ESTRO 2023 - Abstract Book

S645

Monday 15 May 2023

ESTRO 2023

We found significant differences (Wilcoxon signed-rank test) in spatial normalisation between CT- and MRI- based pipelines (p<0.001, Figure 1), however the magnitude of these differences was small (<1 mm). Both IBDM pipelines identified clusters containing the modified dose region ( > 99.9% significance, i.e. family-wise significance of alpha = 0.001) for all structures (Figure 2). IBDM-identified clusters tended to extend beyond the regions of modified doses in the hippocampi and hypothalamus irrespective of whether CT or MRI scans were used, likely due to their location in regions of low dose variability.

Conclusion CT- and MRI-based IBDM pipelines offer comparable reliability to identify dose-response associations in paediatric brain tumour data. Although MRI offers superior contrast, CT-based IBDM remains a viable option to enable multi-institutional data collection and retrospective studies for late effects research.

OC-0777 Automated analysis of internal facial asymmetry on MRI in children A. Davey 1 , A. Bryce-Atkinson 1 , E. Vasquez Osorio 1 , M. van Herk 1 , A. Datta 1 , S. Pan 2 , P. Sitch 2 , G. Whitfield 3 , M. Aznar 1 1 The University of Manchester, Division of Cancer Sciences, Manchester, United Kingdom; 2 The Christie NHS Foundation Trust, Department of Proton Therapy, Manchester, United Kingdom; 3 The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom