ESTRO 2022 - Abstract Book

S542

Abstract book

ESTRO 2022

OC-0618 Comprehensive 3D verification of SRS treatments with virtual spherical phantom EPID dosimetry

P. Greer 1 , C. Dempsey 1 , G. Kaur 1 , B. Zwan 2 , K. Kandasamy 2 , J.F. Calvo-Ortega 3 , P. Ostwald 1

1 Calvary Mater Newcastle Hospital, Radiation Oncology, Newcastle, Australia; 2 Central Coast Cancer Centre, Radiation Oncology, Gosford, Australia; 3 Hospital Quirónsalud Barcelona, Servicio de Oncología Radioterápica, Barcelona, Spain Purpose or Objective SRS and HyperArc stereotactic radiosurgery techniques deliver multiple VMAT arcs with fixed couch angles. Dosimetric verification of this technique is time consuming, and it is difficult to verify multiple target deliveries adequately. A new method was developed where EPID frames captured during each arc are used to reconstruct 3D dose in a 20 cm diameter water equivalent virtual spherical phantom (VSP) incorporating couch rotations.