bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous acquisition of 4D ultrasound and wireless electromagnetic tracking for in-vivo accuracy validation
Authors: Ipsen Svenja , Bruder Ralf , Worm Esben Schjødt , Hansen Rune , Poulsen Per Rugaard , Høyer Morten , Schweikard Achim 
Published: September 2017

Abstract
Ultrasound is being increasingly investigated for real-time target localization in image-guided interventions. Yet, in-vivo validation remains challenging due to the difficulty to obtain a reliable ground truth. For this purpose, real-time volumetric (4D) ultrasound imaging was performed simultaneously with electromagnetic localization of three wireless transponders implanted in the liver of a radiotherapy patient. 4D ultrasound and electromagnetic tracking were acquired at framerates of 12Hz and 8Hz, respectively, during free breathing over 8 min following treatment. The electromagnetic antenna was placed directly above and the ultrasound probe on the right side of the patient to visualize the liver transponders. It was possible to record 25.7 s of overlapping ultrasound and electromagnetic position data of one transponder. Good spatial alignment with 0.6 mm 3D root-mean-square error between both traces was achieved using a rigid landmark transform. However, data acquisition was impaired since the electromagnetic tracking highly influenced the ultrasound equipment and vice versa. High intensity noise streaks appeared in the ultrasound scan lines irrespective of the chosen frequency (1.7-3.3 MHz, 2/4 MHz harmonic). To allow for target visualization and tracking in the ultrasound volumes despite the artefacts, an online filter was designed where corrupted pixels in the newest ultrasound frame were replaced with non-corrupted pixels from preceding frames. Aside from these artefacts, the recorded electromagnetic tracking data was fragmented and only the transponder closest to the antenna could be detected over a limited period of six consecutive breathing cycles. This problem was most likely caused by interference from the metal holder of the ultrasound probe and was solved in a subsequent experiment using a 3D-printed non-metal probe fixation. Real-time wireless electromagnetic tracking was compared with 4D ultrasound imaging in-vivo for the first time. For stable tracking, large metal components need to be avoided during data acquisition and ultrasound filtering is required.
Bioprinting of three dimensional tumor models: a preliminary study using a low cost 3D printer
Authors: Polley Christian , Mau Robert , Lieberwirth Clemens , Stenzel Jan , Vollmar Brigitte , Seitz Hermann 
Published: September 2017

Abstract
The deep understanding of cancer and tumor genesis, as well as the development of new therapy strategies still remains one of the emerging challenges in modern medicine. To meet these challenges it seems to be absolutely necessary to overcome the drawbacks of the established 2D in vitro models. Especially the missing microenvironment of the tumor, which means the absence of stroma and immune cells, results in a missing cell-cell and cell-stroma interaction as well as disrupted functional communication pathways. Modern 3D culture systems and 3D printing or rather bioprinting technologies attempt to solve this issue and aim to closely mimic natural tumor microenvironment. In this preliminary work we are going to present the first steps of establishing an artificial 3D tumor model utilising a low cost 3D printer. Therefore the printer had been modified with an open-source syringe pump to become a functional bioprinter using viscosity modulated alginate hydrogel. In the first attempts L929 mouse fibroblasts, which are an integral component of natural stroma, had been incorporated into the hydrogel matrix and printed into scaffolds. Subsequent to the printing process the scaffolds got ionically crosslinked with a 5% w/v aqueous solution of CaCl2 to become mechanically stable. After three days of cultivation viability testing had been performed by utilising FDG staining and PET CT to obtain a volumetric viability measurement. The viability imaging showed vital cells homogeneously distributed in the scaffold and therefore stands as an evidence for a working low cost bioprinting process and a successful first step for the development of an artificial 3D tumor model.
Treatment planning for MLC based robotic radiosurgery for brain metastases: plan comparison with circular fields and suggestions for planning strategies
Authors: Schmitt Daniela , El Shafie Rami , Klüter Sebastian , Arians Nathalie , Schubert Kai , Rieken Stefan , Debus Jürgen , Paul Angela 
Published: September 2017

