Abstract 

Monte Carlo (MC) radiotherapy treatment planning has become practical in
medical physics, particularly with the rapid development of computer technology.
Requires detailed knowledge of linear medical accelerators (Linacs) beam
radiation. In the present work the basic dosimetric properties of the 6-MV photon
beam and the Varian Clinic 600CLinac were examined. The dosimetric features of
interest are, the absorbed dose from the central axis, beam profiles, photon blockers,
electron and positron, mean energy, spectral distribution, and isodose curves.
Varian Clinic 600C Linac is simulated using the OMEGA BEAMnrc MC code
system. Detailed spectra of phase space profiles of a photon beam with a field of
view of 10 cm × 10 cm were modeled, simulated and finally analyzed using
BEAMdp. The central axis depth dose curves, dose profiles and isodose curves for
photon beams in the aqueous phantom were also recorded and analyzed using the
DOSXYZnrc, STATDOSE and DOSXYZ_SHOW code. This study demonstrates
that MC can generate phase space data files that can be used to generate accurate
MC dose distributions for photon beams produced using a high-powered clinical
linear accelerator in a water phantom or in patients for radiotherapy.