Table 2

The positioning errors before/after (without/with) online set-up correction in the LR, SI and AP axes in this study (mm)

LR
 SI
 AP


Before
 After
 Before
 After
 Before
 After
mean
 0.3
 0.1
 0.4
 0.0
 -0.2
 0.0
SD
 3.2
 0.7
 4.5
 0.8
 3.9
 0.7
Range
 -12.0 ~ 13.5
 -2.6 ~ 1.4
 -17.2 ~ 16.3
 -2.5 ~ 1.5
 -12.9 ~ 10.9
 -1.9 ~ 1.5
Σ
 1.4
 0.2
 2.1
 0.2
 2.3
 0.1
σ
 3.0
 0.8
 4.1
 0.7
 3.2
 0.7
Theoretic margin
 7.4
 1.7
 10.2
 1.6
 8.8
 1.7
Translational shift
 4.4
 7.2
 5.8

Before: before online set-up correction; After: after online set-up correction; Theoretic margin: calculated by 2.27 × SD based on a pre-selected confidence level of 98%; Translational shift: translational shift of the treatment isocenter in simulated IMRT plan to cover the theoretic margin without online set-up correction in three axes, and calculated as "theoretic margin before online set-up correction-3" mm.

Gong et al. Radiation Oncology 2008 3:11   doi:10.1186/1748-717X-3-11