Table 2.

Average glandular dose (mGy) per entrance air kerma (mGy) for the BRTES phantom series

kVp	HVL	$D_{\mathit{\text{gN}}}(70\%)\left(1.86\text{cm}\right)$	$D_{\mathit{\text{gN}}}$ (60%) (2.57 cm)	$D_{\mathit{\text{gN}}}(50\%)\left(3.36\text{cm}\right)$	$D_{\mathit{\text{gN}}}(40\%)\left(4.2\text{cm}\right)$	$D_{\mathit{\text{gN}}}(30\%)\left(5.39\text{cm}\right)$	$D_{\mathit{\text{gN}}}(20\%)\left(6.96\text{cm}\right)$
25	0.37	0.338	0.303	0.261	0.219	0.184	0.150
26	0.377	0.345	0.309	0.267	0.227	0.189	0.153
27	0.389	0.356	0.321	0.275	0.235	0.196	0.159
28	0.398	0.365	0.326	0.282	0.242	0.201	0.164
29	0.408	0.383	0.332	0.288	0.251	0.206	0.167
30	0.418	—	0.341	0.296	0.261	0.212	0.171