IMRT 2017

Radiobiology

The SBRT is based on the Lineal Quadratic Model to compare doses to targets and organs at risk with the doses used in conventional fractionation using the biologically equivalent dose (BED) formulae:

There are some doubts about the use of the LQM in SBRT treatments:

• The LQM in vitro demonstrated fiability to doses up to 15 Gy per fraction. • In vivo the LQM predictions are consistent up to 2-20 Gy.