The linear-quadratic model and fractionated stereotactic radiotherapy.
OBJECTIVE
To determine the dose per fraction that could be used when gamma knife or linear accelerator-based stereotactic treatments are delivered in 2 or more fractions.


METHODS
The linear-quadratic (LQ) model was used to calculate the dose per fraction for a multiple-fraction regimen which is biologically equivalent to a given single-fraction treatment. The results are summarized in lookup tables.


CONCLUSIONS
The tables can be used by practicing clinicians as a guide in planning fractionated treatment. For the large doses used in typical stereotactic treatments and for small fraction numbers, the model is not very sensitive to the value of the alpha/beta ratio in the LQ model. A simple rule of thumb is found that for two-fraction and three-fraction treatments the dose per fraction is roughly two-thirds and one-half of the single-fraction treatment dose, respectively.
Liu
Lizhong
L
Department of Radiation Oncology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA. liul@upstate.edu
Bassano
Daniel A
DA
Prasad
Satish C
SC
Hahn
Seung S
SS
Chung
Chung T
CT
D016014:Linear Models; D016634:Radiosurgery / Q000706:statistics & numerical data*; D011879:Radiotherapy Dosage; D012016:Reference Values; D012062:Relative Biological Effectiveness