What is the difference between optical and magnetic trackers?

A. Optical trackers operate by emitting a light source that is sensed by one of more detectors. While highly accurate, they are obtrusive and require a clear line-of sight between source and detector at all times. If an occlusion occurs, measurements are lost. This precludes use within the body and limits usefulness in application in which heads and hands move freely within a tracking volume.

Magnetic trackers transmit magnetic fields that permeate all non-metallic surfaces. These sensors have been miniaturized for medical applications and can be placed inside the body and even inside some instruments. Its transmitter possesses a small form factor and can be draped to avoid sterilization. As a result, magnetic trackers minimize clutter in procedural fields.