Format

Send to:

Choose Destination
See comment in PubMed Commons below
IEEE Trans Med Imaging. 1998 Oct;17(5):737-42.

Calibration of tracking systems in a surgical environment.

Author information

  • 1Department of Biomedical Engineering and Physics at the General Hospital Vienna, University of Vienna, Austria.

Abstract

The purpose of this paper was to assess to what extent an optical tracking system (OTS) used for position determination in computer-aided surgery (CAS) can be enhanced by combining it with a direct current (dc) driven electromagnetic tracking system (EMTS). The main advantage of the EMTS is the fact that it is not dependent on a free line-of-sight. Unfortunately, the accuracy of the EMTS is highly affected by nearby ferromagnetic materials. We have explored to what extent the influence of the metallic equipment in the operating room (OR) can be compensated by collecting precise information on the nonlinear local error in the EMTS by using the OTS for setting up a calibration look-up table. After calibration of the EMTS and registration of the sensor systems in the OR we have found the average euclidean deviation in position readings between the dc tracker and the OTS reduced from 2.9+/-1.0 mm to 2.1+/-0.8 mm within a half-sphere of 530-mm radius around the magnetic field emitter. Furthermore we have found the calibration to be stable after re-registration of the sensors under varying conditions such as different heights of the OR table and varying positions of the OR equipment over a longer time interval. These results encourage the further development of a hybrid magnetooptical tracker for computer-aided surgery where the electromagnetic tracker acts as an auxiliary source of position information for the optical system. Strategies for enhancing the reliability of the proposed hybrid magnetooptic tracker by detecting artifacts induced by mobile ferromagnetic objects such as surgical tools are discussed.

PMID:
9874297
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for IEEE Engineering in Medicine and Biology Society
    Loading ...
    Write to the Help Desk