Figure 7.

(a) Subtraction of BEAM (BEAMnrc code, National Research Council of Canada implementation) dose from CCC (collapsed cone convolution, Pinnacle implementation) dose, using an 18‐MV beam with a $10\times 10$ cm field. Dose difference ranges from $-6.2\mathrm{\%}$ ($-0.05\mathrm{\%}$ cGy per monitor unit) to $+6.2\mathrm{\%}$ ($+0.05\mathrm{\%}$ cGy per monitor unit). Black box indicates the area used for gamma calculations. (b) Gamma values taken from the boxed region shown in (a), with 3% and 3 mm parameters.