82 results match your criteria: "University of Applied Sciences Giessen[Affiliation]"

: Nuclear fragmentation generates a diverse dosimetric environment in the path ofC ion beams. Concise parametrization of the beam's composition is paramount for determining key correction factors in clinical dosimetry. This study sets out to provide such a parametrization based on detailed Monte Carlo simulations of clinically relevantC beams.

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Ionizing radiation and skin cancer - a review of current evidence.

J Radiol Prot

September 2024

Epidemiology and Biostatistics, Medizinische Hochschule Brandenburg CAMPUS GmbH, Fehrbelliner Straße 38, Neuruppin, 16816, GERMANY.

Cancer of the skin represents a challenge for radiological protection, as it is very common and involves the largest organ of the human body, which is exposed to environmental stress, including ionizing radiation. The most common subtypes, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) have very low mortality. Current consideration of skin cancer in radiological protection is mainly based on data from the 1990s, which indicate that BCC may be induced by ionizing radiation, SCC is only weakly associated with ionizing radiation, and malignant melanoma (MM) is not considered as ionizing radiation-induced.

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Particle therapy (PT) represents a significant advancement in cancer treatment, precisely targeting tumor cells while sparing surrounding healthy tissues thanks to the unique depth-dose profiles of the charged particles. Furthermore, their linear energy transfer and relative biological effectiveness enhance their capability to treat radioresistant tumors, including hypoxic ones. Over the years, extensive research has paved the way for PT's clinical application, and current efforts aim to refine its efficacy and precision, minimizing the toxicities.

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Organization and operation of multi particle therapy facilities: the Marburg Ion-Beam Therapy Center, Germany (MIT).

Health Technol (Berl)

May 2024

Marburg Ion-Beam Therapy Center (MIT), Department of Radiotherapy and Radiation Oncology, Marburg University Hospital, Albrecht-Kossel-Strasse, Marburg, 35043 Germany.

Purpose: The Marburg Ion-Beam Therapy Center (MIT) is one of two particle therapy centers in Germany that enables the treatment of patients with both protons and carbon ions. The facility was build by Siemens Healthineers and is one of only two centers worldwide built by Siemens (Marburg, Germany and Shanghai, China). The present report provides an overview of technical and clinical operations as well as research activities at MIT.

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Objective: To assess the effect of the toothbrush handle on video-observed toothbrushing behaviour and toothbrushing effectiveness.

Methods: This is a randomized counterbalanced cross-over study. N = 50 university students and employees brushed their teeth at two occasions, one week apart, using either a commercial ergonomically designed manual toothbrush (MT) or Brushalyze V1 (BV1), a manual toothbrush with a thick cylindrical handle without any specific ergonomic features.

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Aim: Archaeological objects are often recovered in blocks since highly porous materials and unstable and highly decayed objects cannot always be uncovered undamaged or time and resources for classic uncovering are lacking. Therefore, clinical computed tomography (CT) combined with freely available software solutions should be tested as a simple and fast method for visualizing and analyzing archaeological finds as an alternative to time-consuming restoration.

Materials And Methods: As an example, a block with a shield boss was selected from a block excavation and examined by means of CT.

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Monte Carlo calculated beam quality correction factors for high energy electron beams.

Phys Med

January 2024

Institute of Medical Physics and Radiation Protection, University of Applied Sciences Giessen (THM), Wiesenstraße 14, Giessen, 35390, Germany. Electronic address:

Purpose: As the dosimetry protocol TRS 398 is being revised and the ICRU report 90 provides new recommendations for density correction as well as the mean ionization energies of water and graphite, updated beam quality correction factors k are calculated for reference dosimetry in electron beams and for independent validation of previously determined values.

Methods: Monte Carlo simulations have been performed using EGSnrc to calculate the absorbed dose to water and the dose to the active volumes of ionization chambers SNC600c, SNC125c and SNC350p (all Sun Nuclear, A Mirion Medical Company, Melbourne, FL). Realistic clinical electron beam spectra were used to cover the entire energy range of therapeutic electron accelerators.

