A method for approximating depth dose distributions in skin from external exposure to beta emitting isotopes is developed. The exposures considered are immersion in uniformly contaminated air or water. A semi-empirical point dose rate function is derived for a point source of monoenergetic electrons and this expression is integrated over an appropriate source target geometry to give dose rate as a function of depth in a tissue-equivalent target (water). The dose rate is summed over the energies comprising a spectrum and any discrete emissions. The model's predictions are compared with a rigorous treatment based on Bergers scaled point kernels. Agreement at the conventional radiological significant depth of 70 μm is generally to within 10% for beta spectra with endpoint energies greater than 0.3 MeV and errs on the conservative side for spectra with lower endpoint energies. The aim of this work was to develop a method for calculating dose rates for spectra which could not easily be found in the literature and also to calculate dose rates at depths shallower than the standard 70 μm, in particular, so that infants and children could be considered.
|Number of pages||5|
|Journal||Radiation Protection Dosimetry|
|Publication status||Published - 1991|