Gadolinium Concentration Research Articles

Gadolinium deposition in the liver and brain in a rat model with liver fibrosis after intravenous administration of gadoxetate disodium

ObjectivesTo investigate gadolinium deposition in the liver and brain in a rat model with liver fibrosis (LF) after intravenous administration of gadoxetate disodium (GD) and the histological effects of gadolinium deposition in the liver and brain. MethodsAdult male Sprague–Dawley rats were randomly assigned to one of the three groups: 1) LF group received intraperitoneal injection of carbon tetrachloride (CCl4) for 9 weeks alone; 2) LF&GD group received CCl4 and intravenous administration of GD (for 5 consecutive days); 3) GD group received olive oil and GD. Seven days after the final injection of GD, the deep cerebellar nuclei (DCN) and liver were excised to determine gadolinium concentrations via inductively coupled plasma mass spectrometry, and histologic staining was performed. Bonferroni's post-hoc test and Wilcoxon rank sum test were used to compare the differences between the three groups. ResultsThe concentrations of retained gadolinium in the liver in the LF&GD group (2.18 ± 0.44 μg/g) were significantly greater compared to the LF group (0.02 ± 0.01 μg/g, P < 0.001) and GD group (0.37 ± 0.11 μg/g, P < 0.001). Also, the concentrations of retained gadolinium in DCN were increased in the LF&GD group (0.13 ± 0.06 μg/g) compared to the LF group (0.01 ± 0.00 μg/g, P < 0.001) and GD group (0.06 ± 0.02 μg/g, P = 0.019). No histopathological alterations were detected in the liver and DCN between LF&GD group and LF group. ConclusionsLF aggravated gadolinium deposition in the liver and DCN after administration of GD. However, no significant acute histological alterations were observed due to gadolinium deposition.

Gadolinium Concentration Measurement with an Atomic Absorption Spectrophotometer

Abstract Because gadolinium (Gd) has the highest thermal neutron capture cross section, resulting in an 8 MeV gamma cascade upon capture, it has been proposed for dissolution in water Cherenkov detectors to achieve efficient neutron tagging capabilities. Whereas metallic Gd is insoluble in water, several compounds are very easy to dissolve. Gadolinium sulfate, Gd2(SO4)3, has been thoroughly tested and proposed as the best candidate. Accurate measurement of its concentration, free of doubt from impurities in water, is crucial. An atomic absorption spectrophotometer (AAS) is a device that suits this purpose and is widely used to measure the concentration of many elements. In this study, we describe three different approaches to measure Gd sulfate concentrations in water using an AAS: doping samples with potassium and lanthanum, and employing tantalum and tungsten platforms.

Characterization of quantitative susceptibility mapping in the left ventricular myocardium

Myocardial quantitative susceptibility mapping (QSM) may offer better specificity to iron than conventional T2* imaging in the assessment of cardiac diseases, including intra-myocardial hemorrhage. However, the precision and repeatability of cardiac QSM have not yet been characterized. The aim of this study is to characterize these key metrics in a healthy volunteer cohort and show the feasibility of the method in patients. Free breathing respiratory-navigated multi-echo 3D gradient echo images were acquired, from which QSM maps were reconstructed using the Morphology Enhanced Dipole Inversion toolbox. This technique was first evaluated in a susceptibility phantom containing tubes with known concentrations of gadolinium. In vivo characterization of myocardial QSM was then performed in a cohort of 10 healthy volunteers where each subject was scanned twice. Mean segment susceptibility, precision (standard deviation of voxel magnetic susceptibilities within one segment), and repeatability (absolute difference in segment mean susceptibility between repeats) of QSM were calculated for each American Heart Association (AHA) myocardial segment. Finally, the feasibility of the method was shown in 10 patients, including four with hemorrhagic infarcts. The phantom experiment showed a strong linear relationship between measured and predicted susceptibility shifts (R2 >0.99). For the healthy volunteer cohort, AHA segment analysis showed the mean segment susceptibility was 0.00±0.02ppm, the mean precision was 0.05±0.04ppm, and the mean repeatability was 0.02±0.02ppm. Cardiac QSM was successfully performed in all patients. Focal iron deposits were successfully visualized in the patients with hemorrhagic myocardial infarctions. The precision and repeatability of cardiac QSM were successfully characterized in phantom and in vivo experiments. The feasibility of the technique was also successfully demonstrated in patients. While challenges still remain, further clinical evaluation of the technique is now warranted. This work does not report on a health care intervention.

