The present disclosure generally relates to the field of radiation treatment. More specifically, the present disclosure generally relates to methods and radiation treatment systems for facilitating a multimodal radiation therapy treatment plan, in particular a multimodal radiation therapy plan employing a combined photon beam and electron beam radiation treatment. According to one example embodiment described in the disclosure, a method may comprise obtaining (210) information related to a set of candidate beam types for the combined photon beam and electron beam radiation treatment； comparing (230) the set of candidate beam types against a selection criterion to establish (250) a subset of beam types from the candidate beam types； and generating (260) the combined photon beam and electron beam radiation treatment plan utilizing the thus established subset of beam types.
