176 / 1031
Prescribing
•
Specify median dose ‐ D
median
= D
50 %
Corresponds best to previous ICRU reference point dose
(≈ isocentre dose)
•
Often close to mean dose
•
Not influenced by ‘tails’ on the DVH
•
Acc ratel calc lated in TPSs
u y
u
NB useful to add units e.g D
50 %
or V
20 Gy