The microdosimetry of radon daughters and its significance

The value of the quality factor for radon daughter alpha particles is of some societal significance. The quality factor is usually taken to be the result of folding a radiation quality descriptor function with an appropriate weighting function. In this work we (a) calculate radiation descriptors (microdosimetric spectra) as a function of depth in the epithelium (b) calculate a relevant weighting factor, QT(y) for oncogenic transformation, and (c) fold these together to get an estimate of the low dose relative effectiveness of the alpha particles as a function of depth. The results show a considerable variation with depth, and are also very sensitive to the saturation characteristics of QT(y), implying that more experimental data are needed in the range from 150 to 360 keV.μm-1. (author)