Search results for "gadolinium"

Terbium Medical Radioisotope Production: Laser Resonance Ionization Scheme Development

2021

Terbium (Tb) is a promising element for the theranostic approach in nuclear medicine. The new CERN-MEDICIS facility aims for production of its medical radioisotopes to support related R&D projects in biomedicine. The use of laser resonance ionization is essential to provide radioisotopic yields of highest quantity and quality, specifically regarding purity. This paper presents the results of preparation and characterization of a suitable two-step laser resonance ionization process for Tb. By resonance excitation via an auto-ionizing level, the high ionization efficiency of 53% was achieved. To simulate realistic production conditions for Tb radioisotopes, the influence of a surplus of Gd at…

Suprasellar Granular Cell Tumor

1992

A case of a suprasellar granular cell tumor, approximately 1.5 cm in diameter, in a 68-year-old woman is described. Diagnosis was established postoperatively by histopathological examination of the tumor tissue. The preoperative computed tomographic scan revealed a slightly hyperdense suprasellar mass with strong contrast enhancement. There was no evidence of calcification. The T1-weighted image on magnetic resonance imaging scan showed an isointense tumor with non-homogeneous enhancement after intravenous gadolinium diethylene-triamine-pentaacetic acid. In the proton-weighted image, the suprasellar mass presented a non-homogeneously enhanced signal. A non-homogeneous signal reduction was s…

Site-specific Labelling with a Metal Chelator for Protein-structure Refinement

2004

A single free Cys sidechain in the N-terminal domain of the E. coli arginine repressor was covalently derivatized with S-cysteaminyl-EDTA for site-specific attachment of paramagnetic metal ions. The effects of chelated metal ions were monitored with (15)N-HSQC spectra. Complexation of Co(2+), which has a fast relaxing electron spin, resulted in significant pseudocontact shifts, but also in peak doubling which was attributed to the possibility of forming two different stereoisomers of the EDTA-Co(2+) complex. In contrast, complexation of Cu(2+) or Mn(2+), which have slowly relaxing electron spins, did not produce chemical shift changes and yielded self-consistent sets of paramagnetic relaxat…

Ultrasmall particles for Gd-MRI and68Ga-PET dual imaging

2014

Nanoparticles made of a polysiloxane matrix and surrounded by 1,4,7,10-tetraazacyclododecane-1-glutaric anhydride-4,7,10-triacetic acid (DOTAGA)[Gd(3+) ] and 2,2'-(7-(1-carboxy-4-((2,5-dioxopyrrolidin-1-yl)oxy)-4-oxobutyl)-1,4,7-triazonane-1,4-diyl)diacetic acid) NODAGA[(68) Ga(3+) ] have been synthesized for positron emission tomography/magnetic resonance (PET/MRI) dual imaging. Characterizations were carried out in order to determine the nature of the ligands available for radiolabelling and to quantify them. High radiolabelling purity (>95%) after (68) Ga labelling was obtained. The MR and PET images demonstrate the possibility of using the nanoparticles for a combined PET/MR imaging sca…

Nephrogenic systemic fibrosis--a rapidly progressive disabling disease with limited therapeutic options.

2009

Background Nephrogenic systemic fibrosis (NSF) affects some patients on dialysis after gadolinium contrast agent–enhanced magnetic resonance imaging. It is characterized by progressive skin fibrosis of the extremities, sometimes including the trunk and internal organs. Methods The clinical course of 10 patients with biopsy-proven NSF was analyzed retrospectively with regard to gadolinium exposition, disease onset, and progression of NSF with special emphasis on physical mobility and impact of different therapeutic approaches. Results Despite physiotherapy and different additional therapeutic approaches (eg, immunosuppression, ultraviolet A-1 phototherapy, or extracorporal photopheresis) all…

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

2007

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: a…

Cost-effectiveness of recall strategies for non-invasive diagnosis of small hepatocellular carcinoma

2009

Brain iron deposition after Ferumoxytol-enhanced MRI: A study of Porcine Brains

2020

Recent evidence of gadolinium deposition in the brain has raised safety concerns. Iron oxide nanoparticles are re-emerging as promising alternative MR contrast agents, because the iron core can be metabolized. However, long-term follow up studies of the brain after intravenous iron oxide administration have not been reported thus far. In this study, we investigated, if intravenously administered ferumoxytol nanoparticles are deposited in porcine brains. Methods: In an animal care and use committee-approved prospective case-control study, ten Gottingen minipigs received either intravenous ferumoxytol injections at a dose of 5 mg Fe/kg (n=4) or remained untreated (n=6). Nine to twelve months …

Room-temperature vibrational properties of potassium gadolinium double tungstate under compression up to 32GPa

2015

Abstract KGd(WO 4 ) 2 has been studied by high-pressure Raman spectroscopy at room temperature up to 32.2 GPa. Evidences of two pressure-driven phase transitions have been detected. The low-pressure monoclinic phase undergoes a phase transition at 7.2(±0.9) GPa. The second transition is found at 14.2(±1.6) GPa. Both transitions are reversible. No evidence of pressure-induced amorphization is found up to 32 GPa. The pressure dependence of the Raman active modes of the low- and high-pressure phases is reported. A Raman mode is detected to exhibit a weak softening in the low-pressure phase. Three Raman modes are also observed to have a similar behavior in the second high-pressure phase. The re…

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

2011

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