90 / 1109
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
Accurately calculated in TPSs
Possible to move from isocentre dose (CRT) to median dose
(IMRT) with confidence
•
NB useful to add units e.g D
50 %
or V
20 Gy