Abstract
To evaluate the possible range of application of the new InCise2 MLC for the CyberKnife M6 system in brain radiosurgery, a plan comparison was made for 10 brain metastases sized between 1.5 and 9cm3 in 10 patients treated in a single fraction each. The target volumes consist of a PTV derived by expanding the GTV by 1mm and were chosen to have diversity in the cohort regarding regularity of shape, location and the structures needed to be blocked for beam transmission in the vicinity. For each case, two treatment plans were optimized: one using the MLC and one using the IRIS-collimator providing variable circular fields. Plan re-quirements were: dose prescription to the 70% isodose line (18 or 20Gy), 100% GTV coverage, ≥98% PTV coverage, undisturbed central high dose region (95% of maximum dose) and a conformity index as low as possible. Plan com-parison parameters were: conformity index (CI), high-dose gradient index (GIH), low-dose gradient index (GIL), total number of monitor units (MU) and expected treatment time (TT). For all cases, clinically acceptable plans could be gen-erated with the following results (mean±SD) for CI, GIH, GIL, MU and TT, respectively for the MLC plans: 1.09±0.03, 2.77±0.26, 2.61±0.08, 4514±830MU and 27±5min and for the IRIS plans: 1.05±0.01, 3.00±0.35, 2.46±0.08, 8557±1335MU and 42±7min. In summary, the MLC plans were on average less conformal and had a shallower dose gradient in the low dose region, but a steeper dose gradient in the high dose region. This is accompanied by a smaller vol-ume receiving 10Gy. A plan by plan comparison shows that usage of the MLC can spare about one half of the MUs and one third of treatment time. From these experiences and results suggestions for MLC planning strategy can be de-duced.
“Medicine 4.0”
Authors: Wolf Bernhard , Scholze Christian 
Published: September 2017

Abstract
Not only in the technological world (“Industry 4.0”), but also in medicine, a paradigmatic change is taking place: We are already on the threshold of “Medicine 4.0”. Molecular biology has long played a leading role in life sciences. Scientists now realise that, with increasing miniaturisation, microelectronic systems downsized to the dimensions of cellular systems will facilitate new therapeutic approaches. But conventional telecommunications systems can also be equipped with sensors and transformed into intelligent medical monitoring devices that can help patients become part of the diagnostic and therapeutic process. This article illustrates development trends that will lead to modern, electronically supported healthcare concepts.
Classifying smoke in laparoscopic videos using SVM
Authors: Alshirbaji Tamer Abdulbaki , Jalal Nour Aldeen , Mündermann Lars , Möller Knut 
Published: September 2017

Abstract
Smoke in laparoscopic videos usually appears due to the use of electrocautery when cutting or coagulating tissues. Therefore, detecting smoke can be used for event-based annotation in laparoscopic surgeries by retrieving the events associated with the electrocauterization. Furthermore, smoke detection can also be used for automatic smoke removal. However, detecting smoke in laparoscopic video is a challenge because of the changeability of smoke patterns, the moving camera and the different lighting conditions. In this paper, we present a video-based smoke detection algorithm to detect smoke of different densities such as fog, low and high density in laparoscopic videos. The proposed method depends on extracting various visual features from the laparoscopic images and providing them to support vector machine (SVM) classifier. Features are based on motion, colour and texture patterns of the smoke. We validated our algorithm using experimental evaluation on four laparoscopic cholecystectomy videos. These four videos were manually annotated by defining every frame as smoke or non-smoke frame. The algorithm was applied to the videos by using different feature combinations for classification. Experimental results show that the combination of all proposed features gives the best classification performance. The overall accuracy (i.e. correctly classified frames) is around 84%, with the sensitivity (i.e. correctly detected smoke frames) and the specificity (i.e. correctly detected non-smoke frames) are 89% and 80%, respectively.
Towards microprocessor-based control of droplet parameters for endoscopic laryngeal adductor reflex triggering
Authors: Fast Jacob Friedemann , Muley Apurva , Kühn Daniela , Meisoll Frederik , Ortmaier Tobias , Jungheim Michael , Ptok Martin , Kahrs Lüder Alexander 
Published: September 2017

