Patent ID: 8249215

Claim:
A method comprising: determining, by a processor, a plurality of radiation beams for a radiation treatment fraction, each of the plurality of beams associated with a respective intensity, beam aperture and beam energy, and at least two of the plurality of beams respectively associated with two different beam energies; determining, by the processor, a forward dose associated with the plurality of beams; determining, by the processor, that the forward dose does not conform to a dose prescription; determining, using Gaussian elimination, a beam weight for each of the plurality of beams based on the forward dose and the dose prescription; determining, by the processor, that the beam weight for at least one of the plurality of beams is negative; changing the at least one beam aperture associated with the at least one of the plurality of beams; determining, by the processor, a second beam weight for each of the plurality of beams based on the changed at least one beam aperture; and determining, by the processor, a second forward dose associated with the plurality of beams and the second beam weights.