CPB Ljubljana 2018 course book

Dose calculation – AAPM-TG43: The Source Strength

That is, the air kerma strength, S K , defined as the product of the air kerma rate in free space at a measurement distance r from the source center along the perpendicular bisector, K a (r), and the square of the distance r. This is the actual strength of the specific source we consider.

The recommended unit for air kerma strength S K is µGy.m².h -1 and has been denoted by the symbol U: 1U = 1 µGy.m².h -1 = 1 cGy.cm².h -1

r