Gadolinium Presence in Rat Skin: Assessment of Histopathologic Changes Associated with Small Fiber Neuropathy.

Background The presence of gadolinium traces in the skin after administration of gadolinium-based contrast agents (GBCAs) raised safety concerns regarding a potential association with small fiber neuropathy (SFN). Purpose To investigate signs of SFN in rat foot pads by quantification of the intraepidermal nerve fiber density (IENFD) after multiple GBCA administrations and to evaluate gadolinium concentration, chemical species, and clearance. Materials and Methods Fifty rats received eight intravenous injections of either gadodiamide, gadobutrol, gadoterate, gadoteridol (8 × 0.6 mmol per kilogram of body weight), or saline (1.2 mL per kilogram of body weight), within 2 weeks and were sacrificed 5 days or 5 weeks after the last injection. IENFD was determined with protein gene product (PGP) 9.5 immunofluorescent staining and blinded and automated image analysis. The gadolinium and GBCA concentrations were measured with inductively coupled plasma mass spectrometry (ICP-MS), laser ablation ICP-MS, and matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI). P values were calculated using linear contrasts of model analysis. Results The IENFD (measured as geometric mean [SD] and in number of nerve fibers per millimeter of epidermis) was not significantly altered after 5 days (saline, 8.4 [1.1]; gadobutrol, 9.7 [1.2]; gadoterate, 9.2 [1.2]; gadoteridol, 9.9 [1.3]; gadodiamide, 10.5 [1.2]) or 5 weeks (saline, 19.7 [1.4]; gadobutrol, 16.4 [1.6]; gadoterate, 14.3 [1.6]; gadoteridol, 22.2 [1.8]; gadodiamide, 17.9 [1.4]). Gadolinium skin concentrations were highest for gadodiamide after 5 days (16.0 nmol/g [1.1]) and 5 weeks (10.6 nmol/g [1.2], -33%). Macrocyclic agents were lower at 5 days (gadoteridol, 2.6 nmol/g [1.2]; gadobutrol, 2.7 nmol/g [1.1]; and gadoterate, 2.3 nmol/g [1.2]) and efficiently cleared after 5 weeks (gadoteridol, -95%; gadobutrol and gadoterate, -96%). The distribution of gadolinium and IENF did not visually overlap. For macrocyclic agents, gadolinium was found in sweat glands and confirmed to be intact chelate. Conclusion There were no signs of SFN in rat foot pads using multiple dosing regimens at two time points after administration of GBCAs. Macrocyclic GBCAs exhibited lower levels of gadolinium in the skin and were effectively eliminated within 5 weeks compared with linear gadodiamide, and intact macrocyclic GBCA was detected in sweat glands. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Clement in this issue.

The effect of burnable absorbers on criticality and reactivity coefficient of VVER-1000 assembly

Burnable absorbers play an important role in nuclear reactor safety and exploring their effect on the reactor core behavior is an important issue in the design and operation of the reactor core. The aim of the present work was to discover the effect of burnable absorbers on criticality and reactivity coefficient of VVER-1000 assembly. The calculations were conducted with a 3-D Monte Carlo transport code MCNP6 and ENDF/B-VII.1 nuclear library. The Gd2O3 content varying from 0 wt.% to 8 wt.% was considered to complete the inter-comparison analysis between the criticality and the reactivity coefficients for three UO2+Gd2O3 fuel configurations. At the beginning of the cycle, there is a significant difference between the criticality (kinf) of assembly with and without Gd2O3, however, at the middle of the cycle those differences become very small and almost the same at the end of the cycle. The Doppler temperature coefficient values are always sufficiently negative and demonstrate a more negative trend with increasing gadolinium concentrations and fuel burnup. At beginning of the cycle, the moderator temperature coefficient value increases negatively as gadolinium concentration increases but, at middle of the cycle this trend does not occur. The fuel composition is predicted to be the reason behind this situation. At the end of cycle, there is no clear trend in the moderator temperature coefficient values with respect to Gd2O3 concentration. The absorbing effect of Gd2O3 appears to have diminished significantly. Overall, this research provides insights into the influence of the burnable absorbers on the neutronic parameters of the VVER-1000 assembly and its contribution to reactor safety.

