Proton Therapy of eye using MCNPX code

Introduction: Proton radiotherapy is the one of advanced teletherapy methods. The protons deposit their maximum energy in a position called Bragg peak. Therefore, for treatment of cancer, the tumor should be placed at the Bragg peak or SOBP. The scattered photons and neutrons is a challenge in proton radiotherapy. The aim of this study is calculation of absorbed dose from scattered photon and neutron in eye proton therapy.   Materials and Methods: In this study, the simulations were done using MCNPX simulation code. For this, a spherical tumor with 0.6 cm diameter was considered in the eye phantom. The eye phantom has been irradiated with proton beam of 50MeV. Tally F6 was used for dosimetry of scattered neutron and photons.   Results: The results show that the absorbed dose per proton due to scattered neutron and photons in eye tissue are 8.817e-14 Gy and 1.653e-13 Gy respectively.   Conclusion: In proton therapy of eye, the tumor can be treated accurately and the minimum absorbed dose and damage reaches the surrounding tissues. The results show that less than 1% of the total dose of protons is absorbed in the adjacent tissues.