Abstract
The so-called Laryngeal Adductor Reflex (LAR) protects the respiratory tract from particle intrusion by quickly approximating the vocal folds to close the free glottal space. An impaired LAR may be associated with an increased risk of aspiration and other adverse conditions. To evaluate the integrity of the LAR, we recently developed an endoscopic prototype for LAR triggering by shooting accelerated droplets onto a predefined laryngeal target region. We now modified the existing droplet-dispensing system to adapt the fluid system pressure as well as the valve opening time to user-chosen values autonomously. This has been accomplished using a microcontroller board connected to a pressure sensor and a mechatronic syringe pump. For performance validation, we designed a measurement setup capable of tracking the droplet along a vertical trajectory. In addition to the experimental setup, the influence of parameters such as system pressure and valve opening time on the micro-droplet formation is presented. Further development will enable the physician to adjust the droplet momentum by setting a single input value on the microcontroller-based setup, thus further increasing usability of the diagnostic device.
Optimal orientation for ionization chambers in MRgRT reference dosimetry
Authors: Pojtinger Stefan , Dohm Oliver S. , Thorwarth Daniela 
Published: September 2017

Abstract
The interest in hybrid systems combining magnetic resonance imaging and medical linear accelerator (MR-Linac) is rapidly increasing due to the clinical availability of different systems. Reference dosimetry is a critical issue for integrating these devices into clinical practice. However, the response of ionization chambers changes according to the distinct orientation of the chamber with respect to the magnetic field. In this study, we have carried out Monte Carlo simulations to identify an optimal orientation for thimble type chambers in MRgRT reference dosimetry. Our findings suggest that an orientation where the chamber axis is parallel to the magnetic field axis should be preferred.
Autologous fibrin glue: automated production and adhesive quality
Authors: Düregger Katharina , Frenzel Sabrina , Eblenkamp Markus 
Published: September 2017

Abstract
Fibrin glue is a two-component adhesive used to stop bleeding, seal wound edges and for scaffolds in tissue engineering. Autologous products result in reduced risk of contamination and immunological responses compared to commercially available fibrin glue. However, reproducibility due to patient dependent sealant properties of autologous fibrin glue preparation is low. In this study a fully automated production process for both the fibrinogen and thrombin component from small blood volumes was developed. The resulting fibrinogen concentration, thrombin activity and sealant properties of the fibrin glue were determined. The fully automated and closed production system proved to be a promising tool for fast and easy production of autologous fibrin glue with an effective adhesive quality.
Agglomeration of magnetic nanoparticles and its effects on magnetic hyperthermia
Authors: Engelmann Ulrich , Buhl Eva Miriam , Baumann Martin , Schmitz-Rode Thomas , Slabu Ioana 
Published: September 2017

Abstract
Magnetic fluid hyperthermia (MFH) is a promising approach for organ-confined tumor treatment. In MFH, magnetic nanoparticles (MNP) are magnetically targeted at the tumor site and heated in an alternating magnetic field. The heat produced by the MNP is used to cause tumor cell death. At the tumor site, MNP bind to the cell membrane and form agglomerates before they are internalized into the intracellular compartments. Intracellular immobilization and the formation of agglomerates influence heating properties of MNP making it difficult to control the local heating inside the tumor. In this study, we investigated MNP agglomerated samples for their heating efficiency. We found an increase in heating of 22 % upon agglomeration. If MNP are additionally immobilized, however, the heating decreases by 30 %. Consequently, due to the binding of bigger MNP agglomerates at cellular level, heating efficiency inside tumors is assumed to decrease.
Remote monitoring in emergency medical services
Authors: Follmann Andreas , Rossaint Rolf , Brokmann Jörg Christian , Beckers Stefan K. , Czaplik Michael 
Published: September 2017

