bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of lung tissue dynamics in artificially ventilated rats with optical coherence tomography
Authors: Schnabel Christian , Gaertner Maria , Koch Edmund 
Published: September 2017

Abstract
Diseases of lung tissue and the airways become a major task for medical care and health care systems in modern industrial countries in the future. Suitable treatment methods and strategies for lung support and artificial ventilation are of dare need. Besides the obvious importance as life-saving intervention, the effects of usually used over-pressure ventilation onto the sensitive alveolar tissue are insufficiently understood. Therefore, it is of great interest to characterize lung tissue during artificial ventilation at the alveolar level. Those measurements can be used to link micromechanics of alveolar structures to mechanical properties of the whole lung like compliance and resistance measured at the ventilator device. This can be done only in animal experiments due to the fact that imaging techniques used in human diagnostics like CT or MRT fail to resolve alveolar tissue structures. The disadvantage of high-resolution techniques like optical coherence tomography (OCT) or intravital microscopy (IVM) is the need of a surgical access to the lung due to the limitation in penetration depth of these techniques. Furthermore, imaging dynamic processes with high-resolution imaging techniques during uninterrupted artificial ventilation is a challenging task. In this study, we present a measurement setup for combined imaging of conventional pressure-controlled ventilated rats and the visualization of volume changes of alveolar structures during one cycle of breath. A custom-made OCT system in combination with a triggered scanning algorithm was used to acquire time-resolved 3D OCT image data. Furthermore, this system was combined with a self-adapting autofocus function for intravital microscopy to track the lung surface keeping the tissue in focal plane. The combination of new dynamic measurement modes for OCT and IVM allows new insights into alveolar tissue and will promote the understanding of mechanical behavior during artificial ventilation.
Measurement of the energy spectrum of secondary neutrons in a proton therapy environment
Authors: Dommert Martin , Reginatto Marcel , Zboril Miroslav , Fiedler Fine , Helmbrecht Stephan , Enghardt Wolfgang , Lutz Benjamin 
Published: September 2017

Abstract
Measurement of the energy spectrum of secondary neutrons were carried out at the OncoRay Proton Therapy facility in Dresden, following an approach originating in neutron metrology which is well suited for both the characterization of secondary neutron fields at proton therapy facilities and the validation of Monte Carlo simulations. For the experiment, a brass target was placed in the proton beam and Bonner spheres measurements were made at a distance of 2 m from the target and at different angles, 15° to 120°, with respect to the incoming proton beam. The measured spectra were compared to Monte Carlo simulations.
Deep convolutional neural network approach for forehead tissue thickness estimation
Authors: Manit Jirapong , Schweikard Achim , Ernst Floris 
Published: September 2017

Abstract
In this paper, we presented a deep convolutional neural network (CNN) approach for forehead tissue thickness estimation. We use down sampled NIR laser backscattering images acquired from a novel marker-less near-infrared laser-based head tracking system, combined with the beam’s incident angle parameter. These two-channel augmented images were constructed for the CNN input, while a single node output layer represents the estimated value of the forehead tissue thickness. The models were – separately for each subject – trained and tested on datasets acquired from 30 subjects (high resolution MRI data is used as ground truth). To speed up training, we used a pre-trained network from the first subject to bootstrap training for each of the other subjects. We could show a clear improvement for the tissue thickness estimation (mean RMSE of 0.096 mm). This proposed CNN model outperformed previous support vector regression (mean RMSE of 0.155 mm) or Gaussian processes learning approaches (mean RMSE of 0.114 mm) and eliminated their restrictions for future research.
Prompt gamma spectroscopy for range control with CeBr3
Authors: Martins Paulo Magalhaes , Dal Bello Riccardo , Rinscheid Andreas , Roemer Katja , Werner Theresa , Enghardt Wolfgang , Pausch Guntram , Seco Joao 
Published: September 2017

