Course book Advanced Treatment Planning 2018
Parameters for clinical outcome: Brain
Irradiation type (partial organ unless otherwise stated)
Dose (Gy), or dose/volume parameters
Volume segmented
Notes on dose/volume parameters Data at 72 and 90 Gy, extrapolated from BED models
Endpoint
Rate (%)
Dmax <60 Dmax = 72 Dmax = 90
<3 5 10
Symptomatic necrosis
Whole organ
3D-CRT
Whole organ
SRS (single fraction)
Symptomatic necrosis
V12 <5–10 cc
Rapid rise when V12 > 5–10 cc
<20
= d dN BED 1
2 2
+
1
D
120
+ = 1
D
Gy
=
120
/
2
=
60
1
1
1
/
• High sensitivity for fraction doses > 2 Gy • High sensitivity for multi fractions per day treatments • Evidence for neurocognitive injury is weak in adults • For children the cutoff for neurocognitive injury is about 18-24 Gy (whole brain irradiation for medulloblastoma)
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