OPTICAL AND ELECTROMAGNETIC METHODS OF POSITION RECOGNITION IN SPACE – CONCEPTS, PROBLEMS AND SOLUTIONS

Abstract

The use of surgical navigation in computer assisted or image guided procedures requires the precise measurement of the spatial position of surgical instruments. Investigations of several physical principles have turned out that two technologies are best feasible for application in clinical routines: a) optical technology, b) electromagnetic technology. Available systems based on either principle deliver measurement information for the 3D-position of a surgical instrument, expressed by the x-y-z coordinates of its tip, and for its 3D-orientation, described by the direction of the instrument axis towards the tip. It is therefore common terminology to describe such measurement systems as 3D/6D digitizing or localizing systems.

The presentation will describe basic principles of both technologies, including their main technical features and the design of key components such as rigid bodies for optical systems and sensor coils for electromagnetic systems. The survey includes an overview of known challenges and problems, and how commercial systems cope with these. A comparison of both technologies outlines the advantages and drawbacks in different applications as well as possible future improvements. It leads to the conclusion that both technologies will co-exist for the foreseeable future.