Kiosk 7R-TC-04 - The Relationship of Blood Gadolinium Concentration and Body Mass Index in Weight-based Dosing of Gadolinium Contrast in CMR

Kiosk 7R-TC-04 - The Relationship of Blood Gadolinium Concentration and Body Mass Index in Weight-based Dosing of Gadolinium Contrast in CMR

Influence of gadolinium content on magnetic property and oxidation mechanism of Fe-B-Nb-Gd metallic glass

In this work, we use the rapid solidification technique to prepare five kinds of metallic glasses with different Gd content, and investigate in depth the influences of Gd content on the amorphous formation capability, thermal stability, and magnetic properties of (Fe&lt;sub&gt;73&lt;/sub&gt;B&lt;sub&gt;22&lt;/sub&gt;Nb&lt;sub&gt;5&lt;/sub&gt;)&lt;sub&gt;100–&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;Gd&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; (&lt;i&gt;x&lt;/i&gt; = 0, 0.5, 1.0, 1.5, 2.0) alloys. By comparing the microstructural morphology and solute distribution of oxidation products before adding Gd and those after adding Gd, the amorphous oxidation mechanism is analyzed systematically. With the addition of Gd, the atomic size difference of the alloys exceeds 13%, and the configuration entropy increases from 7.27 kJ/(mol·K) to 9.44 kJ/(mol·K). The glass-forming ability of the alloy is significantly improved. The increase of Gd content can increase the glass transition temperature of the alloy to 864 K, and the undercooled liquid region can reach 73 K, significantly enhancing the thermal stability of the metallic glasses. The Gd limits the local anisotropy of the alloy and reduces the density of quasi-dislocation dipole defects. This can effectively reduce the pinning sites that hinder the rotation of magnetic domain walls, thereby improving the soft magnetic property. By comparing with the metallic glasses without Gd, only 2% (atomic percentage) Gd can reduce the coercivity by 8%. Moreover, the Gd makes the metallic glasses more sensitive to temperature variation in the oxidation process, and the temperature of the maximum oxidation rate is reduced by 15 K. However, their antioxidant performance does not deteriorate. The Gd atoms are influenced by binding energy and migrate to the surface, forming Gd-rich oxides. They fill surface defects and occupy a large part of the top space, leading to the structure becoming more compact near the surface. This structure reduces the channels for oxygen atoms to diffuse through the microstructure interface, which helps to improve antioxidant capability. This work provides a new approach for designing high performance Fe-based metallic glasses.

