Study on the improved internal feedback system of Rapidplan model

Objective: To study whether an interactive improved internal feedback system with the model can be established, we aimed to compare the plans generated by two automatic planning models generated under the same conditions. Methods: 70 cases of pelvic patients were selected. Intensity modulated radiation therapy (IMRT) plans (P0) generated by clinical model (M0) were imported into Rapidplan model, in order to establish dose volume histogram (DVH) predicted model through automatic planning model in clinical used, and the new Rapidplan model (M1) was generated by training and structure matching settings. 70 new IMRT plans (P1) were generated by M1, and new Rapidplan model (M2) was training by P1. By the same way, 70 IMRT plans (Plan2) were generated by M2. Dosimetric differences between P1 and P2 were compared and analysised. Results: From the inside of the model, the values of R 2 2 and X 2 2 in P2 were higher than those in P1, and the CD values of bladder, right femoral head and rectum in P1 were higher than those of corresponding organs in P2. The SR value of bladder and the SR and DA values of left femoral head and right femoral head in P1 were lower than those of P2. In terms of planning, the D 2 , D 98 and HI in P1 were better than those in P2 (P<0.01), the bladder V10 and left femoral head V40 in P2 were lower than those in P1 by 0.08% and 0.15%, respectively (P<0.05), the others in P2 were higher than those in P1 (P<0.05) except the bladder V20, D mean , rectum V10, V20, V30, right femoral head V10 and V40; and the MUs of P2 was lower than that of P1 for 132.2 (P<0.05). Conclusion: The stability of M2 is stronger than that of M1. Therefore, it can be considered that the interactive improved internal feedback system within the model of "plan-model-plan-model" is feasible and meaningful.