAMMS®. The sorbent provides an effective and predicable strategy for removing Gd from patients with impaired renal function, thus it would allow for the continued use of contrast MRI while removing the risk of NSF and would represent a safe alternative to traditional contrast studies in the patient population.

  9. Gadolinium(III) complexes of mono- and diethyl esters of monophosphonic acid analogue of DOTA as potential MRI contrast agents: solution structures and relaxometric studies

    OpenAIRE

    Lebduskova, Petra; Hermann, Petr; Helm, Lothar; Toth, Eva; Kotek, Jan; Binnemans, Koen; Rudovsky, Jakub; Lukes, Ivan; Merbach, Andre E

    2007-01-01

    Two new macrocyclic DOTA-like chelates containing one phosphonate pendant arm were synthesised as potential contrast agents for MRI ( magnetic resonance imaging). The chelates bind to the lanthanide(III) in an octadentate manner, via four nitrogen atoms, three carboxylate and one phosphonate oxygen atoms. Solution structures of [Ln(do3apO(Et2))(H2O)] and [Ln(do3ap(OEt))(H2O)](-) were studied using P-31 and H-1 NMR spectroscopy and SAP (square-antiprismatic)/TSAP ( twisted square-antiprismatic...

  10. Application of extracellular gadolinium-based MRI contrast agents and the risk of nephrogenic systemic fibrosis; Anwendung von extrazellulaeren gadoliniumhaltigen MR-Kontrastmitteln und Risiko der Nephrogenen Systemischen Fibrose

    Energy Technology Data Exchange (ETDEWEB)

    Heverhagen, J.T. [Univ. Hospital Bern (Switzerland). Inst. of Diagnostic, Interventional and Pediatric Radiology, Inselspital; Krombach, G.A. [Justus Liebig Univ. Hopsital Giessen (Germany). Diagnostic and Interventional Radiology; Gizewski, E. [Medical Univ. Innsbruck (Austria). Dept. of Neuroradiology

    2014-07-15

    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.

  11. On the Use of Molecular Weight Cutoff Cassettes to Measure Dynamic Relaxivity of Novel Gadolinium Contrast Agents: Example Using Hyaluronic Acid Polymer Complexes in Phosphate-Buffered Saline

    Directory of Open Access Journals (Sweden)

    Nima Kasraie

    2011-01-01

    Full Text Available The aims of this study were to determine whether standard extracellular contrast agents of Gd(III ions in combination with a polymeric entity susceptible to hydrolytic degradation over a finite period of time, such as Hyaluronic Acid (HA, have sufficient vascular residence time to obtain comparable vascular imaging to current conventional compounds and to obtain sufficient data to show proof of concept that HA with Gd-DTPA ligands could be useful as vascular imaging agents. We assessed the dynamic relaxivity of the HA bound DTPA compounds using a custom-made phantom, as well as relaxation rates at 10.72 MHz with concentrations ranging between 0.09 and 7.96 mM in phosphate-buffered saline. Linear dependences of static longitudinal relaxation rate (R1 on concentration were found for most measured samples, and the HA samples continued to produce high signal strength after 24 hours after injection into a dialysis cassette at 3T, showing superior dynamic relaxivity values compared to conventional contrast media such as Gd-DTPA-BMA.

  12. On the Use of Molecular Weight Cutoff Cassettes to Measure Dynamic Relaxivity of Novel Gadolinium Contrast Agents: Example Using Hyaluronic Acid Polymer Complexes in Phosphate-Buffered Saline

    International Nuclear Information System (INIS)

    The aims of this study were to determine whether standard extracellular contrast agents of Gd(III) ions in combination with a polymeric entity susceptible to hydrolytic degradation over a finite period of time, such as Hyaluronic Acid (HA), have sufficient vascular residence time to obtain comparable vascular imaging to current conventional compounds and to obtain sufficient data to show proof of concept that HA with Gd-DTPA ligands could be useful as vascular imaging agents. We assessed the dynamic relaxivity of the HA bound DTPA compounds using a custom-made phantom, as well as relaxation rates at 10.72 MHz with concentrations ranging between 0.09 and 7.96 mM in phosphate-buffered saline. Linear dependences of static longitudinal relaxation rate (R1) on concentration were found for most measured samples, and the HA samples continued to produce high signal strength after 24 hours after injection into a dialysis cassette at 3T, showing superior dynamic relaxivity values compared to conventional contrast media such as Gd-DTPA-BMA

  13. The effect of demagnetization on the magnetocaloric properties of gadolinium

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Nielsen, Kaspar Kirstein

    2009-01-01

    Gadolinium displays a strong magnetocaloric effect at temperatures close to room temperature making it useful in the field of room temperature magnetic refrigeration. We discuss the importance of including the effects of the demagnetization field when considering the magnetocaloric properties of...... gadolinium. The adiabatic temperature change DeltaTad of gadolinium sheets upon application of a magnetic field has been measured at a range of applied magnetic fields and sample orientations. A significant dependence of DeltaTad on the sample orientation is observed. This can be accounted for by the...

  14. 21 CFR 700.13 - Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic...

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Use of mercury compounds in cosmetics including...) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.13 Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic preparations also regarded as drugs. (a)...

  15. Thin film growth of epitaxial gadolinium oxide, gadolinium yttrium oxide, and gadolinium cerium oxide by electrodeposition

    International Nuclear Information System (INIS)

    Thin films of gadolinium oxide, gadolinium yttrium oxide, and gadolinium cerium oxide were electrodeposited from non-aqueous baths. The films were on the order of 15 nm thick, and were grown epitaxially on textured nickel-tungsten substrates. The effect of deposition rate, annealing temperature and secondary metals on crystallinity and crystal orientation was investigated by X-ray diffraction and transmission electron microscopy. Slower rates, higher temperatures and low concentrations of yttrium improve the crystallinity of gadolinium oxide films, whereas the introduction of cerium induced polycrystallinity.

  16. Thin film growth of epitaxial gadolinium oxide, gadolinium yttrium oxide, and gadolinium cerium oxide by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Jonathan R., E-mail: jonathan.mann@nrel.gov; Bhattacharya, Raghu N.

    2010-10-29

    Thin films of gadolinium oxide, gadolinium yttrium oxide, and gadolinium cerium oxide were electrodeposited from non-aqueous baths. The films were on the order of 15 nm thick, and were grown epitaxially on textured nickel-tungsten substrates. The effect of deposition rate, annealing temperature and secondary metals on crystallinity and crystal orientation was investigated by X-ray diffraction and transmission electron microscopy. Slower rates, higher temperatures and low concentrations of yttrium improve the crystallinity of gadolinium oxide films, whereas the introduction of cerium induced polycrystallinity.

  17. Gadolinium depletion event in a CANDU® moderator - causes and recovery

    International Nuclear Information System (INIS)

    Gadolinium nitrate is added to the moderator of CANDU units to maintain the reactor in a guaranteed shutdown state (GSS). In April 2008, after being in stable GSS for over 30 hours, one of Ontario Power Generation's Pickering-B units showed a gradual depletion of the dissolved gadolinium, despite purification being isolated. Further additions of gadolinium stabilized the moderator gadolinium concentration, however, since the root cause of the depletion was not immediately identified, the unit was placed in the drained shutdown state, per established procedures. The cumulative gadolinium depletion amounted to about 3200 grams, the equivalent of about 12 ppm. Analysis showed the presence of oxalate in the moderator water. It is well-known that gadolinium forms a very insoluble oxalate (log Ksp = -29.1). Although sub-micron filtration of water samples did not show the presence of gadolinium particulate, the measured levels of oxalate, 1.2 to 2 ppm, were sufficient to react with 1.4 to 2.4 ppm of gadolinium. The source of oxalate was traced to radiolysis of dissolved CO2 species. This unit had been experiencing chronic low-level ingress of CO2 from the Annulus Gas System. Free oxalate ion is normally susceptible to radiolytic breakdown back to CO2, but Gd3+ provides a stable sink for radiogenic oxalate, 2 Gd3+ + 3 C2O42- → Gd2(C2O4)3. Subsequent testing confirmed that gadolinium oxalate is quite stable with respect to gamma irradiation. Inspections showed well-crystallized gadolinium oxalate deposited on moderator system surfaces. Estimates indicated that about 1200 grams of gadolinium could have deposited on in-core surfaces, including the outside of the calandria tubes. That amount of negative reactivity was a concern, since it would prevent re-start of the unit. OPG, with support from AECL-Chalk River and Kinectrics, embarked on a two-pronged chemistry recovery program aimed at 1) developing solvents for dissolution of the gadolinium oxalate deposits and 2

  18. Gadolinium and nephrogenic systemic fibrosis: time to tighten practice

    Energy Technology Data Exchange (ETDEWEB)

    Mendichovszky, Iosif A. [University College London, Radiology and Physics Unit, Institute of Child Health, London (United Kingdom); Marks, Stephen D. [Great Ormond Street Hospital for Children NHS Trust, Department of Paediatric Nephrology, London (United Kingdom); Simcock, Clare M.; Olsen, Oeystein E. [Great Ormond Street Hospital for Children NHS Trust, Department of Radiology, London (United Kingdom)

    2008-05-15

    Nephrogenic systemic fibrosis (NSF) is a relatively new entity, first described in 1997. Few cases have been reported, but the disease has high morbidity and mortality. To date it has been seen exclusively in patients with renal dysfunction. There is an emerging link with intravenous injection of gadolinium contrast agents, which has been suggested as a main triggering factor, with a lag time of days to weeks. Risk factors include the severity of renal impairment, major surgery, vascular events and other proinflammatory conditions. There is no reason to believe that children have an altered risk compared to the adult population. It is important that the paediatric radiologist acknowledges emerging information on NSF but at the same time considers the risk:benefit ratio prior to embarking on alternative investigations, as children with chronic kidney disease require high-quality diagnostic imaging. (orig.)

  19. Radiative lifetimes of neutral gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Den Hartog, E A; Bilty, K A; Lawler, J E, E-mail: eadenhar@wisc.edu, E-mail: biltyka@uwec.edu, E-mail: jelawler@wisc.edu [Department of Physics, University of Wisconsin, 1150 University Ave, Madison, WI 53706 (United States)

    2011-03-14

    The current work is part of an ongoing study of radiative properties of rare earth neutral atoms motivated by research needs in several disparate fields including astrophysics, laser chemistry and lighting technology. Time-resolved laser-induced fluorescence on a slow atomic beam has been used to measure radiative lifetimes, accurate to {+-}5%, for 136 levels of neutral gadolinium. Of the 136 levels, 6 are odd parity ranging in energy from 32 929 to 36 654 cm{sup -1}, and the remaining 130 are even parity ranging from 17 750 to 34 175 cm{sup -1}. This set of Gd i lifetimes represents a significant extension to the available published data, with 93 of the 136 level lifetimes measured for the first time. These lifetimes will provide the absolute normalization for a large set of measured Gd i transition probabilities.

  20. Radiative lifetimes of neutral gadolinium

    International Nuclear Information System (INIS)

    The current work is part of an ongoing study of radiative properties of rare earth neutral atoms motivated by research needs in several disparate fields including astrophysics, laser chemistry and lighting technology. Time-resolved laser-induced fluorescence on a slow atomic beam has been used to measure radiative lifetimes, accurate to ±5%, for 136 levels of neutral gadolinium. Of the 136 levels, 6 are odd parity ranging in energy from 32 929 to 36 654 cm-1, and the remaining 130 are even parity ranging from 17 750 to 34 175 cm-1. This set of Gd i lifetimes represents a significant extension to the available published data, with 93 of the 136 level lifetimes measured for the first time. These lifetimes will provide the absolute normalization for a large set of measured Gd i transition probabilities.

  1. Gadolinium DOTA lysine salt and its diagnostic uses

    International Nuclear Information System (INIS)

    The object of this invention is the lysine salt of the complex of gadolinium III of DOTA 1, 4, 7, 10-tetraazacyclododecane-N, N', N'', N'''-tetraacetic acid. This salt having a low toxicity can be used as a contrast agent for magnetic resonance imaging and for X-ray radiography

  2. Nephrogenic systemic fibrosis and gadolinium-based contrast media

    DEFF Research Database (Denmark)

    Thomsen, Henrik S; Morcos, Sameh K; Almén, Torsten;

    2012-01-01

    PURPOSE: 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. AREAS COVERED: 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. KEY POINTS : • Clinical features, risk factors and prevention of nephrogenic systemic fibrosis are reviewed • Patients with GFR below 30 ml/min/1.73 m ( 2 ) have increased risk of developing NSF • Low stability gadolinium contrast media show the strongest association with NSF • Following...

  3. MR imaging with metal artifact-reducing sequences and gadolinium contrast agent in a case-control study of periprosthetic abnormalities in patients with metal-on-metal hip prostheses

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Gunilla M.; Mueller, Markus F.; Ekberg, Olle [Lund University, Skaane University Hospital, Department of Radiology, Malmoe (Sweden); Maansson, Sven [Lund University, Skaane University Hospital, Department of Medical Radiation Physics, Malmoe (Sweden); Schewelov, Thord von [Lund University, Skaane University Hospital, Department of Orthopedic Surgery, Malmoe (Sweden); Nittka, Mathias [Siemens AG, Healthcare Sector, Erlangen (Germany); Lundin, Bjoern [Lund University, Skaane University Hospital, Department of Radiology, Lund (Sweden)

    2014-08-15

    To apply and compare magnetic resonance imaging (MRI) metal artifact reducing sequences (MARS) including subtraction imaging after contrast application in patients with metal-on-metal (MoM) hip prostheses, investigate the prevalence and characteristics of periprosthetic abnormalities, as well as their relation with pain and risk factors. Fifty-two MoM prostheses (35 cases with pain and or risk factors, and 17 controls) in 47 patients were examined in a 1.5-T MR scanner using MARS: turbo spin echo (TSE) with high readout bandwidth with and without view angle tilting (VAT), TSE with VAT and slice encoding for metal artifact correction (SEMAC), short tau inversion recovery (STIR) with matched RF pulses, and post-contrast imaging. The relations of MRI findings to pain and risk factors were analyzed and in five revised hips findings from operation, histology, and MRI were compared. TSE VAT detected the highest number of osteolyses. Soft tissue mass, effusion, and capsular thickening were common, whereas osteolysis in acetabulum and femur were less frequent. Contrast enhancement occurred in bone, synovia, joint capsule, and the periphery of soft tissue mass. There was no significant relation between MRI findings and pain or risk factors. MARS and gadolinium subtraction imaging are useful for evaluation of complications to MoM prosthesis. TSE VAT had the highest sensitivity for osteolysis. Contrast enhancement might indicate activation of aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL). Pain, small head, or steep prosthesis inclination angle are not useful predictors of periprosthetic abnormalities, and wide indications for MR follow-up are warranted. (orig.)

  4. Studies of MRI relaxivities of gadolinium-labeled dendrons

    Science.gov (United States)

    Pan, Hongmu; Daniel, Marie-Christine

    2011-05-01

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

  5. Gadolinium-based nanoparticles for theranostic MRI-radiosensitization

    OpenAIRE

    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 t...

  6. Gadolinium study for a water Cherenkov detector

    CERN Document Server

    Kibayashi, Atsuko

    2009-01-01

    Modification of large water Cherenkov detectors by addition of gadolinium has been proposed. The large cross section for neutron capture on Gd will greatly improve the sensitivity to antielectron neutrinos from supernovae and reactors. A five-year project to build and develop a prototype detector based on Super-Kamiokande (SK) has started. We are performing various studies, including a material soak test in Gd solution, light attenuation length measurements, purification system development, and neutron tagging efficiency measurements using SK data and a Geant4-based simulation. We present an overview of the project and the recent R&D results.

  7. Laser isotope separation of gadolinium

    International Nuclear Information System (INIS)

    Basic studies on laser isotope separation of gadolinium were performed. Spectroscopic data were obtained such as isotope shifts and hyperfine structures using an atomic beam. Enrichment of 157Gd up to 80% was observed by three-step photoionization experiment using linearly polarized dye lasers. Design of an separation system was discussed by the help of computer calculation of excitation dynamics. (author)

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

    Science.gov (United States)

    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

  9. Nuclear-grade gadolinium oxide (Gd2O3) powder

    International Nuclear Information System (INIS)

    The specification covers the minimum chemical and physical characteristics of nuclear-grade gadolinium oxide powder intended for subsequent processing for use in nuclear fuel application, for example, as an addition to uranium dioxide. The specification includes a description of chemical and physical requirements, cleanliness, quality control, inspection, certification, rejection, packaging, and shipping

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

    International Nuclear Information System (INIS)

    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

  11. Discovery of Samarium, Europium, Gadolinium, and Terbium Isotopes

    OpenAIRE

    May, E.; Thoennessen, M

    2012-01-01

    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 discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  12. Serial MRI studies using gadolinium DTPA in active multiple sclerosis

    International Nuclear Information System (INIS)

    It has been suggested that blood brain barrier (BBB) impairment is a necessary early event in the pathogenesis of the multiple sclerosis (MS) lesions. To evaluate such an hypothesis in vivo would require: (1) serial imaging studies using a modality with high sensitivity for detecting plaques; (2) a contrast enhancing agent which demonstrates BBB impairment. A serial magnetic resonance imaging (MRI) study was undertaken of a group of MS patients using the contrast agent gadolinium-DTPA. As it has been suggested that T1 and T2 relaxation times are longer in acute than chronic MS lesions, these were also measured. 3 refs.; 1 figure

  13. Radiotracer gadolinium pre-concentration and detection

    International Nuclear Information System (INIS)

    Radiotracer 153Gd is a low-energy γ-emitter with 8-months half-life, is used as line sources and in calibration phantoms, to ensure that nuclear medicine imaging systems operate correctly and produce useful images of radioisotope distribution inside the patient. The used radiotracer gadolinium is generally disposed as laboratory effluent in different testing experiments. Hence, this toxic radiotracer gadolinium is required to be eliminated from these effluents before disposal to nature. In this paper performance of a 'radiotracer gadolinium selective pre-concentrator' viz, polyacrylamide hydroxamate (PHOA) chelator has been studied for removal and recovery of gadolinium

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

    Science.gov (United States)

    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

  15. Structural and Chemical Analysis of Gadolinium Halides Encapsulated within WS 2 Nanotubes

    KAUST Repository

    Anumol, E A

    2016-05-18

    The hollow cavities of nanotubes could 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 inorganic nanotubes of WS2 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 a non-trivial matter 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.

  16. Gadolinium-containing contrast media for radiographic examinations: a position paper

    International Nuclear Information System (INIS)

    Recently, it has been suggested that gadolinium-based contrast media could be used for radiological examinations in patients with significant renal impairment, previous severe generalized reaction to iodinated contrast media or thyroid disease about to undergo radioactive iodine treatment; however, the indications for and risks of using gadolinium agents in this way are not well known; hence, the Contrast Media Safety Committee of The European Society of Urogenital Radiology reviewed the literature to issue a position paper on this subject. A comprehensive literature review was performed and the resulting report was discussed at the Ninth European Symposium on Urogenital Radiology in Genoa, Italy, June 2002. Review of the literature indicates that according to experimental data on animals gadolinium-based contrast media have more nephrotoxic potential than iodinated contrast media in equivalent X-ray attenuating doses; therefore, gadolinium-based contrast media should not replace iodinated contrast media in patients with renal insufficiency for radiographic examinations. For patients with previous severe generalized reactions to iodinated contrast media, and in patients about to undergo thyroid treatment with radioactive iodine gadolinium-based contrast media in approved intravenous doses, up to 0.3 mmol/kg body weight will not give diagnostic radiographic information in most cases. Gadolinium-based contrast media are not approved for radiographic examinations. (orig.)

  17. Gadolinium-containing contrast media for radiographic examinations: a position paper

    Energy Technology Data Exchange (ETDEWEB)

    Thomsen, Henrik S. [Department of Diagnostic Radiology 54E2, Copenhagen University Hospital at Herlev, Herlev Ringvej 75, 2730 Herlev (Denmark); Almen, Torsten [Lybska vaegen 10, 23940 Falsterbo (Sweden); Morcos, Sameh K. [Department of Diagnostic Imaging, Northern General Hospital, Sheffield Teaching Hospitals NHS Trust, Sheffield S5 7AU (United Kingdom); 4

    2002-10-01

    Recently, it has been suggested that gadolinium-based contrast media could be used for radiological examinations in patients with significant renal impairment, previous severe generalized reaction to iodinated contrast media or thyroid disease about to undergo radioactive iodine treatment; however, the indications for and risks of using gadolinium agents in this way are not well known; hence, the Contrast Media Safety Committee of The European Society of Urogenital Radiology reviewed the literature to issue a position paper on this subject. A comprehensive literature review was performed and the resulting report was discussed at the Ninth European Symposium on Urogenital Radiology in Genoa, Italy, June 2002. Review of the literature indicates that according to experimental data on animals gadolinium-based contrast media have more nephrotoxic potential than iodinated contrast media in equivalent X-ray attenuating doses; therefore, gadolinium-based contrast media should not replace iodinated contrast media in patients with renal insufficiency for radiographic examinations. For patients with previous severe generalized reactions to iodinated contrast media, and in patients about to undergo thyroid treatment with radioactive iodine gadolinium-based contrast media in approved intravenous doses, up to 0.3 mmol/kg body weight will not give diagnostic radiographic information in most cases. Gadolinium-based contrast media are not approved for radiographic examinations. (orig.)

  18. Standard specification for sintered gadolinium oxide-uranium dioxide pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This specification is for finished sintered gadolinium oxide-uranium dioxide pellets for use in light-water reactors. It applies to gadolinium oxide-uranium dioxide pellets containing uranium of any 235U concentration and any concentration of gadolinium oxide. 1.2 This specification recognizes the presence of reprocessed uranium in the fuel cycle and consequently defines isotopic limits for gadolinium oxide-uranium dioxide pellets made from commercial grade UO2. Such commercial grade UO2 is defined so that, regarding fuel design and manufacture, the product is essentially equivalent to that made from unirradiated uranium. UO2 falling outside these limits cannot necessarily be regarded as equivalent and may thus need special provisions at the fuel fabrication plant or in the fuel design. 1.3 This specification does not include (1) provisions for preventing criticality accidents or (2) requirements for health and safety. Observance of this specification does not relieve the user of the obligation to be aw...

  19. Analysis of boron, samarium and gadolinium in rock samples by neutron capture gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Prompt gamma neutron activation analysis (PGNAA) is useful for determining many of the elements found in sedimentary rocks. It is particularly suitable for the trace elements boron, samarium and gadolinium. The sensitivity of detection can be of the order of 0.1 ppm with an adequate neutron source. Twenty-five sedimentary rock samples were analyzed in the PGNAA facility at the University of Missouri Research Reactor. The materials included Ottawa sand, Berea sandstone, Royer dolomite and several other formations of interest in the petroleum industry. Results of the analyses are presented. Correlations of gadolinium and samarium and of boron with the sum of samarium and gadolinium are given. (author)

  20. Gadolinium atom on neutron capture therapy

    International Nuclear Information System (INIS)

    This report describes our measurements of gadolinium concentrations in several brain tumors obtained from fresh surgical specimens, as compared with corresponding concentrations in the blood. Moreover we tried to find out if the gadolinium concentration is high enough to use this compound in the treatment of brain tumors by neutron capture therapy. (J.P.N.)

  1. Consecutive acquisition of time-resolved contrast-enhanced MR angiography and perfusion MR imaging with added dose of gadolinium-based contrast agent Aids diagnosis of suspected brain metastasis

    International Nuclear Information System (INIS)

    Time-resolved contrast-enhanced magnetic resonance (MR) angiography (TCMRA) and perfusion MR imaging (PWI) have been used to assess the hemodynamics of brain tumors. We assessed the feasibility and value of consecutive performance of these techniques to evaluate suspected brain metastasis following supplementary injection of gadolinium-based contrast medium. In 69 patients with suspected brain metastasis, we obtained precontrast MR images followed by TCMRA and postcontrast T1-weighted images after administration of 0.1 mmol/kg gadoteridol. When findings were negative or equivocal, we injected an additional 0.1-mmol/kg dose of gadoteridol and obtained PWI and second postcontrast T1-weighted images. We used a 3-point scale to grade perfusion maps and TCMRA and assessed whether these techniques added information to conventional MR imaging in the differential diagnosis. We also evaluated whether the second contrast injection improved the conspicuity and/or number of enhancing lesions and used a 4-point scoring system to quantitatively analyze diagnostic yield of TCMRA and PWI. We could assess tumor hemodynamics on PWI maps and TCMRA images in all 69 patients. In 14 cases (20%), PWI and/or TCMRA added information to conventional MR findings. After second injection of contrast medium, lesion conspicuity improved in 58 of the 69 cases (84%), and the number of detected lesions increased in 11 of 31 cases diagnosed with metastatic disease (36%). Quantitative analysis revealed TCMRA and PWI provided significant additional diagnostic information (Kruskal-Wallis test, P<0.0001). Consecutive acquisition of TCMRA and PWI using supplementary contrast injection can facilitate differential diagnosis of suspected brain metastasis and improve the number and conspicuity of detected lesions. (author)

  2. Removal of gadolinium nitrate from heavy water

    Energy Technology Data Exchange (ETDEWEB)

    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).

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

    Science.gov (United States)

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

    2016-06-01

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

  4. Production and characterization of quality gadolinium oxide nanoparticles

    International Nuclear Information System (INIS)

    Rare earth system Gadolinium (Gd), in either pure form or oxide form, is highly stable against environmental attack. It has immense potential as a contrast agent in magnetic resonance imaging (MRI) devices. Being mechanically and thermally stable it is always difficult to obtain Gd2O3 nanopowders directly from its bulk counterpart using conventional top-down approach. Recently, we have reported production of Gd2O3 nanopowders by first converting bulk Gd2O3 into a nitrate compound and subsequently reduced into a hydroxide product and finally to the oxide product (nanopowder form)

  5. Dermal inorganic gadolinium concentrations: evidence for in vivo transmetallation and long-term persistence in nephrogenic systemic fibrosis

    DEFF Research Database (Denmark)

    Abraham, J.L.; Thakral, C.; Skov, L.;

    2008-01-01

    Background Gadolinium (Gd)-based magnetic resonance contrast agents (GBMCA), including gadodiamide, have been identified as the probable causative agents of the serious disease, nephrogenic systemic fibrosis (NSF). Objectives To investigate retained Gd-containing deposits in skin biopsies from...... patients with NSF and to determine their relative concentrations over time from administration of GBMCA. Methods An investigator-blinded retrospective study, analysing 43 skin biopsies from 20 patients with gadodiamide-related NSF and one NSF-negative gadodiamide-exposed dialysis patient, ranging from 16...... days to 1991 days after Gd contrast dose. Utilizing automated quantitative scanning electron microscopy/energy-dispersive X-ray spectroscopy we determined the concentration of Gd and associated elements present as insoluble deposits in situ in the tissues. Results We detected Gd in skin lesions of all...

  6. Synergistic extraction of gadolinium from nitrate media by mixtures of bis (2,4,4-trimethylpentyl) dithiophosphinic acid and di-(2-ethylhexyl) phosphoric acid

    International Nuclear Information System (INIS)

    Highlights: • The effect of operating parameters on the gadolinium extraction was investigated. • The mixture of extractants had the synergistic effects on the gadolinium extraction. • Mixture system obtained better stripping in comparison with D2EHPA system. - Abstract: The extraction of gadolinium (III) from aqueous nitrate solution with bis (2,4,4-trimethylpentyl) dithiophosphinic acid (Cyanex301), di-(2-ethylhexyl) phosphoric acid (D2EHPA) and the mixtures of extractants was investigated. Various parameters affecting the extraction process including the pH of aqueous phase, nitrate ion, extractant concentration, temperature, and stripping agents were studied. The stoichiometric coefficients of reactive extraction, thermodynamic and equilibrium parameters were obtained for two extractants and their mixtures. The results showed that the extraction ability of Cyanex301 was lower than that of D2EHPA extractant. As a result, the extraction of Gd3+ at low concentration of Cyanex301 was investigated by the addition of D2EHPA to the extraction system. The reactive extraction in the mixture system was spontaneous in nature as referred to the negative sign of ΔG while it was not favorable in case of single Cyanex301 system as indicated by the positive sign of ΔG. The experimental results showed that the mixture of extractants provided better extraction efficiency and effective stripping performance in comparison with single D2EHPA or Cyanex301 system

  7. Gadolinium and fluorescent bi-functionally labeling and in vitro MRI of rat bone marrow mesenchymal stem cells

    International Nuclear Information System (INIS)

    Objective: To determine the feasibility of magnetically labeling and tracking mesenchymal stem cells (MSCs) in vitro by using a gadolinium and fluorescent bi-functionally transfection agent of polyethylenimine. Methods: A gadolinium bifunctional transfection reagent complex was obtained after the linear polyethylenimine derivative (JetPEI-FluoR) was incubated with Gd-DTPA. Mesenchymal stem cells isolated from the bone marrows of SD rats were cultured and expanded. The mesenchymal stem cells were incubated with the bi-functional labeling agents. After labeling, the MSCs were examined with fluoroscope and electron microscope and the biological characters were detected including trypan blue exclusion test, MTT, and apoptosis detection. On a 1.5 T MR system, the labeled MSCs were examined with spin echo T1WI and T2WI and T1 measurement with mixed sequence. After labeling, the cells were cultured and undergone routine passage. Prior MR examinations were repeated for each passage of labeled cells. All data was statistically prolessed with SPSS for Windows. Results: Of 5 x 105 MSCs incubated with the bi-functional agents, 4.25 x 105 MSCs were successfully labeled, the percentage of labeled MSCs was 85% fluoroscopically. The high density electron particles of gadolinium observed electron microscopically existed around cellular apparatuses, especially around Golgi apparatus. In trypan blue exclusion test, the exclusion rate of labeled MSCs with incubation duration of 3,6,12,24 h was (96.55±2.90)%, (94.17± 2.56)%, (97.16±3.12)% and (94.23±2.67)%, respectively. The corresponding exclusion rate of unlabeled MSCs was (95.86±2.67)%, (92.04±2.21)%, (93.38±3.64)% and (92.12±2.53)%, respectively. There was no statistical difference of trypan blue exclusion rate between labeled cells and control unlabeled cells within 24 hours of incubation (F=4.523, P>0.05). In the proliferation test, the optical absorption value of labeled MSC with 2.5, 5.0, 10.0, 20.0, 30.0 and 40.0

  8. New MR contrast agents in the diagnosis of liver lesions. Clinical experiene with the hepatitis biliary Eovist (Gadolinium-EOB-DTPA) and the RES-specific Resovist (SH U 555 A)

    International Nuclear Information System (INIS)

    The purpose of this work is to describe our initial clinical experience (in 66 patients) with Reovist and Eovist, two new liverspecific MR contrast agents. We focus our report on safety aspects, dose finding, and optimization of technical parameters. Both contrast agents were well tolerated and improved the detectability of focal liver lesions. With Resovist, postcontrast MRI may be started as early as 10 min following injection. The dose of 8 μmol Fe/kg bodyweight was sufficient to achieve diagnostic tumor-liver contrast levels. Since Eovist can also be administered as a bolus, dynamic enhancement patterns may be studied for tumor characterization as well. Breath-hold T1-weighted FLASH images were superior to other T1-weighted techniques with and without fat saturation. (orig.)

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

    Science.gov (United States)

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

    2005-06-01

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

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

    International Nuclear Information System (INIS)

    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. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Judith A.W. [St. Bartholomew' s Hospital, Department of Diagnostic Imaging, London (United Kingdom); Thomsen, Henrik S. [Copenhagen University Hospital at Herlev, Department of Diagnostic Radiology 54E2, Herlev (Denmark); Morcos, Sameh K. [Northern General Hospital, Department of Diagnostic Imaging, Sheffield (United Kingdom)

    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. (orig.)

  12. Actual clinical use of gadolinium-chelates for non-MRI applications

    International Nuclear Information System (INIS)

    For many years, alternatives to iodinated X-ray contrast media have been sought. Of the contrast media investigated to date, only CO2 and the gadolinium-chelates have been shown to be viable alternatives for selected X-ray examinations. Therefore, we have reviewed the general literature and that specific for gadopentetate (Magnevist) in particular, since this agent has been studied the most. This review indicates that diagnostic CT examinations can be achieved following the intravenous administration of gadolinium-containing contrast media (CM) for evaluation of aortic abnormalities. Gadolinium-containing CM at the dose approved for MR imaging are not useful for CT evaluation of the abdominal parenchymal organs. Intravenous/intraarterial injections have also been used in a variety of angiographic and interventional procedures. Image quality, however, is generally inferior to iodinated contrast media. Gadolinium-containing CM require no special handling and can be administered by hand injection or via conventional angiographic automated injectors with the same flow rates and pressures as are used with iodinated contrast media. For CT, a peripheral bolus injection of a diluted gadolinium agent (1:1 with saline) of 60-90 ml at 3-5 ml/s is usually performed. Similar to all other gadolinium-chelates, the non-MRI use of gadopentetate (Magnevist) is not approved by regulatory agencies. However, the literature suggests that a dose of 0.3-0.4 mmol/kg b.w. has been safely administered for CT as well as for angiography and interventional procedures intravenously and intraarterially. Even at this dose, though, this results in a relatively small overall volume to be injected, which limits utility somewhat. (orig.)

  13. Actual clinical use of gadolinium-chelates for non-MRI applications

    Energy Technology Data Exchange (ETDEWEB)

    Strunk, Holger M.; Schild, H. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, 53105, Bonn (Germany)

    2004-06-01

    For many years, alternatives to iodinated X-ray contrast media have been sought. Of the contrast media investigated to date, only CO{sub 2} and the gadolinium-chelates have been shown to be viable alternatives for selected X-ray examinations. Therefore, we have reviewed the general literature and that specific for gadopentetate (Magnevist) in particular, since this agent has been studied the most. This review indicates that diagnostic CT examinations can be achieved following the intravenous administration of gadolinium-containing contrast media (CM) for evaluation of aortic abnormalities. Gadolinium-containing CM at the dose approved for MR imaging are not useful for CT evaluation of the abdominal parenchymal organs. Intravenous/intraarterial injections have also been used in a variety of angiographic and interventional procedures. Image quality, however, is generally inferior to iodinated contrast media. Gadolinium-containing CM require no special handling and can be administered by hand injection or via conventional angiographic automated injectors with the same flow rates and pressures as are used with iodinated contrast media. For CT, a peripheral bolus injection of a diluted gadolinium agent (1:1 with saline) of 60-90 ml at 3-5 ml/s is usually performed. Similar to all other gadolinium-chelates, the non-MRI use of gadopentetate (Magnevist) is not approved by regulatory agencies. However, the literature suggests that a dose of 0.3-0.4 mmol/kg b.w. has been safely administered for CT as well as for angiography and interventional procedures intravenously and intraarterially. Even at this dose, though, this results in a relatively small overall volume to be injected, which limits utility somewhat. (orig.)

  14. Carbon nanotube thermal interfaces on gadolinium foil

    OpenAIRE

    McCarthy, Patrick T.; Marinero, Ernesto E.; Fisher, Timothy S.

    2012-01-01

    We report the thermal behavior of gadolinium foils to be used in magneto thermoelectric generator cells. Magneto thermoelectric generator cell technology exploits the ferromagnetic phase transition of gadolinium to drive the movement of a diaphragm 'shuttle' whose mechanical energy is converted to electrical form and which enhances heat transfer through both conduction and convection. Efficient heat transfer at mechanical interfaces is critical to increase shuttle speed and the commensurate r...

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

    Science.gov (United States)

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

    2014-04-01

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

  16. Extracellular gadolinium-based contrast media: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Bellin, Marie-France [University Paris-Sud 11, Department of Radiology, University Hospital Paul-Brousse, AP-HP, 12, Avenue Paul Vaillant-Couturier, 94804 Villejuif Cedex (France)], E-mail: marie-france.bellin@pbr.aphp.fr; Van Der Molen, Aart J. [University Paris-Sud 11, Department of Radiology, University Hospital Paul-Brousse, AP-HP, 12, Avenue Paul Vaillant-Couturier, 94804 Villejuif Cedex (France)

    2008-05-15

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

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

    Science.gov (United States)

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

    2008-05-01

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

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

    Science.gov (United States)

    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

  19. Gadolinium-DTPA in magnetic resonance tomography

    International Nuclear Information System (INIS)

    Magnetic resonance tomography was performed on 158 patients with different indications before and after the administration of contrast medium. The MR examination included various plain T1 and T2 weighted spin echo sequences as well as T1 weighted examinations after intravenous application of gadolinium-DTPA ('Magnevist', Schering AG) in a dosage of 0.1 mmol/kg body weight. The following conclusions were drawn: The sensitivity of MR in detecting brain tumors, acoustic neuromas and pituitary adenomas was improved considerably after the administration of 'Magnevist'. To diagnose the type of tumor, the criteria which apply to Gd-DPTA are similar to those used for iodine-containing contrast medium in CT. In about 2/3 rds of the cases, delineation of pathological tissues from surrounding edema and normal structures was better than in plain films. Hence, accurate, pretherapeutic staging of bronchial carcinomas and an exact definition of the expansion of the malignancies in the muscle-skeleton system were possible. In respect of tumors in the region of the base of the skull, we could omit T2-weighted sequences without noticeable loss of diagnostically relevant information; the examination time could thus be shortened by about 12 minutes. (orig.)

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

    OpenAIRE

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

    2003-01-01

    Effects caused by the electron electric dipole moment (EDM) in gadolinium garnets are considered. Experimental studies of these effects could improve 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.

  1. Isotope separation of gadolinium using optical pumping

    International Nuclear Information System (INIS)

    The gadolinium atoms in the 533 cm-1 metastable level were photoionized by pulsed laser beams after the population of 160Gd in the 533 cm-1 metastable level had been reduced by optical pumping using a continuous wave ring dye laser. Mass spectra of the ionized gadolinium atoms showed that an abundance ratio of 160Gd decreased from natural isotope abundance of 21.8 % to 1 %. This result demonstrates the isotope separation by photoionization of the atoms after decreasing of the photoionized level population of selected isotope using optical pumping. (author)

  2. Aging of coprecipitated gallium and gadolinium hydroxides

    International Nuclear Information System (INIS)

    The X-ray graphical and X-ray spectroscopic methods have been used to investigate aging under parent solution at 25, 50, 90 deg and thermolysis in the 250-1000 deg range of mixed gallium and gadolinium hydroxides coprecipitated at pH 8.6 by ammonium hydroxide from the nitrate solution (Gd:Ga=3:5). Hydroxopolycompounds With garnet prestructure are stated to be precipitated under the mentioned conditions. Their dehydration and crystallization of gallium-gadolinium garnet take place during aging under parent solution and thermolysis

  3. Study of burnable poisons and gadolinium qualification in light water reactors

    International Nuclear Information System (INIS)

    The aim of this work is to develop a calculation procedure for analyzing light water moderated reactors utilizing gadolinium as a burnable poison. The main points of this work can be summarized as follows: the available cross section data of gadolinium were analysed and corrected whenever it was necessary. The processes which include required precautions for obtaining multigroup cross sections were defined; an exhaustive study of the assumptions used in multicell calculation methods allowed the definition of option to be used for obtaining good results without excessive calculation cost. This study was followed by the interpretation of experimental results; when gadolinium is used in grain structure, a problem of double heterogeneity is encountered. A new calculation method was developed for such situations. Its validity was confirmed by a comparison with the Monte Carlo method; the problems encountered in performing a study of burn up of fuel elements containing gadolinium were analysed and the necessary precautions were established. The effect of the initial charge and geometrical form of the gadolinium and the behavior of lattices during the burn up were examined

  4. Contrast agents for MRI

    International Nuclear Information System (INIS)

    Contrast agents are divided into two categories. The first one is paramagnetic compounds, including lanthanides like gadolinium, which mainly reduce the longitudinal (T1) relaxation property and result in a brighter signal. The second class consists of super-paramagnetic magnetic nanoparticles (SPMNPs) such as iron oxides, which have a strong effect on the transversal (T2) relaxation properties. SPMNPs have the potential to be utilized as excellent probes for magnetic resonance imaging (MRI). For instance, clinically benign iron oxide and engineered ferrite nanoparticles provide a good MRI probing capability for clinical applications. Furthermore, the limited magnetic property and inability to escape from the reticuloendothelial system (RES) of the used nanoparticles impede their further advancement. Therefore, it is necessary to develop the engineered magnetic nanoparticle probes for the next-generation molecular MRI. Considering the importance of MRI in diagnosing diseases, this paper presents an overview of recent scientific achievements in the development of new synthetic SPMNP probes whereby the sensitive and target-specific observation of biological events at the molecular and cellular levels is feasible. - Highlights: • This paper studies the contrast agents for MRI. • Fe―Co alloys and Mn-ferrites exhibit suitable contrast enhancement. • Nonhydrolytic thermal-decomposition synthetic method is suitable to produce MNPs. • This method allows controlling the size, magnetic dopants, magneto-crystalline anisotropy. • The increase in the superparamagnetic size leads to the contrast-enhancement

  5. Multiorgan gadolinium (Gd) deposition and fibrosis in a patient with nephrogenic systemic fibrosis--an autopsy-based review

    DEFF Research Database (Denmark)

    Sanyal, Soma; Marckmann, Peter; Scherer, Susanne;

    2011-01-01

    BACKGROUND: Nephrogenic systemic fibrosis (NSF) is a systemic disorder of patients with severe renal insufficiency who have received gadolinium (Gd)-based magnetic resonance contrast agents (GBCAs). The causative association with Gd exposure was strengthened by the demonstration of Gd in various ...

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

    Science.gov (United States)

    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.

  7. Effect of field strength on gadolinium enhancement in MR imaging

    International Nuclear Information System (INIS)

    This study was designed to evaluate the influence of magnetic field strength on the relative enhancement effect (RE) of gadolinium (Gd)-chelates. Dilution series of two paramagnetic contrast agents (Gd-DTPA and Gd-DOTA) were examined in three commercially available MR systems, operating at different field strengths (0.2 T, 1.0 T, and 1.5 T). The RE was plotted against Gd concentration. The highest increases in signal intensity occurred with Gd concentrations of approximately 1.0 mmol/L. No significant difference in RE was observed between MR systems ranging in field strength from 0.2 T to 1.5 T. The RE of Gd-DTPA and Gd-DOTA was found to be equivalent. (orig.)

  8. Enriched Gadolinium as burnable absorber for PWR

    International Nuclear Information System (INIS)

    This paper is a summary of a master of thesis work in reactor physics made by Ola Seveborn. The work was done at Vattenfall Braensle AB and Ola was guided through the work by the corresponding author of this paper. The results presented are calculations for Ringhals 3, which is a Westinghouse 3-loop PWR within the Vattenfall Group. The fuel is characterized by 17x17 assemblies of AFA type containing 3.80-3.95 w/o 235U and 8 rods containing 2 w/o Gadolinium with an enrichment of 70 w/o 157Gd. The calculations were performed with the Studsvik-Scandpower code package based on the CASMO-4 lattice code and the SIMULATE-3 nodal code. The results are compared to the corresponding calculations for fuel with 5 w/o gadolinium with natural isotopic constitution. The depletion of the cores was done separately for the reference and enriched case. The results show that the gains in average for the five cycles studied are about 70 EFPH per cycle. This is an effect of the lower gadolinium content needed. Also less parasitic absorption of enriched gadolinium in the end of the fuel life contributes to the increased cycle lengths. The abruptly increased reactivity and internal power peaking factor around 10 MWd/kgU do not affect the core design negatively. (authors)

  9. Gadolinium: Central Metal of the Lanthanoids

    Science.gov (United States)

    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…

  10. Analysis of boron, samarium and gadolinium in rock samples by neutron capture gamma ray spectrometry

    International Nuclear Information System (INIS)

    Prompt gamma neutron activation analysis (PGNAA) is useful for determining many of the elements found in sedimentary rocks. It is particularly suitable for the trace elements boron, samarium and gadolinium. The sensitivity of detection can be of the order of 0.1 part per million with an adequate neutron source. Twenty-five sedimentary rock samples were analyzed in the PGNAA facility at the University of Missouri Research Reactor. The materials included Ottawa sand, Berea sandstone, Royer dolomite and several other formations of interest in the petroleum industry. Results of the analyses are presented. Correlations of gadolinium and samarium and of boron with the sum of samarium and gadolinium are given. (author). 8 refs, 2 figs, 4 tabs

  11. Gadolinium-DTPA-enhanced magnetic resonance imaging of musculoskeletal infectious processes

    International Nuclear Information System (INIS)

    The purpose of this study was to assess whether gadolinium-enhanced magnetic resonance imaging (MRI) provides diagnostic information beyond that given by nonenhanced imaging in the evaluation of musculoskeletal infectious processes and whether it can be used for differentiating infectious from noninfectious inflammatory lesions. Magnetic resonance images performed with and without intravenous gadolinium-DTPA in 34 cases in which musculoskeletal infection had been clinically suspected were reviewed. Infectious lesions-including osteomyelitis, pyarthrosis, abscess, and cellulitis-were confirmed in a total of 22 cases: in 15 by biopsy or drainage and in 7 by clinical course. Our results show that gadolinium-DTPA-enhanced MRI is a highly sensitive technique in diagnosing musculoskeletal infectious lesions. It is especially useful in distinguishing abscesses from surrounding cellulitis/myositis. Lack of contrast enhancement rules out infection with a high degree of certainty. However, contrast enhancement cannot be used to reliably distinguish infectious from noninfectious inflammatory conditions. (orig.)

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

    Science.gov (United States)

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

    2005-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Coppens, Emmanuel; Metens, Thierry; Winant, Catherine; Matos, Celso [Hopital Erasme, Universite Libre de Bruxelles, Department of Radiology, Division of Magnetic Resonance, Brussels (Belgium)

    2005-10-01

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

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

    International Nuclear Information System (INIS)

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

  15. Gadolinium induced recurrent acute pancreatitis.

    Science.gov (United States)

    Blasco-Perrin, H; Glaser, B; Pienkowski, M; Peron, J M; Payen, J L

    2013-01-01

    Acute pancreatitis is a sudden swelling and inflammation of the pancreas. The two most common causes are alcohol use and biliary stones. Drug-induced acute pancreatitis are rare (1.4-2%). In this present study, we present a case of recurrent acute pancreatitis induced by a specific magnetic-resonance-imaging (MRI) contrast agent called gadobenate dimeglumine. PMID:23395575

  16. Biodegradable polymer gadolinium contrast agents for magnetic resonance imaging

    Czech Academy of Sciences Publication Activity Database

    Braunová, Alena; Kříž, Jaroslav; Pechar, Michal; Šubr, Vladimír; Ulbrich, Karel

    Egmond aan Zee : University of Twente, 2012 - (Engbersen, J.), s. 72-73 [European Symposium on Controlled Drug Delivery /12./. Egmond aan Zee (NL), 04.04.2012-06.04.2012] R&D Projects: GA AV ČR IAAX00500803 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : biodegradable polymer carrier * polyethylene glycol * PEG Subject RIV: CD - Macromolecular Chemistry

  17. Targeted gadolinium-loaded dendrimer nanoparticles for tumor-specific magnetic resonance contrast enhancement

    Directory of Open Access Journals (Sweden)

    Scott D Swanson

    2008-06-01

    nanoparticles for targeted cancer imaging with the prolonged clearance time compared with the current clinically approved gadodiamide (OmniscanTM contrast agent. Potential application of this approach may include determination of the folate receptor status of tumors and monitoring of drug therapy.Keywords: dendrimer, DOTA, gadolinium, MRI, folate receptor

  18. Manufacturing and in vivo inner ear visualization of MRI traceable liposome nanoparticles encapsulating gadolinium

    Directory of Open Access Journals (Sweden)

    Kinnunen Paavo KJ

    2010-12-01

    Full Text Available Abstract 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.

