Figure 6.

(a) Subtraction of BEAM (BEAMnrc code, National Research Council of Canada implementation) dose from FMC‐NX [fast Monte Carlo code, NumeriX LLC (New York, NY) implementation] dose. Dose calculated using an 18‐MV beam set to a $10\times 10$ cm field. Displayed dose ranging from $-8.7\mathrm{\%}$ ($-0.07\mathrm{\%}$ cGy per monitor unit) to $+8.7\mathrm{\%}$ ($+0.07\mathrm{\%}$ cGy per monitor unit). The red line indicates where the profile for Fig. 8 was taken. (b) Gamma values taken from the boxed region shown in (a), with 3% and 3 mm parameters and 7640 of 7725 voxels having a γ of 1 or less.