Dose rate by photon radiation to the basal layer of the epidermis in the case of skin contamination

The dose rate to the basal layer of the epidermis from photon irradiation has been calculated as a function of photon energy from 3 keV to 3 MeV. For higher energies the dose rate has been calculated using the Monte Carlo code EGS4, for lower energies by using a point kernel method. The calculations take into account the full electron transport at higher energies and absorption in the epidermis for lower energies. The distribution of dose within the skin has been calculated for an extended contamination of the skin as well as for a point contamination. The results agree very well with existing values for medium energies, but for small energies (<10 keV) they are larger by a factor of 2 and for higher energies (>1 MeV) they are smaller by a factor of 2 and more. With the values determined for monoenergetic photons the dose rate to the skin by photon irradiation has been calculated for nearly 800 radionuclides. Considering the total dose rate to the skin by also taking into account the dose rate from electrons and positrons, there are differences of more than 30%; from the hitherto known calculations of the total dose rate to the basal layer of the epidermis, for nearly 7% of the radionuclides.