106 / 1544
M=2.5*√((
1mm
)
2
+(
1.5mm
)
2
+(
0.4mm
)
2
)+0.73*√((
1.5mm
)
2
+(
0.5mm
)
2
+(
1mm
)
2
+(4.05mm)
2
)-0.73*4.05mm
=4.9 mm => 5 mm
Penumbra:
σ
p
=4.05mm
β=0.73
(for 80% isodose)
Prediction error tolerance level of 3 mm
R=3 mm
3 mm
rebuild CM
1.5 mm
σ
= 1.5 mm (dose blurring)
Σ= 1.5 mm (shift)
Gimbals systematic
error
Mechanical tracking
errors
+
marker-TV surrogate
uncertainty
Σ=CT-slice/2=1 mm
Σ= 0.4 mm
σ
= 0.5 mm
3 mm
CTV-PTV margin calculation
Based on Van Herk et al. 2000
Correlation model
Fit errors (
σ
= 1 mm)