Neutron shielding analysis for a gadolinium doped nickel alloy

Rare-earth-nickel (RE-Ni) alloy is a kind of appealing neutron shielding material for advanced reactors and spent fuel storage containers. The incorporation of neutron-absorbing additive RE elements results in a RE-Ni alloy with integrated structural and functional features, which can drastically reduce shielding material weight. Gadolinium (Gd), in comparison to other rare-earth elements, has a much larger thermal neutron absorption cross section, necessitating only a low fraction to achieve the desired shielding capability. Hence, gadolinium is doped into a nickel-based alloy to form a gadolinium-nickel (Gd-Ni) alloy. Due to its extremely low solubility in the nickel phase, gadolinium is commonly manifested as heterogeneously spatially scattered Gd-rich phases in existing preparation procedures of alloys rather than homogeneously distributed gadolinium elements. This would result in a strong neutron tunneling effect, limiting the neutron shielding capability of Gd-Ni alloys. In this work, a superfine layered Gd-Ni alloy doped with Gd-rich phases and arranged in dislocations is proposed to provide an adequate dislocation density of Gd-rich phases to suppress the neutron tunneling effect. With the same Gd content, the thermal neutron shielding ability of a layered Gd-Ni alloy is comparable to the case that Gd is assumed to be an ideally homogeneous distribution in the material. The smaller the particle size of the Gd-rich phase, the weaker the neutron tunneling effect, and the lower the thermal neutron transmission ratio. For a 0.5 cm-thick Gd-Ni alloy, the particle size of Gd-rich phase should be kept within 20μm to achieve a thermal neutron transmission ratio of less than 10−5 for natural gadolinium content of 0.6 at.%. This work provides an important guidance for the design and fabrication of the next-generation neutron shielding materials.

Gd2O3–Carbon Nanoflakes (CNFs) as Contrast Agents for Photon-Counting Computed Tomography (PCCT)

2–3 nm Gd2O3 nanoparticles deposited on carbon nanoflakes were prepared. These are new contrast agents for photon-counting computed tomography based on detectors allowing counting of separate photons. Contrast agents of the Gd2O3@C core–shell structure were prepared by graphitization of the surface of these particles. The Gd2O3 and Gd2O3@C nanoparticles obtained, aqueous solution of Gd(NO3)3·6H2O, and a dispersion of 300–500 nm Gd2O3 particles in gelatin were studied by photon-counting computed tomography. At equal gadolinium concentrations, the highest X-ray absorption was noted for Gd(NO3)3·6H2O and Gd2O3, which is associated with higher density of these samples. Carbon in the contrast agents does not affect the absorption. An algorithm was developed for semiquantitative determination of gadolinium by photon-counting computed tomography.

Associations between maternal urinary rare earth elements during pregnancy and birth weight-for-gestational age: Roles of cord blood vitamin D levels

Prenatal exposure to rare earth elements (REEs) may contribute to adverse birth outcomes in previous studies. Cord blood vitamin D has been suggested to modify or mediate the effects of environmental exposures. However, none has investigated these roles of cord blood vitamin D in the associations of prenatal exposure to REEs with fetal growth. Maternal trimester-specific urinary concentrations of 13 REEs, cord blood total 25-hydroxyvitamin D at delivery, and birth weight (BW)-for-gestational age (GA) were determined in 710 mother-newborn pairs from Wuhan, China. Higher maternal average urinary concentrations of europium (Eu), gadolinium (Gd), dysprosium (Dy), holmium (Ho), erbium (Er), and ytterbium (Yb) across three trimesters, either individually or jointly, were significantly associated with lower BW-for-GA Z-scores and higher odds of small for gestational age (SGA) [β = −0.092; 95 % confidence interval (CI): −0.149, −0.035 for BW-for-GA Z-scores, and odds ratio = 1.60; 95 % CI: 1.14, 2.24 for SGA involved in each unit increase in weighted quantile sum index of REEs mixture]. When stratified by cord blood vitamin D levels, the associations mentioned above persisted in participants with relatively low vitamin D levels (<13.94 μg/L, the first tertile of distribution), but not among those with relatively high levels (≥13.94 μg/L) (all p-values for interaction < 0.05). The mediation analyses taking account of exposure-mediator interaction showed that the relationships between REEs (as individual and mixture) exposure and lower BW-for-GA were partly mediated through decreasing cord blood vitamin D levels. The proportions mediated by cord blood vitamin D levels were 24.48 % for BW-for-GA Z-scores and 29.05 % for SGA corresponding to the REEs mixture exposure. Conclusively, our study revealed that prenatal exposures to Eu, Gd, Dy, Ho, Er, and Yb were related to fetal growth restriction. Cord blood vitamin D might alleviate toxic effects of these REEs and its reduction might partly mediate REE-induced fetal growth restriction.

