An apparatus for use in a medical procedure includes: a camera configured for attachment to a patient, wherein the camera is configured to detect one or more markers outside and away from the patient； and a processing unit configured to receive an input image from the camera, and to process the input image to monitor a position of a target associated with the patient during the medical procedure. An apparatus for use in a medical procedure includes: a camera configured for attachment to a patient support, wherein the camera is configured to detect one or more markers outside and away from the patient support； and a processing unit configured to receive an input image from the camera, and to process the input image to determine a position associated with the patient support during the medical procedure.
