Table 1.

Setup error, motion error and total error

	Mean ± SD [mm] i = 1,..., 8; j = 1,..., 23	Range [mm]
Setup error Δsij
Left-right	0.8 ± 2.8	-8/10
Superior-inferior	0.1 ± 3.4	-9/14
Anterior-posterior	-1.2 ± 3.6	-15/9
Prostate movement Δmij
Left-right	-0.3 ± 1.8	-6/9
Superior-inferior	0.9 ± 2.8	-9/8
Anterior-posterior	0.3 ± 3.5	-10/10
Total error Δtotij
Left-right	0.5 ± 3.5	-10/19
Superior-inferior	0.9 ± 4.4	-14/13
Anterior-posterior	-0.8 ± 4.9	-19/14

Measured deviations for all 184 (= 23 × 8) portal imaging controls (averaged over i = 1,..., 8 weekly portal images in j = 1,..., 23 patients). Mean values <...> in all three directions (left-right LR, superior-inferior SI, anterior-posterior AP) ± standard deviations SD and ranges, i.e. extremal deviations in ± orientations of the axes, in LR, SI and AP direction for setup error <Δs_ij>, prostate movement <Δm_ij> and total errror <Δtot_ij> are listed (see Fig. 2 for explanation of symbols).