Tracker For A Surgical Navigation System

A method of operating a surgical navigation system that comprises an optical sensor and a surgical tool system comprising a surgical tool and

• a tracker, the tracker comprising an optical fibre attached to the surgical tool and having a longitudinal extension and configured to be optically coupled to a light source such that the optical fibre transmits light emitted by the light source, wherein the optical fibre has a lateral surface along its longitudinal extension and is configured to emit light via at least a portion of the lateral surface, wherein the method comprises the steps of:
• detecting, by the optical sensor, light emitted by the portion of the lateral surface of the optical fibre;
• and
• determining a shape of the surgical tool based on the detected light.