75 / 1224
Food for thought
•
Traditionally, we haven t been using
margins
with the frame-based
SRS!
Ø
It was (is) assumed to be perfect
•
Whilst we might should have used margins!
Ø
There are always uncertainties
•
Should we omit margins in frameless SRS, based on clinical
experience with frame-based SRS (the dose distribution covers it)?
•
The concept of “
frame
” comes from the LGK, where the patient is
mechanically fixed to the frame, which in turn is mechanically fixed to
the delivery machine
•
This concept is
NO LONGER VALID
for linac-based or Cyberknife
systems, where a direct coupling between treatment machine and
patient is absent! IGRT is the only safe way to go!!!
SBRT 2016 - D. Verellen
57