1254 / 1674
Take home message:
By using hypofractionation the therapeutic ratio allways falls
α/β
39/13
40/15
50/25
1.8
49.3
47.1
50
2
48.8
46.7
50
3
46.8
45.4
50
4
45.5
44.7
50
6
43.9
43.4
50
8
42.9
42.7
50
10
42.3
42.2
50
Tumor dose is only acceptable if the tumor α/β is very low
If the α/β for tumor is higher than the α/β
for late morbidity,
and
you titrate the
treatment according to late morbidity,
you must accept to underdose tumor!
Based on PRE-START and START trials: tumor α/β is around 4-5 Gy