Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

Filters

14
3
14
Reset filters

Settings
Now showing 1 - 10 of 14
No Thumbnail Available
Publication

Accuracy of a single camera, marker based surgical navigation system - simulation and implementation

2017 , Katanacho, Manuel , Krumpek, Oliver , Uhlmann, Eckart

Surgical navigation systems are used in many fields of surgery to support the surgeon with localization information during operation. Current systems are based on optical or electromagnetic tracking, both with its benefits and drawbacks. The presented approach is an alternative to the established measurement systems to simplify the use of surgical navigation in the operating room. This abstract aims at evaluating if the required accuracy for a surgical navigation application can be achieved by a single camera approach (see Fig. 1). The proposed system uses a single video camera mounted on an instrument and navigates relative to a flat marker mounted on the patient. The required transformation between camera and marker is computed by image processing methods.

View
No Thumbnail Available
Publication

Overlay visualization in endoscopic ENT surgery

2011 , Winne, Christian , Khan, Martin , Stopp, Fabian , Jank, Emanuel , Keeve, Erwin

Purpose In endoscopic ENT surgery, the identification and localization of target structures is challenging-depth information is missing, relevant tissues could be hidden behind opaque material and image distortion affects the instrument handling. In this paper, a novel overlay visualization is presented that supports the surgeon by superimposing planning and navigation information on the endoscopic image. Method Target regions, which have been identified in preoperative CT data, are superimposed on the endoscopic image, allowing the use of guiding lines for distance visualization. To match the overlay information with the geometrically distorted endoscopic images, a new intraoperative calibration procedure has been developed. Results The accuracy of this new method has been verified by cadaver studies. Clinical evaluation in three paranasal sinus interventions was performed to show the intraoperative assistance and practicability with promising results. Conclusion The new techniques safely support the surgeon in locating target structures in the paranasal sinuses with little change in the actual workflow.

View
No Thumbnail Available
Publication

Computer-aided manufacturing technologies for guided implant placement

2010 , Neugebauer, J. , Stachulla, G. , Ritter, L. , Dreiseidler, T. , Mischkowski, R. , Keeve, E. , Zöller, J.

Implant treatment increasingly focuses on the reduction of treatment time and postoperative impairment. The improvement of 3D dental diagnosis by ConeBeam computed tomography allows detailed preparation for the surgical placement of dental implants under prosthetic considerations. While the first generation of implant planning software used high-contrast multislice computed tomography, software that has been specifically designed for ConeBeam computed tomography is now available. Implant placement can be performed using surgical guides or under the control of optical tracking systems. Surgical guides are more commonly used in private office owing to their availability. The accuracy for both techniques is clinically acceptable for achieving implant placement in critical anatomical indicatio ns. When using prefabricated superstructures and in flapless surgery, special abutments or an adjusted workflow are still necessary to compensate misfits of between 150 and 600 microm. The proposition to ensure proper implant placement by dentists with limited surgical experience through the use of surgical guides is unlikely to be successful, because there is also a specific learning curve for guided implant placement. Current and future development will continue to decrease the classical laboratory-technician work and will integrate the fabrication of superstructures with virtual treatment planning from the start.

View
No Thumbnail Available
Publication

Konzept und Prinzip eines Unterstützungssystems für die einzeitige, alloplastische Tumortherapie in der kraniofazialen Chirurgie

2008 , Rose, A. , Klein, M. , Krüger, T. , Tiesenhausen, C. von , Jank, E. , Krüger, J. , Keeve, E.

