852 / 1138
The risk of biological „underdosage“ in hypofractionation
Hypofractionation based on
α/β = 1.5Gy
Error analysis based on
α/β = 3Gy
α/β lower than assumed especially critical in treatment with
very high single fraction doses
7,3
4,9
3,9
3,3 2,9 2,6 2,4 2,2 2,0
0
1
2
3
4
5
6
7
8
5
10
15
20
25
30
35
40
45
Single fraction dose (Gy)
# of fractions
90 Gy 2Gy equivalent
74 78 81 83 85 87 88 89 90
0
10
20
30
40
50
60
70
80
90
100
5
10
15
20
25
30
35
40
45
Total dose EQD2 (Gy)
# of fractions
α/β 3Gy instead of 1.5Gy
27
ESTRO SBRT Course 2014 - Emerging SBRT indications
SBRT for prostate cancer