AN ATLAS OF SELECTED BETA-RAY SPECTRA AND DEPTH-DOSE DISTRIBUTIONS INLITHIUM-FLUORIDE FIND SOFT-TISSUE GENERATED BY A FAST MONTE CARLO-BASED SAMPLING METHOD

A method to generate depth-dose distributions due to beta radiation in LIF and soft tissue is proposed. In this method, the EGS4 Monte Carlo radiation transport code is initially used to generate a library of m onoenergetic electron depth-dose distributions in the material for ele ctron energies in the range of 10 keV to 5 MeV in 10 keV increments. A polynomial least-squares fit is applied to each distribution. In addi tion, a theoretical model is developed to generate beta-ray energy spe ctra of selected radionuclides. A standard Monte Carlo random sampling technique is then employed to sample the spectra and generate the dep th-dose distributions in LiF and soft tissue. The proposed method has an advantage over more traditional methods in that the actual radiatio n transport in the media is performed only once for a set of monoenerg etic cases and the beta depth-dose distributions are easily generated by sampling this previously-acquired database in a matter of minutes. This method therefore reduces the demand on computer resources and tim e. The method can be used to calculate depth-dose distribution due to any beta-emitting nuclide or combination of nuclides with up to ten be ta components. Copyright (C) 1996 Elsevier Science Ltd