Room: Exhibit Hall | Forum 7
Purpose: The purpose of this study was to evaluate a newly developed hybrid VMAT-IMRT multi criteria optimisation (MCO) tool developed specifically to run on graphics processing units (GPU) within the Varian Eclipse treatment planning system.
Methods: A pre-clinical release of the Varian Eclipse TPS (v15.6) with 3 FAS/GPU servers was used to qualitatively and quantitatively compare the outputs from native VMAT MCO and a new hybrid VMAT-IMRT MCO. The hybrid plan generation algorithm aims to reduce VMAT plan generation times with IMRT surrogate fields on GPU, yet retain the spatial isodose features of the original CPU-based VMAT optimisation.50 clinically acceptable treatment plans were used for the testing from a range of anatomical sites including brain, head and neck, lung, mediastinum, oesophagus, and the pelvis area. All dose calculations were performed using AcurosXB on GPU and all optimisation based dose calculations were performed using either the fourier transform dose calculation (FTDC) algorithm on GPU (IMRT component of hybrid VMAT-IMRT) or CPU (VMAT).Comparisons were made in terms of the variability in post MCO trade-off exploration, final plan quality, and optimisation calculation time.
Results: Generation of MCO plan collection for native VMAT MCO ranged from 9 â€“ 93 minutes (average of 34 minutes), whereas for hybrid VMAT-IMRT MCO times ranged from less than 1 minute up to 4 minutes (average of 2 minutes). Plan generation times were, on average, 16.5 times faster with hybrid VMAT-IMRT MCO.Overall, the quality of the hybrid VMAT-IMRT MCO were comparable or better than the native VMAT MCO plans, with increased organ at risk sparing in most cases.
Conclusion: A new hybrid VMAT-IMRT MCO tool was evaluated and found to be capable of producing either comparable or better quality plans compared with the native VMAT MCO plans, but also in a much quicker time.
Funding Support, Disclosures, and Conflict of Interest: Funding support for this work was received from Varian Medical Systems.
TH- External beam- photons: VMAT dose optimization algorithms