Abstract
The ultimate goal of radiotherapy using external beams is to maximize the dose delivered to the tumor while minimizing the radiation given to surrounding healthy critical organs. Prompt Gamma Spectroscopy (PGS) has been proposed for range control of particle beams along with the determination of the elemental composition of irradiated tissues. We aim at developing a PGS system for the German Cancer Research Center – DKFZ that takes advantage of the superior selectivity of Helium and Carbon beams accelerated at the Heidelberg Ion-Beam Therapy Center. Preliminary tests with protons accelerated with an IBA C230 cyclotron located at the Universitäts Protonen Therapie Dresden were performed at OncoRay – National Center for Radiation Re-search in Oncology. We present results obtained with a PGS system composed of CeBr3 detectors (Ø 2’’ × 2’’) and (Ø 1.5’’ × 3’’) coupled to a Hamamatsu R13089 photomulti-plier tube and plugged to a Target U100 Spectrometer. Such system provides accurate time-of-flight measurements to increase the signal-to-noise ratio relative to neutron-induced background. First measurements resulted from the irradiation of PMMA and water phantoms, and graphite and aluminum bricks. Several PG energy lines ranging from 0.511 MeV up to 8 MeV were identified and compared with reference re-sults. Two further experiments consisted in irradiating PMMA phantoms in a slit- and semi-collimated configuration with mono-energetic proton beams of 165 MeV and 224 MeV, respectively. Results acquired by means of trans-versal PGS at different phantom depths, ranging from 6 cm before the Bragg peak (BP) to 3.5 cm beyond the BP in 5 mm steps with a 1 cm slit collimation (tungsten) showed a slight decrease of PG yields after the BP. Similar measurements with a semi-opened collimation configuration demonstrated a steeper decrease of PG yields after the BP.
Investigation of intracochlear dual actuator stimulation in a scaled test rig
Authors: van Drunen Wouter J. , Lachheb Sarra Kacha , Glukhovskoy Anatoly , Twiefel Jens , Wurz Marc C. , Lenarz Thomas , Rau Thomas S. , Majdani Omid 
Published: September 2017

Abstract
For patients suffering from profound hearing loss or deafness still having respectable residual hearing in the low frequency range, the combination of a hearing aid with a cochlear implant results in the best quality of hearing perception (EAS – electric acoustic stimulation). In order to optimize EAS, ongoing research focusses on the integration of these stimuli in a single implant device. Within this study, the performance of piezoelectric actuators, particularly the dual actuator stimulation, in a scaled uncoiled test rig was investigated.
A new device for vein localization and effect of application of disinfectant spray on its efficiency
Authors: Dreyer Jan , Huenges Katharina , Cremer Jochen , Haneya Assad 
Published: September 2017

Abstract
A functional device was developed to immediately show the localization of veins by detecting a temperature increase on the skin directly above them. Our new idea, compared to other developments, is the comparison of temperatures between a small, ideally punctiform, skin area, and a larger circularly surrounding area. This is realized by two infrared temperature sensors, one with a small field of view, and the other one with a larger field of view. The position of the vein is indicated by two laser modules, which beams cross in one spot, when the device is held in a defined distance to the skin. If the device is held over a vein, the laser spot lightens up. The device was tested in ten study participants. Cooling of the skin by disinfectant spray prior to the measurements increases the temperature gradient and thereby improves the efficiency of the device. Temperature profiles of four skin areas of each study participant were measured before and one minute after application of disinfectant spray. After application of disinfectant spray, a temperature difference of more than 0.3 K between a measuring point above a vein and points 15 mm next to this could be found in 36 out of 40 measurements (90%), compared to 26 out of 40 (65%) before disinfection. The mean temperature gradient could be increased from 0.476 K to 1.03 K (p < 0.001).
Expansion characteristics of coronary stents in focal stenoses
Authors: Schmidt Wolfram , Schmitz Klaus-Peter , Behrens Peter , Grabow Niels , Ince Hüseyin , Öner Alper 
Published: September 2017

