1078 / 1224
Example: systematic uncertainties for target
80%
82%
84%
86%
88%
90%
92%
94%
96%
98%
100%
65
75
85
95
105
115
local control probability
total treatment D
90
CTV
HR
(EQD2
a/b
=10Gy
)
mean +3%
mean +5%
mean +10%
mean +20%
model
TCP
effect of systematic underestimation of target D
90
on observed dose-response
(model based on preliminary retroEMBRACE data:
Tanderup et al, GEC-ESTRO workshop, Brussels, 2013
)
Systematic 1.5 mm applicator reconstruction
uncertainty
for MRI- based cervix BT
(Tanderup et al.,
R&O 2008):
e.g.
D
D90 ≤ +3%/fx => „observed“ local
control @85 Gy <1% higher than model
prediction
Systematically larger contours on CT vs. MRI
=>
underestimation of D90 by CT contours
(e.g.
Viswanathan et al. 2007, IJROBP 68):
e.g. i)
D
D
90
=+10%/fx => 2%
overestimation of local control @ 85 Gy
ii)
D
D
90
=+20%/fx => 3.5% overestimation
of local control @ 85 Gy
small targets,
good coverage
high dose, high
rate of local control