ESTRO 2024 - Abstract Book

S3466

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2024

Results:

By using the leave-one-out approach, it was possible to evaluate the prediction capability of the OVH-OZH combination. In Figure 1 the total lung OVH and OZH for one reference plan with its nearest four found plans is displayed. In Figure 2, the according DVH curves are shown. For better comparison between the predicted and the clinically achieved DVHs, the mean dose and the V20 of the four predicted OVHs was combined to their average. A mean deviation of 0.029 in V20 index and 1.00Gy in Mean Dose of the total lung were found. The mean of the coefficient of determination R 2 was calculated as another index of prediction capability. As expected, all linear fits had a slope near to 1. Especially the total lung showed a strong linearity between prediction and achieved DVH curves, resulting in a R 2 value close to 1 (0.97 ± 0.02). For the other OARs a similar analysis was done. Heart and Esophagus showed both a high prediction capability, with a R 2 of 0.94 ± 0.06 and 0.93 ± 0.06 respectively. Only the R 2 of the spinal cord is lower than 0.9 (0.89 ± 0.09) and seems to be more planer dependent.