Room scatter studies in the air kerma strength standardization of the Amersham CDCS-J-type 137Cs source: a Monte Carlo study.

Corrections for room scatter, [kSC (d, H)]RM, as a function of source-to-detector distance, d, and source-to-floor-height, H, and also departure from constant room scatter. ks1, have been computed for rooms of various sizes using Monte Carlo methods for air kerma strength standardization of the Amersham CDCS-J-type 137Cs brachytherapy source. These corrections will also be applicable to any type of 137Cs source that may be considered for standardization. It was found that, depending upon the relative position of the source with respect to the surrounding concrete scattering surfaces (side walls, floor and ceiling) and different set of d values, the assumption of constant room scatter overestimated the air kerma strength, Sk, by between 0.2% and 0.6%.