Effect of external shielding for neutrons during radiotherapy for prostate cancer, considering the 2300 CD linear accelerator and voxel phantom

► Effect of external shielding to neutron during prostate cancer. ► Linac 2300, external shielding, radiotherapy room and MAX phantom were simulated. ► The results equivalent dose due to the photoneutrons in organs of patients decreased. ► The greatest dose reduction was verified in bone structures, approximately 75%. ► The shielding developed is effective for neutrons, decreasing the dose in patients.