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

    Science.gov (United States)

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

    2006-05-01

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

  20. Standard specification for nuclear-grade gadolinium oxide (Gd2O3) powder

    International Nuclear Information System (INIS)

    This specification provides the chemical and physical requirements for nuclear-grade gadolinium oxide powder intended for subsequent processing and use in nuclear fuel applications, for example, as an addition to uranium dioxide. This specification does not include requirements for health and safety

  1. Amino acid PET tracers are reliable markers of treatment responses to single-agent or combination therapies including temozolomide, interferon-β, and/or bevacizumab for glioblastoma

    International Nuclear Information System (INIS)

    Introduction: We examined whether the amino acid PET tracers, trans-1-amino-3-18F-fluorocyclobutanecarboxylic acid (anti-18F-FACBC) and 11C-methyl-L-methionine (11C-Met), are suitable for detecting early responses to combination therapies including temozolomide (TMZ), interferon-β (IFN), and bevacizumab (Bev) in glioblastoma. Methods: Human glioblastoma U87MG (U87) cells were incubated with low dose TMZ to induce chemoresistance. Both trans-1-amino-3-fluoro-1-14C-cyclobutanecarboxylic acid (anti-14C-FACBC) and 3H-methyl-L-methionine (3H-Met) uptake were quantified using triple-label accumulation assays to examine the relationship between tracer uptake and proliferation (3H-thymidine (TdR) accumulation) in vitro. U87 and U87R (TMZ-resistant subculture) cells were inoculated into the right and left basal ganglia, respectively, of F344/N-rnu rats. The efficacy of single-agent (TMZ, Bev) and combination therapy (TMZ/IFN, TMZ/Bev, TMZ/IFN/Bev) was examined in orthotopic gliomas using MRI, Evans blue extravasation, anti-14C-FACBC, and 3H-Met autoradiography, and MIB-1 immunostaining. Results: TMZ treatment decreased 3H-TdR accumulation and the volume distribution of anti-14C-FACBC and 3H-Met in U87 but not U87R cells. TMZ/IFN combination therapy significantly decreased these parameters in U87R cells; however, Bev had no additional effect in vitro. In vivo, U87R-derived gliomas were observed as equivocal tumors on MRI and T2-high intensity lesions. Bev treatment, either alone or in combination, markedly decreased U87 enhancing lesions. By contrast, autoradiographic images using anti-14C-FACBC and 3H-Met clearly delineated tumor extent, which spread widely beyond T2-high intensity lesions and enhancing lesions. TMZ therapy significantly decreased tracer accumulation and proliferation of U87- but not U87R-derived tumors. TMZ/IFN combination treatment significantly decreased these parameters in U87R tumors, which were further reduced (in both tumor types) by Bev addition

  2. Dual contrast enhanced magnetic resonance imaging of the liver with superparamagnetic iron oxide followed by gadolinium for lesion detection and characterization

    International Nuclear Information System (INIS)

    AIM: Iron oxide contrast agents are useful for lesion detection, and extracellular gadolinium chelates are advocated for lesion characterization. We undertook a study to determine if dual contrast enhanced liver imaging with sequential use of ferumoxides particles and gadolinium (Gd)-DTPA can be performed in the same imaging protocol. MATERIALS AND METHODS: Sixteen patients underwent dual contrast magnetic resonance imaging (MRI) of the liver for evaluation of known/suspected focal lesions which included, metastases (n = 5), hepatocellular carcinoma (HCC;n = 3), cholangiocharcinoma(n = 1) and focal nodular hyperplasia (FNH;n = 3). Pre- and post-iron oxide T1-weighted gradient recalled echo (GRE) and T2-weighted fast spin echo (FSE) sequences were obtained, followed by post-Gd-DTPA (0.1 mmol/kg) multi-phase dynamic T1-weighted out-of-phase GRE imaging. Images were analysed in a blinded fashion by three experts using a three-point scoring system for lesion conspicuity on pre- and post-iron oxide T1 images as well as for reader's confidence in characterizing liver lesions on post Gd-DTPA T1 images. RESULTS: No statistically significant difference in lesion conspicuity was observed on pre- and post-iron oxide T1-GRE images in this small study cohort. The presence of iron oxide did not appreciably diminish image quality of post-gadolinium sequences and did not prevent characterization of liver lesions. CONCLUSION: Our results suggest that characterization of focal liver lesion with Gd-enhanced liver MRI is still possible following iron oxide enhanced imaging. Kubaska, S. et al. (2001)

  3. Method of separating and purifying gadolinium-153

    Science.gov (United States)

    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).

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

    Science.gov (United States)

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

    2014-06-01

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

  5. Gadolinium-DTPA: value in MR imaging of extraspinal musculoskeletal infections

    International Nuclear Information System (INIS)

    To determine if paramagnetic contrast agents can improve the detection, delineation, and characterization of extraspinal musculoskeletal infections (MSI) on magnetic resonance (MR) imaging, 42 patients with clinical suspicion of MSI underwent MR imaging before and after intravenous administration of gadolinium-DTPA. The lesions consisted of 27 proven infections and 15 noninfective conditions. Specificity and accuracy in identifying infective lesions averaged 80% and 84%, respectively, on precontrast studies and 80% and 89% on the enhanced examinations, with no statistically significant difference. Rim enhancement around abscess loculi was the only pathognomonic sign of infection seen in ten patients with chronic osteomyelitis and pyogenic or tuberculous infections. In 17 patients with acute osteomyelitis, brucellosis, or mycetoma, detection and delineation of the lesions were best on precontrast studies, while postcontrast examinations resulted in underestimation of the extent of abnormalities in all cases. We conclude that intravenous gadolinium-DTPA has limited usefulness in the MR evaluation of extraspinal MSI. (orig.)

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

    International Nuclear Information System (INIS)

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

  7. Gadolinium-DTPA: value in MR imaging of extraspinal musculoskeletal infections

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, M.C. [Dept. of Radiology, Riyadh Armed Forces Hospital, Riyadh (Saudi Arabia); Sharif, H.S. [Dept. of Radiology, Riyadh Armed Forces Hospital, Riyadh (Saudi Arabia); Aabed, M.Y. [Dept. of Radiology, Riyadh Armed Forces Hospital, Riyadh (Saudi Arabia); Al Shahed, M.S. [Dept. of Radiology, Riyadh Armed Forces Hospital, Riyadh (Saudi Arabia); Sammak, B.M. [Dept. of Radiology, Riyadh Armed Forces Hospital, Riyadh (Saudi Arabia); Clark, D.C. [Dept. of Radiology, Riyadh Armed Forces Hospital, Riyadh (Saudi Arabia)

    1993-12-01

    To determine if paramagnetic contrast agents can improve the detection, delineation, and characterization of extraspinal musculoskeletal infections (MSI) on magnetic resonance (MR) imaging, 42 patients with clinical suspicion of MSI underwent MR imaging before and after intravenous administration of gadolinium-DTPA. The lesions consisted of 27 proven infections and 15 noninfective conditions. Specificity and accuracy in identifying infective lesions averaged 80% and 84%, respectively, on precontrast studies and 80% and 89% on the enhanced examinations, with no statistically significant difference. Rim enhancement around abscess loculi was the only pathognomonic sign of infection seen in ten patients with chronic osteomyelitis and pyogenic or tuberculous infections. In 17 patients with acute osteomyelitis, brucellosis, or mycetoma, detection and delineation of the lesions were best on precontrast studies, while postcontrast examinations resulted in underestimation of the extent of abnormalities in all cases. We conclude that intravenous gadolinium-DTPA has limited usefulness in the MR evaluation of extraspinal MSI. (orig.)

  8. Towards gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    As glioblastoma multiforme has macroscopic areas with poor vascularisation, and thereby poor uptake of an NCT-agent, the long-range γ-rays from GdNCT might enhance dose deposition compared to BNCT and to conformal photon therapy. Multicellular spheroids from a human glioblastoma cell line (Gli-6) were irradiated with conventional X-rays, with neutrons only (from the NRG Argonaut Reactor, LFR), and with neutrons (from the LFR) + 157Gd-DTPA (240 ppm 157Gd). Preliminary results demonstrate that after neutron irradiation in the presence of 157Gd, the spheroids showed growth arrest. By 3D treatment planning calculations on MRI's from patients with brain tumours, dose volume histograms (DVH) for GdNCT were compared to DVH for conventional conformal radiotherapy. The calculations indicate that GdNCT on patients with large, deep-seated tumours yields better tumour/brain dose distribution than conformal radiotherapy. (author)

  9. Calculation qualification of gadolinium burnable poisons in water reactors

    International Nuclear Information System (INIS)

    The work presented in this thesis constitutes the qualification on the one end of Appolo-Neptune scheme for the gadolinium burnable poison in a pressurized water reactor, and on the other end of basis nuclear data on natural gadolinium. This study has permitted to reduce by a factor 3 the actual incertitude on the gadolinium poison comparatively at precisions cited in international benchmarks calculations

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

    Science.gov (United States)

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

    2016-05-01

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

  11. Nickel-based gadolinium alloy for neutron adsorption application in ram packages

    International Nuclear Information System (INIS)

    This paper will outline the results of a metallurgical development program that is investigating the alloying of gadolinium into a nickel-chromium-molybdenum alloy matrix. Gadolinium has been chosen as the neutron absorption alloying element due to its high thermal neutron absorption cross section and low solubility in the expected U.S. repository environment. The nickel-chromium-molybdenum alloy family was chosen for its known corrosion performance, mechanical properties, and weldability. The workflow of this program includes chemical composition definition, primary and secondary melting studies, ingot conversion processes, properties testing, and national consensus codes and standards work. The microstructural investigation of these alloys shows that the gadolinium addition is not soluble in the primary austenite metallurgical phase and is present in the alloy as gadolinium-rich second phase. This is similar to what is observed in a stainless steel alloyed with boron. The mechanical strength values are similar to those expected for commercial Ni-Cr-Mo alloys. The alloys have been corrosion tested in simulated Yucca Mountain aqueous chemistries with acceptable results. The initial results of weldability tests have also been acceptable. Neutronic testing in a moderated critical array has generated favorable results. An American Society for Testing and Materials material specification has been issued for the alloy and a Code Case has been submitted to the American Society of Mechanical Engineers for code qualification. The ultimate goal is acceptance of the alloy for use at the Yucca Mountain repository

  12. First results on study of gadolinium as burnable absorber

    International Nuclear Information System (INIS)

    Following on with the work included in the 'Burnable absorbers research plan' several experiments were carried out oriented to determine Ga2O3 burn up. Cold tests were performed and samples were irradiated in the RA-3 reactor. In this paper, some calculated values are presented together with their comparisons with experimental ones. The parameters foreseen for performing the experiments were verified and also the predictions on burn up of uranium and gadolinium isotopes concentrations. These results imply that the nuclear data of these isotopes included in the library are satisfactory. Next steps will be to measure other isotopes concentrations, gamma spectrum, and the irradiation of one pellet to determine self shielding effects in order to obtain effective cross sections i.e. for CAREM geometry. (author)

  13. Optimization of gadolinium distribution in FAs for WWER-1000

    International Nuclear Information System (INIS)

    In modern WWER-1000 type reactors gadolinium integrated with fuel in the form of is used as burnable poison. At the present time, the operation mode of all Russian WWER-1000 is being changed to 104 % of power in 18-month fuel cycles, where number of uranium-gadolinium fuel rods in a FA may reach 27 pcs. Large quantity of uranium-gadolinium fuel rods in the core leads to intensification of impact on axial and radial power density distribution. As the result, on specific moments during the operation time the power density distribution can reach its boundary conditions and the departure from nucleate boiling ratio decreases. When the power density distribution is higher than its limited curve, it may be necessary to reduce the reactor power. The main goal of this study is the search for the technology that would allow to reduce the power peaking factor and to increase the departure from nucleate boiling ratio in 18-month fuel cycle. Various possible methods of impact on the power density distribution were reviewed. At the first stage of the research the method of impact on the power density distribution when gadolinium is removed from the top part of some uranium-gadolinium fuel rods was studied. Different combinations of profiled uranium-gadolinium fuel rods and lengths of their profiled parts were tested. At the second stage of the research the applicability of uranium-gadolinium fuel rods with different gadolinium concentrations in a FA was tested. The impact on the power density distribution of uranium-gadolinium fuel rods with different gadolinium content proportion and their gadolinium concentrations was taken into account. The departure from nucleate boiling ratio was calculated for the most interesting test results. Based on the research results, recommendations on fuel management of 18 month fuel cycle of WWER-1000 will be given. (authors)

  14. Tissue-specific MR contrast agents

    International Nuclear Information System (INIS)

    The purpose of this review is to outline recent trends in contrast agent development for magnetic resonance imaging. Up to now, small molecular weight gadolinium chelates are the workhorse in contrast enhanced MRI. These first generation MR contrast agents distribute into the intravascular and interstitial space, thus allowing the evaluation of physiological parameters, such as the status or existence of the blood-brain-barrier or the renal function. Shortly after the first clinical use of paramagnetic metallochelates in 1983, compounds were suggested for liver imaging and enhancing a cardiac infarct. Meanwhile, liver specific contrast agents based on gadolinium, manganese or iron become reality. Dedicated blood pool agents will be available within the next years. These gadolinium or iron agents will be beneficial for longer lasting MRA procedures, such as cardiac imaging. Contrast enhanced lymphography after interstitial or intravenous injection will be another major step forward in diagnostic imaging. Metastatic involvement will be seen either after the injection of ultrasmall superparamagnetic iron oxides or dedicated gadolinium chelates. The accumulation of both compound classes is triggered by an uptake into macrophages. It is likely that similar agents will augment MRI of atheriosclerotic plaques, a systemic inflammatory disease of the arterial wall. Thrombus-specific agents based on small gadolinium labeled peptides are on the horizon. It is very obvious that the future of cardiovascular MRI will benefit from the development of new paramagnetic and superparamagnetic substances. The expectations for new tumor-, pathology- or receptor-specific agents are high. However, is not likely that such a compound will be available for daily routine MRI within the next decade

  15. Self-Assembling DNA Quadruplex Conjugated to MRI Contrast Agents

    OpenAIRE

    Cai, Jianfeng; Shapiro, Erik M.; Hamilton, Andrew D.

    2009-01-01

    We report the preparation and magnetic resonance (MR) characterization of new MRI contrast agents based on gadolinium complexes conjugated to a self-assembling DNA quadruplex scaffold. As a single gadolinium-DOTA chelated DNA strand, the r1 molar relaxivity is 6.4 mM-1 s-1 per Gd and increases to 11.7 mM-1 s-1 per Gd upon formation of a DNA quadruplex. Similar results were obtained when a gadolinium-DOTA dendrimer was conjugated to DNA, the r1 molar relaxivity increasing to 12.9 mM-1 s-1 per ...

  16. Detection of pulmonary embolism with gadolinium-enhanced dual energy CT: an experimental study

    International Nuclear Information System (INIS)

    Objective: To evaluate the feasibility of gadolinium-enhanced dual energy CT pulmonary angiography (CTPA) in detecting pulmonary embolism (PE). Methods: In vitro dual energy CT of phantoms of gadolinium and iodinated contrast agents with different diluted ratio was performed, and CT values were measured at different tube voltages. Ten rabbits which were grouped into 3 ml/kg and 5 ml/kg groups underwent dual energy CT scan. CT values of pulmonary artery trunk and the first branch of pulmonary artery were measured. Sponge gelatin were injected into the femoral vein of 6 rabbits to make PE model next day, then lungs were re-imaged with dual energy CT 2 h after embolization. Creatinine was repeatedly measured before and one day after injection of gadolinium via ear marginal vein or femoral vein sampling.One-way ANOVA test and independent student t test were used to analyze the difference of pulmonary artery enhancement between different groups. Results: (1) Compared with iodinated contrast agent, CT value of gadolinium-based contrast agent at 80 kV was higher than those at 140 kV and average-weighted 120 kV. (2) At 140, 80, and average weighted 120 kV, CT values of pulmonary artery trunk [CT values were (463.1 ± 118.0), (664.2 ± 188.0), (522.9 ± 137.7) HU] and of the first branch of pulmonary artery [ CT values were (445.1 ± 82.3), (606.7 ± 207.2), (493.4 ± 117.3) HU] were higher than those at 3 ml/kg [CT value of pulmonary artery trunk was (258.1 ± 55.1), (384.0 ± 92.3), (295.4 ± 73.6) HU, CT value of the first branch of pulmonary artery (245.0 ± 73.2), (309.1 ± 94.2), (263.8 ±78.5) HU; all P<0.05]. CT values of pulmonary artery trunk and the first branch of pulmonary artery at 80 kV were higher than those at 140 kV and average-weighted 120 kV (pulmonary artery trunk: F=6.004, P=0.005; the first branch of pulmonary artery: F=4.374, P=0.018). In 6 rabbits, CTPA showed the enhancement cut-off of bilateral pulmonary arteries, gadolinium mapping showed

  17. Possible involvement of gadolinium chelates in the pathophysiology of nephrogenic systemic fibrosis: A critical review

    International Nuclear Information System (INIS)

    Nephrogenic systemic fibrosis (NSF) is a recently described, highly debilitating scleroderma-like disease occurring in patients with severe or end-stage renal failure. NSF is characterized by cutaneous papules and coalescing plaques ('peau d'orange' appearance) and a wooden consistency. It may ultimately cause disabling contractures of several joints, thus making many patients wheelchair-dependent. NSF has been associated to prior administration of gadolinium chelates (GC) used as contrast agents for magnetic resonance imaging. The best available treatment option at the present time is renal transplantation. The mechanism of NSF has not been fully elucidated. Several hypotheses have been proposed so far and are critically discussed in the present review article. Gadolinium has been found in skin biopsy samples of patients. The most widely accepted hypothesis is related to dechelation of less stable GC, progressively releasing free Gd3+ which may subsequently lead to the attraction of CD34+, CD45+, pro-collagen+ circulating fibrocytes via the release of chemokines, thereby inducing systemic fibrosing disorders. Pre-existing renal failure may facilitate the process by delaying the excretion of GC. A complex interplay between gadolinium and co-factors (pro-inflammatory status, vascular injury, high dose of erythropoietin, high levels of calcium, phosphorus, etc.) may occur in patients with impaired renal function. This and other hypotheses remain to be investigated, as well as the role and independence of co-factors

  18. Coordination chemistry of gadolinium complexes having pyridine carboxylate units in relation with the medical imagery

    International Nuclear Information System (INIS)

    In order to study the influence of the coordination sphere on the properties which govern the relaxivity, ligands containing pyridine carboxylates units have been particularly studied. It has been shown that the tripodal ligand tpaa forms with gadolinium (III) a neutral complex having a relaxivity (r1p=13.3 mM-1 at 298 K and 60 MHz) which is three times superior to the contrast agents currently used in NMR Imaging. To explain this remarkably relaxivity, two new ligands analogous to the tpaa: the tpatcn and the bpeda containing pyridine carboxylate units bound to one or several aliphatic nitrogen have been studied in modulating the number of coordination sites and the symmetry degree. The study of the relaxivity of the corresponding gadolinium (III) complexes gives precious data on the understanding of the results in the case of the complex [Gd(tpaa)]. The synthesis and the properties of these gadolinium (III) complexes will be presented during this conference. (O.M.)

  19. Determination of the Universality Class of Gadolinium

    International Nuclear Information System (INIS)

    We resolve a long-standing puzzle for the static and dynamic critical behavior of gadolinium by a combined theoretical and experimental investigation. It is shown that the spin dynamics of a ferromagnet with hcp lattice structure and a spin-spin interaction given by both exchange and dipole-dipole interaction belongs to a new dynamic universality class, model J* . Comparing results from mode coupling theory with results from three different hyperfine interaction probes we find quantitative agreement. copyright 1997 The American Physical Society

  20. Towards modeling gadolinium-lead-borate glasses

    International Nuclear Information System (INIS)

    Infrared spectra of gadolinium-lead-borate glasses of the xGd2O3.(100 - x)[3B2O3.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 xGd2O3.(1 - x)[3B2O3.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 Gd2O3 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 [BO4] units into trigonal [BO3] units. Then, gadolinium ions have affinity towards [BO3] structural units which contain non-bridging oxygens necessary for the charge compensation because the more electronegative [BO3] 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 3B2O3.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.

  1. Gadolinium-enhanced MR angiography (Gd-MRA) of thoracic vasculature in an animal model using double-dose gadolinium and quiet breathing

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, R.J.; Strouse, P.J. [Section of Pediatric Radiology, University of Michigan Health System, Ann Arbor (United States); Londy, F.J. [Dept. of Radiology, University of Michigan Hospitals, Ann Arbor, MI (United States); Wakefield, T.W. [Dept. of Surgery, Section of Vascular Surgery, University of Michigan Hospitals, Ann Arbor, MI (United States)

    2001-08-01

    Objective. To evaluate a gadolinium-enhanced MR angiography (Gd-MRA) imaging protocol for the assessment of thoracic vessels using double-dose gadolinium and quiet breathing. An animal model was used to simulate imaging in infants and young children. Material and methods. Six baboons (Papio anubis), mean weight 5.7 kg, were sedated and intubated. After the injection of double-dose Gd-DTPA (0.2 mmol/kg) through a peripheral vein, a coronal spoiled 3D gradient-echo volume acquisition was obtained during quiet breathing. Two radiologists reviewed the images for visualization of aortic arch, brachiocephalic vessel origins, pulmonary arteries (central, upper lobe and descending branches), and pulmonary veins (upper and lower). Results. Visualization was excellent for the aortic arch, brachiocephalic vessel origins, and pulmonary arteries, including the hilar branches. Visualization was excellent for the lower and right upper pulmonary veins and fair for the left upper pulmonary vein. There was excellent agreement between radiologists. Conclusion. Imaging of thoracic vessels with Gd-MRA using double gadolinium during quiet breathing was effective in our animal model. The advantages of this technique include a short imaging time and depiction of vascular segments - branches of pulmonary arteries and intraparenchymal segments of pulmonary veins - not optimally visualized with other non-invasive imaging techniques. (orig.)

  2. Gadolinium-enhanced MR angiography (Gd-MRA) of thoracic vasculature in an animal model using double-dose gadolinium and quiet breathing

    International Nuclear Information System (INIS)

    Objective. To evaluate a gadolinium-enhanced MR angiography (Gd-MRA) imaging protocol for the assessment of thoracic vessels using double-dose gadolinium and quiet breathing. An animal model was used to simulate imaging in infants and young children. Material and methods. Six baboons (Papio anubis), mean weight 5.7 kg, were sedated and intubated. After the injection of double-dose Gd-DTPA (0.2 mmol/kg) through a peripheral vein, a coronal spoiled 3D gradient-echo volume acquisition was obtained during quiet breathing. Two radiologists reviewed the images for visualization of aortic arch, brachiocephalic vessel origins, pulmonary arteries (central, upper lobe and descending branches), and pulmonary veins (upper and lower). Results. Visualization was excellent for the aortic arch, brachiocephalic vessel origins, and pulmonary arteries, including the hilar branches. Visualization was excellent for the lower and right upper pulmonary veins and fair for the left upper pulmonary vein. There was excellent agreement between radiologists. Conclusion. Imaging of thoracic vessels with Gd-MRA using double gadolinium during quiet breathing was effective in our animal model. The advantages of this technique include a short imaging time and depiction of vascular segments - branches of pulmonary arteries and intraparenchymal segments of pulmonary veins - not optimally visualized with other non-invasive imaging techniques. (orig.)

  3. Improvement of post-gadolinium contrast with magnetization transfer

    International Nuclear Information System (INIS)

    Magnetization transfer (MT) provides post-gadolinium contrast improvement through decreasing the tissue signal. Our study had two aims: to analyse the effect of MT qualitatively and quantitatively in 13 patients, and to analyse in vitro the competition betwen two relaxation phenomena, dipole-dipole which is characteristic of MT and proton - electron which is characteristic of gadolinium. Contrast between lesion and white matter improved from 20.6 % before MT to 65.1 % after MT, enabling new lesions to be detected in two patients. The improvement was due mainly to the proton - electron effect of gadolinium rather than the dipole relaxation of MT. These results are in agreement with those in the literature. The existence of spontaneous high-signal induced by MT in the absence of gadolinium indicates that it is preferable to perform an MT sequence before and after administration of gadolinium. (orig.)

  4. Improvement of post-gadolinium contrast with magnetization transfer

    Energy Technology Data Exchange (ETDEWEB)

    Huot, P.; Hatier, F.; Carlier, P. [Service de Radiologie, Hopital d`Instruction des Armees Robert Picque, Route de Toulouse, F-33 998 Bordeaux Armees (France); Dousset, V.; Degreze, P.; Caille, J.M. [Service de Neuroradiologie, Hopital Universitaire Pellegrin, F-33 076 Bordeaux (France)

    1997-12-31

    Magnetization transfer (MT) provides post-gadolinium contrast improvement through decreasing the tissue signal. Our study had two aims: to analyse the effect of MT qualitatively and quantitatively in 13 patients, and to analyse in vitro the competition betwen two relaxation phenomena, dipole-dipole which is characteristic of MT and proton - electron which is characteristic of gadolinium. Contrast between lesion and white matter improved from 20.6 % before MT to 65.1 % after MT, enabling new lesions to be detected in two patients. The improvement was due mainly to the proton - electron effect of gadolinium rather than the dipole relaxation of MT. These results are in agreement with those in the literature. The existence of spontaneous high-signal induced by MT in the absence of gadolinium indicates that it is preferable to perform an MT sequence before and after administration of gadolinium. (orig.) With 5 figs., 14 refs.

  5. Magnetically Active and Coated Gadolinium-Filled Carbon Nanotubes

    KAUST Repository

    Fidiani, Elok

    2013-08-15

    Gd-filled carbon nanotubes (which include the so-called gadonanotubes(1)) have been attracting much interest due to their potential use in medical diagnostic applications. In the present work, a vacuum filling method was performed to confine gadolinium(III) iodide in carbon nanotubes (CNTs). Filling yields in excess of 50% were obtained. Cleaning and dosing of the external walls was undertaken, as well as the study of the filled CNT magnetic properties. Overall, we found that the encapsulating procedure can lead to reduction of the lanthanide metal and induce disorder in the initial GdI3-type structure. Notwithstanding, the magnetic response of the material is not compromised, retaining a strong paramagnetic response and an effective magnetic moment of similar to 6 mu B. Our results may entice further investigation into whether an analogous Gd3+ to Gd2+ reduction takes place in other Gd-filled CNT systems.

  6. Effect of gadolinium covers on fast dosimeter response

    International Nuclear Information System (INIS)

    Gadolinium (Gd) has been used extensively at B and W Nuclear Technologies (BWNT) as a dosimetry shielding material for several years. Gadolinium has a significant cross section throughout the energy range of interest (i.e. above 1 MeV) in vessel fluence calculations. While Gd has a number of advantages as a dosimetry cover, it also has the potential for introducing a bias of unknown magnitude into the measured activities of covered fast response dosimeters such as U238 and iron. The Gd cover causes a reduction in the measured dosimeter activity, which means that the calculated fluxes normalized to those activities would be under-predicted. This is, of course, in the non-conservative direction. Since dosimeter covers are generally not included in the typical transport analysis model, corrections for this effect are not generally made. The calculated activities would not include the effects of the Gd while, of course, the measured activities would. The resulting calculation to measurement ratios, (C/M), which are used to remove biases in the calculated fluxes, would therefore be in error, in the non-conservative direction, by some undetermined amount. This study has determined the magnitude of the bias in the fast response dosimeters, U238 and iron caused by the absorption of fast (E > 1.0 MeV) neutrons in 2 mm (0.002 m) Gd covers. The results indicate that the bias is in the 2.9--3.4% range and that it is only a weak function of dosimeter material

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

    Science.gov (United States)

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

    2012-08-01

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

  8. Repeated self-healing of nano and micro scale cracks in epoxy based composites by tri-axial electrospun fibers including different healing agents

    OpenAIRE

    Seyyed Monfared Zanjani, Jamal; Saner Okan, Burcu; Letofsky-Papst, Ilse; Menceloğlu, Yusuf Z.; Menceloglu, Yusuf Z.; Yıldız, Mehmet; Yildiz, Mehmet

    2015-01-01

    Multi-walled healing fibers with a novel architecture are fabricated through a direct, one-step tri-axial electrospinning process to encapsulate different healing agents inside the fibers with two distinct protective walls. Self healing systems based on ring opening metathesis polymerization (ROMP) and an amine–epoxy reaction are redesigned by utilizing these tri-axial fibers. In ROMP, Grubbs' catalysts are integrated in the outer wall of the fibers instead of the composite matrix to reduce t...

  9. Contrast agents in magnetic resonance imaging

    International Nuclear Information System (INIS)

    The origine of nuclear magnetic resonance signal is reminded and different ways for contrast enhancement in magnetic resonance imaging are presented, especially, modifications of tissus relaxation times. Investigations have focused on development of agents incorporating either paramagnetic ions or stable free radicals. Pharmacological and toxicological aspects are developed. The diagnostic potential of these substances is illustrated by the example of gadolinium complexes

  10. Hepatocellular carcinoma. Comparison between gadolinium and ironoxide enhanced MR imaging

    International Nuclear Information System (INIS)

    Purpose of this work is to compare prospectively dynamic gadolinium (Gd)-enhanced with superparamagnetic iron oxide (SPIO)-enhanced MRI for the detection of hepatocellular carcinoma (HCC). Twenty-five patients with histologically proven HCC and liver cirrhosis (28% of them in B or C Child class) underwent dynamic Gd-enhanced MRI and, a few days later, (mean interval: three days) SPIO-enhanced MRI. Only patients with availability of clinical and imaging follow-up for at least seven months were enrolled in this prospective study. MR images were reviewed by two independent radiologists. The readers scored each lesion for the presence of HCC and assigned confidence levels based on a five-grade scale: 1, definitely or almost definitely absent; 2, possibly present; 3, probably present; 4, definitely present; 5, definitely present with optimal liver/lesion contrast or good liver/lesion contrast and morphological signs (intact capsule, intranodular septa, extracapsular infiltration), useful for locoregional treatment planning. A positive diagnostic value was assessed for scores of 3 or higher. Gd-enhanced and SPIO-enhanced MRI found 44 lesions. Eight of twelve lesions visible with a single contrast agent measured less than 1 cm in diameter. HCC detectability was 75% with Gd-enhanced MRI and 97.7% with SPIO-enhanced MRI. SPIO-enhanced T2-weighted TSE images showed significantly higher diagnostic value than SPIO-enhanced T1-T2*GRE images only in three cases, while nodule morphological characteristics (capsule, septa, different cell differentiation components) were better depicted by TSE images. In thi study the combined use of SPIO-enhanced T2-weighted TSE and T1-T2*-weighted GRE sequences showed higher sensitivity than gadolinium-enhanced GRE dynamic imaging (97.7% versus 75%). These results are at least partly related to our study conditions, that is: 1)MRI was performed with a 1T system, 2) both axial and sagittal SPIO-enhanced imaging were performed with respiratory

  11. Application of gadolinium burnable absorber in the VVER reactor core

    International Nuclear Information System (INIS)

    Within the frame of the Coordinated Research Program on Safe Management with Burnable absorbers in VVERs neutronic parameters of hexagonal VVER lattice were computed to test the influence of gadolinium burnable absorber. With the aim to verify the applied method and code, computations of the BWR square assembly containing gadolinium were performed as well. Comparison of the results obtained by applying the WIMSD4 code with other available results show quite a good agreement although this code was not meant for treatment of hexagonal lattices. The inadequacy of the WIMSD4 data library concerning gadolinium isotopes was overcome at this moment by applying the UKNDL80 data. (author)

  12. Alkali metal and alkali earth metal gadolinium halide scintillators

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Monitoring of gadolinium-BOPTA uptake into the vessel wall during magnetic resonance (MR)-guided angioplasty of the peripheral arteries with a paclitaxel/gadolinium-BOPTA-coated balloon. An experimental study at 3 Tesla

    International Nuclear Information System (INIS)

    Purpose: The success of paclitaxel distribution within the vessel wall during paclitaxel-coated balloon angioplasty to prevent restenosis cannot be monitored under X-ray guidance. The aim of this pilot study was to demonstrate the feasibility of monitoring Gadolinium-BOPTA delivery within the vessel wall during magnetic resonance (MR)-guided paclitaxel/Gadolinium-BOPTA-coated balloon angioplasty of the peripheral arteries. Materials and methods: 6 pigs (47 ± 2 kg) were investigated. All experiments were performed using a 3 Tesla MR scanner. MR-guided bilaterial angioplasty of the iliac arteries was performed using a paclitaxel/MR contrast agent-coated balloon catheter. The feasibility of monitoring the delivery of Gadolinium-BOPTA to the vessel was assessed in 4 animals. In two additional animals, bilateral stenosis was surgically induced in the iliac arteries. Delivery of paclitaxel to the vessel wall was monitored using a 3 D T1-weighted gradient echo (GE) sequence for delineation of the vessel wall. Normalized signal intensity (SI) of the vessel wall was measured before and repeatedly after the intervention for 45 min. in all animals. Results: Paclitaxel/gadolinium-BOPTA-coated balloon angioplasty was successfully accomplished in all iliac arteries (n = 12). In animals with stenosis MR-angiography demonstrated successful dilatation (n = 4). The normalized SI of the vessel wall on T1-weighted GE images significantly increased after the intervention in all animals with and without stenosis for more than 45 min. (p < 0.001). Conclusion: Monitoring of Gadolinium-BOPTA into the vessel wall during MR-guided coated balloon angioplasty is feasible. This is a first step towards providing a tool for the online control of homogenous drug delivery after paclitaxel-coated balloon angioplasty. (orig.)

  14. Monitoring of gadolinium-BOPTA uptake into the vessel wall during magnetic resonance (MR)-guided angioplasty of the peripheral arteries with a paclitaxel/gadolinium-BOPTA-coated balloon. An experimental study at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Neizel, M.; Kelm, M. [University Hospital Duesseldorf (Germany). Dept. of Cardiology, Pneumology and Angiology; Ruebben, A.; Weiss, N. [Aachen Resonance, Aachen (Germany); Guenther, R.W. [University Hospital Aachen (Germany). Dept. of Radiology; Krombach, G.A. [University Hospital Giessen (Germany). Dept. of Radiology

    2014-04-15

    Purpose: The success of paclitaxel distribution within the vessel wall during paclitaxel-coated balloon angioplasty to prevent restenosis cannot be monitored under X-ray guidance. The aim of this pilot study was to demonstrate the feasibility of monitoring Gadolinium-BOPTA delivery within the vessel wall during magnetic resonance (MR)-guided paclitaxel/Gadolinium-BOPTA-coated balloon angioplasty of the peripheral arteries. Materials and methods: 6 pigs (47 ± 2 kg) were investigated. All experiments were performed using a 3 Tesla MR scanner. MR-guided bilaterial angioplasty of the iliac arteries was performed using a paclitaxel/MR contrast agent-coated balloon catheter. The feasibility of monitoring the delivery of Gadolinium-BOPTA to the vessel was assessed in 4 animals. In two additional animals, bilateral stenosis was surgically induced in the iliac arteries. Delivery of paclitaxel to the vessel wall was monitored using a 3 D T1-weighted gradient echo (GE) sequence for delineation of the vessel wall. Normalized signal intensity (SI) of the vessel wall was measured before and repeatedly after the intervention for 45 min. in all animals. Results: Paclitaxel/gadolinium-BOPTA-coated balloon angioplasty was successfully accomplished in all iliac arteries (n = 12). In animals with stenosis MR-angiography demonstrated successful dilatation (n = 4). The normalized SI of the vessel wall on T1-weighted GE images significantly increased after the intervention in all animals with and without stenosis for more than 45 min. (p < 0.001). Conclusion: Monitoring of Gadolinium-BOPTA into the vessel wall during MR-guided coated balloon angioplasty is feasible. This is a first step towards providing a tool for the online control of homogenous drug delivery after paclitaxel-coated balloon angioplasty. (orig.)

  15. Phase-Bpre-simulation using boron and gadolinium as poison in the moderators system for Wolsong-1

    International Nuclear Information System (INIS)

    The Wolsong-1 (W-1) Phase-B pre-simulations were carried out in preparation for tests to be conducted for the restart of the reactor after a major refurbishment project that included replacement of the pressure tube. These pre-simulations for Wolsong-1 Phase-B differ from those in the past that were performed for the Wolsong-1,2,3,4 tests in that these tests use the WIMS/DRAGON/RFSP-IST code suite for verification of the tests and gadolinium instead of the traditional PPV/MULTICELL/RFSP code system and boron as poison in the moderator system. The use of gadolinium is deemed not to have domestically accumulated experience gained from the previous Phase-B tests. Thus, it is appropriate to conduct a study in order to gain a correct understanding and interpretation of potential differences in test results stemming from using gadolinium rather than boron. Although the calibration of the reactivity device will not be noticeably different using boron and gadolinium at a constant moderator temperature, the temperature dependency of the neutronic behavior due to the presence of gadolinium in the moderator system might be pronounced. The results of the pre-simulations using gadolinium revealed that the moderator temperature reactivity coefficients indeed showed significant differences in comparison with those with boron. In order to secure the validity of the analysis results, the newly acquired WIMS/DRAGON/RFSP-IST code suite was verified against the W-2,3,4 Phase-B test results. The results of the new code suite verifications revealed some overall improvements in accuracy; justification of the use of the code can be claimed for the validation of the W-1 Phase-B test results.

  16. Hypervascular multifocal hepatoblastoma: dynamic gadolinium-enhanced MRI findings indistinguishable from infantile hemangioendothelioma

    International Nuclear Information System (INIS)

    In this case report we describe a neonate with multifocal hypervascular hepatoblastoma indistinguishable from infantile hemangioendothelioma on dynamic gadolinium-enhanced MRI. Review of the literature revealed a description of a hypervascular form of solitary hepatoblastoma visualized using sonography and CT. Our case is unique in that it illustrates centripetal fill-in of multifocal hepatoblastoma on dynamic gadolinium-enhanced MRI. MRI has several advantages over CT in the characterization and follow-up of neonatal liver tumors. These advantages include the lack of ionizing radiation, as well as an ability to visualize vascular structures that is less dependent upon the timing of contrast material administration. This case further highlights the difficulty in discriminating between infantile hemangioendothelioma and hepatoblastoma in radiology, particularly in a multifocal hypervascular variant of hepatoblastoma. (orig.)

  17. Gadolinium-DOTA enhanced MRI of painful osseous crises in children with sickle cell anemia

    International Nuclear Information System (INIS)

    In order to evaluate the role of gadolinium-DOTA enhanced MRI in the management of painful osseous crises in children with sickle cell anemia (SCA), nine children with SCA underwent MRI, bone scans and ultrasonographic studies during 11 osseous crises. Imaging findings were compared with the final diagnosis: three acute osteomyelitis (AO) and 16 acute infarcts (AI). MRI could not differentiate AO from AI. The appearance of severe AI was very misleading and was similar to the usual appearance of AO, including soft tissue changes, periosteal reaction and patterns of enhancement. Gadolinium-DOTA enhanced MRI was useful for determining the anatomic site and extent of AO or AI and for distinguishing between necrotic material, fluid collection and vascularized inflammatory tissue. It can also help to guide the aspiration of intraosseous, subperiosteal and soft tissue fluid collections. (orig.)

  18. Gadolinium-DOTA enhanced MRI of painful osseous crises in children with sickle cell anemia

    Energy Technology Data Exchange (ETDEWEB)

    Bonnerot, V. (Dept. of Pediatric Radiology, Hopital des Enfants Malades, 75 - Paris (France)); Sebag, G. (Dept. of Pediatric Radiology, Hopital des Enfants Malades, 75 - Paris (France)); Montalembert, M. de (Dept. of Pediatric Hematology, Hopital des Enfants Malades, 75 - Paris (France)); Wioland, M. (Dept. of Nuclear Medicine, Hopital Saint-Antoine, 75 - Paris (France)); Glorion, C. (Dept. of Orthopedics, Hopital des Enfants Malades, 75 - Paris (France)); Girot, R. (Dept. of Pediatric Hematology, Hopital des Enfants Malades, 75 - Paris (France)); Lallemand, D. (Dept. of Pediatric Radiology, Hopital des Enfants Malades, 75 - Paris (France))

    1994-04-01

    In order to evaluate the role of gadolinium-DOTA enhanced MRI in the management of painful osseous crises in children with sickle cell anemia (SCA), nine children with SCA underwent MRI, bone scans and ultrasonographic studies during 11 osseous crises. Imaging findings were compared with the final diagnosis: three acute osteomyelitis (AO) and 16 acute infarcts (AI). MRI could not differentiate AO from AI. The appearance of severe AI was very misleading and was similar to the usual appearance of AO, including soft tissue changes, periosteal reaction and patterns of enhancement. Gadolinium-DOTA enhanced MRI was useful for determining the anatomic site and extent of AO or AI and for distinguishing between necrotic material, fluid collection and vascularized inflammatory tissue. It can also help to guide the aspiration of intraosseous, subperiosteal and soft tissue fluid collections. (orig.)

  19. Gadolinium EUV Multilayers for Solar Imaging Near 60 nm Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop and commercialize a new class of extreme ultraviolet (EUV) multilayer coatings containing the rare-earth element gadolinium (Gd), designed as...

  20. Production of gadolinium nitrate for TAPS 3 and 4 PHWR

    International Nuclear Information System (INIS)

    In India, gadolinium nitrate is being used for the first time in PHWR at Tarapur. Gadolinium is preferred over boron due to high neutron cross section and the water soluble nitrate form works efficiently for reactivity control through moderator liquid poison addition system (MLPS) as well as for reactor shut down system (SDS2). Low concentration of gadolinium (0.1-0.2 g/l) in heavy water is sufficient to shut down the reactor in a very short time. After use, the small amount of gadolinium can be separated quickly from heavy water by ion exchange process. In this paper separation of Gd using of 2-ethyl hexyl phosphoric acid mono 2-ethyl hexyl ester EHEHPA as an extractant has been described

  1. Deposit of isotopically modified gadolinium suitable to detect solar neutrinos

    International Nuclear Information System (INIS)

    Consideration on the possibility to find gadolinium with a modified isotopic composition are envisaged, in particular with respect to the important use of this element by the nuclear energy. These possibility could exist in the far future. (author)

  2. Late gadolinium enhanced cardiovascular magnetic resonance in Becker muscular dystrophy

    OpenAIRE

    Varghese, A; Pennell, D J

    2004-01-01

    Becker muscular dystrophy is a rare cause of dilated cardiomyopathy. A case of Becker muscular dystrophy is reviewed in which cardiovascular magnetic resonance showed previously unreported findings of extensive mid-myocardial late gadolinium enhancement. Similar detection of late gadolinium enhancement in conjunction with other uses of cardiovascular magnetic resonance may contribute significantly to the diagnosis and management of patients with this unusual and important diagnosis.

  3. Discovery and basic pharmacology of erythropoiesis-stimulating agents (ESAs), including the hyperglycosylated ESA, darbepoetin alfa: an update of the rationale and clinical impact.

    Science.gov (United States)

    Kiss, Zoltán; Elliott, Steven; Jedynasty, Kinga; Tesar, Vladimír; Szegedi, János

    2010-04-01

    Cloning of the human erythropoietin (EPO) gene and development of the first recombinant human erythropoietin (rHuEPO) drug were truly breakthroughs. This allowed a deeper understanding of the structure and pharmacology of rHuEpo, which in turn inspired the discovery and development of additional erythropoiesis-stimulating agents (ESAs). In vivo specific activity and serum half-life of rHuEPO are influenced by the amount and structure of the attached carbohydrate. Increased numbers of sialic acids on carbohydrate attached to rHuEPO correlated with a relative increase in in-vivo-specific activity and increased serum half-life. The effect of increasing the number of sialic-acid-containing carbohydrates on in-vivo-specific activity was explored. Initial research focused on solving the problem of how the protein backbone could be engineered so a cell would add more carbohydrate to it. Additional work resulted in darbepoetin alfa, a longer-acting molecule with two additional carbohydrate chains. PMID:20127232

  4. Spectroscopy of gadolinium ion and disadvantages of gadolinium impurity in tissue compensators and collimators, used in radiation treatment planning

    OpenAIRE

    Maqbool, M.; Ahmad, Iftikhar

    2007-01-01

    Intense ultraviolet emission from gadolinium doped amorphous aluminum nitride thin films deposited on Si (111) substrate is studied with cathodoluminescence and photoluminescence. The purpose of the study is to find the merits or demerits of gadolinium ions if added intentionally or present as unintentionally added impurity in tissue compensators or collimators in radiation treatment planning. These films are deposited by reactive sputtering at liquid nitrogen temperature, using 100–200 W RF ...

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

    Science.gov (United States)

    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.

  6. Gadolinium-enhanced MR angiography of the breast: Is breast cancer associated with ipsilateral higher vascularity?

    International Nuclear Information System (INIS)

    The aim of this study was to assess a possible association between breast malignancy and ipsilateral higher vascularity on gadolinium-enhanced MR angiography. One hundred six patients were examined by dynamic gadolinium-enhanced 3D MR imaging. Magnetic resonance angiographic views were generated by image subtraction and maximum intensity projection. The study included 85 patients with unilateral malignant breast neoplasms and 21 with unilateral benign lesions. Three blinded readers independently reviewed the MR angiograms after masking the lesions and the corresponding contralateral sites. The readers were asked to determine whether vascularity was higher on the right side, higher on the left side, or equal on both sides. The results were analyzed by the Kappa statistic and Pearson's chi-square test. The blood vessels of the breasts were clearly seen in all cases. There was good agreement among the observers (kappa > 0.54) in assessing vascularity on both sides. Breasts harboring malignant neoplasms were found to have a higher vascularity than the contralateral breasts (p < 0.005). This sign of malignancy had a sensitivity of 76.5 %, a specificity of 57 %, and an accuracy of 72.6 %. Blood vessels of the breast can be depicted by MR angiography. Unilateral malignant neoplasms are associated with a higher ipsilateral vascularity. In conjunction with other indications of malignancy on gadolinium-enhanced MR images, a higher ipsilateral vascularity may serve as an additional sign of malignancy. (orig.)

