Scatter-air ratios

Abstract

Scatter-air ratios are empirical quantities derived from tissue-air ratios for use in calculating the dose from scattered radiation at a point in an irradiated phantom. Like tissue-air ratios, for each radiation quality, they depend only on depth and beam cross- section but are independent of the distance from the source. Their use for calculations within uniform and non-uniform radiation beams is outlined and the extension to account for tissue- heterogeneities is discussed.