Abstract
The presented experimental in vitro approach was designed to assess the expansion behavior of stent systems in a resistant focal stenosis model with respect to a potential dog-boning effect. Five different stent systems (nominal diameter 3.0 mm) were investigated. The focal stenosis was simulated by a stainless steel tube (ID ≤ 1.20 mm). Stent expansion was performed using a proprietary test device consisting of a test chamber with 37 °C water, 2-axis laser scanner and a pressure controller.
All stents could be properly expanded up to recommended maximum pressure (RBP). At nominal pressure (NP) maximum diameters ranged from 2.923 to 3.560 mm while at RBP the maximum diameters were 3.391 to 3.984 mm. Only minimal flaring of stent struts from the expanded balloon was observed. None of the stent systems failed under the extremely high stress at the edges of the focal stenosis.
A new method for effective dose calculation based on the ambient dose height distribution
Authors: Liebmann Mario , Sangarapillai Niroojiny , Poppe Björn , von Boetticher Heiner 
Published: September 2017

Abstract
The realistic determination of effective dose of the staff in diagnostic radiology has been a challenge both for personal dosimetry and ambient dose measurement. A model for dosimetry of occupational exposure is presented that allows direct determination of effective dose from measured or even manufacturer given ambient dose distribution in front of the personnel. This model considers a wide range of radiation energies, different radiation protection situations, and gender effects.
Video magnification for intraoperative assessment of vascular function
Authors: Naber Ady , Nahm Werner 
Published: September 2017

Abstract
In neurovascular surgery the intraoperative fluorescence angiography has been proven to be a reliable contact-free optical imaging technique to visualize vascular blood-flow. This angiography is obtained by injecting a fluorescence dye e.g. indocyanine green and using an infrared camera system to visualize the fluorescence inside the vessel. Obviously this requires a medical approved dye and an additional camera setup and therefore generating risks and costs. Hence, the aim of our research is to develop a comparable technique for assessing the vascular function. This approach would not require dye nor an additional infrared camera setup. It is achieved by first preprocessing the video data of a camera that records only the visible spectrum and then filter it spatially as well as temporally. The prepared data is again processed to extract information about the vascular function and visualize it. This method would provide an option to compute and visualize the vascular function using the data recorded in the visible spectrum by the surgical microscopes. Given this contact-free optical imaging system, physiological information can be easily provided to the surgeon without an additional setup. In the case of comparable results with the state-of-the-art, this technique provides a straightforward optical intraoperative angiography. Further no drug approval is needed since no dye is injected.
Imaging in hearing using radiotracers
Authors: Berding Georg , Lenarz Thomas 
Published: September 2017

Abstract
Radiotracers offer unique options for brain imaging of functional and molecular processes related to hearing. Such imaging can be applied in a broad spectrum of situations from preclinical research to clinical patient care. Functional imaging to assess activation in brain regions and networks involved in auditory processing uses markers of blood flow or energy-metabolism in well-defined conditions with and without auditory stimulation. Molecular markers can be used in hearing research for example to study changes in inhibitory neurotransmission systems related to hearing loss. For imaging either positron emission tomography (PET) or single-photon emission computed tomography (SPECT) are employed. Data analysis can encompasses voxel-wise statistical analysis of activation and calculation of quantitative parameters like receptor binding-potentials based on bio-kinetic modeling. Functional imaging has been frequently used in the context of auditory implantation. Before implantation it aims to assess intactness of the central auditory pathway and prognosis. After implantation it is used to improve understanding of the outcome with respect to auditory function and finally speech understanding, e.g. by measuring correlates of central auditory processing and neuroplasticity.
ZebrafishMiner: an open source software for interactive evaluation of domain-specific fluorescence in zebrafish
Authors: Reischl Markus , Bartschat Andreas , Liebel Urban , Gehrig Jochen , Müller Ference , Mikut Ralf 
Published: September 2017

