Dose Course 2018_Flipping book
Factor-based dose calculations basic dosimetric quantities
Phantom scatter factor, S p
(
)
(
)
ref D zs D
;
zs D
;
total
total
ref
(
)
(
)
ref zs
;
; z s D
( )
primary
total
ref
ref
=
sS =
(
)
(
)
p
D
ref zs
;
( primary D z s D ref
;
primary
total
ref
) ref z s
(
) ref z s
;
D
;
ref
primary
ref
( ) s
( ) s
( ) s
D
K
=
s: field size
primary
p
p
if s = collimator setting c at the plane of the isocentre
( ) cS cS ( )
( ) ( ) ref p
( ) ( ) ref p c c
S
cK
( )
cp
cp
S cS
=
=
p
cp
( ) c
cK
)
p
p
p
c
S
(
c
c
p
ref
dose to collision kerma ratio
1 under lateral CPE
AAPM TG 74 report, Med Phys 36 (11), 2009
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