  7. Contrast-enhanced peripheral MRA. Technique and contrast agents

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Yousef W. [Dept. of Radiology, Copenhagen Univ. Hospital Bispebjerg, Bispebjerg (Denmark)], e-mail: ywnielsen@gmail.com; Thomsen, Henrik S. [Dept. of Diagnostic Radiology, Copenhagen Univ. Hospital Herlev, Herlev (Denmark)

    2012-09-15

    In the last decade contrast-enhanced magnetic resonance angiography (CE-MRA) has gained wide acceptance as a valuable tool in the diagnostic work-up of patients with peripheral arterial disease. This review presents current concepts in peripheral CE-MRA with emphasis on MRI technique and contrast agents. Peripheral CE-MRA is defined as an MR angiogram of the arteries from the aortic bifurcation to the feet. Advantages of CE-MRA include minimal invasiveness and lack of ionizing radiation. The basic technique employed for peripheral CE-MRA is the bolus-chase method. With this method a paramagnetic MRI contrast agent is injected intravenously and T1-weighted images are acquired in the subsequent arterial first-pass phase. In order to achieve high quality MR angiograms without interfering venous contamination or artifacts, a number of factors need to be taken into account. This includes magnetic field strength of the MRI system, receiver coil configuration, use of parallel imaging, contrast bolus timing technique, and k-space filling strategies. Furthermore, it is possible to optimize peripheral CE-MRA using venous compression techniques, hybrid scan protocols, time-resolved imaging, and steady-state MRA. Gadolinium(Gd)-based contrast agents are used for CE-MRA of the peripheral arteries. Extracellular Gd agents have a pharmacokinetic profile similar to iodinated contrast media. Accordingly, these agents are employed for first-pass MRA. Blood-pool Gd-based agents are characterized by prolonged intravascular stay, due to macromolecular structure or protein binding. These agents can be used for first-pass, as well as steady-state MRA. Some Gd-based contrast agents with low thermodynamic stability have been linked to development of nephrogenic systemic fibrosis in patients with severe renal insufficiency. Using optimized technique and a stable MRI contrast agent, peripheral CE-MRA is a safe procedure with diagnostic accuracy close to that of conventional catheter X

  8. Contrast-enhanced peripheral MRA. Technique and contrast agents

    International Nuclear Information System (INIS)

    In the last decade contrast-enhanced magnetic resonance angiography (CE-MRA) has gained wide acceptance as a valuable tool in the diagnostic work-up of patients with peripheral arterial disease. This review presents current concepts in peripheral CE-MRA with emphasis on MRI technique and contrast agents. Peripheral CE-MRA is defined as an MR angiogram of the arteries from the aortic bifurcation to the feet. Advantages of CE-MRA include minimal invasiveness and lack of ionizing radiation. The basic technique employed for peripheral CE-MRA is the bolus-chase method. With this method a paramagnetic MRI contrast agent is injected intravenously and T1-weighted images are acquired in the subsequent arterial first-pass phase. In order to achieve high quality MR angiograms without interfering venous contamination or artifacts, a number of factors need to be taken into account. This includes magnetic field strength of the MRI system, receiver coil configuration, use of parallel imaging, contrast bolus timing technique, and k-space filling strategies. Furthermore, it is possible to optimize peripheral CE-MRA using venous compression techniques, hybrid scan protocols, time-resolved imaging, and steady-state MRA. Gadolinium(Gd)-based contrast agents are used for CE-MRA of the peripheral arteries. Extracellular Gd agents have a pharmacokinetic profile similar to iodinated contrast media. Accordingly, these agents are employed for first-pass MRA. Blood-pool Gd-based agents are characterized by prolonged intravascular stay, due to macromolecular structure or protein binding. These agents can be used for first-pass, as well as steady-state MRA. Some Gd-based contrast agents with low thermodynamic stability have been linked to development of nephrogenic systemic fibrosis in patients with severe renal insufficiency. Using optimized technique and a stable MRI contrast agent, peripheral CE-MRA is a safe procedure with diagnostic accuracy close to that of conventional catheter X

  9. Nanocrystalline gadolinium iron garnet for circulator applications

    International Nuclear Information System (INIS)

    Due to high resistivity and low microwave losses, gadolinium iron garnets (GdIG) are useful materials for non-reciprocal devices such as circulators or isolators. Keeping the miniaturization and cost reduction in mind, the trend is to modify the conventional methods of preparation of samples. In this connection we have synthesized nanocystalline GdIG by using the Microwave Hydrothermal method at 160 °C/45 min. As synthesized powders were characterized by using X-ray diffraction (XRD), transmission electron microscopy and Fourier Transform Infrared Spectroscopy. XRD patterns show the formation of a garnet phase with crystallite size varying between 19 nm and 40 nm. Differential Thermal Analysis studies were also carried out on the nanopowders. The powders were densified at a lower sintering temperature of 1100 °C/45 min using a microwave sintering method. The sintered samples were characterized by XRD and atomic force microscopy. The frequency dependence of complex permittivity and ferromagnetic resonance were measured in the Ka band frequency (27–40 GHz). Magnetic properties were also measured at room temperature. - Highlights: ► GdIG ferrites were synthesized using the microwave hydrothermal method. ► Densification of the GdIG samples was done at a low temperature of 1100 °C/45 min. ► Our samples possess low dielectric constant and loss at a Ka band frequency. ► Nanocrystalline GdIG samples for circulator application have been tested.

  10. Neutronics Design Flexibilities of the BigT Gadolinium Absorbers

    International Nuclear Information System (INIS)

    A new BA design named 'Burnable absorber-Integrated Guide Thimble' (BigT) was recently proposed for PWR. The BigT offers flexibility in BA self-shielding adjustment per design specifications. It is upon this assertion that this paper was prepared; i.e. this research aims to demonstrate the neutronics design flexibilities of BigT gadolinium absorbers. Specifically, three studies were completed to investigate sensitivities of the BigT gadolinium absorbers: (1) at a constant BA mass, (2) with a similar initial reactivity hold-down, and (3) for an optimal burnup reactivity swing. The paper clearly demonstrates neutronics flexibilities of the BigT gadolinium absorbers. Ascertained design variables are: (1) gadolinium effective shape, (2) BigT loading per lattice, and (3) BigT location in the lattice. Hybrid combination of the BigT designs may also alter the lattice depletion pattern, as well as density of gadolinium installed in the BigT absorbers. It is concluded that self-shielding of Gd can easily be adjusted in the BigT applications

  11. Extraction of gadolinium from high flux isotope reactor control plates

    International Nuclear Information System (INIS)

    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 153Gd 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 153Gd, 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 153Gd. Based on the results of experimental and calculational analyses, up to 25 grams of valuable gadolinium (≥60% enriched in 152Gd) 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 153Gd for each gram of gadolinium re-irradiated, 700 one-curie sources can be produced from each control plate assayed

  12. Validation of gadolinium burnout using PWR benchmark specification

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • We present methodology for validation of gadolinium burnout in PWR. • We model 17 × 17 PWR fuel assembly using MCB code. • We demonstrate C/E ratios of measured and calculated concentrations of Gd isotopes. • The C/E for Gd154, Gd156, Gd157, Gd158 and Gd160 shows good agreement of ±10%. • The C/E for Gd152 and Gd155 shows poor agreement below ±10%. - Abstract: The paper presents comparative analysis of measured and calculated concentrations of gadolinium isotopes in spent nuclear fuel from the Japanese Ohi-2 PWR. The irradiation of the 17 × 17 fuel assembly containing pure uranium and gadolinia bearing fuel pins was numerically reconstructed using the Monte Carlo Continuous Energy Burnup Code – MCB. The reference concentrations of gadolinium isotopes were measured in early 1990s at Japan Atomic Energy Research Institute. It seems that the measured concentrations were never used for validation of gadolinium burnout. In our study we fill this gap and assess quality of both: applied numerical methodology and experimental data. Additionally we show time evolutions of infinite neutron multiplication factor Kinf, FIMA burnup, U235 and Gd155–Gd158. Gadolinium-based materials are commonly used in thermal reactors as burnable absorbers due to large neutron absorption cross-section of Gd155 and Gd157

  13. Neutronics Design Flexibilities of the BigT Gadolinium Absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Yahya, Mohd-Syukri; Kim, Yonghee [KAIST, Daejeon (Korea, Republic of); Kim, HyeongHeon [KEPCO Engineering and Construction Company, Daejeon (Korea, Republic of)

    2015-05-15

    A new BA design named 'Burnable absorber-Integrated Guide Thimble' (BigT) was recently proposed for PWR. The BigT offers flexibility in BA self-shielding adjustment per design specifications. It is upon this assertion that this paper was prepared; i.e. this research aims to demonstrate the neutronics design flexibilities of BigT gadolinium absorbers. Specifically, three studies were completed to investigate sensitivities of the BigT gadolinium absorbers: (1) at a constant BA mass, (2) with a similar initial reactivity hold-down, and (3) for an optimal burnup reactivity swing. The paper clearly demonstrates neutronics flexibilities of the BigT gadolinium absorbers. Ascertained design variables are: (1) gadolinium effective shape, (2) BigT loading per lattice, and (3) BigT location in the lattice. Hybrid combination of the BigT designs may also alter the lattice depletion pattern, as well as density of gadolinium installed in the BigT absorbers. It is concluded that self-shielding of Gd can easily be adjusted in the BigT applications.

  14. Validation of gadolinium burnout using PWR benchmark specification

    Energy Technology Data Exchange (ETDEWEB)

    Oettingen, Mikołaj, E-mail: moettin@agh.edu.pl; Cetnar, Jerzy, E-mail: cetnar@mail.ftj.agh.edu.pl

    2014-07-01

    Graphical abstract: - Highlights: • We present methodology for validation of gadolinium burnout in PWR. • We model 17 × 17 PWR fuel assembly using MCB code. • We demonstrate C/E ratios of measured and calculated concentrations of Gd isotopes. • The C/E for Gd154, Gd156, Gd157, Gd158 and Gd160 shows good agreement of ±10%. • The C/E for Gd152 and Gd155 shows poor agreement below ±10%. - Abstract: The paper presents comparative analysis of measured and calculated concentrations of gadolinium isotopes in spent nuclear fuel from the Japanese Ohi-2 PWR. The irradiation of the 17 × 17 fuel assembly containing pure uranium and gadolinia bearing fuel pins was numerically reconstructed using the Monte Carlo Continuous Energy Burnup Code – MCB. The reference concentrations of gadolinium isotopes were measured in early 1990s at Japan Atomic Energy Research Institute. It seems that the measured concentrations were never used for validation of gadolinium burnout. In our study we fill this gap and assess quality of both: applied numerical methodology and experimental data. Additionally we show time evolutions of infinite neutron multiplication factor K{sub inf}, FIMA burnup, U235 and Gd155–Gd158. Gadolinium-based materials are commonly used in thermal reactors as burnable absorbers due to large neutron absorption cross-section of Gd155 and Gd157.

  15. Enrichment of Gadolinium isotope: column chromatography study

    International Nuclear Information System (INIS)

    Naturally occurring Gadolinium consists of 7 stable isotopes. 152Gd, 154 Gd, 155Gd 156Gd, 157Gd, 158Gd and 160Gd of which abundance ratios are 0.20, 2.18, 14.80, 20.47, 15.65, 24.84 and 21.86% respectively. Gd has the highest cross section for the capture of thermal neutrons of any element due to the high cross section of 157Gd (254,000 barn) and 155Gd (60,900 barn). All the remaining isotopes are having lower values (1.4-735 barn). Gd is used as a burnable poison in nuclear fuel, but the use of 155/157Gd would create an even more effective burnable poison. Gd isotope separation by displacement chromatography was performed in cation exchange resin. Column experiments were performed using 3 jacketed glass columns in series (10 mm dia and 1m length) packed with Dowex 50X8 of bed height of 90 cm. Initially the bed was converted to Cu2+ form. Then 50 cm Gd3+ band was formed using Gd (NO3)3 solution. The band was displaced using (NH4)4-EDTA +NH4NO3 ) solution. The sample was eluted after different migration length of Gd band. The mass spectrometric analysis using TIMS and ICP-MS was performed to measure the enrichment of Gd isotope and the results are found to be encouraging. In the case of natural Gd, the 157/160Gd ratio was found to be 0.7396. The isotopic ratio in the front end was gone down to 0.7077 and in the rear end the value was gone up to 0.7446 which indicates that the front end band is enriched with heavier isotope and rear end is enriched with lighter isotope. Further computational and experimental studies are underway

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

    International Nuclear Information System (INIS)

    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

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

    OpenAIRE

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

    2012-01-01

    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 ef...

  18. Standard specification for nuclear-grade gadolinium oxide (Gd2O3) powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This specification provides the chemical and physical requirements for nuclear-grade gadolinium oxide powder intended for subsequent processing and use in nuclear fuel applications, for example, as an addition to uranium dioxide. 1.2 This specification does not include requirements for health and safety. Observance of this specification does not relieve the user of the obligation to be aware of and comply with all federal, state, and local regulations pertaining to possessing, shipping, processing, or using this material. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

  19. Gadolinio y fibrosis sistémica nefrogénica Gadolinium and nephrogenic systemic fibrosis

    Directory of Open Access Journals (Sweden)

    Claudia Cejas

    2012-06-01

    Full Text Available Inicialmente llamada dermopatía fibrosante nefrogénica, la fibrosis sistémica nefrogénica (FSN está fuertemente ligada a la inyección endovenosa de medios de contraste -basados en gadolinio- en pacientes con insuficiencia renal. En esta revisión corta se analiza la fisiopatología y la clínica, la responsabilidad del radiólogo en la prevención a través de la puesta en práctica de las reglamentaciones vigentes y, por último, se mencionan algunos conceptos sobre el tratamiento de los pacientes con insuficiencia renal crónica que deben exponerse a la inyección de gadolinio.Nephrogenic systemic fibrosis (NSF, initially called nephrogenic fibrosing dermopathy, is strongly linked to the intravenous injection of gadolinium-based contrast agents in patients with renal insufficiency. In this short review, we analyze the pathophysiology and clinical signs and symptoms, the medical responsibility of the radiologist in prevention through the implementation of the existing regulations and, finally, some concepts on the treatment of patients with chronic renal insufficiency who must receive a gadolinium injection.

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

    Science.gov (United States)

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

    2016-06-01

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

  1. Selective photoionization of gadolinium isotopes with a polarized laser

    International Nuclear Information System (INIS)

    The aim of this study is the use of gadolinium 157 as burnable poison in nuclear reactors. Spectroscopic isotopic displacements between Gd 156 and Gd 157 are low and the separation method studied is based on differentiated behavior, concerning polarized light, of even and odd gadolinium isotopes coming from their difference of nuclear spin. On this principle is based the simplest photoionization scheme. Selective ionization of odd isotopes is realized from the fundamental state with three resonating photons colinearly polarized. The experimental study confirms the possibility of efficient photoionization. The measured selectivity between Gd 157 and even isotope is over 48 in defined conditions because it can be destroyed by a magnetic field or if photons are not well polarized. Calculations and observations are in good agreement. Odd gadolinium isotope separation is feasible and effects preventing separation are evidenced

  2. Selective photoionization scheme for atomic gadolinium laser isotope separation

    International Nuclear Information System (INIS)

    The selective photoionization scheme for separating 157Gd from natural gadolinium and the laser irradiation conditions in order to enrich 157Gd to 60-80% are discussed in the case of two- and three-step photoionization. The dependence of excitation pathways on J-values is also discussed. From the view point of ionization rate it is preferable to select the four-colour three-step photoionization scheme by using both the ground and the lowest metastable levels. Optimum laser irradiation conditions for gadolinium isotope separation are presented. (author)

  3. Glioblastoma, gadolinium (III) and NCT. An in vitro study

    International Nuclear Information System (INIS)

    We treated cultured human glioblastoma cells with gadolinium (III) [gadopentetic acid] and we found that: a) cells do internalise this element; b) gadolinium can be localised in the cells nuclei; c) exposure of the cultures to a neutron beam produced a significant and immediate cell death. Although cell survival was also influenced in the irradiated controls it was further reduced (about 50%) in cells pre-exposed to 10 mg/ml gadopentetic acid. We also found that Gd uptake, as measured by ICP-AES, was concentration dependent. (author)

  4. Gadolinium-neutron capture reactions: A radiobiological assay

    International Nuclear Information System (INIS)

    Gadolinium neutron capture(GNC) takes advantage of its extraordinarily large cross section to thermal neutrons. In GNC reactions, prompt high energy gamma rays, x-rays and electrons are released. Because of the photons and electrons, the intracellular presence of gadolinium is not considered critical. This is an advantage over boron-neutron capture therapy where the intracellular presence of boron is required because of the short flight tracks of 2.4 MeV alpha particles. In this study, the radiation effect of GNC reactions was measured using Chinese hamster cells in an attempt to evaluate the contributions of neutrons, gamma rays and electrons on cell inactivation

  5. Growth of bulk gadolinium pyrosilicate single crystals for scintillators

    Science.gov (United States)

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

    2011-03-01

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

  6. Meta-analysis of diagnosis of liver metastatic cancers; comparison of 18FDG PET-CT and gadolinium-enhanced MRI

    International Nuclear Information System (INIS)

    We performed a meta-analysis to compare the performance of 18F-fluorodeoxyglucose (18FDG) positron emission tomography-CT (PET-CT) with that of gadolinium-enhanced MRI for the detection of liver metastatic cancers. The MEDLINE and EMBASE databases were searched for relevant original articles. The histology and/or imaging follow-up data served as the reference standard. We calculated the pooled sensitivities, specificities, positive likelihood ratios, negative likelihood ratios and constructed summary receiver operating characteristic curves for 18FDG PET-CT and gadolinium-enhanced MRI, respectively. Ten studies (1105 patients) were included for this meta-analysis. 18FDG PET-CT has similar patient-based specificity (1.00 and 0.99), positive likelihood ratios (253.1 and 138.2), negative likelihood ratios (0.16 and 0.10) and area under curves (0.99 and 0.99) with gadolinium-enhanced MRI. Gadolinium-enhanced MRI tends to have higher sensitivity (0.91 and 0.84) than 18FDG PET-CT. Both 18FDG PET-CT and gadolinium-enhanced MRI have excellent diagnostic performance for the detection of liver metastatic cancer.

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

    International Nuclear Information System (INIS)

    The feasibility of using a 109Cd 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. (note)

  8. Low Risk for Nephrogenic Systemic Fibrosis in Nondialysis Patients Who Have Chronic Kidney Disease and Are Investigated with Gadolinium-Enhanced Magnetic Resonance Imaging

    OpenAIRE

    Chrysochou, Constantina; Power, Albert; Shurrab, Aladdin E.; Husain, Sayed; Moser, Steven; Lay, James; Salama, Alan D.; Kalra, Philip A.

    2010-01-01

    Background and objectives: During the past decade, nephrogenic systemic fibrosis (NSF) has been reported in patients who have severe renal impairment and have been exposed to a gadolinium (Gd)-based contrast agent during magnetic resonance imaging (MRI). As a result of positive reporting bias, many suitable patients with chronic kidney disease (CKD) are being denied a highly important form of investigation that can be safely undertaken. We analyzed the safety of Gd-MRI in patients with CKD an...

  9. Characteristics of cerium-gadolinium oxide (CGO) suspensions as a function of dispersant and powder properties

    DEFF Research Database (Denmark)

    Phair, John; Lönnroth, Nadja; Lundberg, Mats;

    2009-01-01

    A series of concentrated suspensions ( = 0.18–0.34) of cerium-gadolinium oxide (CGO) in terpineol were prepared as a function of dispersant, powder surface area and solids concentration. The stability of the suspensions was assessed by rheological measurements including viscosity and oscillatory...... measurements. Six dispersants with different molecular weights and terminal groups were compared for their relative efficiency in dispersing the powders by viscosity measurements. A Rhodafac dispersant, a long chain polymer containing phosphoric acid terminal groups, was found to produce suspensions with the...

  10. Characterizing ProstivaTM RF Treatments of the Prostate for BPH with Gadolinium-Enhanced MRI

    Directory of Open Access Journals (Sweden)

    Christian Huidobro

    2009-01-01

    Full Text Available Transurethral needle ablation (TUNA is an accepted and effective therapy for the treatment of lower urinary tract symptoms (LUTS due to benign prostatic hyperplasia (BPH. ProstivaTM (Medtronic, Shoreview, MN is the newest-generation device, which includes a new needle design and radio frequency (RF generator. This device creates temperatures of 120°C and necrotic lesions in less than 2.5 min. Using previously described techniques, we analyzed dynamic, gadolinium-enhanced MRIs to characterize the ablative properties of the new ProstivaTM RF device.

  11. Fluorescent single-stranded DNA-based assay for detecting unchelated Gadolinium(III) ions in aqueous solution.

    Science.gov (United States)

    Edogun, Osafanmwen; Nguyen, Nghia Huu; Halim, Marlin

    2016-06-01

    The main concern pertaining to the safety of Gadolinium(III)-based contrast agents (GBCAs) is the toxicity caused by the unchelated ion, which may be inadvertently present in the solution due most commonly to excess unreacted starting material or dissociation of the complexes. Detecting the aqueous free ion during the synthesis and preparation of GBCA solutions is therefore instrumental in ensuring the safety of the agents. This paper reports the development of a sensitive fluorogenic sensor for aqueous unchelated Gadolinium(III) (Gd(III)). Our design utilizes single-stranded oligodeoxynucleotides with a specific sequence of 44 bases as the targeting moiety. The fluorescence-based assay may be run at ambient pH with very small amounts of samples in 384-well plates. The sensor is able to detect nanomolar concentration of Gd(III), and is relatively unresponsive toward a range of biologically relevant ions and the chelated Gd(III). Although some cross-reactivity with other trivalent lanthanide ions, such as Europium(III) and Terbium(III), is observed, these are not commonly found in biological systems and contrast agents. This convenient and rapid method may be useful in ascertaining a high purity of GBCA solutions. Graphical abstract Fluorescent aptamer-based assay for detecting unchelated Ln(III) ions in aqueous solution. PMID:27071762

  12. A Manganese Alternative to Gadolinium for MRI Contrast.

    Science.gov (United States)

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

    2015-12-16

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

  13. Importance of the use of gadolinium in neurocysticercosis diagnosis

    International Nuclear Information System (INIS)

    Magnetic Resonance (MRI) and Computed Tomography (CT) features of neurocysticercosis are variable and depend fundamentally on the stage in evolution of the infection, location, number and size of the cysts. The authors retrospectively evaluated MRI obtained on O.5 Tesla superconducting unit in four neurocysticercosis patients and observed new MRI features only after Gadolinium enhancement. (author)

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

    Directory of Open Access Journals (Sweden)

    Boiko R.S.

    2014-01-01

    Full Text Available 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.

  15. Gadolinium-enhanced MRI in cerebral Whipple's disease

    International Nuclear Information System (INIS)

    Confusion developed in a 44-year-old man, who had diarrhoea and weight loss for three months. Jejunal biopsy showed infiltration by PAS-positive macrophages, indicating Whipple's disease. Cranial MRI disclosed multiple lesions mainly in the white matter and grey-white matter junction better demonstrated after gadolinium injection. (orig.)

  16. MR imaging of gestational trophoblastic tumor: role of gadolinium enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Si Young; Byun, Jae Young; Kim, Bum Su; Yun, Young Hyun; Mun, Kyung Mi; Park, Kyung Sin; Kim, Byung Kee; Bae, Seog Nyeon; Shinn, Kyung Sub

    1997-12-01

    The purpose of this study is to investigate the role of gadolinium enhanced MR imaging in the evaluation of gestational trophoblastic tumors (invasive mole and choriocarcinoma). Pre-enhanced T1-and T2-weighted images and gadolinium enhanced T1-weighted images of 34 gestational trophoblastic tumors (15 choriocarcinomas, 19 invasive moles) were retrospectively evaluated and enhancement patterns were analyzed. Morphologica differences and structural characteristics were analyzed by the evaluation of tumor margin, patterns of hemorrhagic necroses, the development of intratumoral vascularity, and molar villi. Graded scores of MR findings between pre- and gadolinium enhanced images were based on the following criteria : 1) visualization of tumor margin 2) distinction between tumor necrosis and zone of trophoblastic proliferation ; and 3) molar villi. Statistical differences between graded scores of pre- and post-enhanced images were analyzed. Gadolinium enhanced MR imaging was helpful for the visualization of tumor characteristics in gestational trophoblastic tumors and in differential diagnosis between invasive mole and choriocarcinoma. (author). 16 refs., 4 tabs., 4 figs.

  17. Physical dose evaluation on gadolinium neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kagehira, Katsushi; Sakurai, Yoshinori [Kyoto Univ. (Japan). Faculty of Engineering; Kobayashi, Tooru; Kanda, Keiji; Akine, Yasuyuki

    1994-12-01

    Using thermal neutron irradiation field of Heavy Water Facility in Kyoto University Reactor (KUR), thermal neutron flux distributions and gamma-ray absorbed dose distributions inside a water phantom which contained natural abundant 500 ppm gadolinium region, were measured with gold wire and TLDs (Mg{sub 2}SiO{sub 4}:Tb), respectively. The experimental results were compared with the calculational results which were obtained using a two-dimensional transport code DOT 3.5. Consequently, the calculational results were in good agreement with experimental ones for thermal neutron flux distributions, and were almost in good agreement for gamma-ray absorbed dose rate distributions. But, the calculated data of gamma-ray absorbed dose were overestimated by about 30% in the gadolinium region. The dose contributions of internal conversion electrons and Auger electrons were evaluated by adding components of those electrons to neutron kerma factors of gadolinium. From the calculational results, it is found that those electrons give about 15% of total dose in the gadolinium region. (author).

  18. Joint electroreduction of lanthanum, gadolinium and boron in halide melts

    Directory of Open Access Journals (Sweden)

    Khushkhov KH.B.

    2003-01-01

    Full Text Available The joint electroreduction of La, Gd and B from chloride-fluoride melts has been studied by cyclic voltametry. Based on the analysis of voltamograms the possibility of electrosynthesis of lanthanum-gadolinium borides from chloride-fluoride melts has been shown.

  19. MRI dacryocystography after conjunctival application of gadolinium solution

    International Nuclear Information System (INIS)

    Purpose: To determine the efficacy of MRI for the lacrimal drainage system after conjunctival application of gadolinium-DTPA solution. Material and methods: MRI dacryocystography of 32 nasolacrimal duct systems was performed in 16 patients additional to digital subtraction dacryocystography. The gadolinium solution was prepared by diluting the commercially available gadolinium-DTPA (MagnevistR, Schering AG, Berlin) 1:10 in sterile saline solution. 3x2 drops of this contrast medium were instilled bilaterally immediately before MRI scanning. Results: MRI dacryocystography provided detailed information on the nasolacrimal duct system in all 32 cases. In 16 cases localisation and functional degree of nasolacrimal duct obstruction or stenosis was determined reliably. In 15 cases normal nasolacrimal duct system showed no contrast enhancement. In one case stenosis of the canaliculus was observed. Conclusion: MRI dacryocystography provides detailed morphological soft tissue information of the lacrimal drainage system. Local conjunctival application of gadolinium solution allows functional tests of the lacrimal duct system in patients suffering from epiphora. (orig.)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    1991-11-01

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

  2. Cardiac sarcoidosis evaluated with gadolinium-enhanced magnetic resonance and contrast-enhanced 64-slice computed tomography.

    Science.gov (United States)

    Smedema, Jan-Peter; Truter, Rene; de Klerk, Petra A; Zaaiman, Leonie; White, Leonie; Doubell, Anton F

    2006-09-20

    Sarcoidosis is a multi-system granulomatous disorder of unknown etiology with symptomatic cardiac involvement in up to 7% of patients. The clinical features of sarcoid heart disease include congestive heart failure, arrhythmias, conduction disturbances, and sudden death. We evaluated the value of contrast-enhanced multi-detector computed tomography in delineating myocardial scar and granulomatous inflammation by comparing our findings with gadolinium magnetic resonance in a patient diagnosed with cardiac sarcoidosis. PMID:16257460

  3. Prognostic value of late gadolinium enhancement in dilated cardiomyopathy patients: a meta-analysis

    International Nuclear Information System (INIS)

    Aim: To evaluate the association between late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR) and major adverse events in dilated cardiomyopathy (DCM) patients. Materials and methods: Databases, including PubMed, Ovid, and EMBASE, were searched for studies evaluating LGE at CMR in DCM patient prognostication. Clinical outcomes were analysed using fixed-effects models or, in cases of significant heterogeneity, random-effects models. Results: In the meta-analysis of 13 studies on 1675 DCM patients with a mean follow-up of 3 years, LGE is associated with all-cause mortality (pooled odds ratio, 3.43 [95% confidence interval, 2.26–5.22], p<0.00001), cardiac death/transplantation (3.65 [1.80–7.40], p=0.0003), hospitalisation for heart failure (2.87 [1.53–5.39], p=0.001), major arrhythmia events (sudden cardiac death, sustained ventricular tachycardia or fibrillation, appropriate implantable cardioverter–defibrillator (ICD) discharge/pacing, and syncope: 4.24 [2.95–6.08], p<0.00001), and sudden cardiac death (3.33 [1.80–6.17], p=0.0001). Conclusion: LGE in DCM patients appears to be associated with mortality and major cardiac events, underscoring its potential as an independent index for risk stratification and treatment guidance. -- Highlights: •Cardiac magnetic resonance imaging is a flourishing technique in the field of cardiomyopathy examination for its high space resolution. •Late gadolinium enhancement appears associated with increased risk for all-cause mortality and major cardiavascular events. •Late gadolinium enhancement by cardiac magnetic resonance might guide treatment and clinical care of heart failure patients

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

    Science.gov (United States)

    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

  5. The study of in vivo x-ray fluorescence (XRF) technique for gadolinium (Gd) measurements in human bone

    Science.gov (United States)

    Mostafaei, F.; Nie, L. H.

    2016-08-01

    An in vivo K x-ray fluorescence system, based on 109Cd source, for the detection of gadolinium has been investigated. Gd is of interest because of the extensive use of Gd-based contrast agents in MR imaging. A human simulating bone phantom set has been developed. The phantoms were doped with seven concentrations of Gd. Additional elements important for in vivo x-ray fluorescence, Na, Cl and Ca, were also included to create an overall elemental composition consistent with the Reference Man. A new 5 GBq 109Cd source was purchased to improve the source activity in comparison to the previous study (0.17 GBq). The previously published minimum detection limit (MDL) for Gd phantom measurements using KXRF system was 3.3 ppm. In this study the minimum detection limit for bare bone phantoms was found to reduce the MDL to 0.8, a factor of 4.1. The previous published data used only three layers of plastic as soft tissue equivalent materials and found the MDL of 4–4.8 ppm. In this study we have used the plastic with more realistic thicknesses to simulate a soft tissue at tibia. The detection limits for phantoms with Lucite as a tissue equivalent, using a new source, was determined to be 1.81 to 3.47 ppm (μg Gd per gram phantom). Our next study would be testing an in vivo K x-ray fluorescence system, based on 109Cd source on human volunteers who went through MR imaging and were injected by Gd.

  6. Production of high-purity gadolinium-153. 2. Removal of samarium, terbium, and microamounts of europium from gadolinium by extraction chromatography

    International Nuclear Information System (INIS)

    Extraction and extraction-chromatographic behavior of Sm, Eu, Gd, and Tb in the system di-2-ethylhexyl hydrogen phosphate (DEHP)-decane-nitric acid has been studied at various concentrations of nitric acid and lanthanide in aqueous phase. The optimal range of nitric acid concentrations for extraction-chromatographic separation of samarium, europium, gadolinium, and terbium has been determined. The influence of gadolinium concentration on distribution of europium and terbium has been examined. At gadolinium content in solution below 50% of the dynamic exchange capacity of the column, the gadolinium distribution coefficient slightly decreases with increasing gadolinium concentration in the initial solution, the distribution factors of the impurity lanthanides remaining virtually unchanged. With further increase in gadolinium content in the initial solution, the gadolinium distribution factor drastically decreases, and open-quotes tailsclose quotes are formed at the expense of increasing fraction of the extracted complex form GdA3. These data allowed a conclusion that composition of extracted complexes is different for Sm, Eu, Gd, and Tb. Conditions proposed for extraction-chromatographic purification of gadolinium in the system DEHP-decane-nitric acid provide for removal of impurity lanthanides (samarium, terbium, and microamounts of europium) with the purification factors greater than 100 (Sm, Tb) and about 2 (Eu) at the column charge of up to 50%

  7. Gadolinium-enhanced magnetic resonance angiography in brain death

    Science.gov (United States)

    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.

  8. Magneto-optical properties of gadolinium in interband absorption region

    International Nuclear Information System (INIS)

    Optical constants and magneto-optical effect of the change of reflected light intensity in equatorial magnetization for two incidence angles are measured in the range of 0.4-5 eV on polycrystalline gadolinium sample at the liquid nitrogen temperature. The frequency behaviour of diagonal and gyrotropic components of optical conductivity is calculated from the measurement data. In the framework of the Spicer indirect transition model the comparison is carried out of the conductivity frequency dispersion with the calculation of the energy dependence of the state density for the band systems with the spin projection parallel and perpendicular to magnetization, made by Harmon and Freeman. The main peculiarities of the interzone absorption in the optical and magnetooptical spectra are explained satisfactorily while the detailed correspondence between the experiment and calculation is absent. Therefore, a conclusion is made on the necessity of inclusion of vacant 4f-zones in the region of the Fermi level in the gadolinium zone spectra

  9. Gadolinium-containing phosphatidylserine liposomes for molecular imaging of atherosclerosis

    OpenAIRE

    Maiseyeu, Andrei; Mihai, Georgeta; Kampfrath, Thomas; Simonetti, Orlando P.; Sen, Chandan K.; Roy, Sashwati; Rajagopalan, Sanjay; Parthasarathy, Sampath

    2009-01-01

    Exteriorized phosphatidylserine (PS) residues in apoptotic cells trigger rapid phagocytosis by macrophage scavenger receptor pathways. Mimicking apoptosis with liposomes containing PS may represent an attractive approach for molecular imaging of atherosclerosis. We investigated the utility of paramagnetic gadolinium liposomes enriched with PS (Gd-PS) in imaging atherosclerotic plaque. Gd-PS-containing Gd-conjugated lipids, fluorescent rhodamine, and PS were prepared and characterized. Cellula...

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

    OpenAIRE

    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 an...

  11. Is gadolinium a helical antiferromagnet or a collinear ferromagnet?

    Indian Academy of Sciences (India)

    S N Kaul

    2003-03-01

    Controversial issues concerning the nature of magnetic ordering in gadolinium are briefly reviewed. The recent experimental results are shown to resolve most of such issues in that they rule out the possibility of a helical spin structure in Gd and clearly bring out the role of long-range dipolar interactions in stabilising collinear ferromagnetic order for temperatures between the spin-reorientation temperature and the Curie point.

  12. Thermodynamic studies in the system cerium-gadolinium-oxygen

    International Nuclear Information System (INIS)

    Two independent measuring methods have been applied to studying the phase relations of the system cerium-gadolinium. The calorimetric measurements have been done in a high-temperature calorimeter with cerium dioxide doped with 10 mole % of Gd2O3. Further thermodynamic quantities have been obtained by the electrochemical method and e.m.f. measurements, yielding additional information on disorders in doped cerium dioxide. (orig./BBR)

  13. Microwave and optical diagnostics in a gadolinium plasma

    International Nuclear Information System (INIS)

    The optimization of the separation process of the gadolinium isotopes by Ion Cyclotron Resonance requires a precise knowledge of the physical characteristics of the plasma. Thus, two kinds of diagnostics have been developed: the first one to estimate the microwave power inside the source and the second one to measure the density of atomic and ionic of the gadolinium inside the plasma source and in front of the collector. Microwave diagnostic: A microstrip antenna has been designed and developed in order to characterize the microwave at 36 GHz frequency in the plasma source. The experimental results for different plasma regimes are presented. The measurements inside the plasma source show a maximum of microwave absorption for an argon pressure of 10-4 mb (93% of absorption of the incident wave in the conditions of isotope separation). Laser absorption diagnostic: The theory of laser absorption in presence of a magnetic field is recalled and the first results are presented. In the spectral range between 560 and 620 nm, corresponding to high energy levels of gadolinium, no signal is obtained so that the density is below the detection limit 1010 cm-3. In the spectral range between 380 and 400 nm, two lines are observed, issue from the fundamental and metastable (633 cm-1) levels. The density of metastable level of gadolinium ions is about 1010 cm-3 with a relative precision of 15 % and its variation is studied as a function of argon pressure, at different sections of the plasma column (source, collector). The achieved set of measurements has been performed in order to check the theoretical models. (author)

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

    OpenAIRE

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

    2009-01-01

    Abstract 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.

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

    International Nuclear Information System (INIS)

    Aiming to explore the possibility of using the undoped rare-earth orthovanadates as scintillation materials, we developed the procedure for growth of gadolinium (GdVO4) and yttrium (YVO4) orthovanadate single crystals by Czochralski method, and determined the optimal conditions of their after-growth annealing. Optical, luminescent, and scintillation properties of YVO4 and GdVO4 were discussed versus known literature data. Scintillation characteristics of GdVO4 were determined for the first time.

  16. ELECTRICAL AND MAGNETIC PROPERTIES OF GADOLINIUM AND TERBIUM CLUSTER COMPOUNDS

    OpenAIRE

    Bauhofer, W.; Cockcroft, J; Kremer, R.; Mattausch, Hj.; Schwarz, C.; Simon, A.

    1988-01-01

    Gadolinium and terbium halides with halogen-to-metal ratios X/M < 2 contain distorted octahedral M6 units with a differing degree of condensation. With M2X3 being the only exception, additional non-metal atoms (hydrogen, carbon, silicon, nitrogen) occupy the cavities of the M6 units. The electrical behavior ranges from insulating to metallic. Temperature dependent metal-to-semiconductor transitions are observed for several compounds. The majority of the investigated materials exhibits antifer...

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

    Science.gov (United States)

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

    2012-02-01

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

  18. MRI of acute cerebral infarcts: increased contrast enhancement with continuous infusion of gadolinium

    International Nuclear Information System (INIS)

    We compared contrast enhancement on T1-weighted MRI of acute cerebral infarcts after conventional bolus administration and continuous infusion of gadolinium. We examined 12 patients with a history of acute stroke with contrast-enhanced MRI once a week for a 1 month. Only ischaemic lesions were investigated after cerebral haemorrhage had been excluded by CT. Each MRI study included T2- and proton density-weighted sequences for determination of the size and site of the infarct, immediate postinjection T1-weighted imaging after bolus administration of 0.1 mmol/kg gadolinium-DPTA and delayed T1-weighted imaging after additional continuous infusion of 0.1 mmol/kg over 2 h. A total of 42 MRI studies was performed. In the first week after the onset of stroke, most infarcts (8 of 10) did not enhance after bolus administration, whereas all showed distinct contrast enhancement after the infusion. In the following weeks all but two infarcts showed contrast enhancement after bolus administration; after continuous infusion contrast enhancement could be seen in all cases. While contrast enhancement after bolus administration showed the typical gyriform pattern, enhanced areas were more extensive after the infusion and usually covered the entire infarcted area shown on T2- and proton density-weighted images. We presume that the disturbed blood-brain barrier in ischaemic areas favours delivery of contrast medium to the infarcted tissue if it is offered continuously so that a steady state can develop. (orig.)

  19. Differential diagnosis and prognosis of T1-weighted post-gadolinium intralabyrinthine hyperintensities

    Energy Technology Data Exchange (ETDEWEB)

    Dubrulle, F.; Puech, P.; Ernst, O. [University Nord of France, Department of Radiology, CHU Lille, Huriez Hospital INSERM, Lille (France); Kohler, R. [CHU Lille, Huriez Hospital, Department of Radiology, Lille (France); Vincent, C. [CHU Lille, Department of Otology and Oto-neurosurgery, Lille (France)

    2010-11-15

    The aim of this longitudinal study is to describe the different intralabyrinthine lesions yielding high signal intensity on T1-weighted (T1W) images after intravenous gadolinium and then to analyze the follow-up of these patients. Thirty-seven patients were included and followed clinically and radiologically. A precise analysis of MR labyrinthine signals allowed exact depiction of the different lesions. Special interest is focused on the intralabyrinthine fluid signal on 3D high-resolution T2W images. The enhanced T1W labyrinthine hyperintensities correspond to two different categories: intralabyrinthine enhancement (15 intralabyrinthine schwannomas, 13 labyrinthitis, 1 inflammatory granuloma) and spontaneous T1W hyperintensities (8 intralabyrinthine hemorrhages). Hemorrhagic lesions show a substantial decrease of the intralabyrinthine fluid signal on the 3D HRT2 that evolves to ossification. In labyrinthitis, the importance of the initial labyrinthine fluid signal decrease on the 3D HRT2 is well correlated with the hearing prognosis. A meticulous analysis of inner ear lesions allows various intralabyrinthine lesions, in particular schwannomas, to be differentiated from labyrinthitis. T1W imaging without gadolinium is essential for the correct diagnosis of rapidly evolving hearing loss. In labyrinthitis and intralabyrinthine hemorrhage, 3D HRT2 brings an interesting prognostic factor for the chance of hearing recovery. (orig.)

  20. Structural study of some gadolinium glass ceramics obtained by sol-gel method

    International Nuclear Information System (INIS)

    Increased interest in silicate systems containing different rare earth oxides has resulted from their important applications in various fields of technology including laser, optical fiber and optical waveguides in telecommunication applications, microelectronics and catalysis. Glass-ceramics of 0.95 SiO2-0.05 Na2O composition containing up to 15% molar Gd2O3 were obtained by the sol-gel method. We chose the sol-gel method because this offers the advantage of a good chemical homogeneity and a better control of physical and chemical properties in comparison with traditional methods used to obtain glasses and ceramics. The obtained samples were pressed at 200 kgf/cm2 as disks with a diameter of Φ=22 mm and a thickness of around 1 mm. Then, they were heat-treated at 250 deg C, 500 deg C and 1000 deg C for about 48 hours. The structural study was made using X-ray diffraction, scanning electron microscopy (SEM) and IR spectroscopy. The X-ray diffraction patterns show that addition of Gd2O3 exerts an important influence on the crystallization process of the studied samples. The crystalline phase decreases with increasing the Gd2O3 concentration. SEM data support this assertion. IR spectra point out also that the increasing of the gadolinium oxide content and the thermal treatment temperature produce the strengthening of the glass ceramic network. Thus, the gadolinium ions play the role of network modifier of the glass ceramic structure. (authors)

  1. High temperature interaction studies on equimolar nitrate mixture of uranyl nitrate hexahydrate and gadolinium nitrate hexahydrate

    International Nuclear Information System (INIS)

    Rare earths including gadolinium form a sizeable fraction of the fission products in the nuclear fission of fissile material in the reactor. These fission products can interact with uranium dioxide fuel and can form various compounds which can alter the thermal behavior of the fuel. The mixed oxide formed due to the high temperature interactions of mixture of uranyl nitrate hexahydrate (UNH) and gadolinium nitrate hexahydrate (GdNH) has been studied using thermal and X- ray diffraction techniques. The equimolar mixture of UNH and GdNH was prepared by mixing the weighed amount of individual nitrates and grinding gently with mortar and pestle. Thermogravimetry (TG) measurements were carried out by separately heating 100 mg of mixture and individual nitrates at heating rate of 10°C min-1 using Netzsch thermal analyzer (Model No.: STA 409 PC Luxx) in high purity nitrogen atmosphere with a flow rate of 120 mL min-1. The XRD measurement was carried out on a Philips X-ray diffractometer (Model PW1710) using nickel-filtered Cu-Kα radiation

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

    Directory of Open Access Journals (Sweden)

    Sebastian Kelle

    2010-01-01

    Full Text Available 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.

  3. Prognostic implication of late gadolinium enhancement on cardiac MRI in light chain (AL) amyloidosis on long term follow up

    International Nuclear Information System (INIS)

    Light chain amyloidosis (AL) is a rare plasma cell dyscrasia associated with poor survival especially in the setting of heart failure. Late gadolinium enhancement (LGE) on cardiac MRI was recently found to correlate with myocardial amyloid deposition but the prognostic role is not established. The aim is to determine the prognostic significance of LGE in AL by comparing long term survival of AL patients with and without LGE. Twenty nine consecutive patients (14 females; 62 ± 11 years) with biopsy-proven AL undergoing cardiac MRI with gadolinium as part of AL workup were included. Survival was prospectively followed 29 months (median) following MRI and compared between those with and without LGE by Kaplan-Meier and log-rank analyses. LGE was positive in 23 subjects (79%) and negative in 6 (21%). Left ventricular ejection fraction was 66 ± 17% in LGE-positive and 69 ± 12% in LGE-negative patients (p = 0.8). Overall 1-year mortality was 36%. On follow-up, 14/23 LGE-positive and none of LGE-negative patients died (log rank p = 0.0061). Presenting New York Heart Association heart failure class was also associated with poor survival (p = 0.0059). Survival between two LGE groups stratified by heart failure class still showed a significant difference by a stratified log-rank test (p = 0.04). Late gadolinium enhancement is common and is associated with poor long-term survival in light chain amyloidosis, even after adjustment for heart failure class presentation. The prognostic significance of late gadolinium enhancement in this disease may be useful in patient risk-stratification

  4. Microwave and optical diagnostics in a gadolinium plasma; Diagnostics hyperfrequence et optique dans un plasma magnetise de gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Larousse, B. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes d`Enrichissement]|[Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France)

    1997-12-31

    The optimization of the separation process of the gadolinium isotopes by Ion Cyclotron Resonance requires a precise knowledge of the physical characteristics of the plasma. Thus, two kinds of diagnostics have been developed: the first one to estimate the microwave power inside the source and the second one to measure the density of atomic and ionic of the gadolinium inside the plasma source and in front of the collector. Microwave diagnostic: A microstrip antenna has been designed and developed in order to characterize the microwave at 36 GHz frequency in the plasma source. The experimental results for different plasma regimes are presented. The measurements inside the plasma source show a maximum of microwave absorption for an argon pressure of 10{sup -4} mb (93% of absorption of the incident wave in the conditions of isotope separation). Laser absorption diagnostic: The theory of laser absorption in presence of a magnetic field is recalled and the first results are presented. In the spectral range between 560 and 620 nm, corresponding to high energy levels of gadolinium, no signal is obtained so that the density is below the detection limit 10{sup 10} cm{sup -3}. In the spectral range between 380 and 400 nm, two lines are observed, issue from the fundamental and metastable (633 cm{sup -1}) levels. The density of metastable level of gadolinium ions is about 10{sup 10} cm{sup -3} with a relative precision of 15 % and its variation is studied as a function of argon pressure, at different sections of the plasma column (source, collector). The achieved set of measurements has been performed in order to check the theoretical models. (author) 32 refs.

