Purpose: To evaluate dose volume histogram (DVH) construction differences across eight major commercial treatment planning systems (TPS) and dose reporting systems (DRS) for clinically treated plans of various anatomical sites.
Methods: Dose files from ten selected clinically treated plans with a hypo-fractionation or stereotactic radiotherapy prescription, each calculated at 0.25cm and 0.125cm grid size, were created and anonymized in Eclipse TPS, and exported to seven other major TPS (Pinnacle, RayStation, Elements) and DRS (MIM, Mobius, ProKnow, and Velocity) systems for comparison. Dose-volume constraint points of clinical importance for each plan were collected from each evaluated system (D0.03cc[Gy], volume, and the mean dose were used for structures without specified constraints). Each reported constraint type and structure volume was normalized to the value from Eclipse for a pairwise comparison. A Wilcoxon Rank Sum test was used for statistical significance and a regression multivariable model was evaluated adjusting for plan, grid size, and distance to target center.
Results: For all DVH points relative to Eclipse, all systems reported median values within 1% difference of each other. Considering mean values, Pinnacle, RayStation and Elements averaged at 1.038, 1.046 and 1.024 respectively, while MIM, Mobius, ProKnow, and Velocity reported 1.026, 1.050, 1.033 and 1.022 respectively relative to Eclipse (p<0.001),. Smaller dose grid size improved agreement between the systems marginally without statistical significance. For structure volumes relative to Eclipse, larger differences are seen across all systems with a range in median values up to 3% difference, and mean up to 10.5% difference.
Conclusion: Eclipse generally reported, at statistically significant levels, lower values than all other evaluated systems. The non-significant change resulting from lowering the dose grid resolution indicates that this resolution may be less important than other aspects of calculating DVH curves, such as the 3D modeling of the structure.
Not Applicable / None Entered.
TH- External Beam- Photons: treatment planning/virtual clinical studies