Impact of gadolinium concentration and cell oxygen levels on radiobiological characteristics of gadolinium neutron capture therapy technique in brain tumor treatment.

Neutron capture therapy (NCT) with various concentrations of gadolinium (157Gd) is one of the treatment modalities for glioblastoma (GBM) tumors. Current study aims to evaluate how variations of 157Gd concentration and cell oxygen levels can affect the relative biological effectiveness (RBE) of gadolinium neutron capture therapy (GdNCT) technique through a hybrid Monte Carlo (MC) simulation approach. At first, Snyder phantom including a spherical tumor was simulated by Geant4 MC code and relevant energy electron spectra to different 157Gd concentrations including 100, 250, 500, and 1000 ppm were calculated following the neutron irradiation of simulated phantom. Scored energy electron spectra were then imported to Monte Carlo damage simulation (MCDS) code to estimate RBE values (both RBESSB and RBEDSB) at different gadolinium concentrations and oxygen levels from 10 to 100%. The results indicate that variations of 157Gd can affect the energy spectrum of released secondary electrons including Auger electrons. Variation of gadolinium concentration from 100 to 1000 ppm in tumor region can change RBESSB and RBEDSB values by about 0.1% and 0.5%, respectively. Besides, maximum variations of 4.3% and 2% were calculated for RBEDSB and RBESSB when cell oxygen level changed from 10 to 100%. From the results, variations of considered gadolinium and oxygen concentrations during GdNCT can influence RBE values. Nevertheless, due to the not remarkable changes in the intensity of Auger electrons, a slight difference in RBE values would be expected at various 157Gd concentrations, although considerable RBE changes were calculated relevant to the oxygen alternations inside tumor tissue.

Unveiling the effect of Gd3+ doping on enriching the structural, magnetic, optical, and dielectric properties of biocompatible hematite nanoparticles

This work is an attempt to obtain gadolinium-doped hematite GdxFe2−xO3 (x = 0, 0.05, and 0.1) using the hydrothermal method followed by heat treatment. The work also studies the impact of gadolinium doping on the magnetic, electrical, and optical properties of hematite. X-ray diffraction (XRD) analysis, energy-dispersive X-ray spectroscopy (EDAX) and photoelectron spectroscopy (XPS) showed that the obtained phase for all samples was pure hematite with no evidence of secondary phases, indicating a high solubility limit of gadolinium ions in hematite lattice. The morphology and size distribution of the particles were investigated using high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). It was found that the lattice parameters increased with increasing gadolinium concentration. Magnetization was not enhanced whereas, the coercivity decreased considerably. From UV–Vis diffuse reflection spectroscopy (DRS) measurements, the band gap energies of pure and doped α-Fe2O3 decreased from 2.01 to 1.94 eV respectively. Moreover, measurements of electrical properties showed that the dielectric permittivity decreased while the resistivity increased with increasing the gadolinium content. In addition, sulforhodamine B (SRB) test against oral epithelial cell lines showed low cytotoxicity of the particles. Finally, gadolinium doped hematite is introduced as a novel, environmentally benign material for potential applications in various fields including photocatalysis for water treatment, biosensor and as an antibacterial agent.

Development of a Gadolinium-Boron-Conjugated Albumin for MRI-Guided Neutron Capture Therapy.

