Target Volume Determination 2015

High grade glioma - PTV

Use the ‘ Margin Recipe ’ - PTV = 2.5 Σ + 0.7 σ

Systematic errors (mm) Gaussian Σ doctor

Measure the standard deviations in each department

0.0 0.0 0.1

0.0 0.0 0.1

0.0 0.0 0.1

Σ motion Σ transfer Σ set-up

0.25

0.25

0.25

0.3

0.3

0.3

Σ (combined)

Linear b

0.0 0.0

0.0 0.0

0.0 0.0

a

Treatment Execution errors Gaussian σ set-up

Our dept – PTV margin = 0.3 cm with IGRT

0.3 0.0 5.5 5.5

0.3 0.0 5.5 5.5

0.3 0.0 5.5 5.5

σ motion(target shape)

σ p

σ (combined)

Planning parameter ( β)

1.64

1.64

1.64

Semi-sides systematic execution

0.7 9.0 0.0

0.7 9.0 0.0

0.7 9.0 0.0

breathing

scalar (a- βσ p)

-9.0

-9.0

-9.0

Total CTV-PTV margin

0.7

0.7

0.7