ESTRO 2021 Abstract Book

S1405

ESTRO 2021

of superposition between thresholded and clinical DILs is shown in Fig. 2.

Conclusion This study confirmed the results published in [2], proving that DW MRI is a promising tool for the assessment of boost regions in PCa radiotherapy treatments. Prostate shape changes were found to be minimal among different image modalities, even if performed in different dates and without/with a spacer. Differences between thresholded and clinical DILs could be reduced by assuring the same patient preparation before acquiring DW MRI and planning CT and by employing a standardised imaging protocol for DW MRI with improved image resolution considering the DILs small volumes. Future research should consider the potential dosimetric effects of the thresholded DIL contouring. [1] S. O. S. Osman et al. , “Class solutions for SABR-VMAT for high-risk prostate cancer with and without elective nodal irradiation,” Radiat. Oncol. , 11(1), 2016 [2] D. Pasquier et al. , “Diffusion weighted MRI as an early predictor of tumor response to hypofractionated stereotactic boost for prostate cancer,” Sci. Rep. , 8(1), 2018 PO-1680 Synthetic-CT generation from T1w brain MRIs with a cascaded GANs ensemble approach A. Lombard 1 , K. Shreshtha 1 , C. Robert 2,3 , T. Roque 4 , F. Fauchon 5 , G. Noël 6 , N. Paragios 7,8 , E. Deutsch 2,3 1 Therapanacea, Artificial Intelligence, Paris, France; 2 Gustave Roussy Cancer Campus, Université Paris Saclay, Molecular radiotherapy and innovative therapeutics, INSERM UMR1030, Villejuif, France; 3 Gustave Roussy Cancer Campus, Department of radiation oncology, Villejuif, France; 4 Therapanacea, Research & Partnerships, Paris, France; 5 Centre des Hautes Energies, Department of radiation oncology, Nice, France; 6 Centre Paul Strauss, Department of radiation oncology, Strasbourg, France; 7 Therapanacea, CEO, Paris, France; 8 CentraleSupelec, University of Paris Saclay, Center for visual computing, Gif-sur-Yvette, France