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Warsaw 2017
The generalised EUD…
a
N
i
a
i i
Dv
gEUD
1
1
D
i
is the dose in the ith voxel; v
i
is the fraction of the ROI occupied by the
voxel.
a is a “biological” parameter, derived from clinical observation and chosen
to reflect the desired radiobiological property, eg:
a < 1 (eg for tumours)….Low doses are given higher weight, so that cold
spots “pull down” the gEUD.
a > 1 (eg for critical organs)….Large doses are given higher weight, so that
hot spots “push up” the gEUD.
a = 1….The calculated EUD is simply the mean dose.
Niemierko, Med.Phys., (1999).
n
i
n
i
i
eff
D
V
D
1
) (