ESTRO 2021 Abstract Book

S237

ESTRO 2021

Conclusion The PDD and dose profiles, at various depths, of an eBT source have been measured under full scatter conditions in a water phantom for the first time with high spatial resolution. The measurements were performed with a novel PSD system, which offers a simple method for QA of the relative absorbed dose to water of eBT treatment units. The method can easily be transferred to other low energy X-ray sources. References: [1] Primary Standards and Traceable Measurement Methods for X-ray Emitting Electronic Brachytherapy Devices, Publishable Summary (2018): [2] O. Croce, S. et al. Radiation Physics and Chemistry 81 (2012) 609-617

Poster highlights: Poster highlights 12: Miscellaneous

PH-0326 Treatment for recurrent Ependymoma : A retrospective and multicentric French study J. desrousseaux 1 , L. Chaltiel 2 , L. Claude 3 , L. Padovani 4 , A. Ducassou 1 , S. Bolle 5 , J.L. Habrand 6 , C. Carrié 3 , X. Muracciole 7 , A. Escande 8 , C. Alapetite 9 , S. Supiot 10 , V. Bernier-Chastagner 11 , A. Huchet 12 , J. Lesueur 13 , C. Kerr 14 , G. Truc 15 , S. Servagi-Vernat 16 , P. Leblond 17 , A. Bertozzi 18 , S. Boetto 19 , A. Sevely 20 , F. Tensaouti 21 , A. Laprie 22 1 Institut Universitaire du Cancer de Toulouse, Radiotherapy, Toulouse, France; 2 Institut Universitaire du