engleski

Influence of head cover on the neutron dose equivalent in Monte Carlo simulations of high energy Medical linear accelerator

Neutron contamination of radiotherapeutic photon beam occurs when energies higher than 10 MeV are used in radiotherapy. To correctly assess neutron doses that medical personnel and patients receive, it is highly important to know spectra of produced photoneutrons. One of the most common ways to determine this spectrum is to preform Monte Carlo (MC) simulations of the accelerator. Major issue in the MC modelling is that the manufacturers often does not provide full specifications of the accelerators head so some parts of the head are omitted from the simulation. Within this paper we present model that includes head cover compared to one where it is omitted as it can often be found in the references. Neutron fluxes, spectra, mean energies and place of origin are compared in isocenter, point 1 m above target and point 1 m aside from target in both models. In all considered planes the flux change was found to be more than 20%, with significantly change in neutron energy what is also important in neutron dosimetry. Ignoring the head cover in the MC modelling of the high energy electron linear accelerators in radiotherapy will introduce large uncertainty assessing patient or medical professional neutron doses.

Monte Carlo simulations ; neutron detection ; head cover ; radiotherapy

nije evidentirano