Systems and methods are provided for radiation delivery. An exemplary method includes receiving an image depicting anatomical data of a target region of patient tissue and determining an initial prescribed dose of radiotherapeutic radiation to be delivered to the target region. The method also includes discretizing the arc for VMAT into a plurality of arc segments and performing an iteration process for determining an arc dose according to radiation delivered in the arc segments. The method further includes determining whether a condition for terminating the iteration process is met and terminating the iteration process based on a result of the determination that the condition for terminating the iteration process is met.