SU-E-T-640: DICOM-RT Data Transfer of Structure Sets Between SRS Treatment Planning Systems

Abstract

Purpose: To verify the integrity of data structures created in one treatment planning system and transferred to another using DICOM‐RT for stereotactic radiosurgery. Methods: Ten radiosurgery patients were selected for this retrospective study. Initial planning images were imported into a Brainlab iPlan© RT Image 4.1 workstation. Normal structures and lesions were contoured for each patient. The structure volume as reported by the iPlan software was recorded for each volume. The images and structures were then transferred via DICOM‐RT to a Leksell GammaPlan® workstation (for Perfexion™). The volume of each structure, as reported by GammaPlan, was compared to the iPlan values. Finally, all images and structures from the iPlan workstation and the GammaPlan workstation were sent via DICOM‐RT to a Varian Eclipse™ workstation so that the respective volumes could be determined on a common platform. Results: Structure volumes ranged from less than 0.1 cc (e.g. optic tracks) to over 30 cc (brainstem). Volumes reported by GammaPlan differed from those reported by iPlan, with the former generally being smaller. Differences of up to 0.5 cc were observed. The largest absolute differences tended to be for the larger structures. The greatest percent differences were for the smaller structures, with the reported volumes differing by a factor of two or more. When the structures were sent from iPlan and GammaPlan to Eclipse (and calculated with a single algorithm), the volume differences were found to be much smaller. Conclusions: It is feasible to import DICOM‐RT structure sets into the Leksell GammaPlan from other platforms such as Brainlab's iPlan RT Image. Different planning systems (e.g. GammaPlan, iPlan and Eclipse) use different algorithms to calculate structure volumes. These differences may have significant affects (especially for small structures) when calculating dose volume histograms and conformity indices.