Figure 6. Ratios between depth dose curves with and without heterogeneities for (a) lung, (b) 1.35 g cm^-3 bone, and (c) 1.85 g cm^-3 bone. The shaded region in each graph shows the position of the inhomogeneity. Measurements with film (squares) and ionization chamber (circles) are compared with calculated values (lines). All measurements are for a 5 cm x 5 cm 10 MV field at gantry angle 5°. (d) Ratios between doses with and without heterogeneities at various distances beyond a region of lung density. Measurements using an ionization chamber are compared with calculated values for 6 MV and 10 MV beams with gantry angle 0°.