The RFO was analyzed using two methods briefly described above: a MLC defined field size and a SMLC sweeping leaf test. For the first test, the MLC was set to a nominal
field size of 8 cm×8 cm with the jaws retracted 0.5 cm beyond the MLC defined field size. With the gantry at 0◦and the collimator at 0◦(IEC), Kodak EDR2 film was placed on the couch at 100 cm source to surface distance (SSD) and irradiated using 130 MU of 6 MV photons. The light field
was marked on the film and compared to the radiation field defined by the FWHM. This was repeated for a field size of 16×16 cm2 , and for photon energies of 10 MV and 15 MV.