An object tracking device for a medical imaging system tracks a predetermined movable object such as a medical instrument and/or a patient. The object tracking device includes primary and secondary imagers. The primary imager is configured to provide first image data of a patient's body including the interior of a patient's body. The primary imager is movable between imaging and parking modes. The secondary imager is configured to provide second image data of a patient's body including the exterior of a patient's body. The object tracking device further includes a position monitoring arrangement configured to monitor a position of the secondary imager relative to the position of a reference point. As a result, the medical instrument and/or the patient is traceable in the imaging mode based on the image data of the primary imager, and in the parking mode based on the image data of the secondary imager.