Planning comparison of five automated treatment planning solutions for locally advanced head and neck cancer

Abstract

BackgroundAutomated treatment planning and/or optimization systems (ATPS) are in the process of broad clinical implementation aiming at reducing inter-planner variability, reducing the planning time allocated for the optimization process and improving plan quality. Five different ATPS used clinically were evaluated for advanced head and neck cancer (HNC).MethodsThree radiation oncology departments compared 5 different ATPS: 1) Automatic Interactive Optimizer (AIO) in combination with RapidArc (in-house developed and Varian Medical Systems); 2) Auto-Planning (AP) (Philips Radiation Oncology Systems); 3) RapidPlan version 13.6 (RP1) with HNC model from University Hospital A (Varian Medical Systems, Palo Alto, USA); 4) RapidPlan version 13.7 (RP2) combined with scripting for automated setup of fields with HNC model from University Hospital B; 5) Raystation multicriteria optimization algorithm version 5 (RS) (Laboratories AB, Stockholm, Sweden). Eight randomly selected HNC cases from institution A and 8 from institution B were used. PTV coverage, mean and maximum dose to the organs at risk and effective planning time were compared. Ranking was done based on 3 Gy increments for the parallel organs.ResultsAll planning systems achieved the hard dose constraints for the PTVs and serial organs for all patients. Overall, AP achieved the best ranking for the parallel organs followed by RS, AIO, RP2 and RP1. The oral cavity mean dose was the lowest for RS (31.3 ± 17.6 Gy), followed by AP (33.8 ± 17.8 Gy), RP1 (34.1 ± 16.7 Gy), AIO (36.1 ± 16.8 Gy) and RP2 (36.3 ± 16.2 Gy). The submandibular glands mean dose was 33.6 ± 10.8 Gy (AP), 35.2 ± 8.4 Gy (AIO), 35.5 ± 9.3 Gy (RP2), 36.9 ± 7.6 Gy (RS) and 38.2 ± 7.0 Gy (RP1). The average effective planning working time was substantially different between the five ATPS (in minutes): < 2 ± 1 for AIO and RP2, 5 ± 1 for AP, 15 ± 2 for RP1 and 340 ± 48 for RS, respectively.ConclusionsAll ATPS were able to achieve all planning DVH constraints and the effective working time was kept bellow 20 min for each ATPS except for RS. For the parallel organs, AP performed the best, although the differences were small.

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“…82 Nevertheless, the variability in manual as well as auto-segmentation results cannot be completely eliminated because each individual observer is exposed to his/her subjective bias that is conditioned by experience (i.e., novice vs expert), and because imaging protocols and setups as well as RT protocols and planning systems vary greatly across institutions. 146 For a particular OAR, the observer variability imposes the upper limit for auto-segmentation performance, as we cannot expect any auto-segmentation result to overcome the obtained consensus among the ground truth delineations. Although manual correction of auto-segmentation boundaries is a less labor intensive approach for ground truth generation, it contains auto-segmentation bias and is therefore not the most appropriate reference for performing auto-segmentation evaluation.…”

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“…The current study only shows that for small changes in GTV (< 2%), a smaller fraction of treatment plans was optimized with full optimization, indicating that the amount of GTV volume changes might be a useful indicator for the best suitable optimization approach, considering the trade-off between treatment time and treatment plan quality [28]. In the future, automated planning could possibly contribute to the reduction of treatment time, while improving overall plan quality and reducing inter-planner variability [29].…”

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