852-853 / 3581
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
-10.0
-5.0
0.0
5.0
10.0
cone beamZ
epid Z
Correlation CBCT – EPID for lung
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
-10.0
-5.0
0.0
5.0
10.0
cone beamX
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
-10.0
-5.0
0.0
5.0
10.0
cone beamY
epid Y
Left-Right
Sup-Inf
Ant-Post
Setup error measured with cone beam CT
EPID
EPID
EPID
Observer error in CBCT is negligible
large observer error in EPID
such as a clear under-estimation of AP shift (lung)
Slope: 0.81 .. 1.06
0.66 .. 0.88
0.30 .. 0.66 (95% CI)
Borst et al, IJROBP 2007