ESTRO 2021 Abstract Book

S577

ESTRO 2021

the clinical plans are shown together with the predicted values for all patients. Good correlation was found for selected DVH value: focusing on the lower band predicted values (to be preferred for plan optimization purposes on new patients), R 2 = 0.89 and 0.43 were found for V7 and V10 (Figure 2) respectively, with predicted values slightly lower than the clinical ones, as expected. A worst prediction was found for maximum point dose constraints or dose-volume constraints near to (i.e. V11-V12), probably due to the very small volumes and to the character of hard constraint of D 0.03cc .

Figure 1

Figure 2

Conclusion The feasibility of KB – DVH prediction for spine radiosurgery with CK was demonstrated. The translation of the model into an individually tailored template for automatic plan optimization is currently ongoing.

PD-0748 iCycle-Eclipse: a novel approach to automated multi-criterial treatment planning K. Fjellanger 1,2 , L.B. Hysing 1,2 , B.J.M. Heijmen 3 , H.E.S. Pettersen 1 , I.M. Sandvik 1 , T.H. Sulen 1 , S. Breedveld 3 , L. Rossi 3 1 Haukeland University Hospital, Department of Oncology and Medical Physics, Bergen, Norway; 2 University of Bergen, Institute of Physics and Technology, Bergen, Norway; 3 Erasmus MC Cancer Institute, Department of Radiation Oncology, Rotterdam, The Netherlands Purpose or Objective Automated treatment planning can increase plan quality and consistency while sparing resources, and has become a standard tool in many radiotherapy clinics. Erasmus-iCycle is a well-known system for automated planning, producing Pareto-optimal dose distributions according to a pre-defined wishlist. Here we present a novel approach, where iCycle dose distributions are translated into objective templates for IMRT optimization in Eclipse. The method is validated on a set of locally advanced non-small cell lung cancer (LA-NSCLC) patients, comparing the deliverable iCycle-Eclipse (iC-E) plans to the manually created clinical plans (CP). Materials and Methods An iCycle wishlist for IMRT of LA-NSCLC was developed and tuned according to clinical priorities. An oncologist and a treatment planner were involved in this process. The order of priority for target and OAR objectives was PTV, lungs, heart and esophagus. In addition, there were hard constraints and objectives for normal tissue dose, and maximum dose constraints for the spinal canal, brachial plexus and PTV.