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Dose calculation – AAPM-TG43: S
K
and
Λ
The product of the actual source strength S
K
and the dose rate constant Λ of the source
and radionuclide considered is the actual dose rate at 1 cm radial distance at θ = θ
0
= 90
0
.
Λ =θ
θ
=Λ
.S ) ,r(D
thus
and
) ,r(D
0 0
&
&
(r
0
,
θ
0
)= (1cm, 90
0
)
r
0
= 1cm
Λ is expressed in units of
cGy.h
-1
.U
-1
and
1U = 1 µGy.m².h
-1
= 1
cGy.cm².h
-1
Dose rate is in cGy.h
-1
S
K 0 0
K