ESTRO 2024 - Abstract Book

S2358

Clinical - Urology

ESTRO 2024

the T2-weighted MRI of that day. A fully adaptive workflow was carried out, involving recontouring and replanning. Radcalc (Lifeline Software Inc) was used as a QA check prior to beam on. In subsequent fractions, the adapted plan created at fraction 1 was used as the reference plan.

Results:

The average patient age was 75 years old. All 15 patients successfully completed treatment using the simulation free workflow, with an average treatment time of 49 minutes for fraction 1 (Figure 1). The dose differences between reference plans and fraction 1 plans are displayed in Figure 2. While the OAR doses were higher in the reference plan compared to fraction 1, all dose constraints were clinically acceptable in both the reference plans and the fraction 1 plans. The higher rectal dose in the reference plans is due to the absence of rectal spacers, which were used in fraction 1.

Figure 1: Patient example of (a) PSMA – PET/CT plan versus (b) fraction 1 plan achieved. Rectal spacing was placed following PSMA – PET/CT.