Now showing 1 - 10 of 18
  • Publication
    Instrument calibration for a camera based surgical navigation system
    ( 2017)
    Katanacho, Manuel
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    ; ;
    Melnik, Steffen
    In this abstract, we present a system for mounting a single-camera to arbitrary surgical instruments and calibrating its position relative to the instrument. The camera is used for surgical navigation and can be covered with sterile foil due to a connection mechanism to the mounting system with magnets. The calibration of the cameras' position relative to the instruments' tool center point is done by a checkerboard based calibration procedure and using defined pivot points.
  • Publication
    Three-dimensional TV minimization algorithm using total curvature
    ( 2014)
    Wisotzky, E.
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    Käseberg, M.
    ;
    Keeve, E.
  • Publication
    Craniomaxillofacial surgery planning based on 3D models derived from Cone-Beam CT data
    ( 2013)
    Adolphs, Nicolai
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    Liu, Weichen
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    Keeve, Erwin
    ;
    Hoffmeister, Bodo
    Introduction: Individual planning of complex maxillofacial corrections may require 3D models which can be manufactured based on DICOM datasets. The gold standard for image acquisition is still high-resolution multi-slice computed tomography (MSCT). However, appropriate datasets for model fabrication can be acquired by modern Cone-Beam CT (CBCT) devices that have been developed specifically for maxillofacial imaging. The clinical utility of individual models fabricated on the basis of CBCT datasets was assessed. Methods: In five patients affected by different deficiencies of the maxillofacial skeleton, preoperative imaging was performed with ILUMA CBCT. Segmentation of hard tissues was performed manually by thres holding. Corresponding STL datasets were created and exported to an industrial service provider (Alphaform, Munich, Germany) specializing in rapid prototyping, and 3D models were fabricated by the selective laser sintering (SLS) technique. For variance analysis, landmark measurements were performed on both virtual and 3D models. Subsequently, maxillofacial surgery was performed according to the model-based planning. Results: All CBCT-based DICOM datasets could be used for individual model fabrication. Detailed reproduction of individual anatomy was achieved and a topographic survey showed no relevant aberrance between the virtual and real models. The CBCT-based 3D models were therefore used for planning and transfer of different maxillofacial procedures. Conclusions: CBCT-based datasets can be used for the fabrication of surgical 3D models if the correct threshold is set. Preoperative workflow and patient comfort is improved in terms of the fast-track concept by using this in-house imaging technique.
  • Publication
    A novel concept of integrated process chain for surgical splint generation based on clinical assessment in orthognathic surgery
    ( 2013)
    Liu, W.
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    Holzwarth, F.
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    Adolphs, N.
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    Hoffmeister, B.
    ;
    Keeve, E.
    A surgical splint with its individual negative dental impression defines a critical workflow-step in orthognathic surgery. It transfers the planning into a physical guide and in the same way also all the planning error and system deviation. Knowledge from our pioneer study with phantoms and ten clinic cases builds the fundament of this novel concept. It combines optimization in input modality, data preprocessing, GUI, user-interface, virtual planning and splint Generation. Our goal is to establish an integrated process chain that meets the need of the hectic clinical work. Future work is to realize this concept and a gradual adaption of this integrated process line for other patient specific implant planning application.
  • Publication
    Aktives Spannsystem: Positionieren von Präzisionsteilen in der Werkzeugmaschine
    ( 2011)
    Uhlmann, E.
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    Oberschmidt, D.
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    Essmann, J.
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    Langmack, M.
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    Löwenstein, A.
    Ein neues Konzept für automatisierte Spannsysteme positioniert Bauteile in der Maschine äußerst präzise. Das funktioniert unabhängig vom Maschinentyp, der Anzahl der Bewegungsachsen, vom Werkstückkoordinatensystem, der Maschinensteuerung und der Qualität der Spannflächen.
  • Publication
    Optimierung von Röntgenprojektionsrichtungen für die winkelbeschränkte Tomographie
    ( 2010)
    Stopp, F.
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    Winne, C.
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    Käseberg, M.
    ;
    Keeve, E.
  • Publication
    Multi GPU Kegelstrahlvolumentomographie für iterative Rekonstruktionsalgorithmen
    ( 2010)
    Käseberg, M.
    ;
    Winne, C.
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    Stopp, F.
    ;
    Keeve, E.
    Iterative Rekonstruktionsalgorithmen ermöglichen optimale Bildqualitäten in der digitalen Volumentomographie, insbesondere bei geringer Bildanzahl oder gestörten Bilddaten. Der hohe Berechnungsaufwand erschwert jedoch den Einsatz im klinischen Alltag. Implementierungen auf Basis von Grafikprozessoren (GPU) führen zu erheblichen Beschleunigungen. In diesem Beitrag wird eine Methode vorgestellt, mit der die Rekonstruktionsberechnungen eines simultanen algebraischen Rekonstruktionsalgorithmus auf mehrere GPUs verteilt werden. Erste Ergebnisse zeigen, dass bei gleichbleibender Bildqualität ein erheblicher Geschwindigkeitszuwachs möglich ist.
  • Publication
    Visuelles Biofeedback für die gerätegestützte neurologische Gangrehabilitation nach Schlaganfall
    ( 2010)
    Brüning, M.
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    Hussein, S.
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    Bardeleben, A.
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    Schmidt, H.
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    Krüger, J.
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    Hesse, S.