show the calibration curves using EDR2 radiographic film at depthsof 1.5, 10 and 20 cm for field sizes of 11, 22 and 33 cm2, respectively.Figure 5.1.1 (d), (e) and (f) also show the EDR2 calibration curves but they were to compare the field size-dependence at each depth. These films were irradiated for known dose using SSD technique and the image J software was used for data analysis and generating calibration curves. The best-fitting of the curves in Microsoft Excel were performed using a polynomial equation of degree 2. The agreement of the fittings is reported in Table 5.1.1. The R-squared value is approximately greater than 0.999 which showed that the polynomial equation of degree 2 is suitable to predict the calculated data closed to the measured one.