Quantitative, Multi-institutional Evaluation of MR Thermometry Accuracy for Deep-Pelvic MR-Hyperthermia Systems Operating in Multi-vendor MR-systems Using a New Anthropomorphic Phantom

Clinical outcome of hyperthermia depends on the achieved target temperature, therefore target conformal heating is essential. Currently, invasive temperature probe measurements are the gold standard for temperature monitoring, however, they only provide limited sparse data. In contrast, magnetic resonance thermometry (MRT) provides unique capabilities to non-invasively measure the 3D-temperature. This study investigates MRT accuracy for MR-hyperthermia hybrid systems located at five European institutions while heating a centric or eccentric target in anthropomorphic phantoms with pelvic and spine structures. Scatter plots, root mean square error (RMSE) and Bland–Altman analysis were used to quantify accuracy of MRT compared to high resistance thermistor probe measurements. For all institutions, a linear relation between MRT and thermistor probes measurements was found with R 2 (mean ± standard deviation) of 0.97 ± 0.03 and 0.97 ± 0.02, respectively for centric and eccentric heating targets. The RMSE was found to be 0.52 ± 0.31 ◦C and 0.30 ± 0.20 ◦C, respectively. The Bland-Altman evaluation showed a mean difference of 0.46 ± 0.20 ◦C and 0.13 ± 0.08 ◦C, respectively. This first multi-institutional evaluation of MR-hyperthermia hybrid systems indicates comparable device performance and good agreement between MRT and thermistor probes measurements. This forms the basis to standardize treatments in multi-institution studies of MR-guided hyperthermia and to elucidate thermal dose-effect relations

A multi-institution study: comparison of the heating patterns of five different MR-guided deep hyperthermia systems using an anthropomorphic phantom

Introduction Within the hyperthermia community, consensus exists that clinical outcome of the treatment radiotherapy and/or chemotherapy plus hyperthermia (i.e. elevating tumor temperature to 40 − 44 °C) is related to the applied thermal dose; hence, treatment quality is crucial for the success of prospective multi-institution clinical trials. Currently, applicator quality assurance (QA) measurements are implemented independently at each institution using basic cylindrical phantoms. A multi-institution comparison of heating quality using magnetic resonance thermometry (MRT) and anatomical representative anthropomorphic phantoms provides a unique opportunity to obtain novel QA insights to f

Sulfur Dioxide variability in the Venus Atmosphere

International audienceRecent observations of sulfur oxides (SO2, SO, OCS, and H2SO4) in Venus’ mesosphere have generated controversy and great interest in the scientific community. These observations revealed unexpected spatial patterns and spatial/temporal variability that have not been satisfactorily explained by models. Particularly intriguing are the layer of enhanced gas- phase SO2 and SO in the upper mesosphere, and variability in the maximum observed SO2 abundance and the equator-to-pole SO2 abundance gradient, seemingly on multi-year cycles, that is not uniquely linked to local time variations. Sulfur oxide chemistry on Venus is closely linked to the global- scale cloud and haze layers, which are composed primarily of concentrated sulfuric acid. Consequently, sulfur oxide observations provide important insight into the ongoing chemical evolution of Venus’ atmosphere, atmospheric dynamics, and possible volcanism.Existing observations have been obtained using multiple platforms, observing techniques, and wavelengths. Each has its own unique strengths and limitations. Although there is strong agreement on some features, there are significant unresolved apparent disagreements among current observations and between observations and models. These apparent disagreements need to be analyzed and assessed carefully to synthesize a clear understanding of sulfur oxide chemistry on Venus. These investigations have been performed via 1) the comparison and validation of observations, from past missions, Venus Express, Earth-based telescopes, and the Earth-orbiting Hubble Space Telescope; and 2) modelling of the SO2 and sulfur-oxide family photochemistry. The current study has been carried out within the frame of the ISSI International Team entitled ‘SO2 variability in the Venus atmosphere’

Keratin binding to 14-3-3 proteins modulates keratin filaments and hepatocyte mitotic progression

Keratin polypeptides 8 and 18 (K8/18) are the major intermediate filament proteins of simple-type epithelia. K18 Ser-33 phosphorylation regulates its binding to 14-3-3 proteins during mitosis. We studied the significance of keratin binding to 14-3-3 in transgenic mice that overexpress wild-type or Ser-33→Ala (S33A) K18. In S33A but not wild-type K18-overexpressing mice, pancreatic acinar cell keratin filaments retracted from the basal nuclear region and became apically concentrated. In contrast, K18 S33A had a minimal effect on hepatocyte keratin filament organization. Partial hepatectomy of K18-S33A-overexpressing mice did not affect liver regeneration but caused limited mitotic arrest, accumulation of abnormal mitotic figures, dramatic fragmentation of hepatocyte keratin filaments, with retention of a speckled 14-3-3ζ mitotic cell nuclear-staining pattern that usually becomes diffuse during mitosis. Hence, K18 Ser-33 phosphorylation regulates keratin filament organization in simple-type epithelia in vivo. Keratin binding to 14-3-3 may partially modulate hepatocyte mitotic progression, in association with nuclear redistribution of 14-3-3 proteins during mitosis