Objectives Modern endovascular treatment of unruptured intracranial aneurysms (UIAs) demands for observance of diagnostic reference levels (DRLs). The national DRL (250 Gy cm2) is only defined for coiling. We provide dosimetric data for the following procedures: coiling, flow diverter (FD), Woven EndoBridge (WEB), combined techniques. Methods A retrospective single-centre study of saccular UIAs treated between 2015 and 2019. Regarding dosimetric analysis, the parameters dose area product (DAP) and fluoroscopy time were investigated for the following variables: endovascular technique, aneurysm location, DSA protocol, aneurysm size, and patient age. Results Eighty-seven patients (59 females, mean age 54 years) were included. Total mean and median DAP (Gy cm2) were 119 ± 73 (89–149) and 94 (73; 130) for coiling, 128 ± 53 (106–151) and 134 (80; 176) for FD, 128 ± 56 (102–153) and 118 (90; 176) for WEB, and 165 ± 102 (110–219) and 131 (98; 209) for combined techniques (p > .05). Regarding the aneurysm location, neither DAP nor fluoroscopy time was significantly different (p > .05). The lowest and highest fluoroscopy times were recorded for WEB and combined techniques, respectively (median 26 and 94 min; p < .001). A low-dose protocol yielded a 43% reduction of DAP (p < .001). Significantly positive correlations were found between DAP and both aneurysm size (r = .320, p = .003) and patient age (r = .214, p = .046). Conclusions This UIA study establishes novel local DRLs for modern endovascular techniques such as FD and WEB. A low-dose protocol yielded a significant reduction of radiation dose. Key Points • This paper establishes local diagnostic reference levels for modern endovascular treatment techniques of unruptured intracranial aneurysms, including flow diverter stenting and Woven EndoBridge device. • Dose area product was not significantly different between endovascular techniques and aneurysm locations, but associated with aneurysm size and patient age. • A low-dose protocol yielded a significant reduction of dose area product and is particularly useful when applying materials with a high radiopacity (e.g. platinum coils).

Sb2S3 and CuCl were reacted in the ionic liquid [BMIm]Cl ⋅ 4.4AlCl3 (BMIm=1‐n‐butyl‐3‐methylimidazolium) at 200 °C. Upon cooling to room temperature, orange‐red colored, air‐sensitive crystals of Cu(Sb2S3)[AlCl4] precipitated. X‐ray diffraction on a single‐crystal revealed an orthorhombic crystal structure, in which cationic [Cu(Sb2S3)]+ layers are separated by tetrahedral [AlCl4]− anions. The uncharged Sb2S3 partial structure consists of one‐dimensional strands with covalent Sb−S single bonds. The copper(I) cation is coordinated by three sulfur atoms and by one of chlorine atoms of the [AlCl4]– anion. An optical band gap of 2.14 eV was deduced from UV/Vis spectra. In very good agreement, a band gap of 2.07 eV results from DFT‐based calculations involving a new implementation of the bifunctional formalism for the exchange energy. By treatment with 0.1 molar hydrochloric acid, AlCl3 was leached from Cu(Sb2S3)[AlCl4] yielding a compound with the presumed composition Cu(Sb2S3)Cl. Hydrolysis at higher pH resulted in Cu2–xS and Sb4O5Cl2.

A Correction to this paper has been published: 10.1007/s00330-021-07874-1