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Table 3 Random errors

From: Potentials of on-line repositioning based on implanted fiducial markers and electronic portal imaging in prostate cancer radiotherapy

  Mean [mm] j = 1...23 Range [mm] j = 1...23
Random setup error   
Left-right 2.3 -7.9/7.4
Superior-inferior 2.7 -8.6/7.8
Anterior-posterior 2.7 -12.1/5.4
Random prostate movement   
Left-right 1.4 -5.5/6.3
Superior-inferior 2.3 -5.9/8.6
Anterior-posterior 2.7 -7.0/8.0
Random total error   
Left-right 2.9 -8.0/6.6
Superior-inferior 3.9 -11.5/8.2
Anterior-posterior 4.3 -14.9/11.2
  1. The standard deviations of measured deviations Δsij, Δmij, Δtotij around the systematic errors (of each patient j = 1...23) <Δs>j, <Δm>j, <Δtot>j after averaging over i = 1,..., 8 weekly controls provide the random errors sqrt(1/7Σi = 1..8(<Δs>j - Δsij)2), sqrt(1/7Σi = 1..8(<Δmi>j - Δmij)2), sqrt(1/7Σi = 1..8(<Δtoti>j - Δtotij)2) for patient j = 1,..., 23. They are splitted into the RL, SI and AP direction for every error type, i.e. setup error, prostate movement and total error (see Fig. 1 for explanation of symbols). The mean random errors after averaging over 23 patients and their range, i.e. maximum deviations in both orientations of the axes, are given in the table.