SBRT2015

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): ! Comparable local control rates 96% at 5 years ! 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): ! 2 Groups: dentate patients – FSRT, edentated patients SRS ! Again, comparable results , with small difference in trigeminal nerve preservation rate in favor of FSRT. ! A minimum safety margin of 1mm was used in both groups !

44

SBRT 2015 - D. Verellen