Noninvasive monitoring of boron agent biodistribution is required in advance of neutron capture therapy. In this study, we developed a gadolinium-boron-conjugated albumin (Gd-MID-BSA) for MRI-guided neutron capture therapy. Gd-MID-BSA was prepared by labeling bovine serum albumin with a maleimide-functionalized gadolinium complex and a maleimide-functionalized closo-dodecaborate orthogonally. The accumulation of Gd-MID-BSA in tumors in CT26 tumor-bearing mice reached a maximum at 24 h after the injection, as confirmed by T1-based MRI and biodistribution analysis using inductively coupled plasma optical emission spectrometry. The concentrations of boron and gadolinium in the tumors exceeded the thresholds required for boron neutron capture therapy (BNCT) and gadolinium neutron capture therapy (GdNCT), respectively. The boron concentration ratios of tumor to blood and tumor to normal tissues satisfied the clinical criteria, indicating the reduction of undesired nuclear reactions of endogenous nuclei. The molar ratio of boron to gadolinium in the tumor was close to that of Gd-MID-BSA, demonstrating that the accumulation of Gd-MID-BSA in the tumor can be evaluated by MRI. Thermal neutron irradiation with Gd-MID-BSA resulted in significant suppression of tumor growth compared to the group injected with a boron-conjugated albumin without gadolinium (MID-BSA). The neutron irradiation with Gd-MID-BSA did not cause apparent side effects. These results demonstrate that the conjugation of gadolinium and boron within the albumin molecule offers a novel strategy for enhancing the therapeutic effect of BNCT and the potential of MRI-guided neutron capture therapy as a promising treatment for malignant tumors.

A New Era in Magnetic Resonance Contrast Media.

Next-generation gadolinium-based contrast agents (GBCAs), including both high relaxivity agents and targeted agents, and manganese-based agents with a high probably of commercial success are discussed in some depth. It is highly likely that gadopiclenol and gadoquatrane, both next-generation high relaxivity gadolinium-based compounds, will come in time to replace the current macrocyclic gadolinium chelates, despite the wide acceptance, very high safety profile, and high stability of the latter group. Current research has also made possible the development of 2 new targeted gadolinium chelates, which look very promising, with the potential to improve cancer detection (for both MT218 and ProCA32.collagen) as well as diseases of collagen (for the latter agent). Further work with manganese-based compounds, a topic left fallow for more than 20 years, has also now produced 2 agents with high potential for clinical use, one (manganese chloride tetrahydrate, administered orally) developed primarily for imaging of the liver and the other (Mn-PyC3A, administered intravenously) as a gadolinium-free replacement for the GBCAs. New detail has recently emerged regarding specific circumscribed subregions of the brain with specialized cytoarchitecture and functions in which high gadolinium concentrations are seen following injection of the linear agent gadodiamide. These findings pave the way for tailored functional neurological testing, specifically in patients at potential risk due to the continued wide use in many countries across the world of the linear GBCAs. The impact of artificial intelligence is also critically discussed, with its most likely applications being dose reduction and new clinical indications.

Quantitative MRI of Gd-DOTA Accumulation in the Mouse Brain After Intraperitoneal Administration: Validation by Mass Spectrometry.

In mice, intraperitoneal (ip) contrast agent (CA) administration is convenient for mapping microvascular parameters over a long-time window. However, continuous quantitative MRI of CA accumulation in brain over hours is still missing. To validate a quantitative time-resolved MRI technique for mapping the CA kinetics in brain upon ip administration. Prospective, animal model. 25 C57Bl/6JRj mice underwent MRI. 7-T, gradient echo sequence. Gd-DOTA concentration was monitored by MRI (25 s/repetition) over 135 minutes with (N = 15) and without (N = 10) ip mannitol challenge (5 g/kg). After the final repetition, the brains were sampled to quantify gadolinium by mass spectrometry (MS). Upon manual brain segmentation, the average gadolinium concentration was compared with the MS quantification in transcardially perfused (N = 20) and unperfused (N = 5) mice. Precontrast T1-maps were acquired in 8 of 25 mice. One-tailed Spearman and Pearson correlation between gadolinium quantification by MRI and by MS, D'Agostino-Pearson test for normal distribution, Bland-Altman analysis to evaluate the agreement between MRI and MS. Significance was set at P-value <0.05. MRI showed that ip administered CA reached the blood compartment (>5 mM) within 10 minutes and accumulated continuously for 2 hours in cerebrospinal fluid (>1 mM) and in brain tissue. The MRI-derived concentration maps showed interindividual differences in CA accumulation (from 0.47 to 0.81 mM at 2 hours) with a consistent distribution resembling the pathways of the glymphatic system. The average in-vivo brain concentration 2 hours post-CA administration correlated significantly (r = 0.8206) with the brain gadolinium quantification by MS for N = 21 paired observations available. The presented experimental and imaging protocol may be convenient for monitoring the spatiotemporal pattern of CA uptake and clearance in the mouse brain over 2 hours. The quantification of the CA from the MRI signal in brain is corroborated by MS. N/A TECHNICAL EFFICACY: Stage 1.

