Comparison of doses calculated by the Monte Carlo method and measured by LiF TLD in the buildup region for a 60Co photon beam

This work studied the percent depth doses of 60Co photon beams in the buildup region of a plastic phantom by LiF TLD measurements and by Monte Carlo calculations. An agreement within ±1.5% was found between PDDs measured by TLD and calculated by the Monte Carlo method with the TLD in a plastic phantom. The dose in the plastic phantom was scored in voxels, with thickness scaled by physical and electron density. PDDs calculated by electron density scaling showed a better match with image; the difference is within ±1.5% in the buildup region for square and rectangular field sizes.