A radiation-treatment planning apparatus accesses imaging information regarding at least a patient's treatment volume and surface information regarding dynamic surfaces within the radiation-treatment environment as pertains to the radiation treatment. The apparatus acquires the imaging information using a first imaging technology and the surface information using a second technology that is different than the first imaging technology. The apparatus uses the imaging and surface information to influence a radiation treatment plan for treating the treatment volume with radiation to accommodate dynamic physical changes within the radiation-treatment environment during the radiation treatment of the treatment volume.