A method of selecting a radiation therapy treatment plan for a patient. The treatment plan is implemented through a radiation delivery system including a gantry capable of rotating around a couch, in which the couch is movable in a linear direction relative to the gantry. The movement of the couch and the gantry creates a helical delivery path having a pitch. A radiation module delivers a radiation beam, where the beam has a beam weight corresponding to a radiation fluence. The method includes receiving, by a controller, an objective including a desired dose, a desired dose distribution, or a dose constraint, optimizing the pitch to obtain an optimized pitch, optimizing, the beam weight to obtain optimized beam weight, determining, based on the optimized pitch and the optimized beam weight a treatment plan or a treatment dose, and outputting the treatment plan or the treatment dose.