Neutron spectra inside an adult and children anthropomorphic phantoms in high energy radiotherapy

This work presents the results of the Monte Carlo simulation of the neutron fluence energy spectra at 16 representative points inside three anthropomorphic phantoms mimicking an adult and two children. Simulations were carried out using the MCNPX-2.6.0 code, and the calculation of the neutron spectra for each beam incidence was made in a single simulation file, including the treatment room, each phantom and the linac. Results show that pediatric patients are exposed to higher neutron fluence than adults. Consequences in terms of an increased secondary cancer risk should be analysed.