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Magnetic Materials for Nuclear Magnetic Resonance and Magnetic Resonance Imaging
Published in Sam Zhang, Dongliang Zhao, Advances in Magnetic Materials, 2017
Elizaveta Motovilova, Shaoying Huang
Until 2006 GBCAs were considered as one of the safest CAs used in humans [37]. Over 200 million patients have been exposed to gadolinium since the late 1980s. Worldwide post-marketing surveillance studies have all demonstrated that nearly all drug reactions can be characterized as very mild (<2.5%) or moderately severe (<0.02%) [38]. However in 2006 Grobner et al. reported about the possible association between GBCAs and a new and rare disease, NSF [39]. NSF was first described in the medical literature in 2000. NSF causes fibrosis of the skin, connective tissues like muscles, tendons, ligaments, and blood vessels throughout the body, leading to a thickening of the skin and severe decreasing of joints mobility. However, NSF has been reported only in patients with pre-existing chronic kidney disease and end-stage kidney disease. Due to the weak kidney function, the human body cannot clear itself of GBCAs and the extended presence of gadolinium may lead to irreversible health problems, possible confinement to a wheelchair, and even death. Table 3.7 shows an overview of worldwide unconfounded NSF cases for various GBCAs. A retrospective study with Omnisan in about 370 patients with severe renal insufficiency estimated the risk of NSF to be 4% [40]. It is still unknown what causes NSF, there is no cure for it so far, and skin biopsy is the only true means of diagnosis.
Elimination of Diethylenetriaminepentaacetic Acid from Effluents from Pharmaceutical Production by Ozonation
Published in Ozone: Science & Engineering, 2022
Fares Daoud, Sebastian Zühlke, Michael Spiteller, Oliver Kayser
However, there are also expedient applications for earth alkali and heavy metals in medical systems. One example is the field of diagnostic imaging. The paramagnetic properties of some elements can be used in magnetic resonance imaging (MRI) to resolve certain areas of the human body in more detail. One of these elements is the lanthanide gadolinium (Gd). The outer electron shell of gadolinium has seven unpaired electrons, which leads to its extreme paramagnetism. However, it is highly toxic in the ionic form, with the LD50 of 0.1 mmol/kg of body weight (Vogl 2013), and therefore harmful when employed for MRI applications. Instead, gadolinium is used in a ligated form that is very stable and unable to permeate the blood–brain barrier. However, some Gd-based contrast agents were reported to cause nephrogenic systemic fibrosis, likely related to dechelation, in several patients. Further, considerably higher resistance to chelate disruption was observed in the so-called macrocyclic forms of gadolinium-based contrast media, as compared to their linear counterparts (Montagne, Toga, and Zlokovic 2016). The complexing agent, DPTA forms such stable ligands with gadolinium, resulting in a nontoxic structure, without compromising its effectiveness in MRI applications.