Output measurement for small field photon beams in a sandwiched phantom

Abstract

Small field dosimetry is challenging for radiotherapy dosimetry. We measured output factors for small fields with EBT film in polystyrene and sandwiched phantom. A comprising a combination of polystyrene and lung equivalent slabs is named Sandwiched phantom. EBT film response is in good agreement (within 1.7%) with the diamond detector for polystyrene phantom. Due to the density variation between the sandwiched phantom layers, the difference between EBT and diamond detector responses is significantly larger than for the homogeneous polystyrene phantom. © 2009 Springer-Verlag.