1. A method of optimizing a treatment plan for irradiating a treatment volume within a patient, comprising: establishing at least one treatment parameter; establishing a cost function corresponding to a treatment volume, wherein the treatment volume includes a target volume intended to receive a therapeutic dose of radiation and a non-target volume intended to receive a smaller dose of radiation, wherein the cost function is responsive to the radiation dose received by the treatment volume; back-projecting a plurality of gradients of said cost function to an optimization surface, wherein said gradients are responsive to changes in said at least one treatment parameter and wherein said optimization surface is defined by said at least one treatment parameter; and changing said at least one treatment parameter, wherein said change in said at least one treatment parameter causes a corresponding change in said back projected gradients.