Systems and methods for radiation treatment planning using combined imaging and treatment dose

Systems and methods for radiation treatment planning that integrate the MV therapeutic radiation dose imparted to a subject together with the kV imaging radiation dose imparted to a subject during radiation therapy are provided. For instance, dose optimization is based on the combined effect of both a kV imaging dose that is imparted to the subject during the image guided radiation treatment procedure and the therapeutic dose delivered to the subject by a treatment radiation source, such as an MV source. Using this optimization, the kV beam and MV beam are equally treated as radiation producing sources and are thus optimized together at the treatment planning stage to produce a patient treatment plan that optimally uses the kV imaging dose. Thus, the kV beam is treated both as an additional source of therapeutic radiation and as a tool for imaging the subject.