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Background: Hemorrhage is one of the main causes of death in trauma. Critical bleeding in patients needs to be detected as soon as possible to save the patient. Drones are gaining increasing importance in emergency services and can support rescue forces in accident scenarios such as a mass casualty incident.

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Background: Atherosclerosis forms the pathological basis for the development of cardiovascular disease. Since pathological processes initially develop without clinically relevant symptoms, the identification of early markers in the subclinical stage plays an important role for initiating early interventions. There is evidence that regulatory T cells (Tregs) are involved in the development of atherosclerosis.

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Inpatient rehabilitation is common in Germany to improve return-to-work outcomes. The objective of this systematic scoping review was to identify factors associated with return-to-work outcomes in musculoskeletal, psychological and oncological health conditions to improve tailoring of rehabilitation therapies. A search was completed in Embase, Medline, PsycInfo and AMED until May 2023 for articles investigating inpatient rehabilitation including working-age patients with oncological, musculoskeletal, or psychological diseases using a quantitative design and reporting factors associated with return-to-work outcomes.

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Cross-reactive MHC class I T cell epitopes may dictate heterologous immune responses between respiratory viruses and food allergens.

Sci Rep

September 2023

Institute of Laboratory Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), Philipps University Marburg, German Center for Lung Research (DZL), 35043, Marburg, Germany.

Respiratory virus infections play a major role in asthma, while there is a close correlation between asthma and food allergy. We hypothesized that T cell-mediated heterologous immunity may induce asthma symptoms among sensitized individuals and used two independent in silico pipelines for the identification of cross-reactive virus- and food allergen- derived T cell epitopes, considering individual peptide sequence similarity, MHC binding affinity and immunogenicity. We assessed the proteomes of human rhinovirus (RV1b), respiratory syncytial virus (RSVA2) and influenza-strains contained in the seasonal quadrivalent influenza vaccine 2019/2020 (QIV 2019/2020), as well as SARS-CoV-2 for human HLA alleles, in addition to more than 200 most common food allergen protein sequences.

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It was recently discovered that water and PMMA emit a weak luminescence signal when irradiated with protons within the clinically used energy range. This could offer a fast approach for range measurements in water. However, a complete explanation or investigation on the origin of the signal has not been published.

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Background: Very low birth weight (VLBW) infants on noninvasive ventilation (NIV) experience frequent fluctuations in oxygen saturation (SpO2) that are associated with an increased risk for mortality and severe morbidities.

Methods: In this randomized crossover trial, VLBW infants (n = 22) born 22+3 to 28+0 weeks on NIV with supplemental oxygen were allocated on two consecutive days in random order to synchronized nasal intermittent positive pressure ventilation (sNIPPV) and nasal high-frequency oscillatory ventilation (nHFOV) for 8 h. nHFOV and sNIPPV were set to equivalent mean airway pressure and transcutaneous pCO2.

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Background: The integration of magnetic resonance tomography into clinical linear accelerators provides high-contrast, real-time imaging during treatment and facilitates online-adaptive workflows in radiation therapy treatments. The associated magnetic field also bends the trajectories of charged particles via the Lorentz force, which may alter the dose distribution in a patient or a phantom and affects the dose response of dosimetry detectors.

Purpose: To perform an experimental and Monte Carlo-based determination of correction factors , which correct the response of ion chambers in the presence of external magnetic fields in high-energy photon fields.

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Purpose: Multi-axis ionization chamber arrays can be used for quality assurance (QA) and measurement of linear accelerator (linac) specific data. In this work, the ability of the IC Profiler (Sun Nuclear Corp., Melbourne, Florida) detector array to measure the photon beam quality specifier %dd(10) and TPR was investigated.

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Biofilms and their analysis are increasingly attracting the attention of the scientific community due to the immense importance and impact of biofilms in various natural, technical and medical fields. For these purposes, an optimized and extended antibiofilm assay system based on the Calgary Biofilm Device (MBEC Assay® system) consisting of microtiter plate and PCR tubes was established. Its implementation was used to study the growth characteristics of the sessile phenotype of exposed to antimicrobial peptides.

