ESTRO 2023 - Abstract Book

S565

Sunday 14 May 2023

ESTRO 2023

Conclusion Commercial scintillator range verification devices are capable of monitoring depth changes well within the ±1 mm threshold set out in AAPM TG224. They are robust to setup errors and offer a compelling alternative to multi-layer ionisation chambers. MO-0672 Measurement of anatomical changes during proton therapy using the PETITION PET detector K. McNamara 1,2 , M. Béguin 2 , E. Choulilitsa 1,2 , G. Dissertori 2 , J. Flock 2 , C. Fuentes 2 , J. Hrbacek 1 , S. Makkar 1,2 , C. Ritzer 2 , D.C. Weber 1,3,4 , A. Lomax 1,2 , C. Winterhalter 1 1 Paul Scherrer Institute, Center for Proton Therapy, Villigen, Switzerland; 2 ETH Zurich, Department of Physics, Zurich, Switzerland; 3 University Hospital Zurich, Department of Radiation Oncology, Zurich, Switzerland; 4 Inselspital, Bern University Hospital, University of Bern, Department of Radiation Oncology, Bern, Switzerland Purpose or Objective The PETITION PET detector is currently being developed for the purpose of biologically guided proton therapy and proton range verification in Gantry 2 at PSI. We investigate the capability of the detector to recognise changes in patient anatomy during and following treatment. Treatment of a nasopharyngeal tumour in a head phantom with changeable nasal cavity