1. A method for determining optimal treatment information, comprising: determining a dose distribution for one or more target regions by applying a deformation parameter to a treatment plan dose distribution for a subset of a plurality of phases; determining one or more dose parameters based on the dose distribution for the subset of the plurality of phases, the one or more dose parameters representing a motion of the dose distribution over the plurality of phases for each region; and determining optimal treatment information based on the one or more dose parameters, the optimal treatment information including optimal phase and associated dose distribution, the optimal phase being a phase having a minimum total dose for the one or more target regions.