ESTRO 2024 - Abstract Book

S3505

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

ESTRO 2024

Results:

On average, each center treats about 200 reRT patients per year (range 30 to over 500), and an estimated average of 7% (range 3-16%) of treatments are reRT. Treatment combinations of normo- (N) and hypo- (H) fractionation are on average: NN 29%, HN 15%, NH 32%, and HH 24%. All centers use Dmax constraints which they mainly obtain from literature (81%) and/or derive from first-course constraints with or without recovery (68%). Five centers also use their own clinical data. Regarding dose summation, the majority of centers (94%) use rigid dose registration at least in some cases (25% also apply deformable) and 88% are utilizing an EQD2 approach. As an example, the data for 4 OARs with n>12 are depicted in Fig. 1; the two OARs with lowest inter-center variation (spinal cord and bladder) and two with larger variations (brainstem and rectum). An overview of the variation in reRT Dmax constraints for all OARs is presented in Table 1.