IMRT 2018
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 Δd m = DTA criterion ΔD m = dose deviation criterion
For each r
, the r
c with the lowest gamma value is identified.
m
All r
m with γ ≤ 1 have passed the combined gamma criterion. The percentage of acceptable γ -values can be used as an overall agreement measure.
06/06/2018
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