Attenuation Factors for X Rays in Terms of Ambient and Effective Dose Equivalent

Limitation of the risk due to occupational radiation exposures is ensured by limiting the effective dose equivalent, HE. The dimensions of barriers which are to attenuate the primary radiation to acceptable levels are usually based on measurements of quantities free-in-air such as air kerma. In the present study, the attenuation of the quantities fluence and air kerma free-in-air by various layers of water, aluminium and lead was compared with that of the quantities effective dose equivalent. HE and ambient dose equivalent, H*(10). It was found that in the energy range relevant to diagnostic radiology the attenuation of air kerma can be significantly higher than that of HE and that barriers based on measurements of air kerma might, therefore, be insufficient.