872-873 / 2063
Craniospinal irradiation case
•
What is the physical dose in the overlap zone?
- D = 7 x 3,1 Gy + 2 x 6,2 = 33,9 Gy
•
Do we exceed the spinal cord tolerance, regarding the
biological dose in the overlap zone?
(α/β is assumed to be 2 Gy for spinal cord late toxicity)
- EQD
2
= D
- EQD
2
= 21,7 x
= 27,67 Gy (7 fractions)
- EQD
2
= 12,4 x
= 25,42 Gy (2 overlap fractions)