108794.fig.003a
(a)
108794.fig.003b
(b)
Figure 3: (a) PTW 31010 semiflex ionization chamber (PTW-Freiburg, Germany) as a standard without angular dependence. PTW chamber has been irradiated in spherical phantom to determine the ionization along the central axis to various gantry angles. (b) Angular dependence, measurements using EBT2 film and PTW semiflexible chamber.