Gadolinium-based Contrast Agent Biodistribution and Speciation in Rats.

Background Gadolinium retention has been observed in organs of patients with normal renal function; however, the biodistribution and speciation of residual gadolinium is not well understood. Purpose To compare the pharmacokinetics, distribution, and speciation of four gadolinium-based contrast agents (GBCAs) in healthy rats using MRI, mass spectrometry, elemental imaging, and electron paramagnetic resonance (EPR) spectroscopy. Materials and Methods In this prospective animal study performed between November 2021 and September 2022, 32 rats received a dose of gadoterate, gadoteridol, gadobutrol, or gadobenate (2.0 mmol/kg) for 10 consecutive days. GBCA-naive rats were used as controls. Three-dimensional T1-weighted ultrashort echo time images and R2* maps of the kidneys were acquired at 3, 17, 34, and 52 days after injection. At 17 and 52 days after injection, gadolinium concentrations in 23 organ, tissue, and fluid specimens were measured with mass spectrometry; gadolinium distribution in the kidneys was evaluated using elemental imaging; and gadolinium speciation in the kidney cortex was assessed using EPR spectroscopy. Data were assessed with analysis of variance, Kruskal-Wallis test, analysis of response profiles, and Pearson correlation analysis. Results For all GBCAs, the kidney cortex exhibited higher gadolinium retention at 17 days after injection than all other specimens tested (mean range, 350-1720 nmol/g vs 0.40-401 nmol/g; P value range, .001-.70), with gadoteridol showing the lowest level of retention. Renal cortex R2* values correlated with gadolinium concentrations measured ex vivo (r = 0.95; P < .001), whereas no associations were found between T1-weighted signal intensity and ex vivo gadolinium concentration (r = 0.38; P = .10). EPR spectroscopy analysis of rat kidney cortex samples showed that all GBCAs were primarily intact at 52 days after injection. Conclusion Compared with other macrocyclic GBCAs, gadoteridol administration led to the lowest level of retention. The highest concentration of gadolinium was retained in the kidney cortex, but T1-weighted MRI was not sensitive for detecting residual gadolinium in this tissue. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Tweedle in this issue.

Microbial community and gene dynamics response to high concentrations of gadolinium and sulfamethoxazole in biological nitrogen removal system

The impact of high antibiotic and heavy metal pollution levels on biological nitrogen removal in wastewater treatment plants (WWTPs) remains poorly understood, posing a global concern regarding the issue spread of antibiotic resistance induced by these contaminants. Herein, we investigated the effects of gadolinium (Gd) and sulfamethoxazole (SMX), commonly found in medical wastewater, on biological nitrogen removal systems and microbial characteristics, and the fate of antibiotic resistance genes (ARGs), metal resistance genes (MRGs), and mobile genetic elements (MGEs). Our findings indicated that high SMX and Gd(III) concentrations adversely affected nitrification and denitrification, with Gd(III) exerting a strong inhibitory effect on microbial activity. Metagenomic analysis revealed that high SMX and Gd(III) concentrations could reduce microbial diversity, with Thauera and Pseudomonas emerging as dominant genera across all samples. While the relative abundance of most ARGs decreased under single Gd(III) stress, MRGs increased, and nitrification functional genes were inhibited. Conversely, combined SMX and Gd(III) pollution increased the relative abundance of intl1. Correlation analysis revealed that most genera could host ARGs and MRGs, indicating co-selection and competition between these resistance genes. However, most denitrifying functional genes exhibited a positive correlation with MRGs. Overall, our study provides novel insights into the impact of high concentrations of antibiotics and heavy metal pollution in WWTPs, and laying the groundwork for the spread and proliferation of resistance genes under combined SMX and Gd pollution.

