2017_IGRT course book

Intra-fraction

Analysis of motion (random and systematic errors)

0.0

0.3

0.4

0.1

patient 1 patient 2 patient 3 patient 4

0.3

fraction 1 0.5 fraction 2 0.6 fraction 3 0.9 fraction 4 1.3

0.0

0.2 0.3 0.2 0.3

0.7 0.2

_________

-0.5

Mean = 0.2

0.2

-0.4 -0.1

-1.1

RMS of SD = s f

mean

0.8 0.3

-0.4

0.3 0.1

0.1 0.5

mean =M RMS = s SD = S

sd

0.6

M = group systematic error (equipment) S = standard deviation of the systematic (preparation) error s = standard deviation of the random (execution) error s f = standard deviation of the intra-fraction motion {

van Herk et al, Sem Rad Onc 2004