  5. Safety of Gadoterate Meglumine (Gd-DOTA) as a Contrast Agent for Magnetic Resonance Imaging

    OpenAIRE

    Ishiguchi, Tsuneo; Takahashi, Shoki

    2012-01-01

    Background: Safety is a primary concern with contrast agents used for MRI. If precautions could be taken before the repeated administration of gadolinium-based contrast media, then the awareness and management of adverse reactions would be more efficient. Objectives: To assess the safety and efficacy of gadoterate meglumine (Gd-DOTA) [Magnescope® in Japan, Dotarem® in other countries], a gadolinium-based contrast agent, in patients undergoing imaging of the brain/spinal cord and/or trunk/limb...

  6. Effect of high concentration gadolinium nitrate in reactor moderator system

    International Nuclear Information System (INIS)

    Gadolinium is used as a neutron poison in nuclear reactors to control the reactivity because it has high thermal neutron absorption cross section (∼49,000 b) and good solubility in water. Gadolinium nitrate is added with nitric acid to the moderator heavy water and the pH is maintained in the range of 5.0 to 5.5 to prevent gadolinium precipitation. Usually the concentration of gadolinium (Gd3+) used is ∼15 ppm during the actuation of secondary shutdown system. In the moderator system of a proposed tube type boiling water nuclear reactor of Indian origin, a higher concentration (20-400 ppm) of soluble neutron poison, Gd(NO3)3 is proposed to be used in the emergency safety shutdown system. Effect of this high concentration of gadolinium nitrate in the reactor moderator is evaluated from the angle of generation of molecular products viz. H2 and H2O2 due to radiolysis. H2 yield was found to increase linearly with absorbed dose (10 - 100 kGy). With increasing Gd concentration there was increase in H2 yield but the increase was marginal in 100 to 400 ppm range. Both the initial yield and saturated concentrations of H2O2 (at higher doses) in normal and off - normal conditions were also estimated. It was observed that the head space provided above the liquid phase in irradiation zone has a substantial effect on the generation of H2. With decreasing head space, H2 generation increased and went through a maximum. Production of H2O2 was also observed to be decreased in case of fully filled samples as compared to the ∼ 60% filled cases. Radiolysis of Gd(NO3)3 in high purity D2O was carried out to see the isotope effect and D2 formation was observed to be lowered than H2 for same Gd(NO3)3 concentration solutions in light water. The above results were discussed in detail in this paper. (author)

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

    International Nuclear Information System (INIS)

    Highlights: ► MR contrast agents exert influence on T1 or T2 relaxation time of the surrounding tissue. ► Combined use of iron oxide and Gd-DTPA can improve the sensitivity/specificity of lesion detection. ► Dual contrast MRI enhances the delineation of tumor borders and small lesions. ► The effect of DC-MRI can come from the high paramagnetic susceptibility of Gd3+. ► 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 (T1) or transverse (T2) 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 T2 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 T2 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 delineation of tumor borders and small lesions. Conclusions: DC-MRI will be helpful to improve diagnostic accuracy and decrease the threshold size for lesion

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 (China); Huang, Xinglu [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Qian, Chunqi [Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD 20892 (United States); Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 (China); Zhu, Lei [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 (China); Hida, Naoki [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Niu, Gang, E-mail: niug@mail.nih.gov [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Chen, Xiaoyuan, E-mail: shawn.chen@nih.gov [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States)

    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

  9. Diagnostic Magnetic Resonance Imaging of Atherosclerosis in Apolipoprotein E Knockout Mouse Model Using Macrophage-Targeted Gadolinium-Containing Synthetic Lipopeptide Nanoparticles

    Science.gov (United States)

    Shen, Zu T.; Zheng, Shaokuan; Gounis, Matthew J.; Sigalov, Alexander B.

    2015-01-01

    Cardiovascular disease is the leading cause of death in Western cultures. The vast majority of cardiovascular events, including stroke and myocardial infarction, result from the rupture of vulnerable atherosclerotic plaques, which are characterized by high and active macrophage content. Current imaging modalities including magnetic resonance imaging (MRI) aim to characterize anatomic and structural features of plaques rather than their content. Previously, we reported that macrophage-targeted delivery of gadolinium (Gd)-based contrast agent (GBCA-HDL) using high density lipoproteins (HDL)-like particles significantly enhances the detection of plaques in an apolipoprotein (apo) E knockout (KO) mouse model, with an atherosclerotic wall/muscle normalized enhancement ratio (NER) of 120% achieved. These particles are comprised of lipids and synthetic peptide fragments of the major protein of HDL, apo A-I, that contain a naturally occurring modification which targets the particles to macrophages. Targeted delivery minimizes the Gd dose and thus reduces the adverse effects of Gd. The aims of the current study were to test whether varying the GBCA-HDL particle shape and composition can further enhance atherosclerotic plaque MRI and control organ clearance of these agents. We show that the optimized GBCA-HDL particles are efficiently delivered intracellularly to and uptaken by both J774 macrophages in vitro and more importantly, by intraplaque macrophages in vivo, as evidenced by NER up to 160% and higher. This suggests high diagnostic power of our GBCA-HDL particles in the detection of vulnerable atherosclerotic plaques. Further, in contrast to discoidal, spherical GBCA-HDL exhibit hepatic clearance, which could further diminish adverse renal effects of Gd. Finally, activated macrophages are reliable indicators of any inflamed tissues and are implicated in other areas of unmet clinical need such as rheumatoid arthritis, sepsis and cancer, suggesting the expanded diagnostic

  10. Gadobutrol: an alternative contrast agent for digital subtraction dacryocystography

    International Nuclear Information System (INIS)

    We report the application of gadobutrol as a contrast medium for digital subtraction dacryocystography (DS-DCG) in patients with known allergy to iodinated contrast agent. Gadobutrol has the double gadolinium concentration (1.0 mmol/ml) of other gadolinium-based contrast agents. Quality of the DS-DCG images obtained with gadobutrol was comparable to DS-DCG images obtained with iodinated contrast medium. Radiodensity measurements using a micro-CT scanner confirmed a high radiodensity of gadobutrol which was comparable to the radiodensity of iopentol with a iodine concentration of 250 mg/ml and only approximately 20% lower than the radiodensity of iopentol with a concentration of 300 mg/l. Gadobutrol is a well-suited substitute for DS-DCG in patients with allergy to iodinated contrast agents. (orig.)

  11. Magnetic resonance lymphography of profundus lymph nodes with liposomal gadolinium-diethylenetriamine pentaacetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Yoshiko; Oku, Naoto [Univ. of Shizuoka (Japan). School of Pharmaceutical Sciences; Okuhata, Yoshitaka; Tyngi, Shia; Namba, Yukihiro

    2000-01-01

    Lymphography, especially imaging of profundus lymph nodes, is a useful tool for diagnosis of cancer metastases in lymph nodes. However, positive enhancement agents for magnetic resonance lymphography (MRL) have not been available, since the positive imaging agents so far introduced are low-molecular-weight materials that are not trapped in lymph nodes. For the purpose of improved positive enhanced MRL, we employed liposomes as carriers of a positive enhancer, gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). Magnetic resonance (MR) imaging was performed after subcutaneous injection of Gd-liposomes into the hind feet of rabbits which had reactive enlarged retroperitoneal lymph nodes. As a result, not only popliteal but also profundus retroperitoneal lymph nodes were positively enhanced by Gd-liposomes, especially after 20 min massage of the injected sites. Gd-Liposomes containing dipalmitoylphosphatidylglycerol were more effective than Gd-liposomes containing palmityl-D-glucuronide, a type of long-circulating liposomes, suggesting that liposomal accumulation in lymph node is, at least partly, mediated by the trapping of liposomes by macrophages. These data show that liposomes modified with Gd-DTPA are effective for positive enhancement of both regional and profundus lymph nodes in MR lymphography. (author)

  12. Magnetic resonance lymphography of profundus lymph nodes with liposomal gadolinium-diethylenetriamine pentaacetic acid

    International Nuclear Information System (INIS)

    Lymphography, especially imaging of profundus lymph nodes, is a useful tool for diagnosis of cancer metastases in lymph nodes. However, positive enhancement agents for magnetic resonance lymphography (MRL) have not been available, since the positive imaging agents so far introduced are low-molecular-weight materials that are not trapped in lymph nodes. For the purpose of improved positive enhanced MRL, we employed liposomes as carriers of a positive enhancer, gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). Magnetic resonance (MR) imaging was performed after subcutaneous injection of Gd-liposomes into the hind feet of rabbits which had reactive enlarged retroperitoneal lymph nodes. As a result, not only popliteal but also profundus retroperitoneal lymph nodes were positively enhanced by Gd-liposomes, especially after 20 min massage of the injected sites. Gd-Liposomes containing dipalmitoylphosphatidylglycerol were more effective than Gd-liposomes containing palmityl-D-glucuronide, a type of long-circulating liposomes, suggesting that liposomal accumulation in lymph node is, at least partly, mediated by the trapping of liposomes by macrophages. These data show that liposomes modified with Gd-DTPA are effective for positive enhancement of both regional and profundus lymph nodes in MR lymphography. (author)

  13. Clinical use of intravenous gadolinium-DTPA in magnetic resonance imaging of the central nervous system

    International Nuclear Information System (INIS)

    Following extensive pharmacological and animal studies clinical trials with intravenous gadolinium-DTPA (Gd-DTPA) were begun at the end of 1983. During 1984 one group in Berlin and another in London conducted clinical trials. During 1985 Gd-DTPA was released more widely and now over 20 groups in Europe and four in the United States are involved in clinical evaluation programmes. Gd-DTPA is the first parenteral magnetic contrast agent available for clinical use and the results of these clinical trials have been followed with considerable interest. In general terms the clinical results with Gd-DTPA parallel those seen with iodinated contrast agents used in X-ray computed tomography (CT) but there are important differences, particularly in relation to the use of pulse sequences and effects due to increased concentration of Gd-DTPA. In this chapter the mode of action of Gd-DTPA is reviewed and the clinical results in the central nervous system are summarised

  14. Environmental behaviour und ecotoxiology of gadolinium-containing MRT contrast media

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) is an essential tool in noninvasive diagnostics. In order to improve the sensitivity and specificity of diagnoses, several contrast enhancing agents have been developed in the last few decades by various pharmaceutical manufacturers. Gadolinium (Gd), a lanthanide, is the most widely used metal in MRI contrast agents. Its ion has paramagnetic properties (seven unpaired electrons) and a very long electronic relaxation time. Due to the toxicity of free Gd, clinical use is only possible in a complexed form. Commonly used chelating agents are polyamino-polycarboxylic ligands such as DTPA. Due to the exceptional stability of these highly hydrophilic chelates and the lack of human metabolism, the contrast media are quantitatively excreted unchanged after the administration, and are subsequently emitted into the aquatic environment. Several studies have shown notable increases in Gd concentrations in surface or groundwaters receiving sewage effluents, an observation which has been termed ''Gd anomaly''. The Gd anomaly results from the use of MRI contrast agents for which the most significant entry route is the effluent from wastewater treatment works. Relatively little information on the aquatic toxicity of Gd or Gd-chelates has been published up to 2006. Therefore, in a first step, the acute aquatic toxicity of several MRI contrast agents was investigated in fish, daphnia and algae at high concentrations. Furthermore, chronic toxicity tests on fish and daphnia were conducted. The results showed that contrast enhancing agents containing Gd have no toxic effects on the tested organisms at concentrations being of relevance to the environment. At high concentrations growth inhibition of green algae was observed. The environmental fate and the biological degradation of the contrast media was studied in a model wastewater treatment plant and in aquatic sediment systems. The test compounds were neither biodegradable in the treatment plants nor in

  15. Thermal conductivity of the gadolinium calcium silicate apatites: Effect of different point defect types

    International Nuclear Information System (INIS)

    The apatite crystal structure of the gadolinium calcium silicates can accommodate a wide range of point defects, including oxygen and cation vacancies, as well as anti-site defects, depending on the Gd/Ca ratio. Compositions having only cation or oxygen vacancies were identified and the thermal diffusivity and conductivity were measured up to 1000 deg. C. All the compositions, including the stoichiometric composition, exhibit low thermal conductivities from room temperature to high temperature with the defect-containing compositions having even lower thermal conductivities. The high-temperature thermal conductivity, at temperatures below the onset of significant radiative heat transport, decreases with the inverse square root of the cation and anion vacancy concentration, consistent with simple defect scattering models. Based on the data, it is concluded that the oxygen vacancies are slightly more effective in reducing thermal conductivity.

  16. Similar effects of disease-modifying antirheumatic drugs, glucocorticoids, and biologic agents on radiographic progression in rheumatoid arthritis: meta-analysis of 70 randomized placebo-controlled or drug-controlled studies, including 112 comparisons

    DEFF Research Database (Denmark)

    Graudal, Niels; Jürgens, Gesche

    2010-01-01

    To define the differences in effects on joint destruction in rheumatoid arthritis (RA) patients between therapy with single and combination disease-modifying antirheumatic drugs (DMARDs), glucocorticoids, and biologic agents.......To define the differences in effects on joint destruction in rheumatoid arthritis (RA) patients between therapy with single and combination disease-modifying antirheumatic drugs (DMARDs), glucocorticoids, and biologic agents....

  17. Recombinant high-density lipoprotein nanoparticles containing gadolinium-labeled cholesterol for morphologic and functional magnetic resonance imaging of the liver

    Directory of Open Access Journals (Sweden)

    Rui M

    2012-07-01

    Full Text Available Mengjie Rui,1 Wei Guo,2 Qian Ding,2 Xiaohui Wei,2 Jianrong Xu,3 Yuhong Xu21School of Life Science and Biotechnology, 2School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People's Republic of China; 3Department of Radiology, Renji Hospital Affiliation with Medical School of Shanghai Jiao Tong University, Shanghai, People's Republic of ChinaBackground: Natural high-density lipoproteins (HDL possess important physiological functions to the transport of cholesterol from the peripheral tissues to the liver for metabolic degradation and excretion in the bile.Methods and results: In this work, we took advantage of this pathway and prepared two different gadolinium (Gd-DTPA-labeled cholesterol-containing recombinant HDL nanoparticles (Gd-chol-HDL and Gd-(chol2-HDL as liver-specific magnetic resonance imaging (MRI contrast agents. The reconstituted HDL nanoparticles had structural similarity to native HDL, and could be taken up by HepG2 cells via interaction with HDL receptors in vitro. In vivo MRI studies in rats after intravenous injections of 10 µmol gadolinium per kg of recombinant HDL nanoparticles indicated that both nanoparticles could provide signal enhancement in the liver and related organs. However, different T1-weighted image details suggested that they participated in different cholesterol metabolism and excretion pathways in the liver.Conclusion: Such information could be highly useful to differentiate functional changes as well as anatomic differences in the liver. These cholesterol-derived contrast agents and their recombinant HDL preparations may warrant further development as a new class of contrast agents for MRI of the liver and related organs.Keywords: magnetic resonance imaging, apolipoprotein, high-density lipoprotein, contrast agent, gadolinium, liver

  18. Multifunctional Silica Particles as Contrast Agents for Optical and Magnetic Resonance Imaging

    OpenAIRE

    Feldmann, Verena

    2011-01-01

    The development of magnetic resonance imaging (MRI) towards one of the most powerful techniques in clinical diagnosis is accompanied by progress in the design of paramagnetic contrast agents (CAs) to enhance imaging sensitivity. Most of the currently applied CAs for enhanced T1-contrast are based on gadolinium(III)-chelate-complexes and are mainly extracellular agents which only distribute non-specifically throughout the circulatory system and interstitial space. Since those agents are excret...

  19. Trace determination of gadolinium in biomedical samples by diode laser-based multi-step resonance ionization mass spectrometry.

    Science.gov (United States)

    Blaum, K; Geppert, C; Schreiber, W G; Hengstler, J G; Müller, P; Nörtershäuser, W; Wendt, K; Bushaw, B A

    2002-04-01

    The application of high-resolution multi-step resonance ionization mass spectrometry (RIMS) to the trace determination of the rare earth element gadolinium is described. Utilizing three-step resonant excitation into an autoionizing level, both isobaric and isotopic selectivity of >10(7) were attained. An overall detection efficiency of approximately 10(-7) and an isotope specific detection limit of 1.5 x 10(9) atoms have been demonstrated. When targeting the major isotope (158)Gd, this corresponds to a total Gd detection limit of 1.6 pg. Additionally, linear response has been demonstrated over a dynamic range of six orders of magnitude. The method has been used to determine the Gd content in various normal and tumor tissue samples, taken from a laboratory mouse shortly after injection of gadolinium diethylenetriaminepentaacetic acid dimeglumine (Gd-DTPA), which is used as a contrast agent for magnetic resonance imaging (MRI). The RIMS results show Gd concentrations that vary by more than two orders of magnitude (0.07-11.5 microg mL(-1)) depending on the tissue type. This variability is similar to that observed in MRI scans that depict Gd-DTPA content in the mouse prior to dissection, and illustrates the potential for quantitative trace analysis in microsamples of biomedical materials. PMID:12012186

  20. To gadolinium using for neutron capture therapy researches at WWR-SM reactor

    International Nuclear Information System (INIS)

    The analysis of using gadolinium (isotope and natural) for the medical purposes in neutron-capture therapy of cancer diseases is carried out. Results of definition of the epithermal neutron beam irradiation dose for biological objects with gadolinium-containing preparations are presented by using the WWR-SM reactor. (authors)

  1. Legg-Perthes-Calve disease: staging by MRI using gadolinium

    International Nuclear Information System (INIS)

    Twenty-one patients (26 hips) with typical signs of Legg-Perthes-Calve (LPC) disease on plain radiographs were explored by MRI. Patients were imaged with a 0.5 T MR unit. Gadolinium-enhanced spinecho MR images were obtained after nonenhanced T1-weighted (spin-echo) and T2*-weighted (gradient-echo) images. Four different areas were identified in the femoral epiphysis (necrosis, regenerative, cartilaginous and normal fatty bone tissue). The histological evolution of LPC is well described by Catterall and others. Comparing their descriptions with out MR findings, we suggest classification ofLPC into five phases: necrosis: regeneration, reconstruction, reossification and sequelae. (orig.)

  2. Magnetoresistance of polycrystalline gadolinium with varying grain size

    International Nuclear Information System (INIS)

    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

  3. Dual-Energy X-Radiography With Gadolinium Filter

    Science.gov (United States)

    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.

  4. Peculiarities of electronic structure of gadolinium-scandium-gallium garnet

    International Nuclear Information System (INIS)

    Results of precision X-ray diffraction investigation into gadolinium-scandium-gallium garnet monocrystal (GSGG) grown from Gd3Se1.6Ga3.4O12 composition melt are presented. The crystal space group is Ia3d, Z=8, a=12.549A. The data obtained testify to a complex character of electron distribution in GSGG. Gd-O chemical bond is much of ion character and a part of electron density is transferred from cation to O atoms and auther part is aspherically concentrated near the cation

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

    Energy Technology Data Exchange (ETDEWEB)

    Voloshina, O.V., E-mail: lvoloshina@isma.kharkov.ua [Institute for scintillation materials NAS of Ukraine, 60, Lenin av., 61001 Kharkov (Ukraine); Baumer, V.N. [SSI ' Institute for single crystals' NAS of Ukraine, 60, Lenin av., 61001 Kharkov (Ukraine); Bondar, V.G.; Kurtsev, D.A.; Gorbacheva, T.E.; Zenya, I.M.; Zhukov, A.V.; Sidletskiy, O.Ts. [Institute for scintillation materials NAS of Ukraine, 60, Lenin av., 61001 Kharkov (Ukraine)

    2012-02-01

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

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

    OpenAIRE

    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...

  7. Similar effects of disease-modifying antirheumatic drugs, glucocorticoids, and biologic agents on radiographic progression in rheumatoid arthritis: meta-analysis of 70 randomized placebo-controlled or drug-controlled studies, including 112 comparisons

    DEFF Research Database (Denmark)

    Graudal, Niels; Jürgens, Gesche

    2010-01-01

    To define the differences in effects on joint destruction in rheumatoid arthritis (RA) patients between therapy with single and combination disease-modifying antirheumatic drugs (DMARDs), glucocorticoids, and biologic agents....

  8. Patterns of disease on MRI in 53 children with tuberculous spondylitis and the role of gadolinium

    International Nuclear Information System (INIS)

    Tuberculosis (TB) of the spine is the most common site of osseous involvement and has a higher prevalence in developing nations with an increasing incidence in developed nations. There are few paediatric reports of TB spondylitis (TBS) that include MRI findings.Objective. To determine the MRI characteristics of TBS in children with special reference to gadolinium enhancement and findings on follow-up MRI.Materials and methods. A retrospective review of patient records and MRI scans by three readers using a consensus method of 53 patients below 13 years of age.Results. Seventy-nine percent presented with kyphosis. MRI showed thoracic involvement in 83%. Eighty-five percent showed contiguous involvement of two or more vertebral bodies. An intraspinal or paraspinal soft-tissue mass or abscess was present in 98%. Subligamentous extension was noted in 64% of patients. Gadolinium was administered in 26 patients. Ring enhancement of the soft-tissue mass was shown in 65% of these. Subligamentous enhancement was shown in 35% and bone enhancement was shown in 100% of patients. Follow-up MRI performed in 16 patients showed progressive bone destruction in 10 patients, progressive kyphosis in 2 patients and progression of soft-tissue disease in 4 patients.Conclusions. We have demonstrated an advanced pattern of TBS in this childhood population, which supports other reports that describe a more aggressive process in children. Kyphosis and cord compressions were the most common complications. The use of gadolinium is promising in detecting disease earlier, as it invariably results in bone enhancement and may assist in making the diagnosis when the rim-enhancing pattern of the soft-tissue mass is demonstrated. Follow-up imaging with MRI is a suitable way of assessing resolution of cord compression and decrease in size of the soft-tissue mass. Therefore, considering the pattern of involvement in children with TBS demonstrated by this study, MRI is considered an ideal modality for

  9. Enhancement of the normal pancreas: comparison of manganese-DPDP and gadolinium chelate

    International Nuclear Information System (INIS)

    The purpose of this paper was to compare manganese-DPDP (Mn-DPDP) and gadolinium chelate (Gd-DTPA) contrast agents for enhancement of the normal pancreas. A total of 14 patients with focal liver disease underwent Mn-DPDP-and Gd-DTPA-enhanced 1.5 T MR examinations using spoiled gradient-echo (FLASH) technique at two separate times. Contrast agents were injected according to the currently recommended practices; Gd-DTPA was injected as a rapid bolus injection in a dosage of 0.1 mmol/kg, and Mn-DPDP was injected as a slow IV injection in a dosage of 5 μmol/kg. Quantitative region of interest measurements were made in 11 patients, and percent contrast enhancement of the pancreas and pancreas-fat signal-to-noise ratios (SNR) were determined for each agent. Images were also evaluated qualitativley by consensus reading of two investigators and overall scan quality was rated on a scale from 1 (poor) to 4 (very good). Enhancement of the pancreas immediately post Gd-DTPA was significantly higher than 15 min post Mn-DPDP (73.3 vs 36.3%; p=0.003). On postcontrast images the pancreas-fat SNR measruements were 7.7 (i.e., pancreas higher in signal than fat) and -6.1 for Gd-DTPA and Mn-DPDP, respectively, which was significantly different (p<0.001). Image quality was rated as 3.1 and 2.5 for Gd-DTPA- and Mn-DPDP-enhanced images, respectively. The normal pan creas enhances significantly more with Gd-DTPA than with Mn-DPDP administered under the conditions of this study. Overall image quality is also greater on the Gd-DTPA-enhanced images. (orig.)

  10. Gadolinium-153 production at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Gadolinium-153 production at the Oak Ridge National Laboratory (ORNL) involves the neutron irradiation of natural europium oxide (47.8% /sup 151/Eu, 52.2% /sup 153/Eu). This target material undergoes a series of neutron captures and radioactive decays to produce the desired /sup 153/Gd product. Several undesirable europium isotopes (/sup 152/Eu, /sup 154/Eu, and /sup 156/eu) are also produced during this irradiation process. Recent technical advances and other improvements in the radiochemical processing of this isotope have allowed ORNL to increase production by more than sevenfold. A newly developed electrochemical process has allowed the separation of the bulk of undesirable europium isotopes and has also affected a more efficient use of high-pressure ion exchange to achieve a final product radiochemical purity >99.999%. Specific activities >60 Ci/g of gadolinium oxide and product specific yields >2.9 Ci/g of irradiated europium oxide have been produced. Use of unique glove box manipulators and special equipment designed at ORNL have allowed final source fabrication to keep pace with the increased production rate while minimizing the radiation exposure to operating personnel

  11. Psa study of ETRR-2 Gadolinium injection system

    International Nuclear Information System (INIS)

    one of the main safety feature of ETRR-2, egypt test and reactor 3 2 (new reactor), is the use of a redundant and diverse shutdown systems, called second shutdown system SSS. This system operates through injection of a high absorbing material, gadolinium Gd solution, into four rectangular chambers surrounding the reactor core. In view of the fact that the core is super-moderated, the injected neutron poison between the core and the reflector will cause an immediate reactor shutdown. The SSS triggers due to: manual, seismic, fails of actuation of the first shutdown system FSS, or high power neutron flux signal. Because of safety importance of this new system design, the present probabilistic safety assessment PDA study is initiated. The study carried ou in view of the system acceptable unavailability together with the effects of failure probabilities of relevant parameters and basic events. The effect of system design modifications (remove of high power signal and addition of nitrogen filtering line) on reactor safety and system unavailability is analyzed. A new proposed PSA model which take into consideration all possible failure modes of the system components is developed. The results show that the modification done on the system improves its unavailability while increases the minimal cut sets. The proposed model unavailability is greater (bad) than the designer model (That contains many hypothesis). human error contribution on system unavailability is reflected on failure type of gadolinium concentration. The IAEA psa pack IV code is utilized for calculation purposes

  12. Gadolinium-hydrogen ion exchange of zirconium phosphate

    Science.gov (United States)

    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.

  13. Observation of Neutrons with a Gadolinium Doped Water Cerenkov Detector

    CERN Document Server

    Dazeley, S; Bowden, N S; Svoboda, R

    2008-01-01

    Spontaneous and induced fission in Special Nuclear Material (SNM) such as 235U and 239Pu results in the emission of neutrons and high energy gamma-rays. The multiplicities of and time correlations between these particles are both powerful indicators of the presence of fissile material. Detectors sensitive to these signatures are consequently useful for nuclear material monitoring, search, and characterization. In this article, we demonstrate sensitivity to both high energy gamma-rays and neutrons with a water Cerenkov based detector. Electrons in the detector medium, scattered by gamma-ray interactions, are detected by their Cerenkov light emission. Sensitivity to neutrons is enhanced by the addition of a gadolinium compound to the water in low concentrations. Cerenkov light is similarly produced by an 8 MeV gamma-ray cascade following neutron capture on the gadolinium. The large solid angle coverage and high intrinsic efficiency of this detection approach can provide robust and low cost neutron and gamma-ray...

  14. The effectiveness and cost-effectiveness of erythropoiesis-stimulating agents (epoetin and darbepoetin) for treating cancer treatment-induced anaemia (including review of technology appraisal no. 142): a systematic review and economic model.

    Science.gov (United States)

    Crathorne, Louise; Huxley, Nicola; Haasova, Marcela; Snowsill, Tristan; Jones-Hughes, Tracey; Hoyle, Martin; Briscoe, Simon; Coelho, Helen; Long, Linda; Medina-Lara, Antonieta; Mujica-Mota, Ruben; Napier, Mark; Hyde, Chris

    2016-01-01

    BACKGROUND Anaemia is a common side effect of cancer treatments and can lead to a reduction in quality of life. Erythropoiesis-stimulating agents (ESAs) are licensed for use in conjunction with red blood cell transfusions to improve cancer treatment-induced anaemia (CIA). OBJECTIVE To investigate the effectiveness and cost-effectiveness of ESAs in anaemia associated with cancer treatment (specifically chemotherapy). DATA SOURCES The following databases were searched from 2004 to 2013: The Cochrane Library, MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, Web of Science, Cumulative Index to Nursing and Allied Health Literature, British Nursing Index, Health Management Information Consortium, Current Controlled Trials and ClinicalTrials.gov. The US Food and Drug Administration and European Medicines Agency websites were also searched. Bibliographies of included papers were scrutinised for further potentially includable studies. REVIEW METHODS The clinical effectiveness review followed principles published by the NHS Centre for Reviews and Dissemination. Randomised controlled trials (RCTs), or systematic reviews of RCTs, of ESAs (epoetin or darbepoetin) for treating people with CIA were eligible for inclusion in the review. Comparators were best supportive care, placebo or other ESAs. Anaemia- and malignancy-related outcomes, health-related quality of life (HRQoL) and adverse events (AEs) were evaluated. When appropriate, data were pooled using meta-analysis. An empirical health economic model was developed comparing ESA treatment with no ESA treatment. The model comprised two components: one evaluating short-term costs and quality-adjusted life-years (QALYs) (while patients are anaemic) and one evaluating long-term QALYs. Costs and benefits were discounted at 3.5% per annum. Probabilistic and univariate deterministic sensitivity analyses were performed. RESULTS Of 1457 titles and abstracts screened, 23 studies assessing ESAs within their licensed

  15. The role of gadolinium-enhanced MR imaging in the preoperative evaluation of inflammatory abdominal aortic aneurysm

    Energy Technology Data Exchange (ETDEWEB)

    Anbarasu, A.; McWilliams, R.G. [Department of Radiology, Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP (United Kingdom); Harris, P.L. [Department of Vascular Surgery, Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP (United Kingdom)

    2002-07-01

    Inflammatory abdominal aortic aneurysm is an uncommon variant of abdominal aortic aneurysms. Thorough preoperative imaging of the extent of the aneurysm and inflammation and the associated complications are crucial in the management of this condition. We report a case of inflammatory abdominal aortic aneurysm where, after the initial contrast-enhanced CT, gadolinium-enhanced MR imaging was used to define the true extent of the inflammation and differentiate inflammation from mural thrombus at the iliac extension of the aneurysm. The imaging appearances are presented and the impact of MR imaging on further surgical management options including endovascular repair are discussed. (orig.)

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

    Science.gov (United States)

    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

  17. Microwave-assisted polyol synthesis of gadolinium-doped green luminescent carbon dots as a bimodal nanoprobe.

    Science.gov (United States)

    Gong, Ningqiang; Wang, Hao; Li, Shuai; Deng, Yunlong; Chen, Xiao'ai; Ye, Ling; Gu, Wei

    2014-09-16

    The development of multimodal nanoprobes is highly desired in medical imaging because it integrates the advantages of multiple imaging modes. In this study, the gadolinium-doped green luminescent carbon dots (Gd-CDs) were prepared by the simple one-step microwave-assisted polyol method. The obtained Gd-CDs emitted a unique green photoluminescence with a quantum yield of 5.4%. The Gd-CDs exhibited a low cytotoxicity and could optically label the C6 glioma cells. Meanwhile, the r1 relaxivity of Gd-CDs was measured to be 11.356 mM(-1) s(-1). This high r1 value together with the r2/r1 ratio close to 1 nominates Gd-CDs as an excellent T1 contrast agent for magnetic resonance imaging. These Gd-CDs combining two complementary imaging modalities are therefore a promising bimodal nanoprobe in medical imaging for a better diagnosis. PMID:25157595

  18. Gadolinium-enhanced magnetic resonance imaging of the knee: an experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Sirun; Shen, Si; Zhu, Tianyuan; Liang, Wenbin; Huang, Li; Chen, Hanfang; Wu, Hejia [Medical Imaging Center, the First Affiliated Hospital, Jinan University, Guangzhou, Guang Dong (China)

    2010-09-15

    The purpose of this study was to examine gadolinium-enhanced magnetic resonance imaging (MRI) for monitoring cartilage degeneration. This is a proof-of-concept study in an animal model. Adult New Zealand rabbits were randomly stratified into five groups. Papain was injected intra-articularly in the right knee in four groups to establish the stages of cartilage degeneration. The left knee and group 5 served as controls. Bilateral MRI was performed 24 h after the initial injection of papain, and 1 week, 1 month, and 3 months following three papain injections. Injection of the contrast agent was followed by bilateral MRI examination immediately upon injection, and at 2 and 4 h post-injection. Signal intensities of articular cartilage and peripheral soft tissues were obtained before animals were sacrificed. Post-mortem bilateral cartilage specimens were studied histologically. Histopathology results verified the staged degeneration of papain-treated articular cartilage. Differences in cartilage signal intensity were significant for the staged model using a special three-dimensional MRI method (P < 0.05) but not using ordinary MRI. No differences were observed within or between the control groups (P > 0.05). Contrast-enhanced MRI examination may be a viable tool for early diagnosis of osteoarticular disease. Prospective studies are warranted to evaluate the potential for clinical application. (orig.)

  19. Rapid hydrothermal route to synthesize cubic-phase gadolinium oxide nanorods

    International Nuclear Information System (INIS)

    An inexpensive fabrication route and growth mechanism is being reported for obtaining quality gadolinium oxide ( Gd2O3 ) nanoscale rods. The elongated nanoscale systems, as produced via a hydrothermal process, were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), optical absorption spectroscopy, photoluminescence (PL) spectroscopy, Raman spectroscopy and magnetic hysteresis measurements. XRD patterns of the nanorods, as-prepared from independent precursors of different pH, depict a cubic crystal phase and an average crystallite size of 5-6.5 nm. As revealed from HRTEM micrographs, diameter of the nanorods prepared at pH = 13.3 (∼7 nm) was much smaller than the rods prepared at pH = 10.8 (∼19 nm). However, the aspect ratio was more than double in the former case than the latter case. PL response was found to be dominated by defect mediated emissions, whereas Raman spectrum of a given specimen (pH = 10.8) has revealed characteristic Fg + Ag modes of cubic phase of Gd2O3 nanorods, apart from other independent modes. Furthermore, M ∼ H plot of the nanorod system (pH = 10.8) exhibited slight departure from the ideal superparamagnetic behaviour, with low remanence and coercive field values. The exploitation of one-dimensional Gd2O3 nanorods have immense potential in the production of advanced contrast agents, smart drives and also in making novel ferrofluids of technological relevance. (author)

  20. Sorafenib and gadolinium co-loaded liposomes for drug delivery and MRI-guided HCC treatment.

    Science.gov (United States)

    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 0.21μg/mL to 250μg/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. PMID:26844644

  1. Fabrication of gadolinium hydroxide nanoparticles using ion-exchange resin and their MRI property

    Directory of Open Access Journals (Sweden)

    Y. Kobayashi

    2016-03-01

    Full Text Available This paper describes a method to fabricate gadolinium hydroxide (Gd(OH3 nanoparticles. An opaque solution was prepared by adding basic anion exchange resin (BAER to a Gd(NO33 aqueous solution at room temperature and aging the solution for 12–24 h; the solution became basic because of the exchange of H2O with OH−. The particles in the opaque solution have a needle structure, and their crystal structure was hexagonal Gd(OH3. Their longitudinal and lateral average particle sizes tend to increase in the ranges of 175.0–222.1 and 33.9–52.3 nm when the aging time increases from 12 to 24 h, respectively. The relaxivity value for T1-weighted imaging was 0.79 mM−1 s−1 for the solution that was prepared at the aging time of 18 h, which was ca. 20% of that for a commercial Gd complex contrast agent.

  2. Rapid hydrothermal route to synthesize cubic-phase gadolinium oxide nanorods

    Indian Academy of Sciences (India)

    Samiran Hazarika; Nibedita Paul; Dambarudhar Mohanta

    2014-06-01

    An inexpensive fabrication route and growth mechanism is being reported for obtaining quality gadolinium oxide (Gd2O3) nanoscale rods. The elongated nanoscale systems, as produced via a hydrothermal process, were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), optical absorption spectroscopy, photoluminescence (PL) spectroscopy, Raman spectroscopy and magnetic hysteresis measurements. XRD patterns of the nanorods, as-prepared from independent precursors of different pH, depict a cubic crystal phase and an average crystallite size of 5-6.5 nm. As revealed from HRTEM micrographs, diameter of the nanorods prepared at pH = 13.3 (∼ 7nm) was much smaller than the rods prepared at pH = 10.8 (∼ 19nm). However, the aspect ratio was more than double in the former case than the latter case. PL response was found to be dominated by defect mediated emissions, whereas Raman spectrum of a given specimen (pH = 10.8) has revealed characteristic g + g modes of cubic phase of Gd2O3 nanorods, apart from other independent modes. Furthermore, ∼ plot of the nanorod system (pH = 10.8) exhibited slight departure from the ideal superparamagnetic behaviour, with low remanence and coercive field values. The exploitation of one-dimensional Gd2O3 nanorods have immense potential in the production of advanced contrast agents, smart drives and also in making novel ferrofluids of technological relevance.

  3. Combustion of gadolinium and dysprosium chelates as a cellular integrity marker in MR imaging

    International Nuclear Information System (INIS)

    A combination of gadolinium (Gd) and dysprosium (Dy) chelates was investigated as a potential marker of cell-membrane integrity by means of a double-contrast effect in MR imaging. Blood samples with varying hematocrit (Hct) levels containing intact or lysed cells were used as model systems. With intact cells, the agents were assumed to be distributed solely extracellularly and the highest Hct studied (69%) was assumed to mimic the ratio of extracellular to intracellular water in tissue. The combined effect on image intensity of Gd (in a concentration corresponding to 0.2 mmol/kg b.w. in humans) and Dy (0.6 mmol/kg b.w.) applied simultaneously was a marked difference in signal intensity between samples with intact and lysed cells in both the T1- and T2-weighted spin-echo images with a corresponding increase in the contrast-to-noise ratio. This was the result of a T1 reduction caused by Gd with a negligible Dy susceptibility effect in areas with lysed cells. On the other hand, the Dy susceptibility effect (i.e. reduced apparent T2) dominated in areas with intact cells. Thus, the combination of Gd and Dy may serve as a marker of cell-membrane integrity in MR examinations. (orig.)

  4. Dynamic contrast-enhanced MRI using a macromolecular MR contrast agent (P792): Evaluation of antivascular drug effect in a rabbit VX2 liver tumor model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hee Sun [Dept. of Radiology, Konkuk University School of Medicine, Seoul (Korea, Republic of); Han, Joon Koo; Lee, Jeong Min; Woo, Sung Min; Choi, Byung Ihn [Seoul National University Hospital, Seoul (Korea, Republic of); Kim, Young Il [Dept. of Radiology, Sheikh Khalifa Specialty Hospital, Ras Al Khaimah (United Arab Emirates); Choi, Jin Young [Dept. of Radiology, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2015-10-15

    To evaluate the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using macromolecular contrast agent (P792) for assessment of vascular disrupting drug effect in rabbit VX2 liver tumor models. This study was approved by our Institutional Animal Care and Use Committee. DCE-MRI was performed with 3-T scanner in 13 VX2 liver tumor-bearing rabbits, before, 4 hours after, and 24 hours after administration of vascular disrupting agent (VDA), using gadomelitol (P792, n = 7) or low molecular weight contrast agent (gadoterate meglumine [Gd-DOTA], n = 6). P792 was injected at a of dose 0.05 mmol/kg, while that of Gd-DOTA was 0.2 mmol/kg. DCE-MRI parameters including volume transfer coefficient (Ktrans) and initial area under the gadolinium concentration-time curve until 60 seconds (iAUC) of tumors were compared between the 2 groups at each time point. DCE-MRI parameters were correlated with tumor histopathology. Reproducibility in measurement of DCE-MRI parameters and image quality of source MR were compared between groups. P792 group showed a more prominent decrease in Ktrans and iAUC at 4 hours and 24 hours, as compared to the Gd-DOTA group. Changes in DCE-MRI parameters showed a weak correlation with histologic parameters (necrotic fraction and microvessel density) in both groups. Reproducibility of DCE-MRI parameters and overall image quality was not significantly better in the P792 group, as compared to the Gd-DOTA group. Dynamic contrast-enhanced magnetic resonance imaging using a macromolecular contrast agent shows changes of hepatic perfusion more clearly after administration of the VDA. Gadolinium was required at smaller doses than a low molecular contrast agent.

  5. Dynamic contrast-enhanced MRI using a macromolecular MR contrast agent (P792): Evaluation of antivascular drug effect in a rabbit VX2 liver tumor model

    International Nuclear Information System (INIS)

    To evaluate the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using macromolecular contrast agent (P792) for assessment of vascular disrupting drug effect in rabbit VX2 liver tumor models. This study was approved by our Institutional Animal Care and Use Committee. DCE-MRI was performed with 3-T scanner in 13 VX2 liver tumor-bearing rabbits, before, 4 hours after, and 24 hours after administration of vascular disrupting agent (VDA), using gadomelitol (P792, n = 7) or low molecular weight contrast agent (gadoterate meglumine [Gd-DOTA], n = 6). P792 was injected at a of dose 0.05 mmol/kg, while that of Gd-DOTA was 0.2 mmol/kg. DCE-MRI parameters including volume transfer coefficient (Ktrans) and initial area under the gadolinium concentration-time curve until 60 seconds (iAUC) of tumors were compared between the 2 groups at each time point. DCE-MRI parameters were correlated with tumor histopathology. Reproducibility in measurement of DCE-MRI parameters and image quality of source MR were compared between groups. P792 group showed a more prominent decrease in Ktrans and iAUC at 4 hours and 24 hours, as compared to the Gd-DOTA group. Changes in DCE-MRI parameters showed a weak correlation with histologic parameters (necrotic fraction and microvessel density) in both groups. Reproducibility of DCE-MRI parameters and overall image quality was not significantly better in the P792 group, as compared to the Gd-DOTA group. Dynamic contrast-enhanced magnetic resonance imaging using a macromolecular contrast agent shows changes of hepatic perfusion more clearly after administration of the VDA. Gadolinium was required at smaller doses than a low molecular contrast agent

  6. Closely packed dense network rutile nanorods with gadolinium for efficient dye sensitized solar cells

    International Nuclear Information System (INIS)

    Highlights: • We prepared dense network rutile TiO2 nanorods via a simple solvothermal method. • We investigated the importance of Gadolinium for the improvement of dye sensitized solar cells. • Achieved maximum power conversion efficiency of 5% for gadolinium doped rutile TiO2 nanorods. - Abstract: Gadolinium doped rutile nanorods have been prepared by simple hydrothermal method. By using the prepared gadolinium doped rutile titania nanorods dye sensitized solar cells have been fabricated. The effect of gadolinium on the performance of dye sensitized solar cells has been reported. The synthesized gadolinium doped rutile nanorods were characterized by X-ray diffraction, scanning electron microscope and X-ray photoelectron spectroscopy analysis. Dye sensitized solar cells fabricated using 0.2% gadolinium doped rutile nanorods showed an improved short-circuit current density of 11.66 mA cm−2, open-circuit photo voltage of 0.65 V, fill factor of 0.65, and an overall conversion efficiency of 5%

  7. Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents

    Directory of Open Access Journals (Sweden)

    Estelrich J

    2015-03-01

    Full Text Available Joan Estelrich,1,2 María Jesús Sánchez-Martín,1 Maria Antònia Busquets1,2 1Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain; 2Institut de Nanociència I Nanotecnologia (IN2UB, Barcelona, Catalonia, SpainAbstract: Magnetic resonance imaging (MRI has become one of the most widely used and powerful tools for noninvasive clinical diagnosis owing to its high degree of soft tissue contrast, spatial resolution, and depth of penetration. MRI signal intensity is related to the relaxation times (T1, spin–lattice relaxation and T2, spin–spin relaxation of in vivo water protons. To increase contrast, various inorganic nanoparticles and complexes (the so-called contrast agents are administered prior to the scanning. Shortening T1 and T2 increases the corresponding relaxation rates, 1/T1 and 1/T2, producing hyperintense and hypointense signals respectively in shorter times. Moreover, the signal-to-noise ratio can be improved with the acquisition of a large number of measurements. The contrast agents used are generally based on either iron oxide nanoparticles or ferrites, providing negative contrast in T2-weighted images; or complexes of lanthanide metals (mostly containing gadolinium ions, providing positive contrast in T1-weighted images. Recently, lanthanide complexes have been immobilized in nanostructured materials in order to develop a new class of contrast agents with functions including blood-pool and organ (or tumor targeting. Meanwhile, to overcome the limitations of individual imaging modalities, multimodal imaging techniques have been developed. An important challenge is to design all-in-one contrast agents that can be detected by multimodal techniques. Magnetoliposomes are efficient multimodal contrast agents. They can simultaneously bear both kinds of contrast and can, furthermore, incorporate targeting ligands and chains of polyethylene glycol to enhance the accumulation of

  8. Flotation separation of gadolinium, terbium and dysprosium ions collected by means of potassium abietate

    International Nuclear Information System (INIS)

    The possibility of the flotation separation of gadolinium, terbium and dysprosium ions collected by means of potassium abietate from solutions has been shown. Flotation separation of gadolinium, terbium and dysprosium ions, collected by means of potassium abietate mostly occurs from solutions when pH value is equal to 7.0 in the presence of the collector twofold excess. The kinetics of the flotation separation of gadolinium, terbium and dysprosium ions is limited by the rate of diffusion of sublate colloid particles to the air bubble surface

  9. Effect Of The Gadolinium Oxide Addition On The Electrical Properties Of Tetragonal Zirconium Dioxide

    OpenAIRE

    Cyran J.; Wyrwa J.; Drożdż E.; Dziubaniuk M.; Rękas M.

    2015-01-01

    The aim of this work was examination of gadolinium-doped 3YSZ electrical and structural properties. Such materials may be used as electrolytes in intermediate temperature solid oxide fuel cells (IT-SOFC). First step of the research was synthesis of 3YSZ with different contents of gadolinium (0.25; 0.5; 1.0 at %). Prepared materials were characterized by high porosity. No effect of gadolinium addition on grain size was observed. The experimentally determined values of grain interiors electrica...

