ESTRO 2020 Abstract book

S847 ESTRO 2020

Our study shows electron modulated bolus is feasible as it not only increases the conformity of the electron beam to the PTV, but also decreases the dose to organs-at-risk. However, the drawback is the increase of monitor units. The bolus can be printed in 3D printer. PO-1483 Evaluation of an artificial intelligence driven planning system for online adaptive radiotherapy L. Calmels 1 , L. Andersson 1 , D. Sjöström 1 , M. Sjölin 1 , P. Sibolt 1 1 Herlev hospital, University of Copenhagen- Radiotherapy Research Unit, Herlev, Denmark Purpose or Objective Treatment planning has become more sophisticated over the past decade enabling creation of complex, dynamic radiotherapy plans with conform dose distributions, securing target coverage while sparing normal tissue. More recently artificial intelligence (AI) has been utilized to better support the planners. The aim of this study was to compare the dosimetric performance of intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans generated with both AI driven treatment planning system (TPS), developed for online adaptive radiotherapy, and standard TPS for different treatment sites. Material and Methods The TPS for AI-driven automatic generation of radiotherapy treatment plans uses clinical goals and dose constraints to build the underlying optimization objective functions. These sets of planning directives were, for a range of treatment sites, optimized and saved as templates in order to ensure highest rate of fulfilled goals. Systematic generation of two IMRT (9 and 12 field) and two VMAT (2 and 3 arc) treatment plans, in an emulator with a pre-clinical version of the AI-driven TPS, was based on those same templates. The reference treatment plans were correspondingly optimized to achieve the best level of target coverage with an optimal sparing of organs at risk (OARs). The automatically generated plans were transferred from the AI driven TPS to the standard TPS and compared to the reference plan. The Dose-volumetric data for the planning target volume (PTV) and for the relevant OARs, the homogeneity index (HI), the conformity index (CI), the modulation factor in terms of number of Monitor Units (MU) per Gy, and the dose to the normal tissue of both treatment approaches were all compared. Results