Gynae BT_Lucknow_2018

Skin marks versus daily bony registration

 Daily image guidance with bony fusion

CT

 Initial set-up according to skin marks

 Image fusion according to bone



Verification of fusion

CBCT



Couch correction



Typically 5mm PTV margin

 Set-up on skin marks (no daily image guidance):



Imaging at first RT or e.g. weekly Typically 7-10mm PTV margin

Vertical [mm]

Lateral [mm]

Longitudinal [mm]

Variable

Mean (M)

0,4

2,7

0,4



Σ

3,6

2,9

2,6

σ

3,6

3,2

2,4

Margin*

11,6

9,6

8,2

*Van Herk formalism: 2,5*Σ+0,7*σ Semin Radiat Oncol 2004; 14:52-64

L.Laursen, RO 105 (2012) 220–225

10