SU‐E‐T‐650: Evaluation of Novel IMRT Auto‐Planning Tool for Nasopharyngeal Carcinoma Cases

Purpose: Evaluation of newly developed auto‐planning tool for automatic IMRT plan optimization. Methods: A pre‐defined treatment template is used to configure an auto‐planning engine. A template consists of beam configurations, a prescription, PTV and/or PRV expansions, optional isocenter placement, isodose and DVH display settings, prioritized IMRT optimization goals, and IMRT parameters. The auto‐planning engine uses prioritized optimization goals to formulate optimization objectives. Multiple optimization loops iteratively reformulate and adjust the optimization objectives to meet the goals and further drive down organ at risk sparing with minimal compromise to the target coverage. Ten clinically approved head and neck IMRT plans were selected for test. Target dose levels were 70 Gy, 60 Gy, and 56/54 Gy for high‐, intermediate‐, and low dose level PTVs. Objectives of brainstem, spinal cord, parotid gland, oral cavity, and larynx were selected as a common planning objectives. Target doses were normalized so that the highest PTV dose coverage will be the same as clinically approved plans. Maximum brainstem, spinal cord, and parotid gland doses were compared. Mean dose to normal organs, which were defined as mean doses of the entire bodies except the targets, were also compared. Results: Using the auto‐planning tool, we could achieve similar or better results compared with clinically approved plans. For the brainstem and the spinal cord doses, maximum doses were lower in auto‐plans in most cases. For the parotid glands, mean doses were lower in auto‐plans in all cases. NTCPs were lower in auto‐plans for all cases. Mean doses to normal tissues were lower in the auto‐generated plans for all cases. Conclusion: Using the auto‐planning tool, we could achieve the better IMRT plans with less work and time. WA Tome has a research grant from Philips Healthcare.