Dieser Artikel beschreibt Konzepte und Prinzipien eines Unterstützungssystems für die einzeitige alloplastische Therapie von Tumoren im Schädelknochen. Ziel ist es den behandelnden Arzt sowohl bei der Implantatplanung und -rekonstruktion als auch bei der anschließenden exakten umsetzung der Planung zu unterstützen. Es wird ein Arbeitsablauf für die Planung und Rekonstruktion entwickelt und vorgestellt, der die anatomische Symmetrie ausnutzt und somit weitgehende Automatisierung erlaubt. Bei der Behandlung soll durch wesentliche Zusatzinformationen über die Lage des Instruments bezüglich des Patienten und der Resektiopnslinien eine Unterstützung erreicht werden, die auwendige Nacharbeiten der Passgenauigkeit vermeidet. Anhand von drei Fällen wurde die Funktionsfähigkeit des Planungs- und Rekonstruktionsprinzips nachgewiesen. Zukünftige Arbeiten umfassen die Fertigstellung des Behandlungsteils und die Erbringung des Nachweises der Gesamtgenauigkeit für eine Zulassung nach MPG.

View
No Thumbnail Available
Publication

Region of interest detection with iterative colour clustering and a global weighting scheme

2017 , Katanacho, Manuel , Hoffmann, Jonas , Uhlmann, Eckart

Many modern surgical systems utilize advanced computer vision and image processing techniques for a vast variety of tasks, such as object recognition, segmentation, classification and 3D reconstruction. In many cases, the extraction of a specific region of interest (ROI) in the image is performed prior to further processing steps. This increases the computation speed and may improve the quality of the system´s output because misleading elements in the image are masked out. We present a novel approach that considers global colour distributions to extract one (or more) ROIs in a camera image stream. Our method is both fast and robust against illumination discontinuities, irregularities in the texturing of surfaces and false areas with very similar colour. The method is used for the detection of human skin in an operating room environment for a camera based navigation system.

View
No Thumbnail Available
Publication

Robot-assisted motor activation monitored by time-domain optical brain imaging

2011 , Steinkellner, O. , Wabnitz, H. , Schmid, S. , Steingräber, R. , Schmidt, H. , Krüger, J. , Macdonald, R.

Robot-assisted motor rehabilitation proved to be an effective supplement to conventional hand-to-hand therapy in stroke patients. In order to analyze and understand motor learning and performance during rehabilitation it is desirable to develop a monitor to provide objective measures of the corresponding brain activity at the rehabilitation progress. We used a portable time-domain near-infrared reflectometer to monitor the hemodynamic brain response to distal upper extremity activities. Four healthy volunteers performed two different robot-assisted wrist/forearm movements, flexion-extension and pronation-supination in comparison with an unassisted squeeze ball exercise. A special headgear with four optical measurement positions to include parts of the pre- and postcentral gyrus provided a good overlap with the expected activation areas. Data analysis based on variance of time-of-flight distributions of photons through tissue was chosen to provide a suitable representati on of intracerebral signals. In all subjects several of the four detection channels showed a response. In some cases indications were found of differences in localization of the activated areas for the various tasks.

View
No Thumbnail Available
Publication

An accuracy study on navigated freehand-milling along a cutting path for craniofacial reconstruction surgery

2010 , Liu, W. , Keeve, E.

View
No Thumbnail Available
Publication

3D human face reconstruction for surgical navigation

2016 , Katanacho, Manuel , Hoffmann, Jonas , Engel, Sebastian

View
No Thumbnail Available
Publication

MAR-SART: Metal artifact reduction for simultaneous algebraic reconstruction technique

2010 , Käseberg, M. , Winne, C. , Keeve, E.

In X-ray computed tomography metallic objects, located in the scanned area, lead to streak artifacts in the reconstructed image data. The use of less absorbing materials (like titanium) for implants is often not an option, so the common solution is a modification of the existing 3D reconstruction algorithms. Usually these methods are based on complete scans of the affected area with many projection images. However, some applications like intraoperativ 3D imaging can implicate a limited scan angle and a reduced number of images to reduce the radiation exposure. In this article a new approach for metal artifact reduction using a simultaneous algebraic reconstruction technique is proposed. Metallic components in the projection images are detected and replaced with synthetic projection data t o improve the 3D reconstruction quality. First results from simulations with a computer generated phantom are presented.

View
No Thumbnail Available
Publication

Assumption for improving intraoperative 3D X-ray scanners

2008 , Jank, E.

View