Radiation therapy planning

Systems and methods for radiation therapy planning are described. A radiation therapy includes of a series of radiation treatment fractions each including a sequence of radiation segments with a prescribed cumulative dose intensity profile to be delivered to a therapy site on a patient. In one embodiment, a pair of consecutive radiation treatment fractions is generated, wherein each fraction has a different set of radiation segments. A system, a computer program, and a computer-readable medium carrying instructions for radiation therapy planning also are described. The system, computer program, and computer-readable medium each are operable to combine common radiation segments of two radiation treatment fractions to reduce the total number of radiation segments applied to the patient.