A systematic approach to practical multi-criteria IMRT planning

Purpose: To describe and demonstrate a new practical multi‐objective treatment planning procedure for intensity modulated radiation therapy (IMRT) planning. The approach developed addresses the question of how to generate a useful database of Pareto optimal treatment plans without time consuming human iterations. Method and Materials: The creation of a database of Pareto optimal treatment plans proceeds in two steps. The first step solves an optimization problem which finds a single treatment plan which is close to a set of clinical aspirations. The results of this step are then used to determine mutually satisfiable hard constraints for the subsequent generation of the plan database. Healthy structures are modeled with piecewise linear approximations of EUDs, and targets are modeled with a linear underdose penalty term. Optimizations are done using linear programming. Results: The method is successfully applied to a variety of clinical cases, including a brain, prostate, and lung case. It is shown that the databases generated are both diverse and filled with predominantly clinically interesting plans. Conclusion: The proposed method brings Pareto surface‐based multicriteria IMRT planning closer to clinical usability. With this method, we begin to fulfill the aims of multicriteria IMRT planning: reduce the human‐iteration time common in IMRT treatment planning and make the trade‐offs involved in treatment planning explicitly known. © 2007, American Association of Physicists in Medicine. All rights reserved.