Abstract
An increasing number of missions in emergency medical services and a progressive utilization rate of emergency physicians also require the use of the benefits of telemedicine in prehospital emergency medicine. Through modern technology, such as the transmission of vital data in real time and a secure audio-visual contact, paramedics can be quickly connected to an experienced emergency physician from a distance and supported in diagnostics and therapy of a patient. This tele-emergency services physician is established in the Aachen emergency service since 2014 and has already had numerous successful missions.
A user-specific human-machine interaction strategy for a prosthetic shank adapter
Authors: Stuhlenmiller Florian , Schuy Jochen , Beckerle Philipp , Rinderknecht Stephan 
Published: September 2017

Abstract
For people with lower limb amputation, a user-specific human-machine interaction with their prostheses is required to ensure safe and comfortable assistance. Especially during dynamic turning manoeuvres, users experience high loads at the stump, which decreases comfort and may lead to long-term tissue damage. Preliminary experiments with users wearing a configurable, passive torsional adaptor indicate increased comfort and safety achieved by adaptation of torsional stiffness and foot alignment. Moreover, the results show that the individual preference regarding both parameters depend on gait situation and individual preference. Hence, measured loads in the structure of the prosthesis and subjective feedback regarding comfort and safety during different turning motions are considered in a user-specific human-machine interaction strategy for a prosthetic shank adaptor. Therefore, the interrelations of gait parameters with optimal configuration are stored in an individual preference-setting matrix. Stiffness and foot alignment are actively adjusted to the optimal parameters by a parallel elastic actuator. Two subjects reported that they experienced appropriate variation of stiffness and foot alignment, a noticeable reduction of load at the stump and that they could turn with less effort.
Features for detecting smoke in laparoscopic videos
Authors: Jalal Nour Aldeen , Alshirbaji Tamer Abdulbaki , Mündermann Lars , Möller Knut 
Published: September 2017

Abstract
Video-based smoke detection in laparoscopic surgery has different potential applications, such as the automatic addressing of surgical events associated with the electrocauterization task and the development of automatic smoke removal. In the literature, video-based smoke detection has been studied widely for fire surveillance systems. Nevertheless, the proposed methods are insufficient for smoke detection in laparoscopic videos because they often depend on assumptions which rarely hold in laparoscopic surgery such as static camera. In this paper, ten visual features based on motion, texture and colour of smoke are proposed and evaluated for smoke detection in laparoscopic videos. These features are RGB channels, energy-based feature, texture features based on gray level co-occurrence matrix (GLCM), HSV colour space feature, features based on the detection of moving regions using optical flow and the smoke colour in HSV colour space. These features were tested on four laparoscopic cholecystectomy videos. Experimental observations show that each feature can provide valuable information in performing the smoke detection task. However, each feature has weaknesses to detect the presence of smoke in some cases. By combining all proposed features smoke with high and even low density can be identified robustly and the classification accuracy increases significantly.
Robotic 4D ultrasound solution for real-time visualization and teleoperation
Authors: Al-Badri Mohammed , Ipsen Svenja , Böttger Sven , Ernst Floris 
Published: September 2017

Abstract
Automation of the image acquisition process via robotic solutions offer a large leap towards resolving ultrasound’s user-dependency. This paper, as part of a larger project aimed to develop a multipurpose 4d-ultrasonic force-sensitive robot for medical applications, focuses on achieving real-time remote visualisation for 4d ultrasound image transfer. This was possible through implementing our software modification on a GE Vivid 7 Dimension workstation, which operates a matrix array probe controlled by a KUKA LBR iiwa 7 7-DOF robotic arm. With the help of robotic positioning and the matrix array probe, fast volumetric imaging of target regions was feasible. By testing ultrasound volumes, which were roughly 880 kB in size, while using gigabit Ethernet connection, a latency of ∼57 ms was achievable for volume transfer between the ultrasound station and a remote client application, which as a result allows a frame count of 17.4 fps. Our modification thus offers for the first time real-time remote visualization, recording and control of 4d ultrasound data, which can be implemented in teleoperation.
In-ear photoplethysmography for central pulse waveform analysis in non-invasive hemodynamic monitoring
Authors: Tigges Timo , Rockstroh Jonas , Pielmuş Alexandru , Klum Michael , Feldheiser Aarne , Hunsicker Oliver , Orglmeister Reinhold 
Published: September 2017

