Fig. 5
From: PENELOPE/PRIMO-calculated photon and electron spectra from clinical accelerators
(a) Comparison of 6 and 10 MV photons depth-dose distributions, normalized at the depth of 10 cm, for 10 cm × 10 cm fields obtained from the PSFs (solid lines) with those obtained using the spectrum in a 2 cm × 2 cm central region around the beam central axis (filled circles) and in 10 cm × 10 cm (open circles). Panel (b) is an enlargement of the region around the maximum of the distributions. In all cases the quantity scored in the Monte Carlo simulations is the energy deposition in a region of 1 cm × 1 cm around the beam axis. The corresponding values of TPR 20,10 are given in the insets of panel (a)