  10. Use of high-pressure ion exchange for the production of gadolinium-153. Status report

    International Nuclear Information System (INIS)

    A large high-pressure ion-exchange column, which had been designed for the separation of gadolinium from europium, was tested in the laboratory. Good separations were obtained. Subsequently, columns of the same design were installed in a hot cell and have been used successfully for the separation of gadolinium-153 from irradiated natural europium. The gadolinium-153 production achieved using these columns is substantially greater than that achieved using the previous process. Rapid damage of the resin is a problem and frequent resin changes are required

  11. Separation of high purity gadolinium for reactor applications by solvent extraction process

    International Nuclear Information System (INIS)

    A two cycle solvent extraction process employing 2-ethyl hexyl, 2-ethyl hexyl phosphonic acid (EHEHPA) has been developed for the separation of high purity gadolinium. Intermediate rare earth concentrate obtained during samarium purification process, comprised of 70% gadolinium along with lighter rare earths (Sm, Nd) as well as heavier rare earths (Tb, Dy, Y) have been processed for obtaining >99.5 % gadolinium oxide. The oxide was subsequently converted to its nitrate form for use as a secondary shut down device in PHWR system. The experimental conditions were optimized using computer simulation and validated by bench scale counter-current operations. (author)

  12. Poly(vinylpyrrolidone) as dispersing agent for cerium-gadolinium oxide (CGO) suspensions

    DEFF Research Database (Denmark)

    Marani, Debora; Sudireddy, Bhaskar Reddy; Nielsen, Lotte;

    2016-01-01

    The behaviour of selected poly(vinylpyrrolidone) grades to act as dispersant for ethanol-based ceriumgadolinium oxide suspensions was investigated and related to the molecular weight characteristics. The number, weight, and z-average molecular weights Mn, Mw, and Mz were determined by gel...

  13. Magnetic resonance arthrography of the shoulder: accuracy of gadolinium versus saline for rotator cuff and labral pathology

    Energy Technology Data Exchange (ETDEWEB)

    Helms, Clyde A.; McGonegle, Shane J.; Vinson, Emily N.; Whiteside, Michael B. [Duke University Medical Center, Department of Radiology, Durham, NC (United States)

    2011-02-15

    The purpose of this study was to evaluate the necessity of intra-articular gadolinium versus saline alone in magnetic resonance arthrography (MRA) of the shoulder. Our database was reviewed for 100 consecutive shoulder MRA examinations performed between January 2007 and December 2007. Patient information was blinded and images were retrospectively reviewed by at least two radiologists with dedicated musculoskeletal training. T2-weighted (T2W) images were initially analyzed in isolation to simulate MRA with saline alone. After a delay, the full study was analyzed including T1-weighted (T1W) and T2W images. If there was a significant discordance between the two analyses with regard to rotator cuff or labral pathology, the study was again reviewed by all evaluators in consensus to determine if the T1W images offered additional diagnostic information and increased diagnostic confidence. Of the 100 MRA examinations, there were 15 discordant cases. Two cases were discordant with regard to rotator cuff pathology and 13 were discordant on the basis of labral pathology. When the discordant cases were reviewed in consensus, the T2W images appeared to display rotator cuff and labral pathology as definitively as the T1W images. Interobserver and intraobserver variability was favored to have played a role in causing the discordances. MRA of the shoulder performed with joint distention provided by saline alone appears to offer equivalent diagnostic information to MRA performed with gadolinium enhancement. This protocol modification improves efficiency by eliminating several image series and provides a small cost savings by eliminating gadolinium. (orig.)

  14. Magnetic resonance arthrography of the shoulder: accuracy of gadolinium versus saline for rotator cuff and labral pathology

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the necessity of intra-articular gadolinium versus saline alone in magnetic resonance arthrography (MRA) of the shoulder. Our database was reviewed for 100 consecutive shoulder MRA examinations performed between January 2007 and December 2007. Patient information was blinded and images were retrospectively reviewed by at least two radiologists with dedicated musculoskeletal training. T2-weighted (T2W) images were initially analyzed in isolation to simulate MRA with saline alone. After a delay, the full study was analyzed including T1-weighted (T1W) and T2W images. If there was a significant discordance between the two analyses with regard to rotator cuff or labral pathology, the study was again reviewed by all evaluators in consensus to determine if the T1W images offered additional diagnostic information and increased diagnostic confidence. Of the 100 MRA examinations, there were 15 discordant cases. Two cases were discordant with regard to rotator cuff pathology and 13 were discordant on the basis of labral pathology. When the discordant cases were reviewed in consensus, the T2W images appeared to display rotator cuff and labral pathology as definitively as the T1W images. Interobserver and intraobserver variability was favored to have played a role in causing the discordances. MRA of the shoulder performed with joint distention provided by saline alone appears to offer equivalent diagnostic information to MRA performed with gadolinium enhancement. This protocol modification improves efficiency by eliminating several image series and provides a small cost savings by eliminating gadolinium. (orig.)

  15. Research and Development for a Gadolinium Doped Water Cherenkov Detector

    CERN Document Server

    Renshaw, Andrew

    2012-01-01

    The proposed introduction of a soluble gadolinium (Gd) compound into water Cherenkov detectors can result in a high efficiency for the detection of free neutrons capturing on the Gd. The delayed 8 MeV gamma cascades produced by these captures, in coincidence with a prompt positron signal, serve to uniquely identify electron antineutrinos interacting via inverse beta decay. Such coincidence detection can reduce backgrounds, allowing a large Gd-enhanced water Cherenkov detector to make the first observation of supernova relic neutrinos and high precision measurements of Japan's reactor antineutrino flux, while still allowing for all current physics studies to be continued. Now, a dedicated Gd test facility is operating in the Kamioka Mine. This new facility houses everything needed to successfully operate a Gd doped water Cherenkov detector. Successful running of this facility will demonstrate that adding Gd salt to SK is both safe for the detector and is capable of delivering the expected physics benefits.

  16. Low-lying ($K^{} = 0^{+}$) states of gadolinium isotopes

    Indian Academy of Sciences (India)

    Harun Reşit Yazar

    2013-10-01

    The sd-interacting boson approximation (sd-IBA) and the df-interacting boson approximation (df-IBA) can be related to each other and the states of the interacting boson approximation model can be identified with the fully symmetric states in the sdf interacting boson approximation model. A systematic study of the sdf-IBA model showed that the constructed Hamiltonian can successfully describe the strong octupole correlations in the deformed nuclei. We showed that the interacting boson approximation may account for many of these $K^{} = 0^{+}$ states. It was found that the calculated energy spectra of the gadolinium isotopes agree quite well with the experimental data. The observed (2) values were also calculated and compared with the experimental data.

  17. Corrosion Behavior of Commercial Magnetic Refrigerant Gadolinium in Water

    Institute of Scientific and Technical Information of China (English)

    Zhang Zeyu; Long Yi; Wen Da; Ye Rongchang; Wan Farong

    2004-01-01

    Gadolinium(Gd) used as magnetic refrigerant always works in water environment.However, its poor corrosion resistance is serious impediment against wider application of Gd.In this paper, the corrosion behavior of two types of commercial Gd ( A, B both are 98.9 at.% pure) with the same oxygen content has been studied.The results show that the corrosion rate of A is 3.226 times higher than that of B in deionized water and 6.039 times in tap water.According to SEM, the different corrosion rate is because of the different distribution of impurity in matrix.In addition,NaOH solution was chosen as inhibitor to prevent Gd from being corroded successfully.No pitting corrosion and weight loss were observed for commercial Gd even after immersion for nearly 2000 h in NaOH solution.

  18. SWI enhances vein detection using gadolinium in multiple sclerosis

    International Nuclear Information System (INIS)

    Susceptibility weighted imaging (SWI) combined with the FLAIR sequence provides the ability to depict in vivo the perivenous location of inflammatory demyelinating lesions – one of the most specific pathologic features of multiple sclerosis (MS). In addition, in MS white matter (WM) lesions, gadolinium-based contrast media (CM) can increase vein signal loss on SWI. This report focuses on two cases of WM inflammatory lesions enhancing on SWI images after CM injection. In these lesions in fact the CM increased the contrast between the parenchyma and the central vein allowing as well, in one of the two cases, the detection of a vein not visible on the same SWI sequence acquired before CM injection

  19. Cation antisite disorder in uranium-doped gadolinium zirconate pyrochlores

    International Nuclear Information System (INIS)

    The incorporation of uranium into gadolinium zirconate (Gd2Zr2O7) is investigated by synchrotron X-ray powder diffraction and X-ray absorption near-edge structure (XANES) spectroscopy. The results suggest that the uranium cation is largely located on the pyrochlore B-site instead of the targeted A-site. Cation disorder in Gd2Zr2O7 and U-doped Gd2Zr2O7 is investigated by positron annihilation lifetime spectroscopy (PALS) which demonstrates the absence of cation vacancies in these systems. This work provides direct evidence for cation antisite (A- and B-site mixing) disorder in U-doped and off-stoichiometric Gd2Zr2O7 pyrochlore

  20. Low temperature nuclear orientation of 239Np in gadolinium host

    International Nuclear Information System (INIS)

    The angular distribution of γ-radiation from the decay of 239Np oriented at low temperatures in gadolinium matrix was investigated. The orientation parameters B2 and B4 were determined. The attenuation factors for two long-living states in 239Pu at 391.5 keV and 285.4 keV were calculated. From the anisotropies measured the multipole mixing ratios for 11 γ-transitions in 239Pu were deduced. The results obtained support the assignment of spins of the levels at 492.2 keV and 391.6 keV as 3/2- and 7/2-, respectively. 18 refs.; 2 figs.; 3 tabs

  1. Monitoring of the gadolinium photoionization process by using fluorescence measurements

    International Nuclear Information System (INIS)

    The population dynamics in a resonant three-photon ionization process of the gadolinium (Gd) atom is experimentally studied by investigating ion signals and fluorescence signals. We detect the ion signals by using a time-of-flight mass spectrometer, and at the same time, we probe the fluorescence coming out of the excited states involved in the ionization process. The number of residual atoms that remain in excited states after the laser beams have passed is estimated by measuring the variation of the fluorescence signal. Since this information is directly related to how many atoms are not ionized, we can use this method for monitoring the ionization process. Using this method, we estimate the ionization efficieny of the Gd atom

  2. Is Gadolinium-DTPA required for routine cranial MR imaging

    International Nuclear Information System (INIS)

    Gd-DTPA was administered prospectively to 500 consecutive children and adults referred for routine cranial MR imaging. Blinded readings were performed by two observers, and the results were analyzed in terms of specific criteria to define radio-graphic helpfulness. Gadolinium enhancement of lesions was noted in 99 of 500 cases (19.8%) and was helpful in 74 (15%). In only 15 of 500 cases (3%) did Gd-DTPA permit detection of lesions not also apparent on precontrast images. Lack of contrast enhancement was considered helpful in 112 of 500 cases (22%). Overall, Gd-DTPA administration provided radiographically helpful information in 171 of 500 cases (34%). The cost-effectiveness of administering Gd-DTPA to a nonselected patient population where clinical history is available is analyzed and discussed

  3. The structural response of gadolinium phosphate to pressure

    Science.gov (United States)

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

    2016-09-01

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

  4. Nuclear orientation of 149Pm in gadolinium host

    International Nuclear Information System (INIS)

    The temperature dependence of the anisotropy of the 285.9 keV gamma-ray following the decay of oriented 149Pm was measured. The 149Pm parent nuclei were oriented at low temperatures between 14 and 80 mK in a gadolinium host containing 1 At.% of neodymium admixture. The external magnetic field of 1.2 T was applied to polarize the domains of the host. Limits of experimental values of gamma-ray angular distribution coefficient A2 varies in the region 0.097 2 (γ 285.9 keV) 2=1.53 and the deorientation factor U2=0.925 were used. The result yields multipole mixing ratio, delta (E2/M1) lying in intervals 0.0 < delta < +0.11 or -19 < delta < -5.7

  5. Optimization of micro-strip gas chamber as two-dimensional neutron detector using gadolinium converter

    Energy Technology Data Exchange (ETDEWEB)

    Masaoka, Sei; Nakamura, Tatsuya; Yamagishi, Hideshi; Soyama, Kazuhiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-02-01

    A micro-strip gas chamber (MSGC) has been developing as a two-dimensional position sensitive neutron detector for neutron scattering experiments using high-intensity pulsed-neutron source in a high-intensity proton accelerator facility. MSGC is required for the high count rate, high detective efficiency, high positional resolution, stabilization and covering large area. Our purpose in this paper is to verify the proper of Gadolinium as MSGC converter. First, the basic property of Gadolinium converter was examined by simple experiments using a zero-dimensional neutron detector on the purpose of deriving the detective efficiency. Second, the optimization of the arrangement of a capillary plate in MSGC has been done by simulation on the MSGC using Gadolinium converter. As a result of that, it has been proved that Gadolinium can be theoretically used as a converter of MSGC. (author)

  6. Standard test methods for analysis of sintered gadolinium oxide-uranium dioxide pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 These test methods cover procedures for the analysis of sintered gadolinium oxide-uranium dioxide pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Section Carbon (Total) by Direct CombustionThermal Conductivity Method C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Chlorine and Fluorine by Pyrohydrolysis Ion-Selective Electrode Method C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Gadolinia Content by Energy-Dispersive X-Ray Spectrometry C1456 Test Method for Determination of Uranium or Gadolinium, or Both, in Gadolinium Oxide-Uranium Oxide Pellets or by X-Ray Fluorescence (XRF) Hydrogen by Inert Gas Fusion C1457 Test Method for Determination of Total Hydrogen Content of Uranium Oxide Powders and Pellets by Carrier Gas Extraction Isotopic Uranium Composition by Multiple-Filament Surface-Ioni...

  7. Calculation and preliminary analysis of group cross sections for gadolinium and its isotopes

    International Nuclear Information System (INIS)

    Evaluated nuclear data files ENDL 78 and ENDF/B-IV and the cross section generation code FEDGROUP-R were used to produce averaged group cross sections for group systems BNAB and THSIG for gadolinium and its isotopes. Different sets of group cross sections for gadolinium (due to different evaluated data files or different processing codes) were compared and significant differences analyzed. The group capture cross sections for the isotopes of gadolinium were compared with published data. The group cross sections data sets prepared are analyzed as to what extent they can meet the requirements of cell calculations for gadolinium-loaded fuel. Some group cross section tables and cross section plots are presented. (author)

  8. Optimization of micro-strip gas chamber as two-dimensional neutron detector using gadolinium converter

    International Nuclear Information System (INIS)

    A micro-strip gas chamber (MSGC) has been developing as a two-dimensional position sensitive neutron detector for neutron scattering experiments using high-intensity pulsed-neutron source in a high-intensity proton accelerator facility. MSGC is required for the high count rate, high detective efficiency, high positional resolution, stabilization and covering large area. Our purpose in this paper is to verify the proper of Gadolinium as MSGC converter. First, the basic property of Gadolinium converter was examined by simple experiments using a zero-dimensional neutron detector on the purpose of deriving the detective efficiency. Second, the optimization of the arrangement of a capillary plate in MSGC has been done by simulation on the MSGC using Gadolinium converter. As a result of that, it has been proved that Gadolinium can be theoretically used as a converter of MSGC. (author)

  9. Luminescence study on Eu or Tb doped lanthanum-gadolinium pyrosilicate crystal

    Czech Academy of Sciences Publication Activity Database

    Kurosawa, S.; Shishido, T.; Sugawara, T.; Nomura, A.; Yubuta, K.; Pejchal, Jan; Murakami, R.; Yokota, Y.; Shoji, Y.; Ohashi, Y.; Kamada, K.; Yoshikawa, A.

    2015-01-01

    Roč. 41, Mar (2015), s. 80-83. ISSN 0925-3467 Institutional support: RVO:68378271 Keywords : scintillator * gadolinium pyrosilicate Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.981, year: 2014

  10. ICP-oa TOFMS utilisation to determine the Gd isotopic abundance in gadolinium nitrate

    International Nuclear Information System (INIS)

    This paper is describes the development of a method that should permit the determination of isotope abundance of gadolinium in gadolinium nitrate, used as burnable poison at Cernavoda NPP. To determine the isotopic abundance of gadolinium the inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometer (ICP-oa TOFMS) was used. The ICP-oa TOFMS allows the elimination of noise associated with instrumental drift and instability (flicker noise). The absence of flicker noise in the ICP-oa TOFMS means that the isotope ratios can be measured up to the statistical limit of ion counting. With TOFMS, each spectrum acquired represents signals from ions extracted from the plasma during the same time interval, formed from identical plasma and sample introduction events. Therefore, the ICP-oa TOFMS, Optimass 8000, has been successfully used for isotope ratio measurements of Gd in gadolinium nitrate [Gd (NO3)3 x 6H2O] sample solutions. (authors)

  11. Basic study for development of new tumor specific agents for neutron capture therapy

    International Nuclear Information System (INIS)

    New tissue specific agents for neutron capture therapy was studied. Monoclonal labeled gadolinium-DTPA (Gd-MoAb) and porphyrin (ATN-10)-Gd-DTPA (Gd-ATN10) were studied as possible agents by using 9-L experimental brain tumor model. The tissue concentration were analyzed with magnetic resonance imaging (MRI) and inductively coupled plasma (ICP) analyzer. Gd-MoAb showed persistent retention in the tumor on MRI, but tissue gadolinium concentration was not detectable in the tumor by ICP analyzer, while there was high accumulation of Gd-MoAb in the liver. Gd-ATN10 showed prolonged and high accumulation in the tumor up to 48 hours on MRI. Gadolinium concentration reached up to 9 ppm in the tumor by 0.02 mmol/kg administration, but it disappeared within 6 hours after administration. This dissociation between MRI and ICP analysis was due to separation of ATN-10 and Gd-DTPA. As conclusions, the porphyrin compounds are potential agents for delivering gadolinium or boron specific to the tumor tissue, thus further improvement such as more stable conjugation between porphyrinfic to the tumor tissue, thus further improvement such as more stable conjugation between porphyrin and Gd-DTPA is needed. (author)

  12. Perturbed angular correlations for Gd in gadolinium: in-beam comparisons of relative magnetizations

    OpenAIRE

    Stuchbery, A. E.; Wilson, A. N.; Davidson, P. M.; Benczer-Koller, N.

    2006-01-01

    Perturbed angular correlations were measured for Gd ions implanted into gadolinium foils following Coulomb excitation with 40 MeV O-16 beams. A technique for measuring the relative magnetizations of ferromagnetic gadolinium hosts under in-beam conditions is described and discussed. The combined electric-quadrupole and magnetic-dipole interaction is evaluated. The effect of nuclei implanted onto damaged or non-substitutional sites is assessed, as is the effect of misalignment between the inter...

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

    OpenAIRE

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

    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 contras...

  14. Development of a gadolinium-loaded LAB-based aqueous scintillator for neutrino detection

    International Nuclear Information System (INIS)

    A gadolinium (Gd) complex with carboxylic acid was synthesized by using a neutralization chemical reaction. Gd (0.5%) was doped into a liquid scintillator by using a solvent-solvent extraction under controlled pH. Linear alkyl benzene (LAB) was used as a scintillation solvent. We measured several important physical and optical properties. The preparation, the synthesis procedures and the characterization of the resulting gadolinium-loaded, LAB-based, liquid scintillator are described in this paper.

  15. Recovery of methamphetamine associated cardiomyopathy predicted by late gadolinium enhanced cardiovascular magnetic resonance

    OpenAIRE

    Buonocore Michael; Caputo Gary; Yeo Khung; Lopez Javier E; Schaefer Saul

    2009-01-01

    Abstract Methamphetamine is known to cause a cardiomyopathy which may be reversible with appropriate medical therapy and cessation of use. Late gadolinium enhancement cardiovascular magnetic resonance (CMR) has been shown to identify fibrosis in ischemic and non-ischemic cardiomyopathies. We present a case of severe methamphetamine-associated cardiomyopathy in which cardiac function recovered after 6 months. Evaluation by CMR using late gadolinium enhancement was notable for an absence of enh...

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

    International Nuclear Information System (INIS)

    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

  17. Investigation of gadolinium alloys and intermetallic compounds by the Moessbauer spectroscopy method

    International Nuclear Information System (INIS)

    The resonance absorption of the gamma quanta by 155Gd nuclei was utilized to determine the hyperfine parameters for the alloys of gadolinium with scandium and yttrium and for intermetallic compounds of gadolinium with iron, cobalt and nickel. In all cases, values of hyperfine magnetic fields, electric field gradients and isomer shifts of the Moessbauer line were obtained. Moreover, in some cases, the angle between the direction of the hyperfine field and the main axis of the electric field gradient was determined. (author)

  18. Stimuli-responsive poly(N-isopropyl acrylamide)-co-tyrosine@gadolinium: Iron oxide nanoparticle-based nanotheranostic for cancer diagnosis and treatment.

    Science.gov (United States)

    Roy, Ekta; Patra, Santanu; Madhuri, Rashmi; Sharma, Prashant K

    2016-06-01

    In this paper, we have prepared a stimuli-responsive polymer modified gadolinium doped iron oxide nanoparticle (poly@Gd-MNPs) as cancer theranostic agent. The responsive polymer is composed of the poly(N-isopropyl acrylamide)-co-tyrosine unit, which shows excellent loading for the anti-cancer drug (methotrexate) and stimuli dependent release (change in pH and temperature). The in vitro experiment revealed that the poly@Gd-MNPs exhibited T1-weighted MRI capability (r1=11.314mM(-1)s(-1)) with good in-vitro hyperthermia response. The prepared poly@Gd-MNPs has generated quick heating (45°C in 2min) upon exposure to an alternating magnetic field and able to travel a distance of 35cm in 1min in the presence of an external magnet. The poly@Gd-MNPs shows 86% of drug loading capacity with 70% drug release in first 2h. The cytotoxic assay (MTT) demonstrated that the nanoparticle did not affect the viability of normal human fibroblast and efficiently kill the MCF7 cancer cells in the presence of an external magnetic field. To explore the uptake of poly@Gd-MNPs in the cells, bright field cell imaging study was also performed. This study provides a valuable approach for the design of highly sensitive polymer modified gadolinium doped iron oxide-based T1 contrast agents for cancer theranostics. PMID:26962761

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

    Energy Technology Data Exchange (ETDEWEB)

    Brai, M [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Marrale, M [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gennaro, G [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Bartolotta, A [Dipartimento Farmacochimico, Tossicologico e Biologico, Universita di Palermo, via Archirafi 32, 90123 Palermo (Italy); D' Oca, M C [Dipartimento Farmacochimico, Tossicologico e Biologico, Universita di Palermo, via Archirafi 32, 90123 Palermo (Italy); Rosi, G [Centro di Ricerche ENEA, Casaccia, Rome (Italy)

    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.

  20. Antifungal agents.

    Science.gov (United States)

    Ryder, N S

    1999-12-01

    At this year's ICAAC Meeting, new data on approximately 20 different antifungal agents were presented, while no new agents were disclosed. Drugs in late development include the triazoles, voriconazole (Pfizer Ltd) and Sch-56592 (Schering-Plough Corp), and the echinocandins, caspofungin (Merck & Co Inc) and FK-463 (Fujisawa Pharmaceutical Co Ltd). In contrast to previous years, presentations on these and earlier developmental compounds were relatively modest in scope, with few significant new data. Little new information appeared on the most recent novel class of agents, the sordarins (Glaxo Wellcome plc). Early clinical results were presented for FK-463, showing acceptable tolerability and dose-dependent efficacy in AIDS-associated esophageal candidiasis. A new liposomal formulation of nystatin (Nyotran; Aronex Pharmaceuticals Inc) was shown to be equivalent to conventional amphotericin B in empiric therapy of presumed fungal infection in neutropenic patients, but with reduced toxicity. Intravenous itraconazole (Janssen Pharmaceutica NV) was an effective prophylactic therapy in invasive pulmonary aspergillosis, while oral itraconazole was discussed as a treatment for fungal infection in heart and liver transplant patients. The allylamine compound, terbinafine (Novartis AG), showed good clinical efficacy against fungal mycetoma, a serious tropical infection. A major highlight was the first presentation of inhibitors of fungal efflux pumps as a strategy for overcoming resistance. MC-510027 (milbemycin alpha-9; Microcide Pharmaceuticals Inc) and its derivatives, potentiated the antifungal activity of triazoles and terbinafine in a number of Candida spp. Another pump inhibitor, MC-005172 (Microcide Pharmaceuticals Inc) showed in vivo potentiation of fluconazole in a mouse kidney infection model. Microcide Pharmaceuticals Inc also presented inhibitors of bacterial efflux pumps. PMID:16113946

  1. Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents

    Science.gov (United States)

    Estelrich, Joan; Sánchez-Martín, María Jesús; Busquets, Maria Antònia

    2015-01-01

    Magnetic resonance imaging (MRI) has become one of the most widely used and powerful tools for noninvasive clinical diagnosis owing to its high degree of soft tissue contrast, spatial resolution, and depth of penetration. MRI signal intensity is related to the relaxation times (T1, spin–lattice relaxation and T2, spin–spin relaxation) of in vivo water protons. To increase contrast, various inorganic nanoparticles and complexes (the so-called contrast agents) are administered prior to the scanning. Shortening T1 and T2 increases the corresponding relaxation rates, 1/T1 and 1/T2, producing hyperintense and hypointense signals respectively in shorter times. Moreover, the signal-to-noise ratio can be improved with the acquisition of a large number of measurements. The contrast agents used are generally based on either iron oxide nanoparticles or ferrites, providing negative contrast in T2-weighted images; or complexes of lanthanide metals (mostly containing gadolinium ions), providing positive contrast in T1-weighted images. Recently, lanthanide complexes have been immobilized in nanostructured materials in order to develop a new class of contrast agents with functions including blood-pool and organ (or tumor) targeting. Meanwhile, to overcome the limitations of individual imaging modalities, multimodal imaging techniques have been developed. An important challenge is to design all-in-one contrast agents that can be detected by multimodal techniques. Magnetoliposomes are efficient multimodal contrast agents. They can simultaneously bear both kinds of contrast and can, furthermore, incorporate targeting ligands and chains of polyethylene glycol to enhance the accumulation of nanoparticles at the site of interest and the bioavailability, respectively. Here, we review the most important characteristics of the nanoparticles or complexes used as MRI contrast agents. PMID:25834422

  2. Evaluation of zero power experiments for a homogenous plutonium-uranyl nitrate solution reactor containing boron and gadolinium

    International Nuclear Information System (INIS)

    Several series of experiments with plutonium-uranyl nitrate solution containing soluble poisons (boron and gadolinium) were performed at BNW (Battelle Pacific Northwest Laboratories) in the 1970s. Evaluation of nine homogeneous configurations, which consist of a plutonium-uranyl nitrate [Pu(NO3)4, UO2(NO3)2] solution containing boric acid (H3BO3) and gadolinium nitrate (Gd(NO3)3) is performed in this paper. A Monte-Carlo calculational model with the use of MCNP5 was developed for the determination of the uncertainties. The evaluation of the benchmark was performed for validation of calculational techniques and comparison of calculational results with the experimental data. Effects of various uncertainties on the multiplication factor were studied. Special care was devoted to the determination of the uncertainty in the boron concentration in the fissile solution, since the data available from the experimental report was not sufficient and additional data had to be derived from the logbooks. The sensitivity studies included parametric variation of material composition and geometry and for three of the experiments the combined uncertainty has been found to be less than 1% in keff. (author)

  3. Reversible Low-Light Induced Photoswitching of Crowned Spiropyran-DO3A Complexed with Gadolinium(III Ions

    Directory of Open Access Journals (Sweden)

    André Knoesen

    2012-05-01

    Full Text Available Photoswitchable spiropyran has been conjugated to the crowned ring system DO3A, which improves its solubility in dipolar and polar media and stabilizes the merocyanine isomer. Adding the lanthanide ion gadolinium(III to the macrocyclic ring system leads to a photoresponsive magnetic resonance imaging contrast agent that displays an increased spin-lattice relaxation time (T1 upon visible light stimulation. In this work, the photoresponse of this photochromic molecule to weak light illumination using blue and green light emitting diodes was investigated, simulating the emission spectra from bioluminescent enzymes. Photon emission rate of the light emitting diodes was changed, from 1.75 × 1016 photons·s−1 to 2.37 × 1012 photons·s−1. We observed a consistent visible light-induced isomerization of the merocyanine to the spiropyran form with photon fluxes as low as 2.37 × 1012 photons·s−1 resulting in a relaxivity change of the compound. This demonstrates the potential for use of the described imaging probes in low light level applications such as sensing bioluminescence enzyme activity. The isomerization behavior of gadolinium(III-ion complexed and non-complexed spiropyran-DO3A was analyzed in water and ethanol solution in response to low light illumination and compared to the emitted photon emission rate from over-expressed Gaussia princeps luciferase.

  4. XAFS study of gadolinium and samarium bisporphyrinate complexes.

    Science.gov (United States)

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

    2001-11-19

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

  5. Preferred hydride growth orientations on oxide-coated gadolinium surfaces

    International Nuclear Information System (INIS)

    Highlights: ► The preferred hydride growth orientations on gadolinium metal coated by a thin oxide layer are presented. ► A preferred growth of the (1 0 0)h plane of the face centered cubic (FCC) GdH2 is observed for the hydride spots forming below the oxidation layer. ► A change to the (1 1 1)h plane of the cubic hydride dominates for the hydride's Growth Centers. ► The texture change is attributed to the surface normal compressive stress component exerted by the oxidation layer on the developing hydride. - Abstract: The initial development of hydrides on polycrystalline gadolinium (Gd), as on some other hydride forming metals, is characterized by two sequential steps. The first step involves the rapid formation of a dense pattern of small hydride spots (referred to as the “small family” of hydrides) below the native oxidation layer. The second stage takes place when some of the “small family” nucleants (referred to as “growth centers”, GCs) break the oxide layer, leading to their rapid growth and finally to the massive hydriding of the sample. In the present study, the texture of the two hydride families was studied, by combining X-ray diffraction (XRD) analysis with a microscopic analysis of the hydride, using scanning electron microscopy (SEM) and atomic force microscopy (AFM). It has been observed that for the “small family”, a preferred growth of the (1 0 0)h plane of the cubic GdH2 takes place, whereas for the GCs, a change to the (1 1 1)h plane of the cubic hydride dominates. These preferred growth orientations were analyzed by their structure relation with the (0 0 .1)m basal plane of the Gd metal. It has been concluded that the above texture change is due to the surface normal compressive stress component exerted by the oxidation overlayer on the developing hydride, preventing the (0 0 .1)m||(1 1 1)h growth orientation. This stress is relieved upon the rupture of that overlayer and the development of the GCs, leading to the

  6. Patients' oral hydration levels and incidence of immediate to short-term mild side-effects in contrast agent enhanced MRI diagnostics

    International Nuclear Information System (INIS)

    Aim: Gadolinium-based contrast agents for radiodiagnostic purposes can lead to side effects, including nephrotoxicity in patients with renal insufficiency. This study evaluated whether the occurrence of mild side effects from gadolinium-based contrast enhanced magnetic resonance imaging (MRI) correlates to patients' oral hydration levels. Methods: Oral fluid intake levels 24 h pre- and 24 h post-MRI, as well as incidence of mild side-effects experienced 30 min and 24 h post-MRI were recorded by using a patient self-reporting questionnaire. Results: A total of 174 patients, 29 controls, 98 administered Prohance and 47 receiving Dotarem, were enrolled. Overall, the most frequently reported side-effect was headache; nausea only occurred in patients receiving contrast agent. One or more side-effects experienced 24 h following the MRI scan were reported by 10% (controls), 24% (Prohance) and 22% (Dotarem) of patients, respectively. Multivariate ordinal regression analysis showed that only male gender (OR 0.24, 95% CI 0.11–0.53) was statistically significantly associated with a decreased incidence of side-effects 30 min after MRI. At 24-h post MRI, a lack of contrast agent (OR 0.40, 95% CI 0.09–1.74) and male gender (OR 0.46, 95% CI 0.19–1.09) were associated with fewer side-effects. Conclusions: The level oral fluid intake before and after undergoing gadolinium-based contrast-enhanced MRI does not appear to markedly affect the incidence of common undesirable mild symptoms experienced shortly after the procedure. Confounding differences between patients in reporting side-effects may contribute to these findings. - Highlights: • We assess the incidence of patient-reported side-effects after contrast-enhanced MRI. • We examine the potential impact of oral hydration levels on side-effects. • Patient reported side-effects are high compared to those reported by clinicians. • Female gender and contrast agent itself are associated with increased side

  7. Rare earth contrast agents in hepatic computed tomography

    International Nuclear Information System (INIS)

    Materials with atomic numbers ranging from the upper 50's to the lower 70's proved to have the highest computed tomography (CT) numbers when scanned at 120 kVp. Therefore, to produce particulate contrast agents possessing maximum radiopacity, suspensions of cerium oxide, gadolinium, and dysprosium oxides as well as silver iodide colloid were prepared. All 4 agents were selectively concentrated in the reticulo-endothelial system. The agents produced greater and longer opacification of the normal liver and larger liver-to-tumor differences in rabbits with hepatic tumors than did equivalent amounts of standard intravenous iodinated agents. Lesions as small as 5 mm were visible with CT. These materials have favorable characteristics as hepatic contrast agents, but their toxicity (LD50 in mice = 5.4 g/kg for Ce) and long-term retention may limit clinical use. (Auth.)

  8. Agent engineering

    CERN Document Server

    Liu, Jiming; Zhong, Ning; Wang, Patrick S P

    2001-01-01

    Agent engineering concerns the development of autonomous computational or physical entities capable of perceiving, reasoning, adapting, learning, cooperating and delegating in a dynamic environment. It is one of the most promising areas of research and development in information technology, computer science and engineering. This book addresses some of the key issues in agent engineering: What is meant by "autonomous agents"? How can we build agents with autonomy? What are the desirable capabilities of agents with respect to surviving (they will not die) and living (they will furthermore enjoy

  9. High-Relaxivity MRI Contrast Agents: Where Coordination Chemistry Meets Medical Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Eric J.; Datta, Ankona; Jocher, Christoph J.; Raymond, Kenneth N.

    2008-01-15

    The desire to improve and expand the scope of clinical magnetic resonance imaging (MRI) has prompted the search for contrast agents of higher efficiency. The development of better agents requires consideration of the fundamental coordination chemistry of the gadolinium(III) ion and the parameters that affect its efficacy as a proton relaxation agent. In optimizing each parameter, other practical issues such as solubility and in vivo toxicity must also be addressed, making the attainment of safe, high-relaxivity agents a challenging goal. Here we present recent advances in the field, with an emphasis on the hydroxypyridinone family of Gd{sup III} chelates.

  10. Pinhole X-ray Fluorescence Imaging of Gadolinium Nanoparticles: A Preliminary Monte Carlo Study

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Seong Moon; Sung, Won Mo; Ye, Sung Joon [Seoul National University, Seoul (Korea, Republic of)

    2014-10-15

    X-ray fluorescence imaging is a modality for the element-specific imaging of a subject through analysis of characteristic x-rays produced by exploiting the interaction of high atomic number elements and incoming x-rays. Previous studies have utilized a polychromatic x-ray source to investigate the production of in vivo x-ray fluorescence images for the assessment of concentrations and locations of gold nanoparticles. However, previous efforts have so far been unable to detect low concentrations, such as 0.001% gold by weight, which is an expected concentration accumulated in tumors. We examined the feasibility of a monochromatic synchrotron x-rays implementation of pinhole x-ray fluorescence imaging by Monte Carlo simulations using MCNP5. In the current study, gadolinium (Gd) nanoparticles, which have been widely used as a contrast agent in magnetic resonance imaging and also as a dose enhancer in radiation therapy, were chosen for tumor targeting. Since a monochromatic x-ray source is used, the increased x-ray fluorescence signals allow the detection of low concentrations of Gd. Two different monochromatic x-ray beam energies, 50.5 keV near the Kedge energy (i.e., 50.207 keV) of Gd and 55 keV, were compared by their respective imaging results. Using Monte Carlo simulations the feasibility of imaging low concentrations of Gd nanoparticles (e.g., 0.001 wt%) with x-ray fluorescence using monochromatic synchrotron x-rays of two different energies was shown. In the case of imaging a single Gd column inserted in the center of a water phantom, the fluorescence signals from 0.05 wt% and 0.1 wt% Gd columns irradiated with a 50.5 keV photon beam were higher than those irradiated with 55 keV. Below 0.05 wt% region no significant differences were found.

  11. Pinhole X-ray Fluorescence Imaging of Gadolinium Nanoparticles: A Preliminary Monte Carlo Study

    International Nuclear Information System (INIS)

    X-ray fluorescence imaging is a modality for the element-specific imaging of a subject through analysis of characteristic x-rays produced by exploiting the interaction of high atomic number elements and incoming x-rays. Previous studies have utilized a polychromatic x-ray source to investigate the production of in vivo x-ray fluorescence images for the assessment of concentrations and locations of gold nanoparticles. However, previous efforts have so far been unable to detect low concentrations, such as 0.001% gold by weight, which is an expected concentration accumulated in tumors. We examined the feasibility of a monochromatic synchrotron x-rays implementation of pinhole x-ray fluorescence imaging by Monte Carlo simulations using MCNP5. In the current study, gadolinium (Gd) nanoparticles, which have been widely used as a contrast agent in magnetic resonance imaging and also as a dose enhancer in radiation therapy, were chosen for tumor targeting. Since a monochromatic x-ray source is used, the increased x-ray fluorescence signals allow the detection of low concentrations of Gd. Two different monochromatic x-ray beam energies, 50.5 keV near the Kedge energy (i.e., 50.207 keV) of Gd and 55 keV, were compared by their respective imaging results. Using Monte Carlo simulations the feasibility of imaging low concentrations of Gd nanoparticles (e.g., 0.001 wt%) with x-ray fluorescence using monochromatic synchrotron x-rays of two different energies was shown. In the case of imaging a single Gd column inserted in the center of a water phantom, the fluorescence signals from 0.05 wt% and 0.1 wt% Gd columns irradiated with a 50.5 keV photon beam were higher than those irradiated with 55 keV. Below 0.05 wt% region no significant differences were found

  12. Delayed Gadolinium-Enhanced Magnetic Resonance Imaging (dGEMRIC) of Hip Joint Cartilage: Better Cartilage Delineation after Intra-Articular than Intravenous Gadolinium Injection

    DEFF Research Database (Denmark)

    Boesen, M.; Jensen, K.E.; Quistgaard, E.; Danneskiold-Samsøe, B.; Thomsen, C.; Østergaard, Mikkel; Bliddal, H.

    2006-01-01

    PURPOSE: To investigate and compare delayed gadolinium (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) in the hip joint using intravenous (i.v.) or ultrasound-guided intra-articular (i.a.) Gd-DTPA injection. MATERIAL AND METHODS: In 10 patients (50% males, mean age 58...

  13. MCNP analysis of the nine-cell LWR gadolinium benchmark

    International Nuclear Information System (INIS)

    The Monte Carlo results for a 9-cell fragment of the light water reactor square lattice with a central gadolinium-loaded pin are presented. The calculations are performed with the code MCNP-3A and the ENDF-B/5 library and compared with the results obtained from the BOXER code system and the JEF-1 library. The objective of this exercise is to study the feasibility of BOXER for the analysis of a Gd-loaded LWR lattice in the broader framework of GAP International Benchmark Analysis. A comparison of results indicates that, apart from unavoidable discrepancies originating from different data evaluations, the BOXER code overestimates the multiplication factor by 1.4 % and underestimates the power release in a Gd cell by 4.66 %. It is hoped that further similar studies with use of the JEF-1 library for both BOXER and MCNP will help to isolate and explain these discrepancies in a cleaner way. (author) 4 refs., 9 figs., 10 tabs

  14. Neutronical study of gadolinium solution in light water lattices

    International Nuclear Information System (INIS)

    The aim of this work is to study the effect on light water lattices of a gadolinium solution and to participate to the validation of critical calculations. The objective of the experiments and calculations we have performed were to obtain the ksub(infinity) in function of the concentration of poison in water. With the experimental values obtained, we can qualify calcula - tion of regular light water lattices consisting of UO2 pins and highly poisonned moderator (with bore or Gd). We have obtained through the results of this work the iso-ksub(infinity) curb (ksub(infinity)sup(B) ksub(infinity)sup(Gd) in an infinite lattice. The precision on the equivalence factor (A = Csub(B)/Csub(Gd)), which allows to switch from a Gd concentration to an equivalent bore concentration, is good (1%). Moreover, the interpretation hs demonstrated that this experiment is able to qualify the thermal capture of Gd. The exp.-calc. difference on Gd thermal cross sections is -0.4+-1%

  15. Researches of experimental uranium-gadolinium oxide fuel

    International Nuclear Information System (INIS)

    Full text: The increase of technical and economic indexes of NPP is related to the increase of burning down of nuclear fuel. The prolongation of campaign of exploitation of fuel load of nuclear reactor from 12 to 18 months (and even to 24 months) requires the application of fuel with enrichment on uranium-235 no less than 4.5 %. For suppression of high initial reactivity in the core of water-moderated reactor it is suggested to insert the burning down absorber of neutrons. Such method has the number of advantages over application of burning down absorber of neutrons as an independent construction element. Introduction of burning down absorber as the oxide of gadolinium (Gd2O3) directly in fuels pellets removes the limitations related with placing of control device, does not diminish the amount of fuel elements in core. Linear power flux of fuel elements is not increased, an useful place is saved in the fuel element assembling, parasite absorption of neutrons goes down, a necessity in transporting and storage of irradiated combustible absorbers is no longer relevant. The results of researches of some descriptions of experimental (U,Gd)O2-fuel are represented in this article

  16. A magnetic x-ray diffraction investigation of gadolinium selenide

    Energy Technology Data Exchange (ETDEWEB)

    Costa, M.M.R.; Almeida, M.J.M. de [Departamento de Fisica, Universidade de Coimbra, Coimbra (Portugal); Nuttall, W.J.; Stirling, W.G. [Department of Physics, Keele University, Keele, Staffs (United Kingdom); Tang, C.C. [Daresbury Laboratory, Warrington, Cheshire (United Kingdom); Forsyth, J.B. [Rutherford Appleton Laboratory, Chilton, Oxon (United Kingdom); Cooper, M.J. [Department of Physics, University of Warwick, Coventry (United Kingdom)

    1996-04-01

    A single-crystal synchrotron radiation study of gadolinium selenide has been made in the temperature range 15-100 K. GdSe has the rocksalt structure and becomes antiferromagnetic below a reported Neel temperature of 65 K. At 15 K, magnetic reflections are observed at G+T with modulation wavevector T={l_brace}1/2:1/2:1/2{r_brace} propagating from reciprocal lattice point G. This is achieved by exploiting the resonant enhancement in the vicinity of the Gd L{sub II} and L{sub III} edges. Similar enhancements are observed at the two edges, with the maximum effect occurring approximately 3 eV above the absorption edge. The temperature dependence of the intensity of the magnetic reflections indicates a Neel temperature of 63(1) K. These measurements, together with high-resolution studies of the fundamental reflections (T=0), contribute further evidence of magnetic or structural changes in the sample at 37(1) K. Our observations are discussed and compared with previous x-ray diffraction and magnetic susceptibility measurements. (author)

  17. Impedance spectroscopic characterization of gadolinium substituted cobalt ferrite ceramics

    International Nuclear Information System (INIS)

    Gadolinium (Gd) substituted cobalt ferrites (CoFe2−xGdxO4, 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 CoFe2O4 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.

  18. Structure and properties of gadolinium loaded calcium phosphate glasses

    International Nuclear Information System (INIS)

    The glass samples with composition xGd2O3–(50 − x)CaO–50P2O5 (0 ⩽ x ⩽ 9 mol%) were prepared by the conventional melt quench method. The structure and properties of gadolinium loaded in calcium phosphate glasses were investigated using XRD, SEM, DTA, IR and Raman spectroscopy. The XRD and SEM analysis for the samples show that the majority of samples are amorphous, and crystallization occurs when the content of Gd2O3 containing is up to 6 mol%. Two main crystalline phases, Ca2P2O7 and Gd3(P2O7)3, are embedded in an amorphous matrix. IR and Raman data indicate that glass structure consists of predominantly metaphosphate (Q2) units and the depolymerization of phosphate network with the addition of Gd2O3. Both the chemical durability and the glass transition temperature (Tg) are improved with the increase of Gd2O3, which suggests that the Gd acts a role of strengthening the cross-links between the phosphate chains of the glass

  19. Gadolinium Magnetic resonance with a diagnosis of Bell's facial palsy

    International Nuclear Information System (INIS)

    The intratemporal pathway of the facial nerve has been prospectively studied by means of gadolinium MR in 12 patients with a diagnosis of Bell's facial palsy. All the cases presented total facial paralysis and were studied in the acute phase of the disease. With MR, the intratemporal pathway of the facial nerve has been viewed before and after the administration of a paramagnetic contrast medium, revealing uptake involving mainly the labyrinthine segment and the geniculate ganglion in every case. In no case did the MR findings influence the therapeutic approach, nor did they provide information of prognostic value. Therefore, this exploration is not considered necessary in the assessment of typical facial paralyses. The possible advantages of an MR study with contrast medium in facial paralysis specially apply to those cases with atypical clinical presentation, making it possible to establish a positive diagnosis, ruling out other lesions that may have a similar clinical presentantion. Thus, for the time being, a diagnosis of Bell's paralysis is not necessarily an exclusion diagnosis. (Author)

  20. Nuclear orientation of sup(152,154)Tb in gadolinium

    International Nuclear Information System (INIS)

    The anisotropy in the directional distribution of gamma-rays from the decay of sup(152, 154)Tb, oriented in a gadolinium matrix at low temperatures, has been measured at the angles of 0 and π/2 with respect to the applied magnetic field direction at a temperature of (15+-1)mK. Unambiguous values of spin have been deduced for several levels in 152Gd. Multipole mixing ratios of many gamma-ray transitions occuring in 152Gd have been found and results are compared with the similar transitions in sup(150, 154, 156)Gd and they are discussed in terms of the rotational-vibrational model and dynamic deformation theory based on the Strutinsky method. The results confirm a spin value of 0 for 21.4 h isomer in 154Tb and they establish a spin value of 3 for the 2277.0 and 2336.1 keV levels and a spin value of 4 for the 2416.3 keV level in 154Gd

  1. Design and development of a Gadolinium-doped water Cherenkov detector

    Science.gov (United States)

    Poudyal, Nabin

    This thesis describes a research and development project for neutron capture and detection in Gadolinium doped water. The Sanford Underground Research Facility (SURF) is exploring rare event physics, such as neutrinoless double beta decay (MAJORANA Project) and dark-matter detection (LUX experiment). The success of these experiments requires a careful study and understanding of background radiation, including flux and energy spectrum. The background radiation from surface contamination, radioactive decays of U-238, Th-232, Rn-222 in the surrounding rocks and muon induced neutrons have a large impact on the success of rare-event physics. The main objective of this R&D project is to measure the neutron flux contributing to ongoing experiments at SURF and suppress it by identification and capture method. For this purpose, we first modeled and designed a detector with Geant4 software. The approximate dimension of the detector is determined. The neutron capture percentage of the detector is estimated using Monte Carlo. The energy response of the detector is simulated. Next, we constructed the experimental detector, an acrylic rectangular tank (60cm x 30cm x 30cm), filled with Gadolinium-doped deionized water. The tank is coated with high efficient reflector and then taped with black electrical tape to make it opaque. The voltage dividers attached to PMTs are covered with mu-metal. Two 5-inch Hamamatsu Photomultiplier tubes were attached on both sides facing the tank to collect the Cherenkov light produced in the water. The detector utilizes the principle of Cherenkov light emission by a charged particle moving through a water at a speed higher than the speed of light in the water, hence it has an inherent energy threshold of Cherenkov photon production. This property reduces the lower energy backgrounds. Event data are obtained using the Data Acquisition hardware, Flash Analog to digital converter, along with Multi Instance Data Acquisition software. Post

  2. Chemical crowd control agents.

    Science.gov (United States)

    Menezes, Ritesh G; Hussain, Syed Ather; Rameez, Mansoor Ali Merchant; Kharoshah, Magdy A; Madadin, Mohammed; Anwar, Naureen; Senthilkumaran, Subramanian

    2016-03-01

    Chemical crowd control agents are also referred to as riot control agents and are mainly used by civil authorities and government agencies to curtail civil disobedience gatherings or processions by large crowds. Common riot control agents used to disperse large numbers of individuals into smaller, less destructive, and more easily controllable numbers include chloroacetophenone, chlorobenzylidenemalononitrile, dibenzoxazepine, diphenylaminearsine, and oleoresin capsicum. In this paper, we discuss the emergency medical care needed by sufferers of acute chemical agent contamination and raise important issues concerning toxicology, safety and health. PMID:26658556

  3. Saline as the Sole Contrast Agent for Successful MRI-guided Epidural Injections

    International Nuclear Information System (INIS)

    Purpose. To assess the performance of sterile saline solution as the sole contrast agent for percutaneous magnetic resonance imaging (MRI)-guided epidural injections at 1.5 T. Methods. A retrospective analysis of two different techniques of MRI-guided epidural injections was performed with either gadolinium-enhanced saline solution or sterile saline solution for documentation of the epidural location of the needle tip. T1-weighted spoiled gradient echo (FLASH) images or T2-weighted single-shot turbo spin echo (HASTE) images visualized the test injectants. Methods were compared by technical success rate, image quality, table time, and rate of complications. Results. 105 MRI-guided epidural injections (12 of 105 with gadolinium-enhanced saline solution and 93 of 105 with sterile saline solution) were performed successfully and without complications. Visualization of sterile saline solution and gadolinium-enhanced saline solution was sufficient, good, or excellent in all 105 interventions. For either test injectant, quantitative image analysis demonstrated comparable high contrast-to-noise ratios of test injectants to adjacent body substances with reliable statistical significance levels (p < 0.001). The mean table time was 22 ± 9 min in the gadolinium-enhanced saline solution group and 22 ± 8 min in the saline solution group (p = 0.75). Conclusion. Sterile saline is suitable as the sole contrast agent for successful and safe percutaneous MRI-guided epidural drug delivery at 1.5 T.

