A navigation system (420) comprises an electromagnetic field generator (422) configured to emit electromagnetic waves, a surgical device (424), an electromagnetic reference (428),a display (410, 440) and a controller (408). The controller is configured to: detect the electromagnetic waves via the surgical device (424) and the electromagnetic reference (428)； calculate a spatial relationship between the surgical device (424) and the electromagnetic reference (428)； receive computer tomography (CT) images of the electromagnetic reference (428)； and correlate a position of the surgical device (424) with the CT images； and cause the display to display the CT images including a representation of the surgical device.
