In an imaging acquisition system and method, successive x-ray images and successive optical images are respectively acquired from an examination subject. Positional identifiers associated with the examination subject are detected in the optical images, and acquisition of respective x-ray images is triggered only when the identifiers are detected in the optical images. The number of acquired x-ray images is therefore substantially fewer than the number of acquired optical images, and the x-ray images can be acquired with substantially no overlap, thereby avoiding exposing the examination subject to unnecessary radiation.