Figure 1
From: Testing the portal imager GLAaS algorithm for machine quality assurance
Flattening filter and arm-backscattering correction. Example for an open 15 × 15 cm2 field of Gamma Evaluation matrices (DTA = 3 mm, ΔD = 3%) a) without corrections, b) with flattening filter correction, c) with both flattening filter and arm backscattering correction, d) profiles in x and y directions for 10 × 10, 15 × 15 and 20 × 20 cm2 fields from Eclipse calculations, PV-GLAaS without, with flattening filter, and with flattening filter + arm backscattering corrections included. Data are shown at dmax for a beam energy of 6 MV.