Dose 2016
Derivation of formalism to convert ionisation in plastic to dose to water Converting dose in plastic to dose in water
Phantoms irradiated with the same MV photon beam
In water at a reference depth
In solid plastic at an equivalent depth
z
z
eq
ref
Ψ
s
Ψ
w
µ
µ
( ) ref Ψ= z z D w
( ) ref
w β
en
( ) eq Ψ= z z D
( )
β
en
Qw,
ρ
Qs,
eq s
s
ρ
w
s
( ) ( ) ref eq sp,
2
w
+ +
µ
eq SSD r z D r z D ref z
r S
(
)
(
)
=
w s β
en
Qw,
ref
ref
ref eq Qs, ,
ρ
,
SSD
z
r S
ref
ref
sp,
s
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