Clinical implementation of automated IMRT/VMAT planning for lung cancer radiation therapy using the expedited...

To develop, clinically implement, and use automated treatment planning for lung cancer radiotherapy (RT) via an in-house treatment planning optimization system, the expedited constrained hierarchical optimization (ECHO).

The ECHO system accepts segmented tumor and normal tissue contours and clinical dose/volume criteria as inputs and generates optimized fluence maps for intensity-modulated RT (IMRT) and leaf trajectories for volumetric-modulated arc therapy (VMAT). Dose/volume criteria for our clinically used seven lung cancer fractionation schedules were implemented in ECHO. For each schedule, ECHO internal optimization parameters were tuned using 5-7 previously treated patients and validated with additional 20-25 patients.

Since May 2021, a total of 431 lung cancer patients have been treated with ECHO IMRT. Additionally, from April 2023, 93 lung SBRT patients were planned with ECHO VMAT. Treatment plans optimized with ECHO IMRT and VMAT provide more consistent target coverage and similar organ sparing compared with manually optimized plans. The average planning target volume was 390 cm³ (range: 12-3441) for IMRT and 17 cm³ (range: 2.5-56) for VMAT. The average optimization time was 33 min (range: 7-126) for IMRT and 56 min (range: 21-178) for VMAT. On average, ECHO-optimized plans save 1.5 h per plan compared to manual planning.

We have implemented an automated system for lung RT treatment planning at our institution for seven fractionation schedules. Our ECHO approach is robust and adapts to changes in clinical criteria without requiring algorithm modifications or retraining. The proposed treatment planning automation framework saves resources and improves treatment plan quality and consistency.