A method of the present disclosure includes identifying, based on a reference image, a full motion range of a target, wherein the full motion range of the target defines a full internal target volume (ITV). The method further includes determining, based on a motion image, a partial motion range of the target, wherein the partial motion range is an untracked portion of the full motion range of the target comprising one of an untracked plane or an untracked axis. The method further includes generating, by a processing device, a partial ITV based on the partial range of motion of the target, wherein the partial ITV is a volume swept by the target as the target moves through the partial motion range, and wherein the partial ITV is smaller than the full ITV. The method further includes providing the partial ITV to assist in tracking the target.
