Investigating the generalisation of an atlas-based synthetic-CT algorithm to another centre and MR scanner for prostate MR-only radiotherapy

There is increasing interest in MR-only radiotherapy planning since it provides superb soft-tissue contrast without the registration uncertainties inherent in a CT–MR registration. However, MR images cannot readily provide the electron density information necessary for radiotherapy dose calculation. An algorithm which generates synthetic CTs for dose calculations from MR images of the prostate using an atlas of 3 T MR images has been previously reported by two of the authors. This paper aimed to evaluate this algorithm using MR data acquired at a different field strength and a different centre to the algorithm atlas. Twenty-one prostate patients received planning 1.5 T MR and CT scans with routine immobilisation devices on a flat-top couch set-up using external lasers. The MR receive coils were supported by a coil bridge. Synthetic CTs were generated from the planning MR images with (sCT₁v) and without (sCT) a one voxel body contour expansion included in the algorithm. This was to test whether this expansion was required for 1.5 T images. Both synthetic CTs were rigidly registered to the planning CT (pCT). A 6 MV volumetric modulated arc therapy plan was created on the pCT and recalculated on the sCT and sCT₁v. The synthetic CTs' dose distributions were compared to the dose distribution calculated on the pCT. The percentage dose difference at isocentre without the body contour expansion (sCT–pCT) was ΔDsCT = (0.9 \pm 0.8)% and with sCT₁v–pCT was ΔDsCT₁v = (-0.7 \pm 0.7)% (mean  ±  one standard deviation). The sCT₁v result was within one standard deviation of zero and agreed with the result reported previously using 3 T MR data. The sCT dose difference only agreed within two standard deviations. The mean  ±  one standard deviation gamma pass rate was ΓsCT = 96.1 \pm 2.9% for the sCT and ΓsCT₁v = 98.8 \pm 0.5% for the sCT₁v (with 2% global dose difference and 2mm distance to agreement gamma criteria). The one voxel body contour expansion improves the synthetic CT accuracy for MR images acquired at 1.5 T but requires the MR voxel size to be similar to the atlas MR voxel size. This study suggests that the atlas-based algorithm can be generalised to MR data acquired using a different field strength at a different centre

The paradox from within: research participants doing-being-observed

This article analyses a collection of cases from video recordings of naturally occurring interaction in institutional settings, where members display an orientation to the presence of the recording equipment. Such instances have been treated elsewhere as evidence of contamination of the ecology of the setting. The findings suggest that participants do remain aware of the recording activity, but that they publicly display when they are attending to it. Indeed, it is used as one resource to occasion identity work as competent, knowledgeable members of a particular institutional community, displaying to one another their understanding of the research aims, and their knowledge of how these kinds of data are constituted. Investigating how observational research is oriented to and constituted by the observed allows for a better understanding of what at that moment and in that setting is deemed recording-appropriate or -inappropriate conduct, and offers a more nuanced perspective on how data are co-constituted

Influence of acetylsalicylic acid on hematotoxicity of benzene

Objectives: The aim of the study was to evaluate the influence of acetylsalicylic acid (ASA) on benzene hematotoxicity in rats. Materials and Methods: The study was carried out on rats exposed for 2, 4 and 8 weeks to benzene vapour at a conentration of 1.5 or 4.5 mmol/m3 of air (5 days per week, 6 hours per day) alone or together with ASA at the doses of 5, 150 or 300 mg/kg body weight (per os). Results: Benzene at a concentration of 4.5 mmol/m3 caused a slight lymphopenia, granulocytosis and reticulocytosis in blood. In bone marrow traits of megaloblastic renewal, presence of undifferentiated cells and giant forms of granulocytes as well as an increase in myeloperoxidase and decrease in chloroacetate esterase activity and lipids content were noted. ASA (150 and 300 mg/kg b.w.) influenced some of hematological parameters, altered by benzene intoxication. ASA limited the solvent-induced alteration in blood reticulocyte count and in the case of bone marrow in the erythroblasts count. Traits of megaloblastic renewal in bone marrow were less pronounced. Besides, higher activity of myeloperoxidase and the decrease in the level of lipids in granulocytes were noted. Conclusion: Our results suggest that ASA limited the benzene-induced hematotoxicity

The misasandry myth: An inaccurate stereotype about feminists' attitudes toward men

In six studies, we examined the accuracy and underpinnings of the damaging stereotype that feminists harbor negative attitudes toward men. In Study 1 (n = 1,664), feminist and nonfeminist women displayed similarly positive attitudes toward men. Study 2 (n = 3,892) replicated these results in non-WEIRD countries and among male participants. Study 3 (n = 198) extended them to implicit attitudes. Investigating the mechanisms underlying feminists’ actual and perceived attitudes, Studies 4 (n = 2,092) and 5 (nationally representative UK sample, n = 1,953) showed that feminists (vs. nonfeminists) perceived men as more threatening, but also more similar, to women. Participants also underestimated feminists’ warmth toward men, an error associated with hostile sexism and a misperception that feminists see men and women as dissimilar. Random-effects meta-analyses of all data (Study 6, n = 9,799) showed that feminists’ attitudes toward men were positive in absolute terms and did not differ significantly from nonfeminists'. An important comparative benchmark was established in Study 6, which showed that feminist women's attitudes toward men were no more negative than men's attitudes toward men. We term the focal stereotype the misandry myth in light of the evidence that it is false and widespread, and discuss its implications for the movement