Evaluation of rapidarc optimitation strategies using objetive function values

Abstract

Introduction Eclipse treatment planning system includes various optimization strategies than can be employed to improve the quality of the ultimate treatment plan for RapidArc Purpose The purpose of this study is to analyze the new strategies included in the PRO3 optimization algorithm for three phantoms and to examine the results using the final objective function values. Materials and methods Three phantoms were created in Eclipse 10.0 with varying shapes and locations for the planning target volumes and organs at risk. These phantoms were taken from Oliver et al. described in Med Phys. (Vol. 11, No. 1, Winter 2010) A baseline optimization consisting in a single 358 o arc with collimator at 45 o was applied to all phantoms. Seven different strategies were evaluated and compared to the baseline strategy using the reporting objective function. Each strategy was compared against baselines using paired Student’s t-test. Results The strategies that resulted with a significant difference from the baseline were: add an 358 o arc with a collimator at 315 o (p Conclusion In our study, we conclude that the optimal collimator angle that minimized target function value is 45 o . From the seven different strategies, only three of them produced significant different final objective function values from baseline. These three strategies are: ad a new arc with orthogonal collimator angle from baseline, using the fit and shield option and fit the isocenter with arc geometry tool.