Impact of beam configuration on VMAT plan quality for Pinnacle3Auto-Planning for head and neck cases

Abstract

BackgroundThe purpose of this study was to compare automatically generated VMAT plans to find the superior beam configurations for Pinnacle3 Auto-Planning and share “best practices”.MethodsVMAT plans for 20 patients with head and neck cancer were generated using Pinnacle3 Auto-Planning Module (Pinnacle3 Version 9.10) with different beam setup parameters. VMAT plans for single (V1) or double arc (V2) and partial or full gantry rotation were optimized. Beam configurations with different collimator positions were defined. Target coverage and sparing of organs at risk were evaluated based on scoring of an evaluation parameter set. Furthermore, dosimetric evaluation was performed based on the composite objective value (COV) and a new cross comparison method was applied using the COVs.ResultsThe evaluation showed a superior plan quality for double arcs compared to one single arc or two single arcs for all cases. Plan quality was superior if a full gantry rotation was allowed during optimization for unilateral target volumes. A double arc technique with collimator setting of 15° was superior to a double arc with collimator 60° and a two single arcs with collimator setting of 15° and 345°.ConclusionThe evaluation showed that double and full arcs are superior to single and partial arcs in terms of organs at risk sparing even for unilateral target volumes. The collimator position was found as an additional setup parameter, which can further improve the target coverage and sparing of organs at risk.

Comparison of dose metrics between automated and manual radiotherapy planning for advanced stage non-small cell lung cancer with volumetric modulated arc therapy

“…Furthermore, the beam configuration like for example collimator rotation [23] may influence the plan quality. In this study we used a collimator rotation of 20° and did not investigate how other values could influence the plan quality.…”

Evaluation of Auto-Planning for Left-Side Breast Cancer After Breast-Conserving Surgery Based on Geometrical Relationship

“…For example, the modification of the restriction conditions in the template and the parameter setting of hot and cold spots will affect the result of the APs. (23,24) In addition, the limited number of patients in this study is slightly lower. The result can be more convincing with a larger sample size and more different type of diseases as the research object.…”

Evaluation of Auto-Planning for Left-Side Breast Cancer After Breast-Conserving Surgery Based on Geometrical Relationship

“…Secondly, although the optimization process of AP reduces the interference of human subjective factors, there are certain subjective factors in the initial settings of AP. For example, the modification of the restriction conditions in the template and the parameter setting of hot and cold spots will affect the result of the APs (23,24). In addition, the number of patients enrolled in this study is limited.…”