A multimodal imaging apparatus, comprising a rotatable gantry system positioned at least partially around a patient support, a first source of radiation coupled to the rotatable gantry system, the first source of radiation configured for imaging radiation, a second source of radiation coupled to the rotatable gantry system, the second source of radiation configured for at least one of imaging radiation or therapeutic radiation, wherein the second source of radiation has an energy level more than the first source of radiation, and a second radiation detector coupled to the rotatable gantry system and positioned to receive radiation from the second source of radiation, and a processor configured to combine first measured projection data based on the radiation detected by the first detector with second measured projection data based on the radiation detected by the second detector, and reconstruct an image based on the combined data, wherein the reconstructing comprises at least one of correcting the second measured projection data using the first measured projection data, correcting the first measured projection data using the second projection data, and distinguishing different materials imaged in the combined data using the first measured projection data and the second measured projection.