Monte Carlo simulation of tungsten target x-ray spectra in TE phantom

The propagation of photons in a tissue equivalent phantom was simulated using the Monte Carlo code EGS. The input spectrum incident on the phantom was based on the measured one previously reported. The radial dependence of the photon spectra was also studied. Trajectories of 20, 40, and 80 keV monoenergetic as well as 120 keV bremsstrahlung photons were plotted. The contribution to the measured energy spectra from the photons scattered in the collimator system was also investigated. (author)