55 / 1578
Margins:
Frame-based versus IGRT-frameless
•
Combs
et al.
(IJROBP 2009), the DKFZ experience comparing
fractionated stereotactic radiotherapy (FSRT) using a relocatable
frame-based mask system and stereotactic radiosurgery (SRS) using
an invasive frame for treatment of Vestibular Schwannoma (N=202):
Ø
Comparable local control rates 96% at 5 years
Ø
The PTV was defined after a fusion of CT/MR images as the area
of contrast enhancement on T1-weighted MRI images, with the
addition
of a 1-2 mm safety margin, both for FSRT and SRS
!
•
Meijer
et al.
(IJROBP 2003), the VUMC experience for Vestibular
Schwannoma (N=129):
Ø
2 Groups: dentate patients – FSRT, edentated patients SRS
Ø
Again,
comparable results
, with small difference in trigeminal
nerve preservation rate in favor of FSRT.
Ø
A
minimum safety margin of 1mm was used in both groups
!
SBRT 2017 - D. Verellen
55