  4. Saline as the Sole Contrast Agent for Successful MRI-guided Epidural Injections

    Energy Technology Data Exchange (ETDEWEB)

    Deli, Martin, E-mail: martin.deli@web.de [University of Witten/Herdecke, Department of Radiology and Microtherapy, Groenemeyer Institute for Microtherapy (GIMT) (Germany); Fritz, Jan, E-mail: jfritz9@jhmi.edu [Johns Hopkins University School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science (United States); Mateiescu, Serban, E-mail: mateiescu@microtherapy.de; Busch, Martin, E-mail: busch@microtherapy.de [University of Witten/Herdecke, Department of Radiology and Microtherapy, Groenemeyer Institute for Microtherapy (GIMT) (Germany); Carrino, John A., E-mail: jcarrin2@jhmi.edu [Johns Hopkins University School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science (United States); Becker, Jan, E-mail: j.becker@microtherapy.de; Garmer, Marietta, E-mail: garmer@microtherapy.de; Groenemeyer, Dietrich, E-mail: dg@microtherapy.de [University of Witten/Herdecke, Department of Radiology and Microtherapy, Groenemeyer Institute for Microtherapy (GIMT) (Germany)

    2013-06-15

    Purpose. To assess the performance of sterile saline solution as the sole contrast agent for percutaneous magnetic resonance imaging (MRI)-guided epidural injections at 1.5 T. Methods. A retrospective analysis of two different techniques of MRI-guided epidural injections was performed with either gadolinium-enhanced saline solution or sterile saline solution for documentation of the epidural location of the needle tip. T1-weighted spoiled gradient echo (FLASH) images or T2-weighted single-shot turbo spin echo (HASTE) images visualized the test injectants. Methods were compared by technical success rate, image quality, table time, and rate of complications. Results. 105 MRI-guided epidural injections (12 of 105 with gadolinium-enhanced saline solution and 93 of 105 with sterile saline solution) were performed successfully and without complications. Visualization of sterile saline solution and gadolinium-enhanced saline solution was sufficient, good, or excellent in all 105 interventions. For either test injectant, quantitative image analysis demonstrated comparable high contrast-to-noise ratios of test injectants to adjacent body substances with reliable statistical significance levels (p < 0.001). The mean table time was 22 {+-} 9 min in the gadolinium-enhanced saline solution group and 22 {+-} 8 min in the saline solution group (p = 0.75). Conclusion. Sterile saline is suitable as the sole contrast agent for successful and safe percutaneous MRI-guided epidural drug delivery at 1.5 T.

  5. Environmental behaviour und ecotoxiology of gadolinium-containing MRT contrast media; Umweltverhalten und Oekotoxikologie von gadoliniumhaltigen Magnetresonanztomographie-Kontrastmitteln

    Energy Technology Data Exchange (ETDEWEB)

    Neubert, Claudia

    2008-07-08

    Magnetic resonance imaging (MRI) is an essential tool in noninvasive diagnostics. In order to improve the sensitivity and specificity of diagnoses, several contrast enhancing agents have been developed in the last few decades by various pharmaceutical manufacturers. Gadolinium (Gd), a lanthanide, is the most widely used metal in MRI contrast agents. Its ion has paramagnetic properties (seven unpaired electrons) and a very long electronic relaxation time. Due to the toxicity of free Gd, clinical use is only possible in a complexed form. Commonly used chelating agents are polyamino-polycarboxylic ligands such as DTPA. Due to the exceptional stability of these highly hydrophilic chelates and the lack of human metabolism, the contrast media are quantitatively excreted unchanged after the administration, and are subsequently emitted into the aquatic environment. Several studies have shown notable increases in Gd concentrations in surface or groundwaters receiving sewage effluents, an observation which has been termed ''Gd anomaly''. The Gd anomaly results from the use of MRI contrast agents for which the most significant entry route is the effluent from wastewater treatment works. Relatively little information on the aquatic toxicity of Gd or Gd-chelates has been published up to 2006. Therefore, in a first step, the acute aquatic toxicity of several MRI contrast agents was investigated in fish, daphnia and algae at high concentrations. Furthermore, chronic toxicity tests on fish and daphnia were conducted. The results showed that contrast enhancing agents containing Gd have no toxic effects on the tested organisms at concentrations being of relevance to the environment. At high concentrations growth inhibition of green algae was observed. The environmental fate and the biological degradation of the contrast media was studied in a model wastewater treatment plant and in aquatic sediment systems. The test compounds were neither biodegradable in the

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Gadolinium-enhanced magnetic resonance angiography in neonates and infants suspected of caval or aortic thrombosis

    International Nuclear Information System (INIS)

    Gadolinium-enhanced magnetic resonance angiography (MRA)is a well-established technique in older children and adults. No studies have focused on its use in neonates and small infants. Our objective was to study the use of gadolinium-enhanced MRA in neonates and infants suspected of caval or aortic thrombosis. Materials and Methods:Gadolinium-enhanced MR angiography was performed on seven neonates and small infants for the evaluation of caval or aortic thrombosis. Gadolinium-DTPA at a dose of 0.3 mmol/kg (minimum dose 1 ml) was injected using a power injector (0.2 ml/s). Contrast-enhanced MRA was performed using a 3-D, fast, radiofrequency spoiled gradient-echo sequence (TR/TE: 4.8/1.1, flip angle 45 , matrix 256 x 128, slice thickness 2.6 mm interpolated to 1.3 mm, FOV variable, NEX=1.0). Diagnostic-quality angiograms were obtained in all seven neonates. Superior vena cava thrombosis was identified in two neonates, and abdominal aortic thrombosis was present in one neonate. It is practical to perform gadolinium-enhanced MRA in neonates weighing as little as 600 g for the detection of caval or aortic thrombosis. (orig.)

  8. Three-dimensional gadolinium-enhanced MR angiography of the intracranial venous system

    International Nuclear Information System (INIS)

    The purpose of this study was to assess the usefulness of three-dimensional (3D) gadolinium-enhanced magnetic resonance (MR) angiography for evaluation of the intracranial venous system. Thirty-three patients underwent 3D dynamic gadolinium-enhanced MR angiography as well as two-dimensional (2D) time-of-flight (TOF) MR venography in transverse and coronal planes and conventional catheter cerebral angiography with digital subtraction. MR venography was displayed using a maximum-intensity-projection (MIP) algorithm. The acquisition time of 3D gadolinium-enhanced MR angiography was 102 seconds, and that of 2D TOF MR venography was about 7 minutes in the transverse plane and about 9 minutes in the coronal plane. Degree of visualization of the intracranial venous system on each MR sequence was compared with that on conventional catheter cerebral angiography as a standard. Superficial cortical veins and the dural sinus were better visualized on 3D gadolinium-enhanced MR angiography than on 2D TOF MR venography. Three-dimensional gadolinium-enhanced MR angiography is noninvasive and very useful for imaging of the intracranial venous system. It can replace 2D TOF MR venography not only because of its short examination time but because it better demonstrates intracranial venous structures. For evaluation of the SSS, lateral sinus, sigmoid sinus and straight sinus in particular, conventional catheter angiography seems to be unnecessary. (author)

  9. Three-dimensional gadolinium-enhanced MR angiography of the intracranial venous system

    Energy Technology Data Exchange (ETDEWEB)

    Daikokuya, Hideo; Inoue, Yuichi; Yamada, Ryusaku [Osaka City Univ. (Japan). Medical School

    2001-12-01

    The purpose of this study was to assess the usefulness of three-dimensional (3D) gadolinium-enhanced magnetic resonance (MR) angiography for evaluation of the intracranial venous system. Thirty-three patients underwent 3D dynamic gadolinium-enhanced MR angiography as well as two-dimensional (2D) time-of-flight (TOF) MR venography in transverse and coronal planes and conventional catheter cerebral angiography with digital subtraction. MR venography was displayed using a maximum-intensity-projection (MIP) algorithm. The acquisition time of 3D gadolinium-enhanced MR angiography was 102 seconds, and that of 2D TOF MR venography was about 7 minutes in the transverse plane and about 9 minutes in the coronal plane. Degree of visualization of the intracranial venous system on each MR sequence was compared with that on conventional catheter cerebral angiography as a standard. Superficial cortical veins and the dural sinus were better visualized on 3D gadolinium-enhanced MR angiography than on 2D TOF MR venography. Three-dimensional gadolinium-enhanced MR angiography is noninvasive and very useful for imaging of the intracranial venous system. It can replace 2D TOF MR venography not only because of its short examination time but because it better demonstrates intracranial venous structures. For evaluation of the SSS, lateral sinus, sigmoid sinus and straight sinus in particular, conventional catheter angiography seems to be unnecessary. (author)

  10. Late gadolinium enhancement cardiovascular magnetic resonance predicts clinical worsening in patients with pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Freed Benjamin H

    2012-02-01

    Full Text Available Abstract Background Late gadolinium enhancement (LGE occurs at the right ventricular (RV insertion point (RVIP in patients with pulmonary hypertension (PH and has been shown to correlate with cardiovascular magnetic resonance (CMR derived RV indices. However, the prognostic role of RVIP-LGE and other CMR-derived parameters of RV function are not well established. Our aim was to evaluate the predictive value of contrast-enhanced CMR in patients with PH. Methods RV size, ejection fraction (RVEF, and the presence of RVIP-LGE were determined in 58 patients with PH referred for CMR. All patients underwent right heart catheterization, exercise testing, and N-terminal pro-brain natriuretic peptide (NT-proBNP evaluation; results of which were included in the final analysis if performed within 4 months of the CMR study. Patients were followed for the primary endpoint of time to clinical worsening (death, decompensated right ventricular heart failure, initiation of prostacyclin, or lung transplantation. Results Overall, 40/58 (69% of patients had RVIP-LGE. Patients with RVIP- LGE had larger right ventricular volume index, lower RVEF, and higher mean pulmonary artery pressure (mPAP, all p Conclusions The presence of RVIP-LGE in patients with PH is a marker for more advanced disease and poor prognosis. In addition, this study reveals for the first time that CMR-derived RVEF is an independent non-invasive imaging predictor of adverse outcomes in this patient population.

  11. The efficacy of fat suppressed and gadolinium enhanced dynamic MR imaging in pancreatic adenocarcinomas

    Energy Technology Data Exchange (ETDEWEB)

    Gabata, Toshifumi [Kanazawa Univ. (Japan). School of Medicine

    1994-12-01

    The efficacy of both fat suppressed T1-weighted imaging (T1WI) and dynamic gadolinium-enhanced MR imaging (dynamic MRI) was compared with conventional MR sequences and dynamic CT in 22 patients with histologically proven pancreatic adenocarcinoma (PAC). In the control group of 30 patients without pancreatic disease, the pancreas was shown as a markedly higher signal intensity on fat suppressed T1WI than on conventional MR sequences. The signal noise ratio (SNR) of the normal pancreas and the contrast noise ratio (CNR) between the normal pancreas and muscle were significantly higher on fat suppressed T1WI than the other MR sequences. In the group of PAC patients without chronic pancreatitis (n=14), CNR between the tumor and the normal pancreas significantly differed among imaging techniques, including fat suppressed T1WI, dynamic MRI, and the other conventional MR sequences. In the group of PAC with chronic pancreatitis (n=8), CNR between the tumor and the associated chronic pancreatitis was remarkably diminished on both fat suppressed T1WI and conventional T1WI; however, it was significantly higher on dynamic MRI than the other pulse sequences. The early phase of dynamic MRI clearly identified the tumors in the group of PAC. The capability of conventional T1WI and dynamic CT to demonstrate peripancreatic tumor extension was significantly higher than that of fat suppressed T1WI. In conclusion, fat suppressed T1WI and dynamic MRI were useful in detecting pancreatic carcinoma. (N.K.).

  12. An experimental search for the electron Electric Dipole Moment in Gadolinium Gallium Garnet

    Science.gov (United States)

    Kim, Young Jin; Liu, Chen-Yu

    2011-04-01

    A discovery of a permanent electric dipole moment of the electron (eEDM) would provide crucial information about the nature of T-violation and imply new sources of CP-violation beyond the Standard Model. While the leading experimental technique used to measure EDM is based on the nuclear magnetic resonance, we are pursuing research that would improve the present experimental limit of the eEDM using a new technique in solid-state systems at low temperatures. The experiment uses a paramagnetic insulator Gadolinium Gallium Garnet with a large magnetic response. The presence of the eEDM leads to a finite magnetization when the garnet sample is subjected to a strong electric field. The resulting magnetization can be measured using the Superconducting Quantum Interference Device (SQUID) as a sensitive magnetometer. In this talk, we will discuss the progress to control the systematic effects and improve the sensitivity. The major efforts include the design and implementation of a 24-bit data acquisition system with ultra-low level of channel crosstalk, and the control of the high voltage drift from the supply. With these considerable progresses, we report our first background-free experimental limit of the eEDM on the order of 10-24 e.cm.

  13. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    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

  14. High-technology metals as emerging contaminants: Strong increase of anthropogenic gadolinium levels in tap water of Berlin, Germany, from 2009 to 2012

    International Nuclear Information System (INIS)

    Highlights: • Monitoring study Berlin-2012 confirms tap water contamination with gadolinium. • Contamination confined to western districts of Berlin. • Strong increase of anthropogenic gadolinium from 2009 to 2012. • Anthropogenic gadolinium is tracer for wastewater-derived substances. - Abstract: The distribution of rare earth elements (REE) in tap water sampled in December 2012 in Berlin, Germany, is characterized by anomalously high levels of gadolinium (Gd). While the western districts of the city show strong anthropogenic positive Gd anomalies in REE distribution patterns, the eastern districts are (almost) unaffected. This contamination with anthropogenic Gd results from Gd-based contrast agents used in Magnetic Resonance Imaging, that enter rivers, groundwater and eventually tap water via the clear water effluent from wastewater treatment plants. While the spatial distribution of anthropogenic Gd in 2012 confirms results of an earlier study in 2009 (Kulaksiz and Bau, 2011a), anthropogenic Gd concentrations have increased between 1.5- and 11.5-fold in just three years. This confirms predictions based upon the increase of anthropogenic Gd concentrations in the Havel River over the past two decades and the time it takes the water to migrate from the Havel River to the groundwater production wells. Anomalously high levels of anthropogenic Gd in tap water, which are not confined to Berlin but have also been observed in London, U.K., and in German cities in the Ruhr area and along the Rhine River, reveal that high-technology metals have become emerging contaminants. While non-toxic at the observed concentrations, the anthropogenic Gd is a microcontaminant that may be used as a conservative pseudo-natural tracer for wastewater-derived xenobiotics such as pharmaceuticals, food additives and personal care products. Our results suggest that monitoring the concentrations of such substances in Berlin’s drinking water can be restricted to a few central and

  15. Ultrasound guidance to perform intra-articular injection of gadolinium-based contrast material for magnetic resonance arthrography as an alternative to fluoroscopy: the time is now

    International Nuclear Information System (INIS)

    Magnetic resonance (MR) imaging has been definitively established as the reference standard in the evaluation of joints in the body. Similarly, magnetic resonance arthrography has emerged as a technique that has been proven to increase significantly the diagnostic performance if compared with conventional MR imaging, especially when dealing with fibrocartilage and articular cartilage abnormalities. Diluted gadolinium can be injected in the joint space using different approaches: under palpation using anatomic landmarks or using an imaging guidance, such as fluoroscopy, computed tomography, or ultrasound. Fluoroscopy has been traditionally used, but the involvement of ionizing radiation should represent a remarkable limitation of this modality. Conversely, ultrasound has emerged as a feasible, cheap, quick, and radiation-free modality that can be used to inject joints, with comparable accuracy of fluoroscopy. In the present paper, we discuss the advantages and disadvantages of using fluoroscopy or ultrasound in injecting gadolinium-based contrast agents in joints to perform magnetic resonance arthrography, also in view of the new EuroSAFE Imaging initiative promoted by the European Society of Radiology and the recent updates to the European Atomic Energy Community 2013/59 directive on the medical use of ionizing radiation. (orig.)

  16. Ultrasound guidance to perform intra-articular injection of gadolinium-based contrast material for magnetic resonance arthrography as an alternative to fluoroscopy: the time is now

    Energy Technology Data Exchange (ETDEWEB)

    Messina, Carmelo [Universita degli Studi di Milano, Scuola di Specializzazione in Radiodiagnostica, Milano (Italy); Banfi, Giuseppe [IRCCS Istituto Ortopedico Galeazzi, Milano (Italy); Universita Vita-Salute San Raffaele, Milano (Italy); Aliprandi, Alberto [Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, Milano (Italy); Mauri, Giovanni [Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, Milano (Italy); Istituto Europeo di Oncologia, Unita di Radiologia Interventistica, Milano (Italy); Secchi, Francesco; Sardanelli, Francesco; Sconfienza, Luca Maria [Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, Milano (Italy); IRCCS Policlinico San Donato, Servizio di Radiologia, San Donato, Milanese (Italy)

    2016-05-15

    Magnetic resonance (MR) imaging has been definitively established as the reference standard in the evaluation of joints in the body. Similarly, magnetic resonance arthrography has emerged as a technique that has been proven to increase significantly the diagnostic performance if compared with conventional MR imaging, especially when dealing with fibrocartilage and articular cartilage abnormalities. Diluted gadolinium can be injected in the joint space using different approaches: under palpation using anatomic landmarks or using an imaging guidance, such as fluoroscopy, computed tomography, or ultrasound. Fluoroscopy has been traditionally used, but the involvement of ionizing radiation should represent a remarkable limitation of this modality. Conversely, ultrasound has emerged as a feasible, cheap, quick, and radiation-free modality that can be used to inject joints, with comparable accuracy of fluoroscopy. In the present paper, we discuss the advantages and disadvantages of using fluoroscopy or ultrasound in injecting gadolinium-based contrast agents in joints to perform magnetic resonance arthrography, also in view of the new EuroSAFE Imaging initiative promoted by the European Society of Radiology and the recent updates to the European Atomic Energy Community 2013/59 directive on the medical use of ionizing radiation. (orig.)

  17. Can unenhanced multiparametric MRI substitute gadolinium-enhanced MRI in the characterization of vertebral marrow infiltrative lesions?

    Directory of Open Access Journals (Sweden)

    Dalia Z. Zidan

    2014-06-01

    Conclusion: Unenhanced-multiparametric MRI is compatible with gadolinium-enhanced MRI in reliable characterization of marrow infiltrative lesions. The routine MRI protocol of cancer patients should be altered to accommodate the evolving MRI technology and cost effectively substitute the need for a gadolinium enhanced scan.

  18. Antibiotic Agents

    Science.gov (United States)

    ... either as public health or as non-public health antimicrobial agents. What is the difference between bacteriostats, sanitizers, disinfectants ... bacteria, however, there is considerable controversy surrounding their health benefits. The ... producing agents (Table of Antibacterials) have been used for many ...

  19. Qualification of gadolinium modeling methodology with measurements from Ohi units 1 and 2

    International Nuclear Information System (INIS)

    The Westinghouse methodology implemented to model gadolinium in pressurized water reactor (PWR) fuel is described. Results are presented of the work performed jointly between Mitsubishi Atomic Power Industries, Inc., Mitsubishi Heavy Industries, Ltd., and Westinghouse Commercial Nuclear Fuel Division to qualify the methodology with plant measurements from Kansai Electric Power's PWR Ohi Units 1 and 2. Results of comparisons with the hot zero power start-up tests and plant operational data are provided. These comparisons demonstrate that the codes and methodology accurately model gadolinium. The principal computer codes used to model gadolinia fuel are NITAWL-S, XSDRN-PM, ANISN, PHOENIX-P, and ANC. The gadolinium cross sections are obtained from the CSRL-V 227 group ENDF/B-V cross-section library

  20. Gadolinium-enhanced magnetic resonance angiography of right ventricle to pulmonary artery shunts following Norwood 1 palliation in infants

    International Nuclear Information System (INIS)

    The classic Norwood I palliation for the treatment of hypoplastic left-heart disease includes an atrial septectomy, neoaorta creation, and a systemic-to-pulmonary artery shunt. The Norwood I palliation has been modified by the use of a right ventricle-to-pulmonary artery shunt instead of a traditional systemic-to-pulmonary artery shunt. Right ventricle-to-pulmonary artery shunts were non-invasively imaged in four infants using gadolinium-enhanced magnetic resonance angiography. Diagnostic MR angiograms were performed in all infants throughout the length of the shunt and were useful in the detection of shunt patency, stenosis, and aneurysm. Associated surgical conduits and shunts were also evaluated. All findings were verified by subsequent conventional angiography or surgery. (orig.)

  1. Effect of gadolinium concentration on radiation chemical yields and its corrosion compatibility

    International Nuclear Information System (INIS)

    The effect of Gd+3 ion concentration on the radiolysis of aqueous gadolinium nitrate solutions and its corrosion compatibility with SS 304 LN were determined by measurement of radiolytic yields of H2, H2O2 and NO2- produced by gamma-irradiation of deaerated solutions of gadolinium nitrate, and electrochemical measurements respectively in the concentration range of 20-100 ppm. An increase in the production of H2O2, H2 and NO2- yield was observed. The corrosion rates were comparable and the average corrosion rate was ∼ 0.16 mpy. (author)

  2. Solitary hepatic infantile hemangioendothelioma: dynamic gadolinium-enhanced MR imaging findings

    International Nuclear Information System (INIS)

    We report the MRI findings of a solitary hepatic infantile hemangioendothelioma (IHE) diagnosed in a 14-day-old girl. To the best of our knowledge, only one report has illustrated the dynamic gadolinium-enhanced MR imaging features of IHE previously. Compounding the rarity of presentation as a solitary mass, the gadolinium-enhanced MRI appearance in our case is unique, because the IHE showed an early rim-like pseudocapsular enhancement followed by progressive fill-in of the lesion on delayed imaging. (orig.)

  3. Optimization of the distribution of bars with gadolinium oxide in reactor fuel elements PWR

    International Nuclear Information System (INIS)

    In the schemes of low leakage, currently used in the majority of PWR reactors, it makes use of absorbent consumables for the effective control of the factors of peak, the critical concentration of initial boron and the moderator temperature coefficient. One of the most used absorbing is the oxide of gadolinium, which is integrated within the fuel pickup. Occurs a process of optimization of fuel elements with oxide of gadolinium, which allows for a smaller number of configurations with a low peak factor for bar. (Author)

  4. MRI of osteochontritis dissecans of the knee joint after i.v. gadolinium-DTPA

    International Nuclear Information System (INIS)

    20 patients with osteochondritis dissecans were studied by MRI over a period of 3-34 monts in order to observe healing and determine the viability of the loose fragment. After intravenous contrast, there was increased signal intensity at the junction between the fragment and the epiphyseal bed on T2-weighted sequences; this was interpreted as fibrous granulation tissue surrounding the fragment. The fragments themselves also showed increased signal intensity after Gadolinium-DTPA. Intravenous Gadolinium allows accurate evaluation of the junctional zone between the fragment and the epiphyseal bed by demonstrating fibrous, vascularised granulation tissue. This can be distinguished from synovial fluid, and it also demonstrates viability of the fragment. (orig.)

  5. Rare earth elements determination by ICP OES in high purity gadolinium

    International Nuclear Information System (INIS)

    The ternary U-Rare Earth-O systems are involved in the nuclear technology due to their application as burnable poison in PWR type reactors. Chemical and physical characterization of both constituents, uranium dioxide (UO2) and gadolinium oxide (Gd2O3), used in the burnable poison production, has a special interest. In this context, the optimization of the chemical determination of the impurities in the gadolinium oxide powders by ICP OES analytical technique was researched in this work. It was developed in two different laboratories and with two different ICP OES spectrometers. Good results are obtained with both spectrometers for robustness, limits of detection, linearity, precision and accuracy. (author)

  6. Influence of exchange splitting on optical properties in gadolinium and dysprosium single crystals

    International Nuclear Information System (INIS)

    The temperature dependences of optical conductivity in gadolinium and dysprosium single crystals at the light wave vector polarization along a hexagonal axis and in the basis plane are considered. A substantial anisotropy of interzonal absorption has been found. The sample transition into magnetically ordered state is shown to be accompanied by the emergence of resonance absorption peaks in the near infrared spectral region. The manifestation of these peculiarities is associated with quantum electron transitions between the s-, d-f- interaction-split energy bands near the Fermi level. Main peculiarities of the experimental spectrum of gadolinium optical conductivity found their reflection in theoretically calculated dispersion dependence

  7. Comparison of predicted with observed biokinetics of inhaled plutonium nitrate and gadolinium oxide in humans

    International Nuclear Information System (INIS)

    The absorption kinetics to blood of plutonium and gadolinium after inhalation as nitrate and oxide in humans and animals has been studied. For each material, values describing the time dependence of absorption were derived from the studies in animals and used with the ICRP human respiratory tract model to predict lung retention and cumulative amounts to blood for the volunteers inhaling the same materials. Comparison with the observed behaviour in the volunteers suggests that absorption of plutonium and gadolinium is reasonably species independent, and that data obtained from animal studies can be used to assess their biokinetic behaviour in humans. (author)

  8. Perturbed angular correlations for Gd in gadolinium: in-beam comparisons of relative magnetizations

    CERN Document Server

    Stuchbery, A E; Davidson, P M; Wilson, A N

    2006-01-01

    Perturbed angular correlations were measured for Gd ions implanted into gadolinium foils following Coulomb excitation with 40 MeV O-16 beams. A technique for measuring the relative magnetizations of ferromagnetic gadolinium hosts under in-beam conditions is described and discussed. The combined electric-quadrupole and magnetic-dipole interaction is evaluated. The effect of nuclei implanted onto damaged or non-substitutional sites is assessed, as is the effect of misalignment between the internal hyperfine field and the external polarizing field. Thermal effects due to beam heating are discussed.

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

    Science.gov (United States)

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

    2016-03-01

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

  10. Nuclear orientation experiments on the magnetic moments of europium and gadolinium nuclei

    International Nuclear Information System (INIS)

    In this thesis, experimental results on the ground state nuclear magnetic moments of europium and gadolinium isotopes are presented. The nuclear orientation experiments were performed on europium and gadolinium nuclei embedded in several host lattices. Attention is paid to the hyperfine interactions of the ions. Nuclear moments are discussed in the context of nuclear shell model. The theoretical framework is described for nuclear structure and low temperature nuclear orientation. Furthermore, the experimental techniques, the technical arrangement of the orientation apparatus, the methods for radiative detection and the use of nuclear orientation thermometry are described. (Auth.)

  11. Tetrahydrosalen backboned gadolinium complex as initiator for the ring-opening polymerization of ε-caprolactone

    Institute of Scientific and Technical Information of China (English)

    Guang Ming Wu; Xu Feng Ni; Wei Lin Sun; Zhi Quan Shen

    2008-01-01

    Tetrahydrosalen ligand was employed in the synthesis of gadolinium complex. The ligand was deprotoned by LiBu, and the afforded lithium salt was reacted with anhydrous GdCl3 to produce the gadolinium complex through salt metathesis. This complex was successfully used to initiate the ring-opening polymerization of ε-caprolactone. The initiation conditions in different temperature, monomer-to-initiator ratio and time were investigated. Under the condition: [ε-caprolactone]: [catalyst]=600,56℃, toluene: 2ml, poly(ε-caprolactone) (PCL) with Mw=11,2782 and PDI=1.96 was achieved.

  12. Development of a modified ion exchange resin column for removal of gadolinium from the moderator systems of PHWRs

    International Nuclear Information System (INIS)

    Gadolinium is used as neutron poison in PHWRs. It is injected to the heavy water (D2O) moderator at 15 ppm concentration during emergency shut down and at 2 ppm during the start up of the reactor. As gadolinium precipitates under neutral and alkaline conditions, pHapp range of 5 - 5.5 is recommended for maintaining gadolinium in the solution and to minimize corrosion of moderator system structural materials and radiolysis. Gadolinium has to be progressively removed as the reactor goes to power. It is removed by the purification system containing ion exchange resin columns. It has been observed that gadolinium precipitates in the ion exchange columns. Experimental investigations were carried out to understand the phenomenon of precipitation of gadolinium in the weak base ion exchange resin. It was found that the strong base groups present in the weak base resin was responsible for the precipitation of gadolinium. Hence, attempts were made to selectively cap the strong base groups present in the weak base anion exchange resin. It was found that the strong base groups of weak base resin can be selectively saturated by treating the resin with 0.2 M NaNO3 and it prevented Gd precipitation. Based on studies carried out on gadolinium pick-up and radiation decomposition with weak base anion exchange resins, a simple mixed bed consisting of nitrate treated weak base resin of poly acrylic based macroporous resin and a strong acid cation exchange resin has been recommended for the removal of gadolinium for both 2 ppm and 15 ppm concentrations as it does not precipitate gadolinium and gives optimum chemistry parameters in the outlet. (author)

  13. Thermodynamic studies in the system cerium-gadolinium-oxygen. Thermodynamische Untersuchungen am System Cer-Gadolinium-Sauerstoff; Kalorimetrische und elektrochemische Methoden

    Energy Technology Data Exchange (ETDEWEB)

    Stelzer, N.

    1993-01-01

    Two independent measuring methods have been applied to studying the phase relations of the system cerium-gadolinium. The calorimetric measurements have been done in a high-temperature calorimeter with cerium dioxide doped with 10 mole % of Gd[sub 2]O[sub 3]. Further thermodynamic quantities have been obtained by the electrochemical method and e.m.f. measurements, yielding additional information on disorders in doped cerium dioxide. (orig./BBR)

  14. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    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}.

  15. Erythropoietic Agents and the Elderly

    OpenAIRE

    Agarwal, Neeraj; Prchal, Josef T.

    2008-01-01

    Erythropoietin is a peptide hormone that stimulates erythropoiesis. There are several agents in clinical use and in development, which either act as ligands for the cell surface receptors of erythropoietin or promote erythropoietin production that stimulates erythropoiesis. These are known as erythropoietic agents. The agents already in use include epoetin alfa, epoetin beta, and darbepoetin alfa. Newer agents stimulating erythropoiesis (such as continuous erythropoietin receptor activator (C...

  16. Gadolinium and ruthenium red attenuate remote hind limb preconditioning-induced cardioprotection: possible role of TRP and especially TRPV channels.

    Science.gov (United States)

    Randhawa, Puneet Kaur; Jaggi, Amteshwar Singh

    2016-08-01

    Remote ischemic preconditioning is a well reported therapeutic strategy that induces cardioprotective effects but the underlying intracellular mechanisms have not been widely explored. The current study was designed to investigate the involvement of TRP and especially TRPV channels in remote hind limb preconditioning-induced cardioprotection. Remote hind limb preconditioning stimulus (4 alternate cycles of inflation and deflation of 5 min each) was delivered using a blood pressure cuff tied on the hind limb of the anesthetized rat. Using Langendorff's system, the heart was perfused and subjected to 30-min ischemia and 120-min reperfusion. The myocardial injury was assessed by measuring infarct size, lactate dehydrogenase (LDH), creatine kinase (CK), LVDP, +dp/dtmax, -dp/dtmin, heart rate, and coronary flow rate. Gadolinium, TRP blocker, and ruthenium red, TRPV channel blocker, were employed as pharmacological tools. Remote hind limb preconditioning significantly reduced the infarct size, LDH release, CK release and improved coronary flow rate, hemodynamic parameters including LVDP, +dp/dtmax, -dp/dtmin, and heart rate. However, gadolinium (7.5 and 15 mg kg(-1)) and ruthenium red (4 and 8 mg kg(-1)) significantly attenuated the cardioprotective effects suggesting the involvement of TRP especially TRPV channels in mediating remote hind limb preconditioning-induced cardioprotection. Remote hind limb preconditioning stimulus possibly activates TRPV channels on the heart or sensory nerve fibers innervating the heart to induce cardioprotective effects. Alternatively, remote hind limb preconditioning stimulus may also activate the mechanosensitive TRP and especially TRPV channels on the sensory nerve fibers innervating the skeletal muscles to trigger cardioprotective neurogenic signaling cascade. The cardioprotective effects of remote hind limb preconditioning may be mediated via activation of mechanosensitive TRP and especially TRPV channels. PMID:27118661

  17. Gadolinium borosilicate glass-bonded Gd-silicate apatite: a glass-ceramic nuclear waste form for actinides

    International Nuclear Information System (INIS)

    A Gd-rich crystalline phase precipitated in a sodium gadolinium alumino-borosilicate glass during synthesis. The glass has a chemical composition of 45.4-31.1 wt% Gd2O3, 28.8-34.0 wt% SiO2,10.8-14.0 wt% Na2O, 4.3-5.9 wt% Al2O3, and 10.8-14.9 wt% B2O3. Backscattered electron images revealed that the crystals are hexagonal, elongated, acicular, prismatic, skeletal or dendritic, tens of μm in size, some reaching 200 μm in length. Electron microprobe analysis confirmed that the crystals are chemically homogeneous and have a formula of NaGd9(SiO4)6O2 with minor B substitution for Si. The X-ray diffraction pattern of this phase is similar to that of lithium gadolinium silicate apatite. Thus, this hexagonal phase is a rare earth silicate with the apatite structure. We suggest that this Gd-silicate apatite in a Gd-borosilicate glass is a potential glass-ceramic nuclear waste form for actinide disposition. Am, Cm and other actinides can easily occupy the Gd-sites. The potential advantages of this glass-ceramic waste form include: 1) both the glass and apatite can be used to immobilize actinides, 2) silicate apatite is thermodynamically more stable than the glass, 3) borosilicate glass-bonded Gd-silicate apatite is easily fabricated, and 4) the Gd is an effective neutron absorber.Copyright (2001) Material Research Society

  18. Ultrasmall superparamagnetic iron oxides (USPIOs): a future alternative magnetic resonance (MR) contrast agent for patients at risk for nephrogenic systemic fibrosis (NSF)?

    OpenAIRE

    Neuwelt, Edward A.; Hamilton, Bronwyn E.; Varallyay, Csanad G; Rooney, William R.; Edelman, Robert D.; Jacobs, Paula M; Watnick, Suzanne G.

    2008-01-01

    Gadolinium (Gd) based contrast agents (GBCAs) in magnetic resonance imaging (MRI) are used in daily clinical practice and appear safe in most patients; however, nephrogenic systemic fibrosis (NSF) is a recently recognized severe complication associated with GBCAs. It affects primarily patients with renal disease, such as stage 4 or 5 chronic kidney disease (CKD; glomerular filtration rate

  19. Three-dimensional gadolinium-enhanced MR venography to evaluate central venous steno-occlusive disease in hemodialysis patients

    Energy Technology Data Exchange (ETDEWEB)

    Gao, K.; Jiang, H.; Zhai, R.Y.; Wang, J.F.; Wei, B.J. [Department of Radiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing (China); Huang, Q., E-mail: hq0713@163.com [Department of Radiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing (China)

    2012-06-15

    Aim: To determine the agreement and diagnostic accuracy of three-dimensional gadolinium-enhanced magnetic resonance venography (3D-Gd-MRV) in central venous steno-occlusive disease (CVSD) in haemodialysis patients. Materials and methods: Fourteen consecutive haemodialysis patients underwent interventional procedures to evaluate or treat CVSD. 3D-Gd-MRV was performed before the procedures and the results were compared with digital subtraction angiography (DSA). Results: DSA showed >50% stenosis in all 14 patients, 13 of whom were diagnosed correctly using 3D-Gd-MRV. Moderate stenosis was missed at 3D-Gd-MRV in one case whereby the indwelling dialysis central venous catheter may have caused an artefact on the images and hindered the accuracy of the result. The sensitivity of 3D-Gd-MRV in revealing stenosis was 93% (13/14). No complications caused by contrast agent toxicity occurred in any patient. Conclusion: 3D-Gd-MRV employing a non-breath-hold technique is highly sensitive in the diagnosis of CVSD and may be an alternative technique to DSA for the visualization of central veins.

  20. Increases in Anthropogenic Gadolinium Anomalies and Rare Earth Element Concentrations in San Francisco Bay over a 20 Year Record.

    Science.gov (United States)

    Hatje, Vanessa; Bruland, Kenneth W; Flegal, A Russell

    2016-04-19

    We evaluated both the spatial distribution of gadolinium (Gd) and other rare earth elements (REE) in surface waters collected in a transect of San Francisco Bay (SFB) and their temporal variations within the Bay over two decades. The REE were preconcentrated using the NOBIAS PA-1 resin prior to analysis by high-resolution inductively coupled plasma mass spectrometry. Measurements revealed a temporal increase in the Gd anomaly in SFB from the early 1990s to the present. The highest Gd anomalies were observed in the southern reach of SFB, which is surrounded by several hospitals and research centers that use Gd-based contrast agents for magnetic resonance imaging. Recent increases in that usage presumably contributed to the order of magnitude increase in anthropogenic Gd concentrations in SFB, from 8.27 to 112 pmol kg(-1) over the past two decades, and reach the northeast Pacific coastal waters. These measurements (i) show that "exotic" trace elements used in new high-tech applications, such as Gd, are emerging contaminants in San Francisco Bay and that anthropogenic Gd concentrations increased substantially over a 20 year period; (ii) substantiate proposals that REE may be used as tracers of wastewater discharges and hydrological processes; and (iii) suggest that new public policies and the development of more effective treatment technologies may be necessary to control sources and minimize future contamination by REE that are critical for the development of new technologies, which now overwhelm natural REE anomalies. PMID:26742888

  1. Anthropogenic gadolinium anomalies and rare earth elements in the water of Atibaia River and Anhumas Creek, Southeast Brazil.

    Science.gov (United States)

    de Campos, Francisco Ferreira; Enzweiler, Jacinta

    2016-05-01

    The concentrations of rare earth elements (REE), measured in water samples from Atibaia River and its tributary Anhumas Creek, Brazil, present excess of dissolved gadolinium. Such anthropogenic anomalies of Gd in water, already described in other parts of the world, result from the use of stable and soluble Gd chelates as contrast agents in magnetic resonance imaging. Atibaia River constitutes the main water supply of Campinas Metropolitan area, and its basin receives wastewater effluents. The REE concentrations in water samples were determined in 0.22-μm pore size filtered samples, without and after preconcentration by solid-phase extraction with bis-(2-ethyl-hexyl)-phosphate. This preconcentration method was unable to retain the anthropogenic Gd quantitatively. The probable reason is that the Gd chelates dissociate slowly in acidic media to produce the free ion that is retained by the phosphate ester. Strong correlations between Gd and constituents or parameters associated with effluents confirmed the source of most Gd in water samples as anthropogenic. The shale-normalized REE patterns of Atibaia River and Anhumas Creek water samples showed light and heavy REE enrichment trends, respectively. Also, positive Ce anomalies in many Atibaia River samples, as well as the strong correlations of the REE (except Gd) with terrigenous elements, imply that inorganic colloidal particles contributed to the REE measured values. PMID:27068533

  2. Development and in vitro testing of liposomal gadolinium-formulations for neutron capture therapy of glioblastoma multiforme

    International Nuclear Information System (INIS)

    For the improvement of current neutron capture therapy, several liposomal formulations of neutron capture agent gadolinium were developed and tested in a glioma cell model. Formulations were analyzed regarding physicochemical and biological parameters, such as size, zeta potential, uptake into cancer cells and performance under neutron irradiation. The neutron and photon dose derived from intracellular as well as extracellular Gd was calculated via Monte Carlo simulations and set in correlation with the reduction of cell survival after irradiation. To investigate the suitability of Gd as a radiosensitizer for photon radiation, cells were also irradiated with synchrotron radiation in addition to clinically used photons generated by linear accelerator. Irradiation with neutrons led to significantly lower survival for Gd-liposome-treated F98 and LN229 cells, compared to irradiated control cells and cells treated with non-liposomal Gd-DTPA. Correlation between Gd-content and -dose and respective cell survival displayed proportional relationship for most of the applied formulations. Photon irradiation experiments showed the proof-of-principle for the radiosensitizer approach, although the photon spectra currently used have to be optimized for higher efficiency of the radiosensitizer. In conclusion, the newly developed Gd-liposomes show great potential for the improvement of radiation treatment options for highly malignant glioblastoma.

  3. Clinical impact of gadolinium in the MRI diagnosis of musculoskeletal infection in children

    Energy Technology Data Exchange (ETDEWEB)

    Kan, J.H.; Young, Robert S.; Hernanz-Schulman, Marta [Vanderbilt University, Department of Radiology and Radiological Sciences, Vanderbilt Children' s Hospital, Nashville, TN (United States); Yu, Chang [Vanderbilt University, Department of Biostatistics, Nashville, TN (United States)

    2010-07-15

    The incremental value of gadolinium in the diagnosis of musculoskeletal infection by MRI is controversial. To compare diagnostic utility of noncontrast with contrast MRI in the evaluation of pediatric musculoskeletal infections. We reviewed 90 gadolinium-enhanced MRIs in children with suspected musculoskeletal infection. Noncontrast and contrast MRI scans were evaluated to determine sensitivity and specificity in the diagnosis of musculoskeletal infection and identification of abscesses. Pre- and post-contrast diagnosis of osteomyelitis sensitivity was 89% and 91% (P = 1.00) and specificity was 96% and 96% (P = 1.00), respectively; septic arthritis sensitivity was 50% and 67% (P = 1.00) and specificity was 98% and 98% (P = 1.00), respectively; cellulitis/myositis sensitivity was 100% and 100% (P = 1.00) and specificity was 84% and 88% (P = 0.59), respectively; abscess for the total group was 22 (24.4%) and 42 (46.6%), respectively (P < 0.0001). Abscesses identified only on contrast sequences led to intervention in eight additional children. No child with a final diagnosis of infection had a normal pre-contrast study. Intravenous gadolinium should not be routinely administered in the imaging work-up of nonspinal musculoskeletal infections, particularly when pre-contrast images are normal. However, gadolinium contrast significantly increases the detection of abscesses, particularly small ones that might not require surgical intervention. (orig.)

  4. Clinical impact of gadolinium in the MRI diagnosis of musculoskeletal infection in children

    International Nuclear Information System (INIS)

    The incremental value of gadolinium in the diagnosis of musculoskeletal infection by MRI is controversial. To compare diagnostic utility of noncontrast with contrast MRI in the evaluation of pediatric musculoskeletal infections. We reviewed 90 gadolinium-enhanced MRIs in children with suspected musculoskeletal infection. Noncontrast and contrast MRI scans were evaluated to determine sensitivity and specificity in the diagnosis of musculoskeletal infection and identification of abscesses. Pre- and post-contrast diagnosis of osteomyelitis sensitivity was 89% and 91% (P = 1.00) and specificity was 96% and 96% (P = 1.00), respectively; septic arthritis sensitivity was 50% and 67% (P = 1.00) and specificity was 98% and 98% (P = 1.00), respectively; cellulitis/myositis sensitivity was 100% and 100% (P = 1.00) and specificity was 84% and 88% (P = 0.59), respectively; abscess for the total group was 22 (24.4%) and 42 (46.6%), respectively (P < 0.0001). Abscesses identified only on contrast sequences led to intervention in eight additional children. No child with a final diagnosis of infection had a normal pre-contrast study. Intravenous gadolinium should not be routinely administered in the imaging work-up of nonspinal musculoskeletal infections, particularly when pre-contrast images are normal. However, gadolinium contrast significantly increases the detection of abscesses, particularly small ones that might not require surgical intervention. (orig.)