Potential for Phytomining of Rare Earth Elements by Naturally Occurring Plants in Reclaimed Tailing Ponds

Rare earth elements (REEs) from the ex-mining area (reclaimed tailing ponds) in East Rodope, Bulgaria, were investigated in soil and different plant species using inductively coupled plasma-optical emission spectrometry (ICP-OES). The tailings pond was reclaimed 20 years ago. The research work aims to determine the potential for phytomining of rare earth elements by naturally occurring plants in reclaimed tailing ponds. In the soil samples, the concentrations of cerium (Ce), lanthanum (La), and gadolinium (Gd) exceeded the average content of the elements in soils. The bioconcentration factor (BCF) was calculated. It was found that light rare earth elements (LREEs) are in greater concentration in plant samples than heavy rare earth elements (HREEs).

X-ray/gamma radiation attenuation and cytotoxic properties of Gadolinium doped Maghemite nanoparticles

In the present work, Gadolinium doped (1–6 mol%) Maghemite nanoparticles (NPs) were synthesized via solution combustion method using Sapodilla fruit extract as a reducing agent followed by calcination at 500 °C and characterized with different techniques. The Bragg reflections consists of (hkl) planes corresponding to γ-Fe2O3 (Maghemite). Addition to this, few planes corresponding to α-Fe2O3 and Gd2O3 were also observed. The estimated crystallite size and direct energy band gap was found to decrease with increase in Gd3+ concentration. Cytotoxic properties were examined on cervical cancer cell lines HeLa cells as the Gadolinium dopant concentration increases, cell death decreases, eventually toxicity is going to reduced. Because of the non-toxicity, these NPs might be used as a drug carrier and also in the biochemical modification process called PEGylation. Theoretically, X-ray/Gamma ray attenuation parameter such as mass attenuation coefficient is studied in detail which is an essential parameter in radiation dosimetry. Gamma attenuation ion properties are increased by increase in the dopant concentration of Gadolinium. Compared to other concentrations, Gadolinium at 6 mol% shows maximum cytotoxic and mass attenuation coefficient. Thus, the present synthesized material might finds an application in biomedical field as well as in radiation dosimetry.

Evaluation of the reactivity of dense lanthanum‑gadolinium zirconate ceramics with Colima volcanic ashes

The effects of ingestion of airborne particles from pyroclastic events of active volcanoes by aircraft turbines and their subsequent reaction with thermal barrier coatings have attracted the attention of the scientific community in recent years. The reaction products of infiltration experiments of lanthanum‑gadolinium zirconate (LGZO) ceramics with molten ashes from the active Colima volcano at 1250 °C for 10 h are presented and discussed as a function of the Gd3+ content. Five ceramic compositions, varying the Gd3+ content in solid solution were synthesized by the chemical coprecipitation and calcination method of pressed powders. These compositions include pure lanthanum and gadolinium zirconates, LZO, and GZO, respectively. Penetration depth and identification, and in some cases quantification of the reaction products between the molten ash and LGZO ceramics were performed by scanning electron microscopy, chemical composition with energy dispersive X-ray spectroscopy, grazing incident X-ray diffraction as well as micro-Raman spectroscopy. The LZO ceramic exhibited the greatest infiltration resistance with an infiltration depth of approximately 23 μm from the surface. The phase characteristics of the reaction layers were dependent on the gadolinium content. LZO, LGZO25, and LGZO50 (x = 0, 0.25, and 0.5) showed the presence of apatite as well as monoclinic and tetragonal zirconia, while LGZO75 and GZO (x = 0.75 and 1), additionally showed the presence of cubic zirconia and anorthite. As the Gd3+ content increases in the LGZO solid solutions, the wavenumber value corresponding to the stretching vibrational mode of the silicon tetrahedra in apatite shifts from 862 to 877 cm−1, which is associated with a decrease in SiO bond lengths. These findings indicate that the amount and kind of rare earth cations dissolved in the melt plays an important role in the precipitation of the reaction products.