The invention relates to an active marker device (100) for being introduced into a human tissue and for tracking a region of interest of a human body. The active marker device comprises a light source (101) for emitting light such that the emitted light can be detected by an optical sensor. In this way, the active marker device and/or the region of interest can be tracked by a tracking system comprising the optical sensor. The active marker device (100) further comprises a switch (102) for turning the light source on and off and for operating the light source in a pulsed mode.
