Figure 9.

(a) Subtraction of CCC (collapsed cone convolution, Pinnacle implementation) from FMC‐NX [fast Monte Carlo code, NumeriX LLC (New York, NY) implementation], with an 18‐MV beam and field set to $5\times 5$ cm. Dose values range from $-10.6\mathrm{\%}$ ($-0.08\mathrm{\%}$ cGy per monitor unit) to $+10.6\mathrm{\%}$ ($-0.08\mathrm{\%}$ cGy per monitor unit). (b) The 6‐MV $3\times 3$ cm beam shows a wider penumbra for collapsed cone. Subtraction of CCC from FMC‐NX, with dose ranging from $-14.2\mathrm{\%}$ ($-0.1\mathrm{\%}$ cGy per monitor unit) to $+14.2\mathrm{\%}$ ($+0.1\mathrm{\%}$ cGy per monitor unit). The red line indicates the location from which the profile for Fig. 11 was taken. (c,d) Gamma values taken from the regions shown in (a) and (b) respectively, with 3% and 3 mm parameters.