Abstract
In recent years, the analysis of the photoplethys-mographic (PPG) pulse waveforms has attracted much research focus. However, the considered signals are primarily recorded at the fingertips, which suffer from reduced peripheral perfusion in situations like hypovolemia or sepsis, rendering waveform analysis infeasible. The ear canal is not affected by cardiovascular centralization and could thus prove to be an ideal alternate measurement site for pulse waveform analysis. Therefore, we developed a novel system that allows for highly accurate photoplethysmographic measurements in the ear canal. We conducted a measurement study in order to assess the signal-to-noise ratio of our developed system Hereby, we achieved a mean SNR of 40.65 dB. Hence, we could show that our system allows for highly accurate PPG recordings in the ear canal facilitating sophisticated pulse waveform analysis. Furthermore, we demonstrated that the pulse decomposition analysis is also applicable to in-ear PPG recordings.
Sub-3mm spatial resolution from a large monolithic LaBr3 (Ce) scintillator
Authors: Liprandi Silvia , Mayerhofer Michael , Aldawood Saad , Binder Tim , Dedes George , Miani Agnese , Schaart Dennis R. , Lozano Ingrid I. Valencia , Parodi Katia , Thirolf Peter G. 
Published: September 2017

Abstract
A Compton camera prototype for ion beam range monitoring via prompt (< 1 ns) gamma detection in hadron therapy is being developed and characterized at the Medical Physics Department of LMU Munich. The system consists of a large (50x50x30 mm3) monolithic LaBr3(Ce) scintillation crystal as absorber component to detect the multi-MeV Compton scattered photons, together with a stack of 6 double-sided silicon strip detectors (DSSSD) acting as scatterer component. Key ingredient of the γ-source reconstruction is the determination of the γ-ray interaction position in the scintillator, which is read out by a 256-fold segmented multi-anode photomultiplier tube (PMT). From simulations an angular resolution of about 1.5o for the photon source reconstruction can be expected for the energy range around 3 – 5 MeV, provided that a spatial resolution of 3 mm can be reached in the absorbing scintillator [1]. Therefore, particular effort was dedicated to characterize this latter property as a function of the γ-ray energy. Intense, tightly collimated 137Cs and 60Co photon sources were used for 2D irradiation scans (step size 0.5 mm) as prerequisite for studying the performance of the “k-Nearest-Neighbors” algorithm developed at TU Delft [2] (together with its variant ”Categorical Average Pattern”, CAP) and extending its applicability into the energy range beyond the original 511 keV. In this paper we present our most recent interaction position analysis in the absorbing scintillator, leading to a considerably improved value for the spatial resolution: systematic studies were performed as a function of the k-NN parameters and the PMT segmentation. A trend of improving spatial resolution with increasing photon energy was confirmed, resulting in the realization of the presently optimum spatial resolution of 2.9(1) mm @1.3 MeV, thus reaching the design specifications of the Compton camera absorber. The specification goal was reached also for a reduced PMT segmentation of 8x8 anode segments (each with 6x6 mm2 active area), thus allowing to reduce the complexity of the signal processing while preserving the performance.
Microfluidic drive for flexible brain implants
Authors: Gopalakrishnaiah Shubratha Koralagundi , Joseph Kevin , Hofmann Ulrich G. 
Published: September 2017

Abstract
Flexible polyimide probes, used for neuronal signal acquisition, are thought to reduce signal deteriorating gliosis, improving the quality of recordings in brain machine interfacing applications. These probes suffer from the disadvantage that they cannot penetrate brain tissue on their own, owing to their limited stiffness and low buckling forces. A microfluidic device as an external micro-drive which aids in the insertion of flexible polyimide neural probes in 0.6% Agarose gel is presented here.