1. A method for producing a radiation treatment plan for a patient, the steps of the method comprising: (a) providing at least one image of a patient; (b) identifying a target volume in the patient based on the at least one image of the patient, the target volume comprising a volume bounded by an outer boundary; (c) identifying an organ at risk (OAR) volume based on the at least one image of the patient; (d) generating a plurality of avoidance volumes based on the identified OAR volume; (e) determining a target objective based on the identified treatment volume, the target objective indicating a desired dose distribution in the target volume; (f) determining a physical objective for each of the plurality of avoidance volumes, each physical objective being based a physical capability of a radiation treatment system and indicating a desired dose gradient across the plurality of avoidance volumes; and (g) generating a radiation treatment plan by providing the target objective and physical objectives to a radiation treatment planning system that is programmed to generate an optimized radiation treatment plan by optimizing an objective function based at least in part on the target objective and physical objectives.