CPB Ljubljana 2018 course book

Dose calculation – AAPM-TG43: The Dose Rate Constant 

The dose rate constant, Λ, is defined as the dose rate to water in water at the reference point, namely at a distance of r 0 = 1 cm on the transverse axis (θ 0 = 90 0 ), per unit air kerma strength, S K :

0 )= (1cm, 90 0 )

(r

, θ

0

r

= 1cm

0

Λ is expressed in units of cGy.h -1 .U -1 and 1U = 1 µGy.m².h -1 = 1 cGy.cm².h -1