Study on the feasibility of quality improvement for automatic plans based on rapid plan model

To study whether an interactive improved internal feedback system with the model can be established, we compared the plans generated by two automatic planning models.

Seventy cases of pelvic patients were selected. Intensity-modulated radiation therapy (IMRT) plans (P0) generated by the clinical model (M0) were imported into the Rapid plan model to establish a dose-volume histogram. The predicted model through automatic planning model in clinical, and the new rapid plan model (M1) was generated by training and structure matching settings. The 70 new IMRT plans (P1) were generated by M1, and the new rapid plan model (M2) was trained by P1. In this same method, 70 IMRT plans (P2) were generated by M2. Dosimetric differences between P1 and P2 were then compared and analyzed.

For the model parameters, R² and X² in P2 were higher than those in P1, and the CD values of the bladder, right femoral head, and rectum in P1 were higher than those of corresponding organs in P2. The studentized residual (SR) value of the bladder and SR and difference of estimate values of the left femoral head and right femoral head in P1 were lower than P2. In planning, (D₂, D₉₈, and HI) P1 were better than P2 (P < 0.01); the bladder V10 and left femoral head V40 in P2 were lower than in P1 by 0.08% and 0.15%, respectively (P < 0.05); 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).

The stability of M2 is stronger than that of M1. Therefore, the interactive improved internal feedback system within the model of "plan-model-plan-model" is feasible and meaningful.