Table 3.

Central‐axis photon dose difference (Cerrobend ‐ copper) at a depth of $\text{Rp}+1$. Values presented are a percentage of the central‐axis maximum dose. Generally, as the applicator size and energy increase, the difference increases. In addition as the field size increases, the difference decreases.

$\Delta {\mathrm{D}}_x(\%{\mathrm{D}}_{\text{max}})(\text{Cerr}-\text{Cu})$	6 MeV			12 MeV			20 MeV
Field Size (cm2)	Applicator (cm2)			Applicator (cm2)			Applicator (cm2)
	$6\times 6$	$20\times 20$	$25\times 25$	$6\times 6$	$20\times 20$	$25\times 25$	$6\times 6$	$20\times 20$	$25\times 25$
$2\times 2$	0.0%	0.0%	0.0%	0.0%	0.2%	0.3%	0.0%	0.5%	0.5%
$4\times 4$	$-0.1\%$	0.0%	0.0%	0.0%	0.1%	0.2%	0.0%	0.1%	0.4%
$12\times 12$	N/A	0.0%	0.1%	N/A	0.1%	0.1%	N/A	0.2%	0.3%