  5. Efficacy of gadolinium enhanced MR imaging for the diagnosis of Legg-Calve-Perthes disease

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the efficacy of gadolinium enhanced MR imaging for making the diagnosis of Legg-Calve-Perthes (LCP) disease. We studied the gadolinium enhanced MR images of 14 hips in 12 children who had the diagnosis of LCP disease. We retrospectively analyzed the extent of necrosis, the epiphyseal revascularization pathways and the metaphyseal changes. The absence of enhancement on gadolinium enhanced MRI was noted in all cases of LCP disease. Diffuse absence of enhancement was observed in 9 femoral epiphyses. Two of them showed normal bone marrow signal intensity on the T1 and T1-weighted images. Focal absence of enhancement was observed in 5 femoral epiphyses. Enhanced MRI showed better epiphyseal revascularization in the lateral column (five cases), in the lateral and medial columns (four cases) and in the transphyseal pathway (three cases). Metaphyseal change was observed in two cases. Gadolinium enhanced MRI allows detection of LCP disease and an accurate analysis of the different revascularization patterns, and this helpful for predicting the prognosis

  6. Growth, characterization and dielectric studies of gadolinium fumarate heptahydrate single crystals

    Indian Academy of Sciences (India)

    M D Shah; B Want

    2015-02-01

    Gadolinium fumarate heptahydrate single crystals were grown by the single gel diffusion technique using silica gel as a medium of growth. Nucleation rate of these crystals was studied corresponding to the effect of various growth parameters. An attempt was made to relate the experimental results with the classical nucleation theory. The crystals were characterized by different physico-chemical techniques of characterization. Powder X-ray diffraction pattern showed that gadolinium fumarate is a crystalline compound and is isomorphous with samarium fumarate heptahydrate crystals. Fourier transform infrared spectroscopy was performed for the identification of water and other functional groups present in the compound. Elemental analysis sugested the chemical formula of the crystals to be Gd2(C4H2O4)3.7H2O. The presence of seven molecules of water was also supported by the thermogravimetric analysis. The hydrated compound was found to be thermally stable up to a temperature of about 110°C and its anhydrous form up to the temperature of 420°C. The thermal decomposition of the compound in the nitrogen atmosphere leads to the formation of gadolinium oxide as the final product. The dielectric properties and AC conductivity of gadolinium fumarate heptahydrate complex were carried out in the frequency range of 20 Hz–3MHz and over the temperature range of 15–130°C, both showing a hump at about 95°C, which could be attributed to water molecules in the crystal boundary.

  7. Preparation of thin gadolinium samples via electrodeposition for excitation function studies

    International Nuclear Information System (INIS)

    A preparation method for gadolinium targets with a thickness up to 4 mg/cm2 on aluminum supports from aqueous electrolytes was developed. These electrodeposited adhesive and mechanically stable natGd layers were used to measure excitation functions of Gd + p nuclear reactions relevant to the production of medically important 152Tb (PET) and 155Tb (SPECT) radioisotopes. (author)

  8. Determination of integrated neutron flux by the measurement of the isotopic ratios of cadmium and gadolinium

    International Nuclear Information System (INIS)

    In this work, the possibility of the indirect determination of the integrated neutron flux, through the change of isotopic ratios of cadmium and gadolinium was investigated. The samples of cadmium we/e gadolinium were irradiated in the IEA-Rl reactor. These elements were chosen because they have high thermal neutron absorption cross section which permit the change in the isotopic composition during a short irradiation time to be measured accurately. The isotopic ratios were measured with a thermionic mass spectrometer the silica-gel technique and arrangement with single filament were used for the cadmium analysis, where as the oxi - reduction technique and arrangement with double filaments were used for gadolinium analysis. The mass fractionation effects for cadmium and gadolinium were corrected respectively by the exponential and potential expansion of the isotopic fractionation factor per atomic mass unit. The flux values supplied by the Centro de Operacao e Utilizacao do Reator de Pesquisas do IPEN were extrapolated. These values and the integrated flux values obtained experimentally were compared. (author)

  9. Magnetocaloric properties of distilled gadolinium: effects of structural inhomogeneity and hydrogen impurity

    Czech Academy of Sciences Publication Activity Database

    Burkhanov, G.S.; Kolchugina, N.B.; Tereshina, Evgeniya; Tereshina, I. S.; Politova, G.A.; Chzhan, V.B.; Badurski, D.; Chistyakov, O.D.; Paukov, M.; Drulis, H.; Havela, L.

    2014-01-01

    Roč. 104, č. 24 (2014), "242402-1"-"242402-5". ISSN 0003-6951 R&D Projects: GA ČR GAP204/12/0150 Institutional support: RVO:68378271 Keywords : high-purity rare-earth metals * gadolinium * magnetocaloric effect * hydrogenation * structural studies Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.302, year: 2014

  10. Measuring the effect of demagnetization in stacks of gadolinium plates using the magnetocaloric effect

    DEFF Research Database (Denmark)

    Lipsø, Hans Kasper Wigh; Nielsen, Kaspar Kirstein; Christensen, Dennis; Bahl, Christian Robert Haffenden; Engelbrecht, Kurt; Kuhn, Luise Theil; Smith, Anders

    2011-01-01

    The effect of demagnetization in a stack of gadolinium plates is determined experimentally by using spatially resolved measurements of the adiabatic temperature change due to the magnetocaloric effect. The number of plates in the stack, the spacing between them and the position of the plate on...

  11. Equilibrium and transient conductivity for gadolinium-doped ceria under large perturbations: I. Experiments

    DEFF Research Database (Denmark)

    Ricote, Sandrine; Zhu, Huayang; Coors, W. Grover; Chatzichristodoulou, Christodoulos; Kee, Robert J.

    2014-01-01

    This is the first of a two-part paper that is concerned with measuring and interpreting equilibrium and transient conductivity for 10at.% gadolinium-doped ceria (Ce0.9Gd0.1O1.95-δ, GDC10). AC impedance spectroscopy is used to measure conductivity of slender extruded GDC10 rods at temperatures...

  12. Research in gadolinium scandium gallium garnet (GSGG) crystal development. Final report, 1 May-31 December 1984

    International Nuclear Information System (INIS)

    The Czochralski growth technique was utilized for the development of a large diameter, laser quality gadolinium, scandium gallium garnet co-doped with neodymium and chromium (Nd:Cr:GSGG). Vary aspects of the development were determinations of raw material purity, foule growth runs, boule composition and lattice parameters, and losses. 8 refs., 13 figs., 10 tabs

  13. Late gadolinium enhancement cardiovascular magnetic resonance in genotyped hypertrophic cardiomyopathy with normal phenotype

    OpenAIRE

    Jassal Davinder S; Soni Reeni; Ariyarajah Vignendra; Strijack Bradford; Greenberg Cheryl R; McGregor Robert; Morris Andrew

    2008-01-01

    Abstract A 35 year-old asymptomatic Caucasian female with a family history of hypertrophic cardiomyopathy (HCM) was referred for cardiologic evaluation. The electrocardiogram and transthoracic echocardiogram were normal. Cardiovascular magnetic resonance (CMR) was performed for further assessment of myocardial function and presence of myocardial scar. CMR showed normal left ventricular systolic size, measurements and function. However, there was extensive, diffuse late gadolinium enhancement ...

  14. Property investigations of (U,Gd)O2 fuel with higher content of Gadolinium Oxide

    International Nuclear Information System (INIS)

    Currently the production of fuel containing above 5 % Gadolinium Oxide has been started in Russia. When mastering the fabrication process it has been noted that Gadolinium introduced in the quantity of more then 5 % leads to noticeable changes in fuel properties, viz, density and Oxygen to metal ratio, thermal conductivity and strength characteristics become lower. In the process of fabrication this type of fuel in subject to more intensive cracking. To resolve the above problems JSC 'MSZ' together with JSC 'VNIINM' embarked on improving the fabrication process and investigating the quality characteristics of fuel pellets containing above 5 % Gadolinium Oxide. JSC 'VNIINM' and JSC 'MSZ' investigated density, Oxygen to metal ratio, strength characteristics, microstructure parameters and thermal stability (resintering) of U-Gd pellets with the aim of their qualification. At JSC 'VNIINM' the procedure has been updated that is used to determine thermal stability of geometrical sizes and density (resintering) of U-Gd fuel pellets for WWER-440 and WWER-1000 reactors via widening the range of measurement up to the gadolinium oxide content of 8.5 %. (authors)

  15. Separation and purification of gadolinium and others rare earths, and yttrium

    International Nuclear Information System (INIS)

    The experimental works in laboratories for developing a solvent extraction process with the purpose of gadolinium separation and purification, and secondarily samarium, europium, lanthanum and yttrium are described. Using as solvent di-2-ethylhexylphosphoric acid (DEHPA) a preliminary flow chart for separation for these elements are developed. (author)

  16. Programming Service Oriented Agents

    OpenAIRE

    Hirsch, Benjamin; Konnerth, Thomas; Burkhardt, Michael; Albayrak, Sahin

    2010-01-01

    This paper introduces a programming language for service-oriented agents. JADL++ combines the ease of use of scripting-languages with a state-of-the-art service oriented approach which allows the seamless integration of web-services. Furthermore, the language includes OWL-based ontologies for semantic descriptions of data and services, thus allowing agents to make intelligent decisions about service calls.

  17. Adrenal imaging agents

    International Nuclear Information System (INIS)

    The goals of this proposal are the development of selenium-containing analogs of the aromatic amino acids as imaging agents for the pancreas and of the adrenal cortex enzyme inhibitors as imaging agents for adrenal pathology. The objects for this year include (a) the synthesis of methylseleno derivatives of phenylalanine and tryptophan, and (b) the preparation and evaluation of radiolabeled iodobenzoyl derivatives of the selenazole and thiazole analogs of metyrapone and SU-9055

  18. Criticality experiments with low enriched UO2 fuel rods in water containing dissolved gadolinium

    International Nuclear Information System (INIS)

    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 UO2 and PuO2-UO2 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 UO2 rods at two enrichments (2.35 wt % and 4.31 wt % 235U) and on mixed fuel-water assemblies of UO2 and PuO2-UO2 rods containing 4.31 wt % 235U and 2 wt % PuO2 in natural UO2 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 235U 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

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

    Directory of Open Access Journals (Sweden)

    Tetsuo Konno

    Full Text Available 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

  20. Paramagnetic Gd2O3 Nanoparticle-Based Targeting Theranostic Agent for C6 Rat Glioma Cell

    Directory of Open Access Journals (Sweden)

    Seong-Pyo Hong

    2016-01-01

    Full Text Available This study aimed to synthesize theranostic agent targeting C6 rat glioma cell, which was based on the dextran coated paramagnetic gadolinium oxide nanoparticles (D-PGONs conjugated with folic acid (FA or paclitaxel (PTX. The D-PGONs were synthesized by the in situ coprecipitation method, and the average value of the size distribution was 2.9 nm. FTIR spectroscopy was fulfilled to confirm the conjugations of FA or PTX with D-PGONs. The bioprotective effects of dextran coating and chemotherapeutic effect of PTX in the C6 glioma cell were evaluated by the MTT assay. The differences in uptakes between the synthesized theranostic agents into C6 cells were observed by confocal laser scanning microscopy. In addition, the magnetic contrast enhancement with different concentration of the synthesized agent was compared by the T1-weighted MRI imaging. It was experimentally shown that the synthesized theranostic agent targets C6 cells due to the ligand-receptor-mediated endocytosis and provides enhancement in MR contrast depending on the concentration due to the paramagnetic property of gadolinium nanoparticle. In addition, it was shown by the results of MTT assay that the synthesized nanocomposites were more effective in reducing cell viability than bare gadolinium nanoparticles. In conclusion, it was shown that FA and PTX conjugated D-PGONs could be used as the theranostic agent with paramagnetism and chemotherapeutic property.

  1. MRI dacryocystography after conjunctival application of gadolinium solution; MRT-Dakryozystographie nach Applikation gadoliniumhaltiger Augentropfen

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelm, K.; Keller, E.; Textor, J.; Schueller, H.; Schild, H. [Radiologische Universitaetsklinik Bonn (Germany); Walther, E. [Universitaets-Hals-Nasen-Ohrenklinik Bonn (Germany)

    1997-07-01

    Purpose: To determine the efficacy of MRI for the lacrimal drainage system after conjunctival application of gadolinium-DTPA solution. Material and methods: MRI dacryocystography of 32 nasolacrimal duct systems was performed in 16 patients additional to digital subtraction dacryocystography. The gadolinium solution was prepared by diluting the commercially available gadolinium-DTPA (Magnevist{sup R}, Schering AG, Berlin) 1:10 in sterile saline solution. 3x2 drops of this contrast medium were instilled bilaterally immediately before MRI scanning. Results: MRI dacryocystography provided detailed information on the nasolacrimal duct system in all 32 cases. In 16 cases localisation and functional degree of nasolacrimal duct obstruction or stenosis was determined reliably. In 15 cases normal nasolacrimal duct system showed no contrast enhancement. In one case stenosis of the canaliculus was observed. Conclusion: MRI dacryocystography provides detailed morphological soft tissue information of the lacrimal drainage system. Local conjunctival application of gadolinium solution allows functional tests of the lacrimal duct system in patients suffering from epiphora. (orig.) [Deutsch] Ziel: Darstellung des Traenenapparates nach lokaler Applikation gadoliniumhaltiger Augentropfen mittels MRT-Dakryozystographie. Material und Methode: Bei 16 Patienten wurden 32 Traenenapparate untersucht. Appliziert wurden 3x2 Tropfen einer 1:10 verduennten Gadolinium-Loesung (Magnevist{sup R}, Schering AG, Berlin). Als Kontrolluntersuchungen standen die klinische Untersuchung und die Dakryozystographie zur Verfuegung. Ergebnisse: Die 16 postsakkalen Traenenwegsverschluesse und -stenosen wiesen jeweils ein praestenotisches Kontrastmitteldepot im Traenenapparat auf und stellten sich MR-tomographisch funktionell als Traenenwegsverschluss dar. Bei den 15 klinisch unauffaelligen Traenenapparaten erfolgte dagegen der Kontrastmittelabstrom so schnell, dass keine Kontrastmittelretention auftrat. In

  2. Experimental and thermodynamic study of the erbium-oxygen-zirconium and gadolinium-oxygen-zirconium systems

    International Nuclear Information System (INIS)

    This work is a contribution to the development of innovative concepts for fuel cladding in pressurized water nuclear reactors. This concept implies the insertion of rare earth (erbium and gadolinium) in the zirconium fuel cladding. The determination of phase equilibria in the systems is essential prior to the implementation of such a promising solution. This study consisted in an experimental determination of the erbium-zirconium phase diagram. For this, we used many different techniques in order to obtain diagram data such as solubility limits, solidus, liquidus or invariant temperatures. These data allowed us to present a new diagram, very different from the previous one available in the literature. We also assessed the diagram using the CALPHAD approach. In the gadolinium-zirconium system, we determined experimentally the solubility limits. Those limits had never been determined before, and the values we obtained showed a very good agreement with the experimental and assessed versions of the diagram. Because these alloys are subjected to oxygen diffusion throughout their life, we focused our attention on the erbium-oxygen-zirconium and gadolinium-oxygen-zirconium systems. The first system has been investigated experimentally. The alloys fabrication has been performed using powder metallurgy. In order to obtain pure raw materials, we fabricated powder from erbium and zirconium bulk metals using hydrogen absorption/desorption. The characterisation of the ternary pellets allowed the determination of two ternary isothermal sections at 800 and 1100 C. For the gadolinium-oxygen-zirconium system, we calculated the phase equilibria at temperatures ranging from 800 to 1100 C, using a homemade database compiled from literature assessments of the oxygen-zirconium, gadolinium-zirconium and gadolinia-zirconia systems. Finally, we determined the mechanical properties, in connexion with the microstructure, of industrial quality alloys in order to identify the influence of

  3. MRI of spondylodiscities: contribution of gadolinium-DTPA and fat suppression sequence

    International Nuclear Information System (INIS)

    Twenty-six patients with a clinical diagnosis of spondylodiscitis were examined with non-contrast and contrast-enhanced MRI in order to define the contribution of gadolinium-DTPA (Gd-DTPA) and different pulse sequences, including a fat suppression sequence (SPIR). Spin echo (SE) T1-weighted images before and after Gd-DTPA injection and SE T2-weighted images were obtained in all patients. Twelve patients were also examined using the SPIR sequence following Gd-DTPA injection. Signal intensity and morphological features of the disc and vertebral lesions were then evaluated. The SE T1-weighted sequence with Gd-DTPA was very effective in showing the pathological changes at the level of the disc as an area of low signal intensity surrounded by a peripheral rim of enhancement in 24 of 26 cases (92%). This feature was not visible on non-enhanced images. As regards contiguous vertebral lesions this sequence was less informative, since in 8 of 26 cases (31%) the vertebral lesions became isointense and therefore not detectable. In 12 cases there was extension into the surrounding structures (spinal canal and/or paravertebral tissues). An enhanced SE T1-weighted sequence provided good anatomical definition of the extension of the infection in the spinal canal in all cases with this type of involvement (7 of 12). Regarding the 7 cases with paravertebral extension, no extension was visible in 1 case due to the reduced contrast with the surrounding fat following Gd-DTPA injection. The enhanced SPIR sequence was very effective, particularly in detecting the lesions in the vertebral bodies, avoiding the limitation of the enhanced SE T1-weighted sequence. The SPIR sequence was also effective in showing the extension within the spinal canal and the paravertebral fat. On the basis of our results the combination of a SE T1-weighted sequence without contrast and SPIR sequence with Gd-DTPA seems to be the best approach in cases of spondylodiscitis. (orig.)

  4. Oscillator strengths, Huang-Rhys parameters, and vibrational quantum energies of cerium-doped gadolinium oxyorthosilicate

    International Nuclear Information System (INIS)

    Temperature-dependent optical absorption of cerium-doped gadolinium oxyorthosilicate (Gd2SiO5:Ce) has been measured and analyzed for impurity-ion-lattice coupling parameters and oscillator strengths. Although the spectrum consists of overlapping Ce3+ bands and Gd3+ lines, two well-resolved Ce3+ bands with 10 K maxima at 3.32 eV (peak a) and 3.61 eV (peak b) are amenable to spectral analysis. These bands, previously assigned to Ce3+ ions occupying crystallographically inequivalent substitutional sites, are characterized by Gaussian line shapes and temperature-dependent half widths that are well described by the linear model of impurity-ion-lattice coupling. Huang-Rhys [Proc. R. Soc. A 204, 404 (1950)] parameters of peaks a and b are 22.7 and 5.7, respectively, indicating strong ion-lattice coupling, with vibrational frequencies 1.83x1013 s-1 (peak a) and 5.07x1013 s-1 (peak b). Peak b centroid is approximately temperature independent, but peak a centroid shifts to higher energy with increasing temperature. This dependence is adequately described by including higher-order coupling terms in the ion-lattice interaction, although crystal-field contributions cannot be excluded. Absorption band oscillator strengths, f, are calculated from Smakula's [Z. Phys. 59, 603 (1930)] formula and knowledge of cerium concentration for the two inequivalent sites. In the interval 10-300 K, peak a f values range from (9.8 to 26.8)x10-4 and peak b f values vary from (7.8 to 5.8)x10-3. From the known correlation between oscillator strength and metal-ion-ligand separation, we identify peaks a and b as the seven- and nine-oxygen-coordinated sites, respectively. (c) 2000 American Institute of Physics

  5. Macromolecular and dendrimer-based magnetic resonance contrast agents

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) is a powerful imaging modality that can provide an assessment of function or molecular expression in tandem with anatomic detail. Over the last 20-25 years, a number of gadolinium-based MR contrast agents have been developed to enhance signal by altering proton relaxation properties. This review explores a range of these agents from small molecule chelates, such as Gd-DTPA and Gd-DOTA, to macromolecular structures composed of albumin, polylysine, polysaccharides (dextran, inulin, starch), poly(ethylene glycol), copolymers of cystamine and cystine with GD-DTPA, and various dendritic structures based on polyamidoamine and polylysine (Gadomers). The synthesis, structure, biodistribution, and targeting of dendrimer-based MR contrast agents are also discussed

  6. Macromolecular and dendrimer-based magnetic resonance contrast agents

    Energy Technology Data Exchange (ETDEWEB)

    Bumb, Ambika; Brechbiel, Martin W. (Radiation Oncology Branch, National Cancer Inst., National Inst. of Health, Bethesda, MD (United States)), e-mail: pchoyke@mail.nih.gov; Choyke, Peter (Molecular Imaging Program, National Cancer Inst., National Inst. of Health, Bethesda, MD (United States))

    2010-09-15

    Magnetic resonance imaging (MRI) is a powerful imaging modality that can provide an assessment of function or molecular expression in tandem with anatomic detail. Over the last 20-25 years, a number of gadolinium-based MR contrast agents have been developed to enhance signal by altering proton relaxation properties. This review explores a range of these agents from small molecule chelates, such as Gd-DTPA and Gd-DOTA, to macromolecular structures composed of albumin, polylysine, polysaccharides (dextran, inulin, starch), poly(ethylene glycol), copolymers of cystamine and cystine with GD-DTPA, and various dendritic structures based on polyamidoamine and polylysine (Gadomers). The synthesis, structure, biodistribution, and targeting of dendrimer-based MR contrast agents are also discussed

  7. Ultra low-dose of gadobenate dimeglumine for late gadolinium enhancement (LGE) imaging in acute myocardial infarction: A feasibility study

    International Nuclear Information System (INIS)

    Highlights: • We compared two gadolinium dose for late enhancement imaging in acute infarction. • We evaluated image quality both qualitatively and quantitatively. • Low dose regimen is feasible and provides better image quality at 5–10 min delay. • Standard dose warrants better image quality and should be routinely preferred. - Abstract: Purpose: To assess the feasibility of using an ultra-low dose (0.05 mmol/kg of body weight [BW]) of high relaxivity contrast agent for late gadolinium enhancement (LGE) imaging in patients with acute myocardial infarction (AMI). Materials and methods: 17 consecutive patients (mean age, 60.1 ± 10.3 years) with ST-segment elevation AMI underwent two randomized cardiac magnetic resonance studies (exam intervals between 24 and 48 h) on a 1.5 T unit during the first week after the event using gadobenate dimeglumine (Gd-BOPTA) at the dose of 0.1 mmol/kg BW (standard dose or SD group) and 0.05 mmol/kg BW (half dose or HD group). Image quality was qualitatively assessed. Quantitative analysis of LGE were performed by measuring signal intensity (SI), signal-to-noise ratio (SNR) in the infarcted myocardium (IM), non-infarcted myocardium (N-IM) and left ventricular cavity (LVC) in images acquired at 1, 3, 5, 10, 15 and 20 min after administration of Gd-BOPTA using both contrast media protocol. Contrast-to-noise ratio (CNR) between IM and N-IM (CNR IM/N-IM) and between IM and LVC (CNR IM/LVC) were also quantified for each time point. Moreover the extent of infarcted myocardium was measured. Results: 102 LGE images were evaluated for each dose group. Quality score was significantly higher for SD at 1, 15 and 20 min (0.002 < p < 0.046) and for HD at 5 min (p = 0.013). SNR has been higher in the SD group compared to the HD group even though not statistically significant at any time-point for both IM (SD vs. HD: 87.7 ± 73 vs. 65 ± 66; 0.15 < p < 0.38) and N-IM (SD vs. HD: 22 ± 61 vs. 9.9 ± 6.5; 0.09 < p < 0.43). LVC SNR was

  8. Biodegradable gadolinium-chelated cationic poly(urethane amide) copolymers for gene transfection and magnetic resonance imaging.

    Science.gov (United States)

    Gao, Xiaolong; Wang, Gangmin; Shi, Ting; Shao, Zhihong; Zhao, Peng; Shi, Donglu; Ren, Jie; Lin, Chao; Wang, Peijun

    2016-08-01

    Theranostic nano-polyplexes containing gene and imaging agents hold a great promise for tumor diagnosis and therapy. In this work, we develop a group of new gadolinium (Gd)-chelated cationic poly(urethane amide)s for gene delivery and T1-weighted magnetic resonance (MR) imaging. Cationic poly(urethane amide)s (denoted as CPUAs) having multiple disulfide bonds, urethane and amide linkages were synthesized by stepwise polycondensation reaction between 1,4-bis(3-aminopropyl)piperazine and a mixture of di(4-nitrophenyl)-2, 2'-dithiodiethanocarbonate (DTDE-PNC) and diethylenetriaminepentaacetic acid (DTPA) dianhydride at varied molar ratios. Then, Gd-chelated CPUAs (denoted as GdCPUAs) were produced by chelating Gd(III) ions with DTPA residues of CPUAs. These GdCPUAs could condense gene into nanosized and positively-charged polyplexes in a physiological condition and, however, liberated gene in an intracellular reductive environment. In vitro transfection experiments revealed that the GdCPUA at a DTDE-PNC/DTPA residue molar ratio of 85/15 induced the highest transfection efficiency in different cancer cells. This efficiency was higher than that yielded with 25kDa branched polyethylenimine as a positive control. GdCPUAs and their polyplexes exhibited low cytotoxicity when an optimal transfection activity was detected. Moreover, GdCPUAs may serve as contrast agents for T1-weighted magnetic resonance imaging. The results of this work indicate that biodegradable Gd-chelated cationic poly(urethane amide) copolymers have high potential for tumor theranostics. PMID:27157741

  9. A phantom-based feasibility study for detection of gadolinium in bone in-vivo using X-ray fluorescence.

    Science.gov (United States)

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

    2016-06-01

    Gadolinium (Gd) based contrast agents have been commonly used over the past three decades to improve contrast in magnetic resonance imaging. These complexes, originally thought to be stable and clear from the body shortly after administration, have been shown to dissociate to a small extent and deposit in organs such as bone. A safe and non-invasive method for measuring Gd in bone is necessary for further exploring Gd retention in the body following the administration of a contrast agent. A feasibility study using a K x-ray fluorescence (K-XRF) system to measure Gd in human tibias was investigated. Bone phantoms mimicking human tibia were created with Gd concentrations ranging from 0 to 120ppm. The minimum detection limit (MDL) was calculated from 20-hour and 7-hour phantom measurements with a source activity of 0.11GBq. All MDL values were scaled to a more realistic measurement time of 30-minutes with a stronger source. Scaling arguments were based on activity ratio, measurement time, and system dead time. The MDL for a 1GBq source was estimated to be 3.60-3.64ppm, for an average range of tissue thicknesses overlaying a human tibia. For a stronger source of 5GBq and a four detector cloverleaf system, the MDL was estimated to be 1.49-1.52ppm. Determined and predicted MDLs are within the range of previous in-vitro Gd measurement data. The K-XRF system shows promising results for detecting Gd in bone and should be seriously considered for in-vivo measurements. PMID:27019028

  10. Comparison of renewable oil, recycled oil, and commercial rejuvenating agent derived from crude oil in paving asphalt modification[Includes the CSCE forum on professional practice and career development : 1. international engineering mechanics and materials specialty conference : 1. international/3. coastal, estuarine and offshore engineering specialty conference : 2. international/8. construction specialty conference

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, C.; Ho, S.; Zanzotto, L. [Calgary Univ., AB (Canada). Schulich School of Engineering

    2009-07-01

    The asphalt industry relies heavily on crude oil. In response to increasing oil prices, there have been efforts to save money on asphalt by taking harder asphalts, such as recycled asphalt pavement (RAP), and softening them with rejuvenating agents. For asphalt that is to be used in cold climates, softer asphalts are preferred because they will perform better under extreme cold conditions without cracking. This study compared the performance, economic benefits, and environmental benefits of renewable materials, recycled oil and a commercially used rejuvenating agent derived from crude oil. Different oily materials including margarine, Cyclogen L (a crude oil-derived material), a vegetable wax, and recycled cooking oil were used to modify paving asphalt. Their effectiveness at improving the superpave low-temperature performance grade was compared. The samples were all tested using the 2008 AASHTO M320 procedures. The high temperature grades were determined using the dynamic shear rheometer test, and the low-temperature grades were determined using the bending beam rheometer test. The 3 varieties of margarine that were tested were able to improve the low-temperature grade, but they caused a greater depreciation of the high-temperature performance grade than the other materials, and were much more expensive. The best candidate for an effective, economic asphalt softening agent was found to be the recycled cooking oil. It out-performed the Cyclogen L oil in terms of improving the low- temperature performance grade, and was less expensive. 12 refs., 4 tabs., 6 figs.

  11. Agent-Based Modeling and Mapping of Manufacturing System

    Institute of Scientific and Technical Information of China (English)

    Z; Zhang

    2002-01-01

    Considering the agent-based modeling and mapping i n manufacturing system, some system models are described in this paper, which are included: Domain Based Hierarchical Structure (DBHS), Cascading Agent Structure (CAS), Proximity Relation Structure (PRS), and Bus-based Network Structure (BNS ). In DBHS, one sort of agents, called static agents, individually acts as Domai n Agents, Resources Agents, UserInterface Agents and Gateway Agents. And the oth ers, named mobile agents, are the brokers of task and ...

  12. Agent, autonomous

    OpenAIRE

    Luciani, Annie

    2007-01-01

    The expression autonomous agents, widely used in virtual reality, computer graphics, artificial intelligence and artificial life, corresponds to the simulation of autonomous creatures, virtual (i.e. totally computed by a program), or embodied in a physical envelope, as done in autonomous robots.

  13. Following unenhanced MRI assessment for local recurrence after surgical resection of mesenchymal soft tissue tumors, do additional gadolinium-enhanced images change reader confidence or diagnosis?

    Energy Technology Data Exchange (ETDEWEB)

    Diana Afonso, P., E-mail: p.diana.a@gmail.com [Department of Radiology, Duke University Medical Center, 2301 Erwin Road, Durham, NC 27710 (United States); Kosinski, A.S., E-mail: andrzej.kosinski@duke.edu [Department of Biostatistics and Bioinformatics, Duke University Medical Center, 2301 Erwin Road, Durham, NC 27710 (United States); Spritzer, C.E., E-mail: chuck.spritzer@duke.edu [Department of Radiology, Duke University Medical Center, P.O. Box 3808, Duke University Medical Center, Durham, NC (United States)

    2013-05-15

    Highlights: ► Gadolinium enhanced imaging improves reader confidence in detecting soft tissue tumor recurrence. ► Gadolinium enhanced imaging modestly improves inexperienced reader accuracy for detecting tumor recurrence. ► Where possible, gadolinium should be used in the assessment of MSK tumor residual or recurrence. -- Abstract: Purpose: Evaluate if gadolinium enhanced MR imaging (GeMRI) improves confidence, changes the final diagnosis, or improves accuracy in the assessment of musculoskeletal (MSK) tumor residual or recurrence following surgical resection. We also assess if different experience levels change the above results. Methods and materials: Initially, pre-contrast images were independently reviewed by two radiologists, one with 25 years of experience (R1) and one undergoing MSK specialty training (R2). Two questions were answered: (1) Mass present? and (2) Likelihood of malignancy? Subsequently, both pre-contrast and post-contrast images were independently reviewed. The same questions were again answered plus four others including if GeMRI changed mass characterization, better defined cystic versus solid, better defined tumor extent, or improved conspicuity. Lastly, the readers answered whether GeMRI changed confidence, and changed their final diagnosis. Histologic diagnoses were available in 43 cases, with the remaining 44 cases based upon clinical and/or imaging follow-up. Results: GeMRI definitely improved confidence in 8/7 cases, and slightly improved confidence in 20/29 cases and changed the final diagnosis in 11/8 cases for R1 and R2 respectively. Positive and negative predictive values statistically improved for R2 (positive predictive value 36.4% versus 50%, p = 0.02; negative predictive value 75.4% versus 79.1%, p = 0.04) but not for R1. Reader concordance for malignancy improved with GeMRI (κ = 0.44 pre-contrast and κ = 0.71 post-contrast). Conclusion: GeMRI improved reader confidence, improved reader concordance and modestly improved

  14. Following unenhanced MRI assessment for local recurrence after surgical resection of mesenchymal soft tissue tumors, do additional gadolinium-enhanced images change reader confidence or diagnosis?

    International Nuclear Information System (INIS)

    Highlights: ► Gadolinium enhanced imaging improves reader confidence in detecting soft tissue tumor recurrence. ► Gadolinium enhanced imaging modestly improves inexperienced reader accuracy for detecting tumor recurrence. ► Where possible, gadolinium should be used in the assessment of MSK tumor residual or recurrence. -- Abstract: Purpose: Evaluate if gadolinium enhanced MR imaging (GeMRI) improves confidence, changes the final diagnosis, or improves accuracy in the assessment of musculoskeletal (MSK) tumor residual or recurrence following surgical resection. We also assess if different experience levels change the above results. Methods and materials: Initially, pre-contrast images were independently reviewed by two radiologists, one with 25 years of experience (R1) and one undergoing MSK specialty training (R2). Two questions were answered: (1) Mass present? and (2) Likelihood of malignancy? Subsequently, both pre-contrast and post-contrast images were independently reviewed. The same questions were again answered plus four others including if GeMRI changed mass characterization, better defined cystic versus solid, better defined tumor extent, or improved conspicuity. Lastly, the readers answered whether GeMRI changed confidence, and changed their final diagnosis. Histologic diagnoses were available in 43 cases, with the remaining 44 cases based upon clinical and/or imaging follow-up. Results: GeMRI definitely improved confidence in 8/7 cases, and slightly improved confidence in 20/29 cases and changed the final diagnosis in 11/8 cases for R1 and R2 respectively. Positive and negative predictive values statistically improved for R2 (positive predictive value 36.4% versus 50%, p = 0.02; negative predictive value 75.4% versus 79.1%, p = 0.04) but not for R1. Reader concordance for malignancy improved with GeMRI (κ = 0.44 pre-contrast and κ = 0.71 post-contrast). Conclusion: GeMRI improved reader confidence, improved reader concordance and modestly improved

  15. Improvement of the LET sensitivity in ESR dosimetry for {gamma}-photons and thermal neutrons through gadolinium addition

    Energy Technology Data Exchange (ETDEWEB)

    Marrale, M. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Unita CNISM, Palermo and Gruppo V Sezione INFN, Catania (Italy)], E-mail: marrale@difter.unipa.it; Brai, M. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Unita CNISM, Palermo and Gruppo V Sezione INFN, Catania (Italy); Gennaro, G.; Triolo, A. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Bartolotta, A. [Dipartimento Farmacochimico Tossicologico e Biologico, Universita di Palermo, Via Archirafi 32, 90123 Palermo (Italy); Unita CNISM, Palermo and Gruppo V Sezione INFN, Catania (Italy)

    2007-07-15

    We investigated the ESR response of new materials, alanine and ammonium tartrate to which gadolinium was added. The addition of gadolinium enhances sensitivity for {sup 60}Co{gamma}-photons because of its high atomic number (Z=64) and an enhancement of sensitivity for thermal neutrons because of its high thermal neutron cross section and high linear energy transfer (LET) secondary particles produced after the reaction with neutrons. In particular, in this paper we analyzed the microwave power saturation properties of dosimeters of alanine and ammonium tartrate with or without gadolinium exposed to different LET beams. The power saturation trends of dosimeters exposed to photons and to thermal neutrons are different. For ammonium tartrate dosimeters the gadolinium addition intensifies significantly these differences and therefore, it improves the ammonium tartrate's ability to discriminate the radiation LET.

  16. Standard test methods for chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide (Gd2O3) powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 These test methods cover procedures for the chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide powders to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Carbon by Direct CombustionThermal Conductivity C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Total Chlorine and Fluorine by Pyrohydrolysis Ion Selective Electrode C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Loss of Weight on Ignition 7-13 Sulfur by CombustionIodometric Titration Impurity Elements by a Spark-Source Mass Spectrographic C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical,Nuclear, and Radiochemical Analysis of Uranium Hexafluoride C1287 Test Method for Determination of Impurities In Uranium Dioxide By Inductively Coupled Plasma Mass Spectrometry Gadolinium Content in Gadolinium Oxid...

  17. Technical requirements, biophysical considerations and protocol optimization with magnetic resonance angiography using blood-pool agents

    International Nuclear Information System (INIS)

    In order to maximize the potential benefits of contrast-enhanced magnetic resonance angiography, careful attention must be paid to the choice of hardware, data acquisition and processing, and to the choice of contrast agent. Typically, contrast-enhanced magnetic resonance angiography uses parallel-imaging techniques, which shorten the acquisition time, enhance spatial resolution and reduce artefacts. The timing of data acquisition is crucial for maximal enhancement of the arteries: for optimal arterial depiction, the centre of k-space should be acquired at the time of peak concentration of contrast agent in the arterial bed being investigated, and a number of k-space acquisition techniques are available to achieve this. SENSE or GRAPPA techniques can be used to facilitate parallel-imaging reconstruction of either the image data or k-space data, respectively. Gadolinium contrast agents shorten the proton relaxation times (most importantly T1) of blood, thereby increasing the signal-to-noise ratio and enhancing differentiation between blood vessels and other tissues. The blood-pool (intravascular) contrast agent gadofosveset trisodium (Vasovist, Bayer Schering Pharma AG, Berlin, Germany) is reversibly protein-bound in human plasma. This results in a marked increase in relaxivity, and hence a strong T1 shortening effect compared with other gadolinium-based contrast agents. Furthermore, the blood retention time of gadofosveset trisodium is substantially prolonged compared with conventional contrast agents. As a result, gadofosveset trisodium permits both first-pass and steady-state imaging. (orig.)

  18. MR angiography of the carotid arteries and intracranial circulation: advantage of a high relaxivity contrast agent

    International Nuclear Information System (INIS)

    Several studies have shown the usefulness of contrast-enhanced MR angiography (CE-MRA) for imaging the supraortic vessels, and, as a consequence, it has rapidly become a routine imaging modality. The main advantage over unenhanced techniques is the possibility to acquire larger volumes, allowing demonstration of the carotid artery from its origin to the intracranial portion. Most published studies on CE-MRA of the carotid arteries have been performed with standard Gd-based chelates whose T1 relaxivity values are similar. Recently new gadolinium chelates such as gadobenate dimeglumine (Gd-BOP-TA, MultiHance; Bracco Imaging, Milan, Italy) have been developed which have markedly higher intravascular T1 relaxivity values. When administered at an equivalent dose to that of a standard agent, these newer contrast agents produce significantly greater intravascular signal enhancement. The availability of an appropriate high-relaxivity contrast agent might also help to overcome some of the intrinsic technical problems (e. g. those related to flow) that affect time-of-flight (TOF) and phase contrast (PC) MR angiography of the intracranial vasculature. To avoid the problem of superimposition of veins, ultrafast gradient echo MRA techniques with very short TR and TE have been developed. Although the precise sequence parameters vary between manufacturers, they are basically similar. The choice between performing a time-resolved or high spatial resolution CE-MRA examination depends upon the precise clinical application. The most common applications include the study of cerebral aneurysms, arteriovenous malformations, dural arteriovenous fistulas and dural venous diseases

  19. Appearance of microvascular obstruction on high resolution first-pass perfusion, early and late gadolinium enhancement CMR in patients with acute myocardial infarction

    Directory of Open Access Journals (Sweden)

    Redwood Simon

    2009-08-01

    Full Text Available Abstract Background The presence and extent of microvascular obstruction (MO after acute myocardial infarction can be measured by first-pass gadolinium-enhanced perfusion cardiovascular magnetic resonance (CMR or after gadolinium injection with early or late enhancement (EGE/LGE imaging. The volume of MO measured by these three methods may differ because contrast agent diffusion into the MO reduces its apparent extent over time. Theoretically, first-pass perfusion CMR should be the most accurate method to measure MO, but this technique has been limited by lower spatial resolution than EGE and LGE as well as incomplete cardiac coverage. These limitations of perfusion CMR can be overcome using spatio-temporal undersampling methods. The purpose of this study was to compare the extent of MO by high resolution first-pass k-t SENSE accelerated perfusion, EGE and LGE. Methods 34 patients with acute ST elevation myocardial infarction, treated successfully with primary percutaneous coronary intervention (PPCI, underwent CMR within 72 hours of admission. k-t SENSE accelerated first-pass perfusion MR (7 fold acceleration, spatial resolution 1.5 mm × 1.5 mm × 10 mm, 8 slices acquired over 2 RR intervals, 0.1 mmol/kg Gd-DTPA, EGE (1–4 minutes after injection with a fixed TI of 440 ms and LGE images (10–12 minutes after injection, TI determined by a Look-Locker scout were acquired. MO volume was determined for each technique by manual planimetry and summation of discs methodology. Results k-t SENSE first-pass perfusion detected more cases of MO than EGE and LGE (22 vs. 20 vs. 14, respectively. The extent of MO imaged by first-pass perfusion (median mass 4.7 g, IQR 6.7 was greater than by EGE (median mass 2.3 g, IQR 7.1, p = 0.002 and LGE (median mass 0.2 g, IQR 2.4, p = 0.0003. The correlation coefficient between MO mass measured by first-pass perfusion and EGE was 0.91 (p Conclusion The extent of MO following acute myocardial infarction appears larger on

  20. Factors influencing the biosorption of gadolinium by micro-organisms and its mobilisation from sand

    International Nuclear Information System (INIS)

    The present work was devoted to the study of the biosorption capacities of various microbial species (Bacillus subtilis, Pseudomonas aeruginosa, Ralstonia metallidurans CH34 previously Alcaligenes eutrophus CH34, Mycobacterium smegmatis, Saccharomyces cerevisiae) for ions of the lanthanide gadolinium (Gd3+). The uptake by sand of this element was also measured. Saturation curves and Scatchard models were established for all biosorbants used in this work. The results enabled us to determine the binding affinities and the maximum capacities for biosorption of Gd3+, which ranged from 350 μmol g-1 for B. subtilis to 5.1 μmol g-1 for S. cerevisiae. This study demonstrated the usefulness of optimisation of experimental conditions in biosorption investigations. Experimental results showed that bisorption could be influenced by the growth stage and by the composition of the growth medium of microbial cells. Finally, particular attention was given to the transfer of gadolinium ions from a loaded sand to a bacterial suspension. (orig.)

  1. production of uranium dioxide and uranium dioxide-gadolinium oxide by sol-gel technique

    International Nuclear Information System (INIS)

    In this research work pure urania and urania-gadolinia (5 and 10 %) fuels were produced by the sol-gel technique. Calcination and sintering process of the fuels were performed in Cekmece Nuclear Research and Training Center. The density of the fuels produced was found to be very close to their theoretical values.Addition of gadolinium increased the BET surface area of the fuels. X-ray diffraction spectrum analysis of all three type of fuels are in agreement with the literature values. However when the gadolinium content was increased, the peaks broadened especially after 2θ >60. The average grain size of UO2 was found to be 4μm for UO2-Gd2O3 (5%), and 12μm UO2-Gd2O3 (10 %)

  2. Radiomodifying effect of boron and gadolinium compounds in human peripheral lymphocytes evaluated by the comet assay

    International Nuclear Information System (INIS)

    This study was carried out to investigate the modification of radioresponse due to pretreatment of boron (Borax) and gadolinium compounds (Gd- DTPA) in human peripheral lymphocytes using the comet assay, single cell gel electrophoresis (SCGE) assay. The lymphocytes were treated with boron and gadolinium compounds for 10 minutes right before irradiation. The doses of gamma-ray were 0, 1, 2 and 4 Gy. Pretreatment with 10B (each of 50 nM and 250 nM) gave rise to a dose-dependent reduction in radiosensitivity of lymphocytes. On the other hand, pretreatment of 157 Gd- DTPA (50 nM) resulted in a dose-dependent increase in radiosensitivity, especially in the lymphocytes irradiated with 4 Gy. (P<0.001)

  3. Phantom experiment of depth-dose distributions for gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    Depth-dose distributions in a tumor simulated phantom were measured for thermal neutron flux, capture gamma-ray and internal conversion electron dose rates for gadolinium neutron capture therapy. The results show that (i) a significant dose enhancement can be achieved in the tumor by capture gamma-rays and internal conversion electrons but the dose is mainly due to capture gamma-rays from the Gd(n, γ) reactions, therefore, is not selective at the cellular level, (ii) the dose distribution was a function of strongly interrelated parameters such as gadolinium concentrations, tumor site and neutron beam size (collimator aperture size), and (iii) the Gd-NCT by thermal neutrons appears to be a potential for treatment of superficial tumor. (author)

  4. Out-of-pile researches of modernized Uranium-Gadolinium fuel for WWER reactors

    International Nuclear Information System (INIS)

    Thermal conductivity and creeping characteristics (creep rate) of modernized uranium-gadolinium fuel as a composite - solid solution granules (U,Gd)O2 dispersed into UO2 matrix have been researched in wide temperature range. The main peculiarity of the fuel which is under study is a thin fine-grained zone surrounding each granule (U,Gd)O2. Presence of this zone blocks intergranular diffusion of components preventing decrease of concentration of solid solution (U,Gd)O2. In addition fine-grained zone is the original buffer relaxing both interphase tensions and tensions that can be resulted from radiation-thermal loads during irradiation of fuel. Higher thermal and physical characteristics of describable composite uranium-gadolinium fuel (creep rate, thermal conductivity, peculiarity of microstructure), in comparison with conventional obtained by dry blending of UO2 and Gd2O3 powders, allow consider this fuel as candidate for using in WWER and PWR reactors. (authors)

  5. Rare earth elements determination by ICP OES in high purity gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luis Claudio de; Silva, Ieda de Souza, E-mail: luis.claudio@ctmsp.mar.mil.b, E-mail: ieda@ctmsp.mar.mil.b [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Ipero, SP (Brazil). Centro Experimental Aramar; Rucandio, Maria Isabel, E-mail: isabel.rucandio@ciemat.e [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain). Unidad de Espectroscopia. Div. de Quimica

    2009-07-01

    The ternary U-Rare Earth-O systems are involved in the nuclear technology due to their application as burnable poison in PWR type reactors. Chemical and physical characterization of both constituents, uranium dioxide (UO{sub 2}) and gadolinium oxide (Gd{sub 2}O{sub 3}), used in the burnable poison production, has a special interest. In this context, the optimization of the chemical determination of the impurities in the gadolinium oxide powders by ICP OES analytical technique was researched in this work. It was developed in two different laboratories and with two different ICP OES spectrometers. Good results are obtained with both spectrometers for robustness, limits of detection, linearity, precision and accuracy. (author)

  6. Magnetic refrigeration cycle analysis using selected thermodynamic property characterizations for gadolinium gallium garnet

    International Nuclear Information System (INIS)

    Magneto-thermodynamic property characterizations were selected, adapted, and compared to material property data for gadolinium gallium garnet in the temperature range 4--40 K and magnetic field range 0--6 T. The most appropriate formulations were incorporated into a model in which methods similar to those previously developed for other materials and temperature ranges were used to make limitation and relative performance assessments of Carnot, ideal regenerative, and pseudo-constant field regenerative cycles. Analysis showed that although Carnot cycle limitations on available temperature lift for gadolinium gallium garnet are not as severe as those for materials previously examined, substantial improvements in cooling capacity/temperature lift combinations can be achieved using regenerative cycles within specified fields limits if significant loss mechanisms are mitigated

  7. Gadolinium Iron Garnet as a Solid State Material for an Electron Electric Dipole Moment Search

    CERN Document Server

    Lamoreaux, S K

    2007-01-01

    The possibility of a solid state electron electric dipole moment (EDM) experiment based on Gadolinium Iron Garnet (GdIG) is investigated. GdIG appears to exhibit superparamagnetism and this effect can be used to enhance the electric-field-induced EDM signal at relatively a high temperatures, as compared to a simple paramagnetic system such as Gadolinium Gallium Garnet. The sensitivity of a GdIG based experiment might be large enough that an improvement by over three orders of magnitude, compared to the existing electron EDM limit, could be obtained at a modest temperature of 4 K, assuming that the superparamagnetic effect is not suppressed at this temperature, and that the spin relaxation time remains sufficiently rapid.