Abstract
High-throughput microscopy makes it possible to observe the morphology of zebrafish on large scale to quantify genetic, toxic or drug effects. The image acquisition is done by automated microscopy, images are evaluated automatically by image processing pipelines, tailored specifically to the requirements of the scientific question. The transfer of such algorithms to other projects, however, is complex due to missing guidelines and lack of mathematical or programming knowledge. In this work, we implement an image processing pipeline for automatic fluorescence quantification in user-defined domains of zebrafish embryos and larvae of different age. The pipeline is capable of detecting embryos and larvae in image stacks and quantifying domain activity. To make this protocol available to the community, we developed an open source software package called „ZebrafishMiner“ which guides the user through all steps of the processing pipeline and makes the algorithms available and easy to handle. We implemented all routines in an MATLAB-based graphical user interface (GUI) that gives the user control over all image processing parameters. The software is shipped with a manual of 30 pages and three tutorial datasets, which guide the user through the manual step by step. It can be downloaded at https://sourceforge.net/projects/scixminer/.
Optimization of diffusion imaging for multiple target regions using maximum likelihood estimation
Authors: Bielak Lars , Bock Michael 
Published: September 2017

Abstract
In this work a procedure is proposed to determine an optimal distribution of b-values in diffusion MRI measu-rements. The optimization procedure uses a method of Maximum Likelihood Estimation which can operate on any given number of b-values, values of the diffusion coefficients (ADC) and measurement noise strengths. Optimal b-values are calculated for white and gray brain matter. An optimi-zation for more than one ADC is demonstrated using multiple target values.
Clinical utility of an endorectal MRI-guided prostate probe: preliminary examinations
Authors: Tödter Julia , Gerken Sarah , Wegener Hans-Peter , Beging Stefan , Ziemons Karl 
Published: September 2017

Abstract
Prostate cancer (PCa) is one of the most common cancer diseases in men in the western countries [1]. Besides the palpation, and the amount of prostate-specific-antigen’s (PSA) inside the blood, the current diagnostic imaging technologies are not appropriate. Early diagnosis defining the exact tumor location, spread and margins could make efficient targeted biopsies and image-guided surgery. A multimodal imaging technique containing a transmit-receive surface coil for anatomical MR imaging, a (S)PET detector module, consisting of silicon photomultipliers (SiPM), for functional imaging and an ultrasound (US) probe are placed as close as possible to the prostate designed as an endorectal tube to increase sensitivity and spatial resolution. All materials that are used are non-magnetic. Advantages of the SiPM are diversified, like non-sensitive to magnetic fields, higher gain (105–106) than standard avalanche photodiodes (APD), good timing properties and compactness. The PET detector should reach approximately 1mm3 spatial resolution together with 60ps FWHM Time-of-Flight resolution and a high efficiency to reduce scanning time and injected dose. A home-made transmit-receive coil surrounding the PET module improves signal-to-noise-ratio (SNR) with respect to standard coils will be present. The system will be used as a MRI-insert and be able to visualize anatomic and metabolic information together. The US-probe is guiding examination for correct overlapping of the multimodal images. This procedure will save time, costs and the need of co-registration. By combining all advantages of each system, it will necessarily update the non-invasive treatment of PCa. The system is adapted and tested to a 3 Tesla MR scanner called Trio A Tim system and Allegra system from the company Siemens healthcare with a larmor frequency of 123.2 MHz and an input of 50 Ω free from artifacts. First results on homogeneity of the transmit-receive coil will be presented. Preliminary measurements showing the proposed device is challenging but feasible.
Influence of a transverse magnetic field on the dose deposited by a 6 MV linear accelerator
Authors: Richter Sebastian , Pojtinger Stefan , Mönnich David , Dohm Oliver S. , Thorwarth Daniela 
Published: September 2017

