ESTRO 2022 - Abstract Book

S128

Abstract book

ESTRO 2022

Conclusion Nyul normalization performed best in each ROI. However, it has caveats not addressed in this evaluation, e.g. it affects the image texture. The normalization methods which are based on known tissue characteristics (WhiteStripe and custom) performed well in at most 2 out of 3 ROI. The same was observed for z-score. This suggests that a nonlinear normalization is necessary to achieve consistent intensities for all brain tissue types. This knowledge will be used to further develop the methods.

PD-0154 Early prediction of therapeutic response by regular functional MRI during the treatment of NPC

W.L. Mui 1,2 , A.W.M. Lee 2 , W.T. Ng 2 , V.H.F. Lee 2 , V. Vardhanabhuti 3 , S.Y. Man 1 , D.T.T. Chua 4 , X.Y. Guan 2

1 Hong Kong Sanatorium and Hospital, Department of Radiotherapy, Hong Kong, Hong Kong (SAR) China; 2 The University of Hong Kong, Department of Clinical Oncology, Hong Kong, Hong Kong (SAR) China; 3 The University of Hong Kong, Department of Diagnostic Radiology, Hong Kong, Hong Kong (SAR) China; 4 Hong Kong Sanatorium and Hospital, Department of Medicine, Hong Kong, Hong Kong (SAR) China Purpose or Objective Conventional magnetic resonance imaging (MRI) is used to review tumour morphological changes. Functional MRI measures tumour physiological changes like vascular permeability, cellularity and metabolite concentrations, which occur earlier than morphological changes during treatment. Whether these early physiological changes in nasopharyngeal tumours during treatment can be predictive biomarkers for treatment outcomes are still unknown.