Scatter dose model for therapeutic photon beams

The scatter component of an absorbed dose from therapeutic photon beams in water is studied using a model that treats the buildup and attenuation of scatter dose as separate phenomena. Monte Carlo simulated data for /sup 60/Co and 15 MV photons are used as database for the study. A hypothesis on equal attenuation rate of primary and scatter dose in phantom material is formulated. A method and pertinent data are developed to examine a proposed hypothesis. It is shown that the attenuation of scatter dose with phantom depth can be described by the exponential function given. Thus, the results suggest that the assumption of equal attenuation rate for primary and scatter dose in phantom material is realistic.