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Determination of the dose rate around a HDR Ir brachytherapy source with the microDiamond and the microSilicon detector.

Z Med Phys

November 2023

Division of Medical Physics, Department of Radiation Oncology, Medical Center, Faculty of Medicine, University of Freiburg, Germany; German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany.

Purpose: To employ the microDiamond and the microSilicon detector (mDD and mSD, both PTW-Freiburg, Germany) to determine the dose rate around a HDR Ir brachytherapy source (model mHDR-v2r, Elekta AB, Sweden).

Methods: The detectors were calibrated with a Co beam at the PTW Calibration Laboratory. Measurements around the Ir source were performed inside a PTW MP3 water phantom.

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Purpose: Monte Carlo simulations are crucial for calculating magnetic field correction factors k for the dosimetry in external magnetic fields. As in Monte Carlo codes the charged particle transport is performed in straight condensed history (CH) steps, the curved trajectories of these particles in the presence of external magnetic fields can only be approximated. In this study, the charged particle transport in presence of a strong magnetic field B→ was investigated using the Fano cavity test.

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The fast calibration model for dosimetry with an electronic portal imaging device.

J Appl Clin Med Phys

November 2022

Institute of Medical Physics and Radiation Protection, University of Applied Sciences Giessen, Wiesenstrasse, Giessen, Germany.

Purpose: The aim of this study was to develop an algorithm that corrects the image of an electronic portal imaging device (EPID) of a linear accelerator so that it can be used for dosimetric purposes, such as in vivo dosimetry or quality assurance for photon radiotherapy. For that purpose, the impact of the field size, phantom thickness, and the varying spectral photon distribution within the irradiation field on the EPID image was investigated.

Methods: The EPID measurements were verified using reference measurements with ionization chambers.

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Hemicelluloses are an abundant biopolymer resource with interesting properties for applications in coatings and composite materials. The objective of this investigation was to identify variables of industrially relevant extraction processes that increase the purity of hemicelluloses extracted from fruit residues. Our main finding is that extraction with subcritical water, followed by precipitation with alcohol, can be adjusted to yield products with a purity of at least 90%.

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Size-specific dose estimate ($\mathbf{SSDE}$) index appears to be more suitable than the commonly used volume computed tomography dose index ($\mathbf{C}{\mathbf{TDI}}_{\mathbf{vol}}$) to estimate the dose delivered to the patient during a computed tomography (CT) scan. We evaluated whether an ${\mathbf{SSDE}}_{\mathbf{BMI}}$ can be determined from the patient's body mass index ($\mathbf{BMI}$) with sufficient reliability in the case that a $\mathbf{SSDE}$ is not given by the CT scanner. For each of the three most used examination types, CT examinations of 50 female and 50 male patients were analyzed.

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Purpose: Although several studies provide data for reference dosimetry, the SNC600c and SNC125c ionization chambers (Sun Nuclear Corporation, Melbourne, FL) are in clinical use worldwide for which no beam quality correction factors k are available. The goal of this study was to calculate beam quality correction factors k for these ionization chambers according to dosimetry protocols TG-51, TRS 398 and DIN 6800-2.

Methods: Monte Carlo simulations using EGSnrc have been performed to calculate the absorbed dose to water and the dose to air within the active volume of ionization chamber models.

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In particle therapy of lung tumors, modulating effects on the particle beam may occur due to the microscopic structure of the lung tissue. These effects are caused by the heterogeneous nature of the lung tissue and cannot be completely taken into account during treatment planning, because these micro structures are too small to be fully resolved in the planning CT. In several publications, a new material parameter called modulation power () was introduced to characterize the effect.

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Craniofacial anomaly including deformational plagiocephaly as a result of deformities in head and facial bones evolution is a serious health problem in newbies. The impact of such condition on the affected infants is profound from both medical and social viewpoint. Indeed, timely diagnosing through different medical examinations like anthropometric measurements of the skull or even Computer Tomography (CT) image modality followed by a periodical screening and monitoring plays a vital role in treatment phase.

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