Physics Bucharest 2017
6/3/2017
The inverse problem How do we create the cost function Optimise:
Physical dose Target coverage (min, max, …) Target homogeneity OAR exposure (max, …) Surrounding tissues …
Biological effect TCP, NTCP EUD …
DVH goals
21
ESTRO physics course 2017
Cost function
Penalty for not having uniform dose d 0 (optimising uniformity in target)
Is the relative weight factor
1
2
T
C
d d
i
0
n
Ti
T
1
d
Penalty for any dose to OAR (minimising the mean of the OAR)
OAR
1
i
n
OAR i
1
OAR
1
1
H
d d d d
OAR
2
i
0
i
0
n
OAR i
2
OAR
2
Penalty for dose above “tolerance dose d 0 (keeping max dose below d 0 )
“ in OAR
H(x)
22
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