ABSTRACT
The EGS4 Monte Carlo system (Nelson et al., 1985) was used for the earlier work, EGSnrc (Kawrakow, 2000), once it was available. The EGS4/EGSnrc user code BEAM (Rogers et al., 1995) was used for treatment head simulation, sometimes with modification, the MCRTP user code (Faddegon et al., 1998) for dose calculation. The results include experimental validation, showing the accuracy of simulation for practical applications. The devices designed have for the most part been fabricated and tested (with the exception of the secondary scattering foils). Many are commercially available.
