Inter-planner variation in treatment-plan quality of plans created with a knowledge-based treatment planning system

Abstract Purpose This study aimed to clarify the inter-planner variation of plan quality in knowledge-based plans created by nine planners. Methods Five hypofractionated prostate-only (HPO) volumetric modulated arc therapy (VMAT) plans and five whole-pelvis (WP) VMAT plans were created by each planner using a knowledge-based planning (KBP) system. Nine planners were divided into three groups of three planners each: Senior, Junior, and Beginner. Single optimization with only priority modification for all objectives was performed to stay within the dose constraints. The coefficients of variation (CVs) for dosimetric parameters were evaluated, and a plan quality metric (PQM) was used to evaluate comprehensive plan quality. Results Lower CVs ( Conclusion Inter-planner variation in the plan quality with RapidPlan remains, especially for the complicated VMAT plans, due to planners’ heuristics.