ESTRO 2024 - Abstract Book

S3720

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

ESTRO 2024

3779 vs. 3785 cGy, p < 0.001). Membranous urethra dosimetry was also evaluated and demonstrated no significant difference in maximum or mean between the three groups (p = 0.052 and p = 0.381, respectively). When the entire cohort who underwent any MIB was dichotomized by the median MIB overall volume (< 1.58 vs. ≥ 1.58 cc), no significant differences were observed in prostatic urethra dosimetry, however membranous urethra mean was higher in the larger MIB volume group (3459 vs. 3399 cGy, p = 0.0456). Finally, location of MIB within the transitional zone did not significantly impact urethral dosimetry.

Conclusion:

Robotic SBRT multifocal MIB is dosimetrically achievable while maintaining generally accepted urethral dosimetric constraints. Counterintuitively, intraprostatic urethral mean doses were observed to be lower in those patients undergoing an MIB, perhaps reflecting a planner’s focus on boosting specific prostate locations while sparing others. The larger integral microboost volume may yield more important urethral dosimetric implications rather than the uni- or multifocality of the MIBs. Future research should explore the resultant toxicity and oncologic outcomes when novel MIBs are utilized.

Keywords: Prostate, SBRT, Urethra

2940

Digital Poster

analysis of delivered dose to primary CTV using DIR for OSCC patients with locoregional recurrences

Hannah Price, Kevin Chiu, Andrea Fischer

Mount Vernon Cancer Centre, Radiotherapy, London, United Kingdom

Purpose/Objective: