Systems and methods for generating a radiation treatment plan using inverse planning objectives that are automatically determined based on patient data and the physical capabilities of the radiation treatment system are provided. In particular, the planned target volumes and organ-at-risk (OAR) volumes are used to automatically partition the OAR volumes into one or more avoidance volumes, for which particular inverse planning objectives are established based on the physical capabilities of the treatment system. As an example, an inverse planning objective may include establishing a particular dose gradient over one or more avoidance volumes. Because such inverse planning objectives are based on conditions and constraints of the treatment system physics, rather than a desired percentage of the prescribed dose, they may be referred to as “physical objectives.”
