Evaluation of improvement probability for IMRT plans

In intensity-modulated radiotherapy (IMRT) planning, the planner iteratively generates treatment plans for the patient. Upon completion of a new plan, it is critical to know the improvement potential of the plan. If the current best plan is assessed to have significant improvement potential, additional time should be spent for planning. Otherwise, the planner may decide to stop the planning process. In this research, we propose a assessment method for the improvement potential based on the threshold model (TM). The probability of improvement for the current best plan is calculated to help the planner make decisions. Numerical tests were performed on three head and neck patients and the results illustrated that the probability of improvement can be a powerful decision support tool for planners.