Andreas Petersik

Haptic volume interaction with anatomic models at sub-voxel resolution

An approach for haptic volume interaction with high resolution voxel-based anatomic models is presented. The haptic rendering is based on a multi-point collision detection approach which provides realistic tool interaction with the models. Both haptics and graphics are rendered at sub-voxel resolution, which leads to a high level of detail and enables the exploration of the models at any scale. Forces are calculated at an update rate of 6000 Hz and sent to a 3-degree-of-freedom (3-DOF) force-feedback device. Compared to point-based haptic rendering, the unique approach of the multi-point collision detection in combination with sub-voxel rendering provides more realistic and very detailed haptic sensations. As a main application, a simulator for petrous bone surgery was developed. With a simulated drill, bony structure can be removed and the access path to the middle ear can be studied.

Virtual reality: A new paranasal sinus surgery simulator

Virtual surgical training systems are of growing value. Current prototypes for endonasal sinus surgery simulation are very expensive or lack running stability. No reliable system is available to a notable number of users yet. The purpose of this work was to develop a dependable simulator running on standard PC hardware including a detailed anatomic model, realistic tools and handling, stereoscopic view, and force feedback.

Virtual dental surgery as a new educational tool in dental school

PURPOSE The virtual environment of the Voxel-Man simulator that was originally designed for virtual surgical procedures of the middle ear has been adapted to intraoral procedures. To assess application of the simulator to dentistry, virtual apicectomies were chosen as the pilot-test model. METHODS A group of 53 dental students provided their impressions after virtual simulation of apicectomies in the Voxel-Man simulator. RESULTS Fifty-one of the 53 students recommended the virtual simulation as an additional modality in dental education. The students indicated that the force feedback (e.g. simulation of haptic pressure), spatial 3D perception, and image resolution of the simulator were sufficient for virtual training of dental surgical procedures. CONCLUSION The feedback from dental students involved in this pilot-test has encouraged our interdisciplinary group to continue further development of the simulator with the goal of creating new training strategies in dental and medical education.

Realistic haptic volume interaction for petrous bone surgery simulation

In this paper, a new approach for haptic volume interaction with high resolution voxel-based anatomic models is presented. The haptic rendering is based on a multi-point collision detection approach which provides realistic tool interaction with the models. Both haptics and graphics are rendered at sub-voxel resolution, which leads to a high level of detail and enables the exploration of the models at any scale. Forces are calculated at an update rate of 6000 Hz and sent to a 3-Degree-of-Freedom (3-DOF) force-feedback device. Compared to single-point based haptic rendering, the unique approach of the multi-point collision detection in combination with sub-voxel rendering provides more realistic and very detailed haptic sensations. As a main application, a simulator for petrous bone surgery was developed. With a simulated drill, bony structure can be removed and the access path to the middle ear can be studied in a realistic manner.

Individual models for virtual bone drilling in mastoid surgery

Segmented training cases for virtual simulation of bone-drilling interventions in middle ear surgery have proven to be helpful in learning about surgical anatomy of the temporal bone. The anatomy of the mastoid shows a high degree of variability, however, and the aim of this study was to evaluate whether individual virtual models could be created within an affordable timeframe, and to what extend they reflected natural individual anatomy during virtual mastoid surgery. Automatic segmentation schemes were used, and these reduced the time required to create individual models on the basis of DICOM CT scans to less than 5 minutes. Models based on CT data with a slice distance of 0.4 mm or better were found to provide excellent handling, an acceptable depiction of mastoidal organs, and a helpful impression of the individual surgical situation. Although landmarks are still more easily detected in real mastoids, virtual drilling of individual models makes the 3D estimation of specific anatomy more effective than estimations based on interpretation of CT scans alone.

Enhancing the diagnostic capabilities of MRCP by highresolution image acquisition and stereoscopic viewing

Though magnetic resonance cholangiopancreatography (MRCP) is one of the most useful modalities, its capability for precise and realistic description of the biliary system has been inferior to endoscopic retrograde cholangiopancreatography (ERCP). Current MR scanner’s spatial resolution of MRCP has become remarkably improved. However, it is time consuming and unpractical to read HR image data as a series of pictures on plain films. This presentation is to show that the combination of HR data and stereoscopic viewing leads to a decisive increase of speed and diagnostic value of MRCP.

Die realistische haptische Interaktion mit anatomischen Modellen für die Simulation der Felsenbeinchirurgie

Es wird ein neuer Ansatz fur die realistische haptische Interaktion mit anatomischen Modellen vorgestellt.