Abstract: A method includes determining a set of candidate beam directions. The radiation therapy method further includes selecting a sub-set of non-coplanar beam directions of interest from the set of candidate beam directions based on a fluence optimization using a beam angle selection algorithm. The radiation therapy method further includes determining a set of delivery options based on a beam trajectory algorithm, wherein the delivery options at least include a non-coplanar trajectory during radiation treatment delivery. The radiation therapy method further includes optimizing the delivery options to generate a VMAT radiation plan with non-coplanar beam trajectories. The optimizing of the delivery options includes optimizing at least one machine parameter.