  8. Study of points defects produced by irradiation of monocrystalline nickel and polycrystalline gadolinium

    International Nuclear Information System (INIS)

    The work described in this thesis falls into two parts: the first comprises a study of magnetocrystalline nickel by resistivity measurements; the second is a description of resistivity and magnetic after effect measurements on an h.c.p. ferromagnetic crystal other than cobalt, namely gadolinium. For the first part we have demonstrated the existence of a small but definite orientation dependence in the creation of point defects by electron irradiation (20 deg. K) of a nickel single crystal. In particular, the effect is manifested in the form of the stage IC, II and III in the resistivity recovery. In the second part an important result has emerged: namely that there is no magnetic after effect phenomenon in a neutron irradiated (27 deg. K) ferromagnetic metal. Several considerations are discussed by way of a preliminary interpretation of this important difference between gadolinium and cobalt. (author)

  9. A new material in the nuclear technology. Gadolinium zirconate pyrochlore prepared by reactive sintering

    International Nuclear Information System (INIS)

    The ability of gadolinium zirconate pyrochlore for actinides incorporation in its lattice makes this material a possible matrix for the immobilization of nuclear wastes. The aim of the presented work was to develop a novel method of gadolinium zirconate synthesis by using a reactive sintering procedure under high pressure based on commercial ZrO2 and Gd2O3 nanopowders. Samples were analyzed using X-ray diffraction and SEM to check their phase composition and microstructure. The obtained sintered pellets demonstrated peaks characteristic for pyrochlore structure for a wide range of preparation temperatures and high density (99.5 % of the theoretical value). It was found that the resulting materials exhibited a homogeneous microstructure and the average grain size dependent on sintering temperature. (author)

  10. Hydrothermal synthesis and characterization of polycrystalline gadolinium aluminum perovskite (GdAlO3, GAP

    Directory of Open Access Journals (Sweden)

    N. Girish H.

    2015-06-01

    Full Text Available Gadolinium aluminum perovskite (GdAlO3, GAP is a promising high temperature ceramic material, known for its wide applications in phosphors. Polycrystalline gadolinium aluminum perovskites were synthesized using a precursor of co-precipitate gel of GdAlO3 by employing hydrothermal supercritical fluid technique under pressure and temperature ranging from 150 to 200 MPa and 600 to 700 °C, respectively. The resulted products of GAP were studied using the characterization techniques, such as powder X-ray diffraction analysis (XRD, infrared spectroscopy (IR, scanning electron microscopy (SEM and energy dispersive analysis of X-ray (EDX. The X-ray diffraction pattern matched well with the reported orthorhombic GAP pattern (JCPDS-46-0395.

  11. New High-Resolution Gadolinium-GEM Neutron Detectors for the NMX Instrument at ESS

    CERN Document Server

    Pfeiffer, Dorothea; Birch, Jens; Etxegarai, Maddi; Hall-Wilton, Richard; Höglund, Carina; Hultman, Lars; Llamas-Jansa, Isabel; Oliveri, Eraldo; Oksanen, Esko; Robinson, Linda; Ropelewski, Leszek; Schmidt, Susann; Streli, Christina; Thuiner, Patrik

    2016-01-01

    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 {\\mu}TPC analysis, proven to improve the spatial resolution in the case of $^{10}$B converters, is extended to gadolinium based detectors. For the first time, a Gd-GEM was successfully operated to detect neutrons with an estimated efficiency of 10% at a wavelength of 2 {\\AA} and a position resolution better than 350 {\\mu}m.

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

    International Nuclear Information System (INIS)

    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

  13. Apparent molar volumes and compressibilities of lanthanum, gadolinium and lutetium trifluoromethanesulfonates in dimethylsulfoxide

    International Nuclear Information System (INIS)

    Highlights: ► Sequence of volumes and compressibilities of Ln3+ ions in DMSO is: La3+ > Gd3+ 3+. ► Sequence of the partial molar volumes do not change with temperature. ► These results are the consequence of nature of the ion–solvent bonding. - Abstract: Temperature dependencies of the densities of dimethylsulfoxide solutions of lanthanum, gadolinium and lutetium trifluoromethanesulfonates have been determined over a wide range of concentrations. The apparent molar volumes and partial molar volumes of the salts at infinite dilution, as well as the expansibilities of the salts, have been calculated from density data. Additionally, the apparent molar isentropic compressibilities of lanthanum, gadolinium and lutetium trifluoromethanesulfonates have been calculated from sound velocity data at 298.15 K. The data obtained have been interpreted in terms of ion−solvent interactions.

  14. Specific features of the WWER Uranium-Gadolinium fuel behavior at BOL

    International Nuclear Information System (INIS)

    The calculated-experimental analysis of the WWER fuel behavior with 5%wt of gadolinium oxide at the beginning of life (BOL) is presented. The results are based on the data on fuel centerline temperature measurements, gas media pressure inside the cladding and fuel elongation obtained during irradiation of the test fuel rods in HBWR (Halden). Computer analysis of experimental data is performed with TOPRA-2, version 2 code. It is shown that specific features of the uranium-gadolinium fuel behavior at the early of life is due to presence of burnable absorber influencing the average linear heat rating, radial power distribution and lower thermal conductivity. In particular, the analysis of “late” relocation effect on the maximum Gd fuel temperature is presented. (authors)

  15. Pulmonary Vein Inflow Artifact Reduction for Free-Breathing Left Atrium Late Gadolinium Enhancement

    OpenAIRE

    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

    2011-01-01

    Two-dimensional “pencil-beam” navigator, placed on the right hemidiaphragm (RHD), is used for free-breathing late gadolinium enhancement (LGE) of the left atrium (LA) in patients with atrial fibrillation (AF). The pencil-beam navigator creates an inflow artifact in the right PVs and atrial wall that may obscure local PV and LA scars. To reduce this artifact, we propose a large slab RHD projection navigator that measures the respiratory motion while reducing the associated inflow artifact. Eig...

  16. Gadolinium scandate thin films as an alternative gate dielectric prepared by electron beam evaporation

    OpenAIRE

    Wagner, M.; Heeg, T.; Schubert, J.; Lenk, S.; Mantl, S.; Zhao, C; Caymax, M.; De Gendt, M. A.

    2006-01-01

    Gadolinium scandate thin films deposited on silicon substrates using electron beam evaporation were investigated. Measurements with Rutherford backscattering spectrometry, high temperature x-ray diffraction, x-ray reflectometry, transmission electron microscopy, and atomic force microscopy were performed. A stoichiometric transfer of material from the source to the substrate in high vacuum could be demonstrated. Homogeneous, amorphous, and smooth films (root mean square surface roughness < 1 ...

  17. Production of a gadolinium-loaded liquid scintillator for the Daya Bay reactor neutrino experiment

    International Nuclear Information System (INIS)

    We report on the production and characterization of liquid scintillators for the detection of electron antineutrinos by the Daya Bay reactor neutrino experiment. A 185 tons of gadolinium-loaded (0.1% by mass) liquid scintillator (Gd-LS) and a 200 tons of unloaded liquid scintillator (LS) were successfully produced from a linear-alkylbenzene (LAB) solvent in 6 months. The scintillator properties, the production and purification systems, and the quality assurance and control (QA/QC) procedures are described

  18. Effect of thermal treatment and γ-irradiation on optical properties of gadolinium silicate (GSO) crystals

    International Nuclear Information System (INIS)

    Absorption spectra (AS) and thermoluminescence (TL) curves are studied for γ-irradiated and thermally treated gadolinium silicate (Gd2SiO5:Ce) crystals in oxidized and reducible environment. It is demonstrated that reducing thermal treatment leads to increase of absorption band intensities and TL peaks, whereas oxidisation thermal treatment does not lead to changes in the above properties. The nature of traps causing TL peaks is determined. (authors)

  19. Study on the effects of gadolinium-based MRI contrast medium on X-ray scanning

    International Nuclear Information System (INIS)

    Gadolinium has a higher atomic mass (64) than iodine (53). The K-edge absorption energy of gadolinium is 50.2 keV, which is in the absorbed wavelength range of the X-rays used by a CT scanner, suggesting that it has a high X-ray absorption ability. This study examined the effects of a gadolinium-based MRI contrast medium on the quality (mAs) and the quality (kVp) of radiation during a X-ray scan. A contrast medium phantom was manufactured after diluting the contrast medium to various concentrations. A CT scanner (Siemens, Somatom Senation 64, Germany) was used to obtain images by changing the quality of radiation from 80 kVp to 100, 120, and 140 kVp. At a constant quality of radiation of 120 kVp, the mAs was changed from 100 mAs to 200 and 300 mAs and images were obtained under each condition. The Hounsfield units (HUs) in a test tube were measured for analysis and comparison. The contrast enhancement by the contrast medium for CT scanning was 100% at a tube voltage of 80 kVp. The contrast enhancements at 100 kVp, 120 kVp, and 140 kVp were 93.8%, 87.7%, and 69.5%, respectively. In addition, although the quantity increased a fixed tube voltage, the HU of the test tube remained relatively constant, indicating that the absorption of the contrast medium had little association with the quantity of X-rays but had some correlation with the quality of radiation. A tube voltage of 80 kVp or lower is recommended when a MRI contrast medium is used CT scanning. When MRI scanning and X-ray scanning are conducted together, X-ray scanning should be performed first or after sufficient gadolinium contrast medium has been excreted.

  20. Dynamic gadolinium-enhanced MR imaging in active and inactive immunoinflammatory gonarthritis

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Lorenzen, I; Henriksen, O

    1994-01-01

    Dynamic T1-weighted FLASH MR imaging, obtained just after i.v. gadopentetate dimeglumine injection, and pre- and postcontrast T1-weighted spin-echo (T1-SE) MR imaging were performed to compare their information value with respect to inflammatory activity in immunoinflammatory gonarthritis. We exa...... synovium could differentiate between healthy and arthritic knees. Gadolinium-enhanced dynamic FLASH imaging may provide clinically useful information about the actual inflammatory activity of arthritic joints....

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

    Science.gov (United States)

    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.

  2. Microstructural effect of gadolinium oxide nanocrystals upon annealing on electrical properties of memory devices

    International Nuclear Information System (INIS)

    The microstructure evolution of sputtered gadolinium oxide nanocrystal (NC) memory devices upon annealing has been characterized in detail by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). TEM results indicate that the as-deposited film is composed of metallic Gd clusters embedded in an amorphous GdxOy matrix. The Gd clusters undergo phase transformation to oxide NCs upon annealing, reaching a maximum density of 7.9–9.1 × 1011 cm−2 at 850 °C, which is consistent with the largest memory window width. Upon annealing at even higher temperature, TEM diffraction patterns and XPS composition profiles indicate apparent Si diffusion into the NC layer, probably from the SiO2 tunneling oxide or the Si substrate, leading to the formation of gadolinium silicate NCs. The presence of silicate NCs gradually deteriorates the device performance due to the reduction of barrier confinement for stored charges, although the dot density is only marginally decreased. The results suggest that the optimum memory device performance is dominated by not only the most considered size and density of NCs, but also the composition and phase inside. - Highlights: ► Memory devices with gadolinium oxide nanocrystals have been realized. ► X-ray photoelectron spectroscopy shows annealing-induced interdiffusion of Si. ► Transmission electron microscopy indicates the formation of gadolinium silicate. ► Migrating Si from substrate can further modify NC phase upon annealing. ► Both nanocrystal density and phase influence the device performance.

  3. Microstructural effect of gadolinium oxide nanocrystals upon annealing on electrical properties of memory devices

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Michael R.S. [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Liu, Chuan-Pu, E-mail: cpliu@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China); Wang, Jer-Chyi; Chen, Yu-Kai; Lai, Chao-Sung [Department of Electronic Engineering, Chang-Gung University, Kweishan 333, Taoyuan, Taiwan (China); Fang, Yu-Ching; Shu, Li [Materials and Electro-Optics Research Division, Chung Shan Institute of Science and Technology, Longtan 325, Taoyuan, Taiwan (China)

    2012-06-30

    The microstructure evolution of sputtered gadolinium oxide nanocrystal (NC) memory devices upon annealing has been characterized in detail by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). TEM results indicate that the as-deposited film is composed of metallic Gd clusters embedded in an amorphous Gd{sub x}O{sub y} matrix. The Gd clusters undergo phase transformation to oxide NCs upon annealing, reaching a maximum density of 7.9-9.1 Multiplication-Sign 10{sup 11} cm{sup -2} at 850 Degree-Sign C, which is consistent with the largest memory window width. Upon annealing at even higher temperature, TEM diffraction patterns and XPS composition profiles indicate apparent Si diffusion into the NC layer, probably from the SiO{sub 2} tunneling oxide or the Si substrate, leading to the formation of gadolinium silicate NCs. The presence of silicate NCs gradually deteriorates the device performance due to the reduction of barrier confinement for stored charges, although the dot density is only marginally decreased. The results suggest that the optimum memory device performance is dominated by not only the most considered size and density of NCs, but also the composition and phase inside. - Highlights: Black-Right-Pointing-Pointer Memory devices with gadolinium oxide nanocrystals have been realized. Black-Right-Pointing-Pointer X-ray photoelectron spectroscopy shows annealing-induced interdiffusion of Si. Black-Right-Pointing-Pointer Transmission electron microscopy indicates the formation of gadolinium silicate. Black-Right-Pointing-Pointer Migrating Si from substrate can further modify NC phase upon annealing. Black-Right-Pointing-Pointer Both nanocrystal density and phase influence the device performance.

  4. Increased blood–brain barrier permeability in type II diabetes demonstrated by gadolinium magnetic resonance imaging

    OpenAIRE

    Starr, J; Wardlaw, J; Ferguson, K; MacLullich, A; Deary, I; Marshall, I

    2003-01-01

    Objectives: Patients with type II diabetes are at increased risk of cognitive impairment. The retinal and renal complications of diabetes follow microvascular damage permitting small arterioles to leak, hence the cerebral damage might also follow loss of blood–brain barrier (BBB) integrity. Magnetic resonance (MR) brain imaging with intravenous gadolinium (Gd) diethylenetriamine pentaacetic acid (Gd-DTPA) was used to identify increased BBB permeability.

  5. Simulation and Design of Multi-modulars Detector System of Gadolinium-Loaded Liquid Scintillator

    Institute of Scientific and Technical Information of China (English)

    HOU; Long; WANG; Zhao-hui; YU; Guo-liang; WANG; Qi; KANG; Guo-guo; SU; Xiao-bin; ZHANG; Xiao-peng; ZHANG; Kai

    2012-01-01

    <正>The gadolinium-loaded liquid scintillator has the superiority of high detecting efficiency, and it can be used to measure many kinds of nucleus. We improved this technique and construct a 4π liquid scintillator detecting systems which is composed by many liquid scintillators. By coupling with fission chamber, we form a novel research platform which can be used to measure the (n, 2n) and (n, 3n) cross sections of many nuclei.

  6. Lipoma arborescens of the glenohumeral joint causing bone erosion: MRI features with gadolinium enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Eun Young; Chung, Hye Won; Shin, Myung Jin; Lee, Sang Hoon [Asan Medical Center, Department of Radiology, University of Ulsan College of Medicine, Seoul (Korea)

    2009-08-15

    Lipoma arborescens is a rare benign intra-articular lesion that principally affects the knee joint. We present a case of lipoma arborescens involving the glenohumeral joint and associated with prominent large bony erosions. The gadolinium diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (MRI) features of this lesion are also described. The characteristic MRI findings permit precise preoperative diagnosis of this rare condition even if it occurs in an atypical location and there are confusing radiological findings. (orig.)

  7. Comparison between biokinetics of inhaled plutonium nitrate and gadolinium oxide in humans and animals

    International Nuclear Information System (INIS)

    Due to the paucity of human data after inhalation of different chemical forms of radionuclides, the implications for human exposure are often based on animal studies. Biokinetic studies of plutonium nitrate and gadolinium oxide in human volunteers and rats are described. The results, together with information from other studies with radionuclides, suggests that animal studies can be used with advantage for assessing the biokinetic behavior in humans, and for providing guidance on the assessment of intake and optimal monitoring regimens. (author)

  8. Rotation-vibration structure of even-A samarium and gadolinium isotopes

    International Nuclear Information System (INIS)

    The extended rotation-vibration model, which consists of an asymmetric rotor and breathing mode deformation vibrations, was applied to several even-A samarium and gadolinium isotopes. The comparison between the theoretical and experimental energy levels and the comparison with other model calculations are presented. Also shown are the comparison between the experimental and theoretical B(E2) ratios for the isotopes studied. 1 figure, 2 tables

  9. Magnetic moments in a gadolinium iron garnet studied by soft-X-ray magnetic circular dichroism

    NARCIS (Netherlands)

    Rudolf, P.; Sette, F.; Tjeng, L.H.; Meigs, G.; Chen, C.T.

    1992-01-01

    The magnetic moments of Gd and Fe in gadolinium iron garnet (Gd3Fe5O12) were probed at 77 and 300 K by soft-X-ray magnetic circular dichroism (SXMCD) measurements at the GdMa4,5 and at the FeL2,3 absorption edges. The SXMCD signal at each edge allows one to independently determine the magnetic order

  10. Comparison of Lithium Gadolinium Borate Crystal Shards in Scintillating and Nonscintillating Plastic Matrices

    OpenAIRE

    Kazkaz, Kareem; Bowden, Nathaniel S.; Pedretti, Marisa

    2011-01-01

    We present a method for detecting neutrons using scintillating lithium gadolinium borate crystal shards in a plastic matrix while maintaining high gamma rejection. We have procured two cylindrical detectors, 5"\\times5", containing 1% crystal by mass. Crystal shards have a typical dimension of 1 mm. One detector was made with scintillating plastic, and one with nonscintillating plastic. Pulse shape analysis was used to reject gamma ray backgrounds. The scintillating detector was measured to ha...

  11. Comparison between a linear versus a macrocyclic contrast agent for whole body MR angiography in a clinical routine setting

    OpenAIRE

    Rittig Kilian; Tepe Gunnar; Klumpp Bernhard; Döring Jörg; Bretschneider Christiane; Grimm Florian; Fenchel Michael; Kramer Ulrich; Seeger Achim; Seidensticker Peter R; Claussen Claus D; Miller Stephan

    2008-01-01

    Abstract Background Previous experiences of whole body MR angiography are predominantly available in linear 0.5 M gadolinium-containing contrast agents. The aim of this study was to compare image quality on a four-point scale (range 1–4) and diagnostic accuracy of a 1.0 M macrocyclic contrast agent (gadobutrol, n = 80 patients) with a 0.5 M linear contrast agent (gadopentetate dimeglumine, n = 85 patients) on a 1.5 T whole body MR system. Digital subtraction angiography served as standard of ...

  12. Benign versus malignant vertebral compression fractures: distinction with T1-weighted, fast spin-echo T2-weighted, and fat-suppressed gadolinium-enhanced T1-weighted images

    International Nuclear Information System (INIS)

    To differentiate malignant vertebral compression fractures from benign fractures, as seen on spin-echo T1-wieghted, fast spin-echo T2-weighted, and fat-suppressed gadolinium-enhanced T1-weighted MR images. Thirty two benign (18 acute and 14 chronic) and 28 malignant vertebral collapses were studied in 54 patients aged between 15 and 78 (mean, 51) years. Malignant compression fractures involved only metastasis. We obtained sagittal and axial fast spin-echo T2-weighted images, and unenhanced and fat-suppressed gadolinium-enhanced T1-weighted images, and analyzed MR signal intensity, enhancement patterns, and morphologic changes including convex posterior cortex vs retropulsion of a bone fragment, focal vs diffuse paraspinal mass, and epidural mass. All cases of acute benign and malignant compression fractures showed low signal intensity within the vertebral body on T1-weighted images, and substantial contrast enhancement on fat-suppressed gadolinium-enhanced T1-weighted images. Acute benign and malignant compression fractures were distinguished on the basis of three signal intensity characteristics : hypointense band (acute benign cases 77% ; malignant cases 0%), diffuse low signal intensity(17% vs 86%) and involvement of pedicle (0% vs 75%). Fast spin-echo T2-weighted images played little role in distinguishing between the two. Three morphologic changes were suggestive of malignancy : convex posterior cortex (malignant cases 75% ; benign 0%), epidural mass (79% vs 5%), and focal paraspinal mass (57% vs 0%). Retropulsion of a bone fragment (benign cases 63% ; malignant cases 14%) was preferable for benignancy. In addition, thin diffuse paraspinal mass (benign cases 15% ; malignant cases 14%) was seen. The morphologic and signal intensity characteristics seen on T1-weighted images were useful for distinguishing benign and malignant vertebral compression fractures. Fast spin-echo T2-weighted and fat-suppressed gadolinium-enhanced T1-weighted images played little role

  13. Depletion of gadolinium burnable poison in a PWR assembly with high burnup fuel

    International Nuclear Information System (INIS)

    A tendency to increase the discharge burnup of nuclear fuel for Advanced Pressurized Water Reactors (PWR) has been a characteristic of its operation for many years. It will be able to burn at very high burnup of about 70 GWd/t with UO2 fuels. The U-235 enrichment must be higher than 5 %, which leads to the necessity of using an extremely efficient burnable poison like Gadolinium oxide. Using gadolinium isotope is significant due to its particular depletion behavior (''Onion-Skin'' effect). In this paper, the MCNPX2.7 code is used to calculate the important neutronic parameters of the next generation fuels of PWR. K-infinity, local peaking factor and fission rate distributions are calculated for a PWR assembly which burn at very high burnup reaching 70 GWd/t. The calculations are performed using the recently released evaluated Gadolinium cross section data. The results obtained are close to those of a LWR next generation fuel benchmark problem. This demonstrates that the calculation scheme used is able to accurately model a PWR assembly that operates at high burnup values.

  14. Late radiation change in the CNS: MR imaging following gadolinium enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Norris, A.M.; Carrington, B.M.; Slevin, N.J. [Christie Hospital and Holt Radium Inst., Manchester (United Kingdom)

    1997-05-01

    Magnetic resonance imaging is the best imaging technique for the detection of radiotherapy-induced changes in the central nervous system but there are few studies detailing the MRI appearances of radiation effects following enhancement with intravenous gadolinium. In this paper, gadolinium enhanced MR imaging findings were reviewed in seven patients with evidence of late radiation injury following radiotherapy for primary head and neck tumours. On T1-weighted enhanced sequences, abnormal focal areas were present in the anterior temporal lobes and antero-inferior aspects of the frontal lobes. These lesions were well defined and enhanced intensely following intravenous gadolinium. They were present in the white matter in five patients and involved both grey and white matter in two patients. Cystic components were present in larger lesions in three patients and mass effect was present around the enhancing lesions in four patients. All abnormalities occurred within the radiation treatment portals and corresponded to the distribution of increased signal intensity changes in the brain on T2-weighted images. Late radiation-induced injury should be considered in the differential diagnosis of any intensely enhancing lesion occurring within irradiated brain tissue. (author).

  15. Late radiation change in the CNS: MR imaging following gadolinium enhancement

    International Nuclear Information System (INIS)

    Magnetic resonance imaging is the best imaging technique for the detection of radiotherapy-induced changes in the central nervous system but there are few studies detailing the MRI appearances of radiation effects following enhancement with intravenous gadolinium. In this paper, gadolinium enhanced MR imaging findings were reviewed in seven patients with evidence of late radiation injury following radiotherapy for primary head and neck tumours. On T1-weighted enhanced sequences, abnormal focal areas were present in the anterior temporal lobes and antero-inferior aspects of the frontal lobes. These lesions were well defined and enhanced intensely following intravenous gadolinium. They were present in the white matter in five patients and involved both grey and white matter in two patients. Cystic components were present in larger lesions in three patients and mass effect was present around the enhancing lesions in four patients. All abnormalities occurred within the radiation treatment portals and corresponded to the distribution of increased signal intensity changes in the brain on T2-weighted images. Late radiation-induced injury should be considered in the differential diagnosis of any intensely enhancing lesion occurring within irradiated brain tissue. (author)

  16. Evaluation of depth-dose distributions for gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    The radiation effect of gadolinium neutron capture reaction in cultured Chinese hamster cells was reported before. The comparison of the results at 10% survival level between the cell cultures with and without gadolinium showed 3.5-fold difference in the neutron fluence. In this paper, total depth dose distribution is calculated for a cylindrical phantom with a simulated tumor containing gadolinium. The distributions of neutron and capture gamma-ray fluxes were calculated by using the two-dimensional coupled neutron-photon transport code. The coupled neutron-photon cross section used for the calculation was based on the vitamin C library. The prompt gamma-ray and internal conversion electron spectra of 157Gd(n,γ) reaction were taken from published data. The model was a R-Z geometry water phantom. A cylindrical tumor was placed near the surface. The thermal neutron beam of the Musashi reactor was used. The absorbed dose rates of neutrons and capture gamma-ray were calculated. The notable reduction of thermal neutron flux was observed across the simulated tumor, while the capture gamma-ray dose rate increased. (K.I.)

  17. Depletion of gadolinium burnable poison in a PWR assembly with high burnup fuel

    Energy Technology Data Exchange (ETDEWEB)

    Refeat, Riham Mahmoud [Nuclear and Radiological Regulatory Authority (NRRA), Cairo (Egypt). Safety Engineering Dept.

    2015-12-15

    A tendency to increase the discharge burnup of nuclear fuel for Advanced Pressurized Water Reactors (PWR) has been a characteristic of its operation for many years. It will be able to burn at very high burnup of about 70 GWd/t with UO{sub 2} fuels. The U-235 enrichment must be higher than 5 %, which leads to the necessity of using an extremely efficient burnable poison like Gadolinium oxide. Using gadolinium isotope is significant due to its particular depletion behavior (''Onion-Skin'' effect). In this paper, the MCNPX2.7 code is used to calculate the important neutronic parameters of the next generation fuels of PWR. K-infinity, local peaking factor and fission rate distributions are calculated for a PWR assembly which burn at very high burnup reaching 70 GWd/t. The calculations are performed using the recently released evaluated Gadolinium cross section data. The results obtained are close to those of a LWR next generation fuel benchmark problem. This demonstrates that the calculation scheme used is able to accurately model a PWR assembly that operates at high burnup values.

  18. Criticality safety when using gadolinium as a neutronic poison with plutonium

    International Nuclear Information System (INIS)

    The authors have discovered that under special circumstances it is possible to have a criticality accident which can release tons of high explosive energy equivalent. We report a computer calculational, experiment which illustrates this point so that the circumstances which might lead to such an accident can be avoided. Our computer calculation gives the energy release in a criticality event involving a water solution of plutonium where (1) gadolinium has been used as a neutron poison and (2) the mass is then allowed to go slightly super-critical at room temperature. The reactivity has a strong positive temperature coefficient in this system. The result is that the self-heating from a small amount of fissioning of the plutonium in the delayed supercriticality regime raises the temperature to the prompt criticality regime and an explosive release of energy becomes possible. In this computer experiment the release is 19 tonnes (metric tons) of high explosive equivalent for a two-cubic meter sphere of water containing 50 grams of plutonium per liter. Our concern is confined to gadolinium in moderating solutions and does not relate to any other known neutronic poison, because gadolinium is the only isotope having the special absorption characteristics that make possible this type of energy release

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

    International Nuclear Information System (INIS)

    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

  20. Optical properties of pure and Ce3+ doped gadolinium gallium garnet crystals and epitaxial layers

    International Nuclear Information System (INIS)

    Results of X-ray diffraction and low temperature optical absorption measurements of cerium doped gadolinium gallium garnet single crystals and epitaxial layers are reported. In the region of intra-configurational 4f–4f transitions the spectra of the bulk crystals exhibit the signatures of several different Ce3+ related centers. Apart from the dominant center, associated with Ce substituting gadolinium, at least three other centers are found, some of them attributed to the so-called antisite locations of rare-earth ions in the garnet host, i.e., in the Ga positions. X-ray diffraction data prove lattice expansion of bulk GGG crystals due to the presence of rare-earth antisites. The concentration of the additional Ce-related centers in epitaxial layers is much lower than in the bulk crystals. However, the Ce-doped layers incorporate a large amount of Pb from flux, which is the most probable source of nonradiative quenching of Ce luminescence, not observed in crystals grown by the Czochralski method. - Highlights: • Ce3+ multicenters found in Gadolinium Gallium Garnet crystals and epitaxial layers. • High quality epitaxial layers of pure and Ce-doped GGG were grown. • Luminescence quenching of Ce3+ by Pb ions from flux detected in GGG epitaxial layers. • X-ray diffraction allows measuring the amount of the rare-earth antisites in GGG

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

    International Nuclear Information System (INIS)

    Super-??Kamiokande 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, GdCl3. 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 GdCl3 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 GdCl3 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

  2. Dosimetry method for measurements of energy outcome from gadolinium after neutron capture

    International Nuclear Information System (INIS)

    A very important task now is to measure a real absorbed dose for Gadolinium Neutron Capture Therapy. A method for direct measurement of Gd reaction dose was offered and worked through in the study. A chemical dosimeter for measurement of absorbed dose from neutron capture Gd(n,y) reaction products - gamma-radiation, internal conversion electrons, and Auger electrons, that are very essential for neutron capture therapy, is described in the paper. Auger electrons are of interest, since their dose measurement or direct registration is a very involved problem due their low mean energy - less then 10 keV. Substances with gadolinium of Gd(NO3)3.?6H2O and GdCl3.?6H2O, and two different dosimeters - FBX and Fricke were investigated. The absorbed dose measurements were carried out with the Fricke dosimeter for different gadolinium concentrations in the solution; thus, this simulated probable treatment condition for thermal and fast neutron beams. The experimental results were compared with calculations made using the MCNP Monte Carlo code. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    Vagins, Mark R.

    2013-04-10

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

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

    International Nuclear Information System (INIS)

    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.

  5. Removal of lanthanum and gadolinium from nitrate medium using Aliquat-336 impregnated onto Amberlite XAD-4

    International Nuclear Information System (INIS)

    Aliquat-336 in benzene was supported on Amberlite XAD-4 crosslinked polystyrene resin. The use of XAD-4 impregnated with Aliquat-336 resin for removal of lanthanum(III) and gadolinium(III) from nitrate medium was carried out using batch technique. Various parameters affecting the uptake of these metal ions such as contact time, metal ion concentrations, V/m and pH value were separately studied. Effect of temperature on the equilibrium distribution values has been studied to evaluate the changes in standard thermodynamic quantities. A comparison of kinetic models applied to the adsorption rate data was evaluated for Lagergren first order, the pseudo second order and Morris-Weber kinetic models. From the results, both pseudo second order and intraparticle diffusion models were found to best correlate the experimental rate data. The capacity of the impregnated resin for both lanthanum(III) and gadolinium(III) was found to be 4.73 and 4.44 mg/g. From the results, impregnation of Aliquat-336 onto Amberlite XAD-4 provides an efficient impregnated resin for the removal of lanthanum(III) and gadolinium(III) from 0.1 M nitrate aqueous solution

  6. Radioactive diagnostic agent

    International Nuclear Information System (INIS)

    A dispersion of denatured aggregates of serum albumin to which tin is attached is prepared and lyophilized. A mixture of polycarboxylic acid and a disaccharide or monosaccharide is included in the dispersion in sufficient amount to reduce degradation during lyophilization and aging. The dispersion is suitable for radioactive labelling and use as a diagnostic agent

  7. Biomimetic Emotional Learning Agents

    OpenAIRE

    Kenyon, Samuel H.

    2005-01-01

    This extended abstract proposes a type of AI agent comprised of: an autonomous real-time control system, low-level emotional learning (including a simple knowledge base that links homeostatic/innate drives to sensory perception states), and a novel sliding-priority drive motivation mechanism. Learning occurs in both phylogenetic and ontogenetic training.

  8. Agents of Change

    DEFF Research Database (Denmark)

    Hansen, Jens Aage; Lehmann, Martin

    2004-01-01

    at large, it emphasises universities as key change agents and providers in new learning, including tools such as project based and problem oriented learning (PBL) as well as information and communication technology (ICT); as providers of competent and motivated graduates to fill key positions in society...

  9. Trading Agents

    CERN Document Server

    Wellman, Michael

    2011-01-01

    Automated trading in electronic markets is one of the most common and consequential applications of autonomous software agents. Design of effective trading strategies requires thorough understanding of how market mechanisms operate, and appreciation of strategic issues that commonly manifest in trading scenarios. Drawing on research in auction theory and artificial intelligence, this book presents core principles of strategic reasoning that apply to market situations. The author illustrates trading strategy choices through examples of concrete market environments, such as eBay, as well as abst

  10. Distribution of late gadolinium enhancement in various types of cardiomyopathies:Significance in differential diagnosis, clinical features and prognosis

    Institute of Scientific and Technical Information of China (English)

    Hiroshi; Satoh; Makoto; Sano; Kenichiro; Suwa; Takeji; Saitoh; Mamoru; Nobuhara; Masao; Saotome; Tsuyoshi; Urushida; Hideki; Katoh; Hideharu; Hayashi

    2014-01-01

    The recent development of cardiac magnetic resonance(CMR)techniques has allowed detailed analyses of cardiac function and tissue characterization with high spatial resolution.We review characteristic CMR features in ischemic and non-ischemic cardiomyopathies(ICM and NICM),especially in terms of the location and distribution of late gadolinium enhancement(LGE).CMR in ICM shows segmental wall motion abnormalities or wall thinning in a particular coronary arterial territory,and the subendocardial or transmural LGE.LGE in NICM generally does not correspond to any particular coronary artery distribution and is located mostly in the mid-wall to subepicardial layer.The analysis of LGE distribution is valuable to differentiate NICM with diffusely impaired systolic function,including dilated cardiomyopathy,end-stage hypertrophic cardiomyopathy(HCM),cardiac sarcoidosis,and myocarditis,and those with diffuse left ventricular(LV)hypertrophy including HCM,cardiac amyloidosis and Anderson-Fabry disease.A transient low signal intensity LGE in regions of severe LV dysfunction is a particular feature of stress cardiomyopathy.In arrhythmogenic right ventricular cardiomyopathy/dysplasia,an enhancement of right ventricular(RV)wall with functional and morphological changes of RV becomes apparent.Finally,the analyses of LGE distribution have potentials to predict cardiac outcomes and response to treatments.

  11. Novel design of multimodal MRI/NIR optical contrast agent

    Science.gov (United States)

    Guo, Kevin; Lin, Franck; Akers, Walter; Zheng, Jie; Teng, Bao; Vasalatiy, Olga; Griffiths, Gary L.; Gandjbakhche, Amir; Berezin, Mikhail Y.; Achilefu, Samuel

    2011-03-01

    We present a novel, dual modality gadolinium based MRI/near-infrared optical probe. Utilizing a fluorescent dye as a scaffold with attached Gd-chelating moiety, we demonstrated a substantial shortening of T1 relaxation time of water protons in vitro. The probe was compared to the commonly used MRI Gd-based contrast agents Magnevist® and Multihance® and showed superior contrast properties. The enhancement was due to strong albumin binding of the hydrophobic fluorophore and overall rigidification of the contrast agent. Due to the near-infrared optical properties of the probe and excellent MRI activity the proposed construct can be potentially utilized as a dual probe in multimodal MRI/NIR optical imaging.

  12. UTBot: A Virtual Agent Platform for Teaching Agent System Design

    Directory of Open Access Journals (Sweden)

    In-Cheol Kim

    2007-02-01

    Full Text Available We introduce UTBot, a virtual agent platform for teaching agent system design. UTBot implements a client for the Unreal Tournament game server and Gamebots system. It provides students with the basic functionality required to start developing their own intelligent virtual agents to play autonomously UT games. UTBot includes a generic agent architecture, CAA (Context-sensitive Agent Architecture, a domain-specific world model, a visualization tool, several basic strategies (represented by internal modes and internal behaviors, and skills (represented by external behaviors. The CAA architecture can support complex long-term behaviors as well as reactive short-term behaviors. It also realizes high context-sensitivity of behaviors. We also discuss our experience using UTBot as a pedagogical tool for teaching agent system design in undergraduate Artificial Intelligence course.

  13. Anchor Toolkit - a secure mobile agent system

    OpenAIRE

    Mudumbai, Srilekha S.; Johnston, William; Essiari, Abdelilah

    2008-01-01

    Mobile agent technology facilitates intelligent operation in software systems with less human interaction. Major challenge to deployment of mobile agents include secure transmission of agents and preventing unauthorized access to resources between interacting systems, as either hosts, or agents, or both can act maliciously. The Anchor toolkit, designed by LBNL, handles the transmission and secure management of mobile agents in a heterogeneous distributed computing environment. It provide...

  14. Gadolinium-enhanced magnetic resonance angiography of the abdominal vessels

    International Nuclear Information System (INIS)

    Contrast enhanced (CE) magnetic resonance angiography (MRA) provides high resolution angiograms within 20-40 sec. The technique is based on the acquisition of heavily T1-weighted threedimensional (3D) gradient-echo data sets (FISP) with ultrashort echo-(<2 ms) and repetition times (<5 ms) during the arterial phase of an intravenously injected bolus of a T1-shortening agent such as Gd-DTPA. For MR-angiography of abdominal vessels CE-MRA is better suited than 'time-of-flight' (TOF) and phase-contrast (PC) MRA because motional artifacts can be obviated with breath-held acquisitions. We have optimised the technique and evaluated its potential for angiography of the abdominal aorta and its branches as well as the portal vein and its tributaries. Whilst CE-MRA provides reliable diagnostic accuracy in the aorta and the proximal sections of its branches, small peripheral arteries cannot be assessed accurately. The portal vein and its tributaries can often be depicted better with CE-MRA than with conventional angiography but, like conventional angiography, CE-MRA is hampered by slow and reversed flow, conditions under which TOF or 'true FISP' MRA may perform bst. We have also investigated FLASH-echo-planar imaging (EPI) hybrid techniques, a further technical development which due to shorter acquisition times of 12-15 sec. allows semi-dynamic imaging of the arterial and venous phase and provide better vessel contrast due to the use of fat-suppression. (orig.)

  15. Enthesitis of lumbar spinal ligaments in clinically suspected spondyloarthritis: value of gadolinium-enhanced MR images in comparison to STIR

    Energy Technology Data Exchange (ETDEWEB)

    Agten, Christoph A.; Zubler, Veronika; Rosskopf, Andrea B.; Pfirrmann, Christian W.A. [Balgrist University Hospital, Radiology, Zurich (Switzerland); University of Zurich, Faculty of Medicine, Zurich (Switzerland); Weiss, Bettina [Balgrist University Hospital, Rheumatology, Zurich (Switzerland); University of Zurich, Faculty of Medicine, Zurich (Switzerland)

    2016-02-15

    To compare detection of spinal ligament enthesitis between gadolinium-enhanced fat-saturated T1-weighted gadolinium-enhanced fat-saturated T1-weighted (T1+Gd) and STIR sequences in patients with suspected spondyloarthritis. Sixty-eight patients (37 males, 42 ± 14 years) with a sacroiliac-joint (SIJ) and lumbar spine MRI for suspected spondyloarthritis were prospectively included. Sagittal T1+Gd and STIR images of the lumbar spine were assessed by two readers for enthesitis of interspinous/supraspinous ligaments, and for capsulitis of facet-joints between T12-S1. Patients' MRI were grouped according to ASAS (Assessment of SpondyloArthritis international Society) criteria in positive (group A) or negative (group B) SIJs. Enthesitis/capsulitis were compared between groups. Interreader agreement was assessed. Enthesitis/capsulitis per patient was statistically significantly more frequent with T1+Gd compared to STIR (p ≤ 0.007), except for interspinous ligaments for reader 1 (p = 0.455). Interspinous enthesitis, supraspinous enthesitis, and capsulitis were present with T1+Gd(STIR) in 64.7 %(72.1 %), 60.3 %(17.7 %), and 61.8 %(29.4 %) for reader 1, and 51.5 %(41.2 %), 45.6 %(7.4 %), and 91.2 %(45.5 %) for reader 2. There were 76.5 %(52/68) patients in group A and 23.5 %(16/68) in group B. Total number of enthesitis/capsulitis on T1+Gd was statistically significantly higher in group A than B (4.96 vs. 2.94, p = 0.026; 8.12 vs. 5.25, p = 0.041 for reader 1 and 2, respectively). Interreader agreement showed mixed results for interspinous/supraspinous/capsulitis but was higher on T1+Gd (ICC = 0.838/0.783/0.367; p ≤ 0.001) compared to STIR (ICC = 0.652/0.298/0.224; p ≤ 0.032). In patients with suspected spondyloarthritis, enthesitis/capsulitis in the lumbar spine are common findings and more frequently/reliably detected with T1+Gd than STIR. In patients with positive SIJ-MRI, the total number of enthesitis/capsulitis in T1+Gd was higher compared to patients with

  16. Enthesitis of lumbar spinal ligaments in clinically suspected spondyloarthritis: value of gadolinium-enhanced MR images in comparison to STIR

    International Nuclear Information System (INIS)

    To compare detection of spinal ligament enthesitis between gadolinium-enhanced fat-saturated T1-weighted gadolinium-enhanced fat-saturated T1-weighted (T1+Gd) and STIR sequences in patients with suspected spondyloarthritis. Sixty-eight patients (37 males, 42 ± 14 years) with a sacroiliac-joint (SIJ) and lumbar spine MRI for suspected spondyloarthritis were prospectively included. Sagittal T1+Gd and STIR images of the lumbar spine were assessed by two readers for enthesitis of interspinous/supraspinous ligaments, and for capsulitis of facet-joints between T12-S1. Patients' MRI were grouped according to ASAS (Assessment of SpondyloArthritis international Society) criteria in positive (group A) or negative (group B) SIJs. Enthesitis/capsulitis were compared between groups. Interreader agreement was assessed. Enthesitis/capsulitis per patient was statistically significantly more frequent with T1+Gd compared to STIR (p ≤ 0.007), except for interspinous ligaments for reader 1 (p = 0.455). Interspinous enthesitis, supraspinous enthesitis, and capsulitis were present with T1+Gd(STIR) in 64.7 %(72.1 %), 60.3 %(17.7 %), and 61.8 %(29.4 %) for reader 1, and 51.5 %(41.2 %), 45.6 %(7.4 %), and 91.2 %(45.5 %) for reader 2. There were 76.5 %(52/68) patients in group A and 23.5 %(16/68) in group B. Total number of enthesitis/capsulitis on T1+Gd was statistically significantly higher in group A than B (4.96 vs. 2.94, p = 0.026; 8.12 vs. 5.25, p = 0.041 for reader 1 and 2, respectively). Interreader agreement showed mixed results for interspinous/supraspinous/capsulitis but was higher on T1+Gd (ICC = 0.838/0.783/0.367; p ≤ 0.001) compared to STIR (ICC = 0.652/0.298/0.224; p ≤ 0.032). In patients with suspected spondyloarthritis, enthesitis/capsulitis in the lumbar spine are common findings and more frequently/reliably detected with T1+Gd than STIR. In patients with positive SIJ-MRI, the total number of enthesitis/capsulitis in T1+Gd was higher compared to patients with

  17. Radioprotective Agents

    Directory of Open Access Journals (Sweden)

    Ilker Kelle

    2008-01-01

    Full Text Available Since1949, a great deal of research has been carried out on the radioprotective activity of various chemical substances. Thiol compounds, compounds which contain –SH radical, different classes of pharmacological agents and other compounds such as vitamine C and WR-2721 have been shown to reduce mortality when administered prior to exposure to a lethal dose of radiation. Recently, honey bee venom as well as that of its components melittin and histamine have shown to be valuable in reduction of radiation-induced damage and also provide prophylactic alternative treatment for serious side effects related with radiotherapy. It has been suggested that the radioprotective activity of bee venom components is related with the stimulation of the hematopoetic system.

  18. Core–shell monodisperse spherical mSiO2/Gd2O3:Eu3+@mSiO2 particles as potential multifunctional theranostic agents

    International Nuclear Information System (INIS)

    Core–shell nanoparticles with diameters in the range 100–500 nm have been synthesized as monodisperse spherical mesoporous (pore diameter 3 nm) silica particles with size deviation of less than 4 %, filled with gadolinium and europium oxides and coated with a mesoporous silica shell. It is shown that the melt technique developed for filling with gadolinium and europium oxides provides a nearly maximum filling of mesopores in a single-run impregnation, with gadolinium and europium uniformly distributed within the particles and forming no bulk oxides on their surface. The coating with a shell does not impair the monodispersity and causes no coagulation. The coating technique enables controlled variation of the shell thickness within the range 5–100 % relative to the core diameter. The thus produced nanoparticles are easily dispersed in water, have large specific surface area (300 m2 g−1) and pore volume (0.3 cm3 g−1), and are bright solid phosphor with superior stability in aqueous media. The core–shell structured particles can be potentially used for cancer treatment as a therapeutic agent (gadolinium neutron-capture therapy and drug delivery system) and, simultaneously, as a multimodal diagnostic tool (fluorescence and magnetic resonance imaging), thereby serving as a multifunctional theranostic agent

  19. Odor Classification using Agent Technology

    Directory of Open Access Journals (Sweden)

    Sigeru OMATU

    2014-03-01

    Full Text Available In order to measure and classify odors, Quartz Crystal Microbalance (QCM can be used. In the present study, seven QCM sensors and three different odors are used. The system has been developed as a virtual organization of agents using an agent platform called PANGEA (Platform for Automatic coNstruction of orGanizations of intElligent Agents. This is a platform for developing open multi-agent systems, specifically those including organizational aspects. The main reason for the use of agents is the scalability of the platform, i.e. the way in which it models the services. The system models functionalities as services inside the agents, or as Service Oriented Approach (SOA architecture compliant services using Web Services. This way the adaptation of the odor classification systems with new algorithms, tools and classification techniques is allowed.

  20. Stability of Evolving Agent Populations

    CERN Document Server

    Briscoe, G

    2007-01-01

    Stability is perhaps the most desired feature in the systems that we design. It is important for us to be able to predict the response of a Multi-Agent System (MAS) to various environmental conditions prior to its actual deployment. The Chli-DeWilde agent stability measure views a MAS as a discrete time Markov chain with a potentially unknown transition probabilities. A MAS is considered to be stable when its state, a stochastic process, has converged to an equilibrium distribution. We investigate an extension of their agent stability definition to include MASs with evolutionary dynamics, focusing on evolving agent populations. Additionally, using our extended agent stability measure, we construct an entropy-based definition for the degree of instability. An example system, the Digital Ecosystem, is considered in detail to investigate the stability of an evolving agent population through simulations. The results are consistent with the original Chli-DeWilde measure.