Monte carlo dose calculations in conventional thorax fields for 60Co photons.

Purpose: Our purpose was to apply the MCNP4C Monte Carlo (MC) code for dose calculations in the thorax region and compare the results with those of measurements and a conventional treatment planning system (TPS).

Materials And Methods: We modeled a Theratron 780E 60Co unit and benchmarked our modeling with percent depth doses (PDDs), beam profiles, and output factors measured in a water phantom. For PDDs and beam profiles, the differences between measurements and MC calculations were less than 1% and 2%, respectively.