ESTRO 2024 - Abstract Book

S3472

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

ESTRO 2024

Figure 2: OAR dose statistics comparison between patients treated with (blue) and without (red) optimisation objective to limit maximum dose to CAA.

The median value of CAA mean dose is reduced from 7.5Gy to 5.2Gy after introduction of the CAA dose limiting optimisation objective (P<0.001), and 1cc max dose is reduced from median 29.0Gy to 17.5Gy (P<0.001). Figure 2b shows a large peak in the cohort 2 histogram at just less than 20Gy, which is not present in the cohort 1 histogram. This is caused by plans where the CAA 1cc max dose would previously have been higher than 20Gy being optimised to reduce the CAA max dose to below 20Gy. Figure 2b also shows that some patients in cohort 2 still have CAA maximum dose greater than 20Gy. These are cases where the PTV is close to or overlapping with the