Effective Dose per Unit of Fluence Calculated for Adults and a 7 Year Old Girl in Broad Antero-Posterior Beams of Monoenergetic Electrons of 0.1 to 10 MeV

For broad antero-posterior beams of monoenergetic (0.1-10 MeV) electrons organ doses per unit fluence were computed through Monte Carlo simulation in a reference male and female adult and a 7 year old girl. Effective doses (E) per unit fluence were calculated for the three phantoms and for an average adult. E increases from about 8 x 10-14 to about 1.2 x 10-10 Svcm2 with increasing electron energy. Uncertainties were (often much) better than 6% for the adults, and 18% for the child. E as calculated for the average adult may be used for both males and females as under- or overestimations stay within 25% from E for the average adult. The child's radiation risk is underestimated for electron energies in the range of 0.6 to 3 MeV. This underestimation up to a factor of about 20 is unacceptable for radiological protection purposes. The present results were compared with literature data on operational quantities associated with radiation hazard from weakly penetrating radiation. Neither directional nor personal dose equivalent appears to be a realistic quantity in this case. Both would yield an unnecessarily large safety factor for radiological protection.