Search results for "hdr"

First Characterization of Novel Silicon Carbide Detectors with Ultra-High Dose Rate Electron Beams for FLASH Radiotherapy

2023

Ultra-high dose rate (UHDR) beams for FLASH radiotherapy present significant dosimetric challenges. Although novel approaches for decreasing or correcting ion recombination in ionization chambers are being proposed, applicability of ionimetric dosimetry to UHDR beams is still under investigation. Solid-state sensors have been recently investigated as a valuable alternative for real-time measurements, especially for relative dosimetry and beam monitoring. Among them, Silicon Carbide (SiC) represents a very promising candidate, compromising between the maturity of Silicon and the robustness of diamond. Its features allow for large area sensors and high electric fields, required to avoid ion r…

Everolimus With Reduced Tacrolimus Improves Renal Function in De Novo Liver Transplant Recipients: A Randomized Controlled Trial

2012

    In a prospective, multicenter, open-label study, de novo liver transplant patients were randomized at day 30±5 to (i) everolimus initiation with tacrolimus elimination (TAC Elimination) (ii) everolimus initiation with reduced-exposure tacrolimus (EVR+Reduced TAC) or (iii) standard-exposure tacrolimus (TAC Control). Randomization to TAC Elimination was terminated prematurely due to a higher rate of treated biopsy-proven acute rejection (tBPAR). EVR+Reduced TAC was noninferior to TAC Control for the primary efficacy endpoint (tBPAR, graft loss or death at 12 months posttransplantation): 6.7% versus 9.7% (-3.0%; 95% CI -8.7, 2.6%; p<0.001 for noninferiority [12% margin]). tBPAR occurred in…

Soziale Integration und deren Bedeutung für die Lebensqualität nach Laryngektomie

2013

Soziale Netzwerke und gesellschaftliche Teilhabe wirken sich im Allgemeinen positiv auf das psychische Befinden aus. Inwiefern Patienten nach einer Kehlkopfentfernung wieder in die Gesellschaft eingebunden werden, ist jedoch wenig untersucht. Ziel der Studie war es, zu prufen, inwieweit Patienten nach einer Laryngektomie sozial integriert sind und ob die soziale Integration mit bestimmten Bereichen der Lebensqualitat zusammenhangt. In einer multizentrischen Studie wurden 161 Patienten ein Jahr nach Laryngektomie befragt. Die soziale Integration wurde anhand eines Index erhoben. Dieser setzt sich aus Fragen zur sozialen Unterstutzung und dem Fragenkomplex zur Einbindung in die Gesellschaft, …

Dosimetric perturbations of a lead shield for surface and interstitial high-dose-rate brachytherapy.

2014

In surface and interstitial high-dose-rate brachytherapy with either (60)Co, (192)Ir, or (169)Yb sources, some radiosensitive organs near the surface may be exposed to high absorbed doses. This may be reduced by covering the implants with a lead shield on the body surface, which results in dosimetric perturbations. Monte Carlo simulations in Geant4 were performed for the three radionuclides placed at a single dwell position. Four different shield thicknesses (0, 3, 6, and 10 mm) and three different source depths (0, 5, and 10 mm) in water were considered, with the lead shield placed at the phantom surface. Backscatter dose enhancement and transmission data were obtained for the lead shields…

Risk assessment of component failure modes and human errors using a new FMECA approach: application in the safety analysis of HDR brachytherapy

2014

Failure mode, effects and criticality analysis (FMECA) is a safety technique extensively used in many different industrial fields to identify and prevent potential failures. In the application of traditional FMECA, the risk priority number (RPN) is determined to rank the failure modes; however, the method has been criticised for having several weaknesses. Moreover, it is unable to adequately deal with human errors or negligence. In this paper, a new versatile fuzzy rule-based assessment model is proposed to evaluate the RPN index to rank both component failure and human error. The proposed methodology is applied to potential radiological over-exposure of patients during high-dose-rate brach…

A generic TG-186 shielded applicator for commissioning model-based dose calculation algorithms for high-dose-rate Ir-192 brachytherapy

2017

PurposeA joint working group was created by the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) with the charge, among others, to develop a set of well-defined test case plans and perform calculations and comparisons with model-based dose calculation algorithms (MBDCAs). Its main goal is to facilitate a smooth transition from the AAPM Task Group No. 43 (TG-43) dose calculation formalism, widely being used in clinical practice for brachytherapy, to the one proposed by Task Group No. 186 (TG-186) for MBDCAs. To do so, in this work a hypothetical, generic high-dose rate (HDR) Ir-19…

Permeability and its effect on the utilization of geothermal energy

2008

Sepsis at ICU admission does not decrease 30-day survival in very old patients : a post-hoc analysis of the VIP1 multinational cohort study

2020

AbstractBackgroundThe number of intensive care patients aged ≥ 80 years (Very old Intensive Care Patients; VIPs) is growing. VIPs have high mortality and morbidity and the benefits of ICU admission are frequently questioned. Sepsis incidence has risen in recent years and identification of outcomes is of considerable public importance. We aimed to determine whether VIPs admitted for sepsis had different outcomes than those admitted for other acute reasons and identify potential prognostic factors for 30-day survival.ResultsThis prospective study included VIPs with Sequential Organ Failure Assessment (SOFA) scores ≥ 2 acutely admitted to 307 ICUs in 21 European countries. Of 3869 acutely admi…

Sul potere della Commissione europea di ritirare una proposta legislativa e sui suoi riflessi sugli equilibri istituzionali nel diritto dell'Unione e…

2015

L'articolo si propone di commentare la sentenza del 14 aprile 2015, nella causa C-409/13, con cui la Corte di Giustizia ha risolto un antico contrasto di tesi giuridiche (e politiche) tra il Consiglio dell’Unione europea e la Commissione europea, avente ad oggetto la questione se quest’ultima possa ritirare una proposta legislativa e, se sì, a quali condizioni e in quali casi. Respingendo il ricorso del Consiglio, la Corte ha risolto il conflitto a favore della Commissione, ma ha anche dato alcune indicazioni riguardo a requisiti di ordine sia procedurale che sostanziale che devono essere rispettati ai fini di un “legittimo” esercizio del potere di ritiro. L'articolo si propone anche di sot…

Efficacy of N-acetylcysteine in the prevention of alcohol relapse-like drinking: Study in long-term ethanol-experienced male rats

2021

Alcohol use disorders are chronic and highly relapsing disorders, thus alcoholic patients have a high rate of recidivism for drug use even after long periods of abstinence. The literature points to the potential usefulness of N-acetylcysteine (NAC) in the management of several substance use disorders probably due to its capacity to restore brain homeostasis of the glutamate system disrupted in addiction. However, there is little evidence in the case of alcohol. The aim of this study was to explore the potential anti-relapse efficacy of NAC using the alcohol deprivation effect (ADE) model in long-term experienced rats. Two experiments were performed in male Wistar rats to: (a) test the effic…