Hippocampal sparing radiotherapy for glioblastoma patients: a planning study using volumetric modulated arc therapy

Background: The purpose of this study is to investigate the potential to reduce exposure of the contralateral hippocampus in radiotherapy for glioblastoma using volumetric modulated arc therapy (VMAT). Methods: Datasets of 27 patients who had received 3D conformal radiotherapy (3D-CRT) for glioblastoma with a prescribed dose of 60Gy in fractions of 2Gy were included in this planning study. VMAT plans were optimized with the aim to reduce the dose to the contralateral hippocampus as much as possible without compromising other parameters. Hippocampal dose and treatment parameters were compared to the 3D-CRT plans using the Wilcoxon signed-rank test. The influence of tumour location and PTV size on the hippocampal dose was investigated with the Mann-Whitney-U-test and Spearman's rank correlation coefficient. Results: The median reduction of the contralateral hippocampus generalized equivalent uniform dose (gEUD) with VMAT was 36 % compared to the original 3D-CRT plans (p < 0.05). Other dose parameters were maintained or improved. The median V30Gy brain could be reduced by 17.9 % (p < 0.05). For VMAT, a parietal and a non-temporal tumour localisation as well as a larger PTV size were predictors for a higher hippocampal dose (p < 0.05). Conclusions: Using VMAT, a substantial reduction of the radiotherapy dose to the contralateral hippocampus for patients with glioblastoma is feasible without compromising other treatment parameters. For larger PTV sizes, less sparing can be achieved. Whether this approach is able to preserve the neurocognitive status without compromising the oncological outcome needs to be investigated in the setting of prospective clinical trials

Underpinning the precautionary principle with evidence: A spatialconcept for guiding wind power development in endangered species’habitats

The precautionary principle is an essential guideline in decision making, particularly for regulating novel developments with unknown or insufficiently proven environmental impact. However, due to the inherent component of uncertainty it has been widely criticized for being “unscientific”, i.e. hindering progress without sufficient evidence. The consequential postulation, that precautionary measures are only justified if the addressed threats are plausible and the measures reasonable, calls for methods to guide action in the face of uncertainty. Using the example of species conservation versus wind-farm construction, an expanding development with hypothesized – but unexplored – effects on our model species the capercaillie (Tetrao urogallus), we present an approach that aims at compensating the lack of knowledge about the threat itself by making best use of the available knowledge about the object at risk. By systematically combining information drawn from population monitoring and spatial modelling with population ecological thresholds, we identified areas of different functionality and importance to metapopulation persistence and connectivity. We integrated this information into a spatial concept defining four area-categories with different implications for wind power development. Highest priority was assigned to areas covering the spatial and functional requirements of a minimum viable population, i.e. sites where the plausibility for threat is highest, the uncertainty as regards importance for the population is lowest, and thus the justification for precautionary measures is strongest. This gradated approach may also enhance public acceptance, as it attempts to avoid either error-minimization bias (i.e. being too restrictive or permissive) the precautionary principle is frequently criticized for

Electrical characterization of alkane monolayers using micro-transfer printing : tunneling and molecular transport

We present the characterization of a decanedithiol monolayer using a technique which is based on micro-transfer printing. This technique allows us to contact molecular monolayers on the scale of 100μm2 without producing electrical shorts between the metallic contacts. This opens the possibility to characterize the behavior of metal molecule contacts on a large ensemble. Electrical measurements of the decanes show that two main transport mechanisms dominate conduction through this monolayer, tunneling between the electrodes and transport through electric states of the molecules. In our setup, tunneling is temperature dependent, because a length change of the molecules causes changes of the effective tunneling width

Hippocampal sparing radiotherapy for glioblastoma patients: a planning study using volumetric modulated arc therapy

Background: The purpose of this study is to investigate the potential to reduce exposure of the contralateral hippocampus in radiotherapy for glioblastoma using volumetric modulated arc therapy (VMAT). Methods: Datasets of 27 patients who had received 3D conformal radiotherapy (3D-CRT) for glioblastoma with a prescribed dose of 60Gy in fractions of 2Gy were included in this planning study. VMAT plans were optimized with the aim to reduce the dose to the contralateral hippocampus as much as possible without compromising other parameters. Hippocampal dose and treatment parameters were compared to the 3D-CRT plans using the Wilcoxon signed-rank test. The influence of tumour location and PTV size on the hippocampal dose was investigated with the Mann-Whitney-U-test and Spearman's rank correlation coefficient. Results: The median reduction of the contralateral hippocampus generalized equivalent uniform dose (gEUD) with VMAT was 36 % compared to the original 3D-CRT plans (p < 0.05). Other dose parameters were maintained or improved. The median V30Gy brain could be reduced by 17.9 % (p < 0.05). For VMAT, a parietal and a non-temporal tumour localisation as well as a larger PTV size were predictors for a higher hippocampal dose (p < 0.05). Conclusions: Using VMAT, a substantial reduction of the radiotherapy dose to the contralateral hippocampus for patients with glioblastoma is feasible without compromising other treatment parameters. For larger PTV sizes, less sparing can be achieved. Whether this approach is able to preserve the neurocognitive status without compromising the oncological outcome needs to be investigated in the setting of prospective clinical trials

Tech & Science @ School. Ein fachpraktisches Handbuch für Technik-Lehrkräfte

Kunstgegenstände & Schmuck herzustellen ist ein urmenschliches Bedürfnis. Aus diesem Kernbereich der Schmuckfertigung und des Drechselns sind die vorliegenden Projektideen entstanden. Die in dieser Handreichung vorgestellten Projektideen sind alle von Lehramtsstudierenden im Fach Technik an den Pädagogischen Hochschulen in Schwäbisch Gmünd und Ludwigsburg in offener und selbstgesteuerter Werkstattarbeit seit dem Sommersemester 2021 entstanden. Die Studierenden haben dabei ihre Idee stets fachpraktisch erprobt und fachdidaktisch in den vorliegenden Erklärfilmen und Schritt für Schritt-Anleitungen ausgearbeitet. Der Projektrahmen umfasst das curricular verankerte, handwerklich bedeutsame Arbeiten mit den grundlegenden Werkstoffen Holz, Metall und Kunststoffen sowie den Bereich der Elektrotechnik und des Mikrocontrolling. Die Umsetzung dieser Projektideen soll unterstützend wirken, um individuelle handwerkliche Kompetenzen zu entdecken, erproben und vertiefen sowie technische Interessensbildung und vorberufliche Orientierung in Schulen fördern. Eine Schlüsselrolle für die Anfertigung der Werkstücke nimmt hierbei das Vorführen und Erklären (modellhaftes Vormachen) der notwendigen Fertigungsschritte durch Experten in Form von Erklärfilmen ein. Die zugrundeliegende didaktische Konzeption lehnt sich an die Kognitive Meisterlehre aus der gewerblich-technischen beruflich orientierten Bildung an (Collins et al., 1989). Das Projekt KunstHandWerk wurde durch eine Kooperation zwischen der PH Ludwigsburg und der PH Schwäbisch Gmünd in Zusammenarbeit mit der Gold- und Silberschmiede-Innung Stuttgart-Heilbronn-Reutlingen initiiert und von TRAFO - dem Netzwerk transferorientierter Lehre in Baden-Württemberg gefördert. Die Projektfortsetzung Tech&Science@School mit der Uhland-Realschule Aalen wurde durch die Vector Stiftung gefördert