A Fully-Automated Intensity-Modulated Radiation Therapy Planning System

We designed and implemented a linear programming based IMRT treatment plan generation technology that effectively and efficiently optimizes beam geometry as well as beam intensities. The core of the technology is a fluence map optimization model that approximates partial dose volume constraints using conditional value-at-risk constraints. Conditional value-at-risk constraints require careful tuning of their parameters to achieve desirable plan quality and therefore we developed an automated search strategy for parameter tuning. Another novel feature of our fluence map optimization model is the use of virtual critical structures to control coverage and conformity. Finally, beam angle selection has been integrated with fluence map optimization. The beam angle selection scheme employs a bi-criteria weighting of beam angle geometries and a selection mechanism to choose from among the set of non-dominated geometries. The technology is fully automated and generates several high-quality treatment plans satisfying dose prescription requirements in a single invocation and without human guidance. The technology has been tested on various real patient cases with uniform success. Solution times are an order of magnitude faster than what is possible with currently available commercial planning systems and the quality of the generated treatment plans is at least as good as the quality of the plans produced with existing technology.