Abstract
An integrated system of a linear accelerator and a magnetic resonance imaging (MRI) device may provide real-time imaging during radiotherapy treatments. This work investigated changes affecting the dose deposition caused by a magnetic field (B-field) transverse to the beam direction by means of Monte Carlo simulations. Two different phantoms were used: A water phantom (Ph1) and a water-air phantom (Ph2) with a 4-2-4 cm water-air-water cross section. Dose depositions were scored for B-field values of 0 T, 0.35 T, 0.5 T, 1.5 T, 3 T and 5 T. Beams were based on a precalculated photon spectrum taken from an earlier simulated Elekta 6 MV FFF accelerator. All lateral profiles in Ph1 showed a Lorentz force driven shift w.r.t. the B-field strength, presenting a steeper penumbra in the shift's direction. Depositions were shifted up to 0.3 cm for 5 T, showing a constant central axis plateau-dose or an increase by 2.3 % for small fields. Depth-dose curves in Ph1 showed a shift of the dose maximum towards the beam entrance direction for increasing B-field of up to 1.1 cm; the maximum dose was increased by 6.9 %. In Ph2, an asymmetric dose increase by up to 36.9 % was observed for 1.5 T at the water-air boundary, resulting from the electron return effect (ERE). In our scenario, B-field dependent dose shifts and local build-ups were observed, which consequently affect the resulting dose distribution and need to be considered in magnetic resonance guided radiotherapy treatment planning.
Comparative investigation of beam quality index Q on flattening filter and flattening filter free 6 and 15 MV photon beams of an medical linear accelerator
Authors: Schaks Michael , Zähle Johannes , Janich Martin , Hübsch Patrick , Homonnay Nico , Gerlach Reinhard 
Published: September 2017

Abstract
An Elekta Synergy LINAC was used to investigate the beam quality index Q and the beam quality correction factor kQ, which is used for absolute dosimetry, in off-axis photon fields. It was found that the beam quality index Q of the photon energies with flattening filter decreases with increasing distance to the central axis, at 6 MV by 4.27% and at 15 MV by 3.98% inside a range of 15 cm off-axis. The beam quality index for flattening filter free photon fields also decreases with increasing distance to the central axis. In this case Q changed only by 1.01% inside the above range.
Comparison of pressure reconstruction approaches based on measured and simulated velocity fields
Authors: Manthey Samuel , Voß Samuel , Roloff Christoph , Stucht Daniel , Thévenin Dominique , Janiga Gábor , Berg Philipp 
Published: September 2017

Abstract
The pressure drop over a pathological vessel section can be used as an important diagnostic indicator. However, it cannot be measured non-invasively. Multiple approaches for pressure reconstruction based on velocity information are available. Regarding in-vivo data introducing uncertainty these approaches may not be robust and therefore validation is required. Within this study, three independent methods to calculate pressure losses from velocity fields were implemented and compared: A three dimensional and a one dimensional method based on the Pressure Poisson Equation (PPE) as well as an approach based on the work-energy equation for incompressible fluids (WERP). In order to evaluate the different approaches, phantoms from pure Computational Fluid Dynamics (CFD) simulations and in-vivo PC-MRI measurements were used. The comparison of all three methods reveals a good agreement with respect to the CFD pressure solutions for simple geometries. However, for more complex geometries all approaches lose accuracy. Hence, this study demonstrates the need for a careful selection of an appropriate pressure reconstruction algorithm.
Comparison of the effectiveness of different antimicrobial surface technologies
Authors: Buhl Sebastian , Käs Sebastian , Stich Alexander , Gruber Sabine , Bulitta Clemens 
Published: September 2017

Abstract
The risk of infection via microbiologically contaminated surfaces has already been demonstrated by other publications. In this work two different antibacterial surface technologies transition metalloacids (AMiSTec) and TiO2/AgNO3 (Health Complete) were compared regarding feasibility as well as their advantages and disadvantages. The examination of the antimicrobial activity was assessed according to the JIS Z 2801. We could demonstrate that all of our tested samples showed a strong antimicrobial activity (>log 3 germ reduction) in the JIS experiments. Furthermore this strong antibacterial effect could be shown already after <30min incubation and at low light intensity (approx. 300 Lux) for the TiO2/AgNO3 samples. Both technologies provide a high potential for an improved infection control for example in a high risk environment like operation rooms or intensive care units.