ESTRO 2023 - Abstract Book

S1334

Digital Posters

ESTRO 2023

Conclusion Our in-house DL-based planning solution based on fluence prediction has potential to be used for ART on sCT+D or D+RS as input. However, in most cases, it led to plans with higher doses on OAR and underdosage on PTV in comparison with current planning. The AI-model seems to be focusing more on the relation between initial beam dose and corresponding fluence maps but investigating this in-depth is required. Furthermore, the need for better CBCT-imaging is essential for improved veracity of the actual anatomy. By this, we can avoid using sCT’s and eliminate associating uncertainties.

PO-1638 Physician-specific preferences yield minor differences in knowledge-based planning generated plans

R. Kaderka 1 , N. Dogan 1 , E. Bossart 1

1 University of Miami, Radiation Oncology, Miami, USA

Purpose or Objective Knowledge-based planning (KBP) models can automate, standardize and improve treatment planning. Training KBP models requires many plans, and the effect of a particular physician’s preferences on a model is unclear. We developed four head and-neck (HN) KBP models to evaluate whether model or using a model with plans from a single physician impacts plan quality. Materials and Methods Four HN models were built in a commercial KBP solution: “Full” was trained with 207 plans, while “Half”, Physician “A”, and Physician “B” models were trained with 101 patients each. Full and Half were trained with a mix of patients treated by physicians A and B, while the A and B model were trained with only a single physician’s plans. As optimization objectives and priorities have a considerable impact on KBP plan quality, optimization parameters were adjusted iteratively on the Full model to maximize plan quality then applied to all models. Differences between plans created from different models result solely from variations in the training sets and not from mismatched parameters. 39 validation patients were re-planned with each of the four KBP models. Plan quality was tested in terms of dosimetric parameters for Body, PTV High/Int/Low, brainstem, cochlea, constrictors, cord, eyes, mandible, larynx, optic chiasm, optic nerves, oral cavity, parotids and submandibular glands. Each plan was compared to the manually created clinical treatment plan and the four KBP model created plans. Differences between plans were tested for significance using a paired t-test (p<0.05). Results The comparison of the clinical, Full and Half plans is shown in Fig. 1. The boxplot compares the distribution of mean doses with brackets indicating statistical significance. Both the Full and Half models decrease dose to the cochlea, constrictors and larynx, but increase dose to the left parotid slightly compared to the clinical plan. Dose to the left cochlea is slightly elevated and larynx dose is slightly reduced in the Half model compared to the Full model. No other parameters were statistically significant. Differences in plans between models were <0.5Gy.