CPB Ljubljana 2018 course book

Dose calculation – AAPM-TG43: The Radial Dose Function g(r):

g(r): The radial dose function that considers the distance dependence of absorption and scatter of the photon rays in the water medium along the transversal axis, that is the y-axis or equivalently for θ = 90 0 . g(r) is a dimensionless quantity. It is always g(r 0 )=g(r=1cm) = 1.00.

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g(r)

g(r) depends in general on source design and radionuclide. The “Inverse-Square-Law” is filtered out !!!