Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

Filters

4
4
Reset filters

Settings
Now showing 1 - 4 of 4
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

Assumption for improving intraoperative 3D X-ray scanners

2008 , Jank, E.

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

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

2010 , Liu, W. , Keeve, E.

View