Abstract: Background and purpose: RapidPlan can be used to extract patient’s anatomy and dose information from intensity-modulated radiotherapy (IMRT) plans to predict the dose-volume histogram (DVH) of a new one, in the method of DVH estimation models. Establishing a knowledge-based model for treatment planning system (TPS) and accelerator separately requires a lot of efforts, and the selection will be cumbersome. This study aimed to investigate whether a knowledge-based treatment planning model can smoothly migrate to different machine and TPS. Methods: The clinical treatment plans of 50 cervical cancer patients treated in Fudan University Shanghai Cancer Center from 2015 to 2016 were added in RapidPlan to develop a knowledge-based planning model. All training data were created with Pinnacle and optimized for 6 MV photon beams from a Synergy accelerator. Model was used to estimate the DVH in 15 IMRT plans. Plans were reoptimized to evaluate the impact of the accelerator model and TPS on knowledge-based planning model after extracting the objective function value. The evaluation included 3 groups. In Group 1, the knowledge based plan (KBP) and manual plan used the same accelerator and TPS as model training data (Pinnacle and Synergy). In Group 2, the KBP and manual plan used the same TPS, while the accelerator model was different (Pinnacle and Truebeam). In Group 3, the KBP and manual plan used different TPS and accelerator models (Eclipse and Truebeam). DVH quantitative analysis was performed to make comparison between the KBP and the manual plans in 3 groups respectively. Results: In Group 2 and Group 3, KBP plans showed similar quality of planning target volume (PTV) as manual plans. However, KBP plans improved D ₂ % (0.95 Gy, P<0.01) and HI (0.02, P<0.01) in Group 1. RapidPlan decreased the average values of V ₃₀ , V ₄₅ and mean dose of bladder in all 3 groups. RapidPlan also generated better mean dose of bowel in 3 groups. Conclusion: KBP does not significantly depend on machine and TPS .

Key words:  Cervical cancer, RapidPlan, Intensity-modulated radiotherapy