2032-2033 / 2953
Data analysis: gamma index
A gamma analysis compares each calculated value to all measured values, both
in terms of dose deviation and DTA.
r
m
= point in measured distribution
r
c
= point in caculated distribution
r(r
m
,r
c
)= distance between r
m
and r
c
δ
(r
m
,r
c
)= dose deviation in r
m
to r
c
∆d
m
= DTA criterion
For each r
m
, the r
c
with the lowest gamma value is identified.
All r
m
with
γ
≤ 1 have passed the combined gamma criterion. The percentage of
acceptable
γ
-values can be used as an over all agreement measure.
05/04/2016
∆D
m
= dose deviation criterion