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Evaluation of a Novel Multi-Criteria Optimization Algorithm in a Commercially Available Treatment Planning System

D Christ

D Christ*, D DiCostanzo , A Ayan , J Woollard , N Gupta , Ohio State University Medical Center, Columbus, OH


SU-I-GPD-T-324 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: To investigate and evaluate the benefit of new Eclipse TPS multi-criteria optimization (MCO) features using clinical VMAT head and neck plans.

Methods: The Eclipse MCO features in a pre-clinical system enable the user to explore the plan optimization solution space and perform real-time trade-off analysis for a selected set of structures. We hypothesize that this analysis will yield a net improvement in DVH metrics (hence referred to as “free dose”), however small it may be, amongst normal tissue structures and target volumes compared to the initial plan without compromising the plan quality. We performed the MCO trade-off analysis on eleven previously treated head and neck VMAT plans to search for free dose. Plans were selected such that they all have the same prescription, coverage requirements, and normal tissue constraints. The initial plans and MCO plans were both normalized to the same coverage (100% dose covers 95% of target volume). DVH metrics for all targets and normal tissue structures (including structures not selected for MCO) were analyzed to determine which clinical objectives were met.

Results: Of the eight normal tissue structures selected for MCO, three on average went from initially failing to meet a given clinical objective to passing the clinical objective with the use of MCO. This improvement in plan quality with MCO was achieved without causing any structures to fail to meet a clinical objective after initially passing the objective. Additionally, hot spots remained consistent between respective treated and MCO plans. Representative dose improvements are presented in the DVH metrics table.

Conclusion: Analysis of the DVH metrics supports our hypothesis that free dose exists. MCO proves a useful tool for evaluating trade-offs between target volume and normal tissue DVH metrics and demonstrates the potential to produce clinically superior treatment plans for a given set of plan parameters.

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