GDR in Radiotherapy Treatment Fields with 18 MV Accelerators

Abstract

Giant dipole photo-nuclear reactions generated during Linac radiotherapy are of concern due to the undesirable neutron dose delivered to patients. Nuclear track methodology provides an estimation of gradients of photo-neutrons fields in radiotherapy treatments for 18 MV linear accelerators and it revealed an unexpected behaviour around isocenter. Enhancement effects are observed on absorbed dose due to both scattered photo-neutrons and ( ,n) reactions. Thermal neutrons can give a dose boost if the tumour is loaded with 10B and a new BNCT approach combined with the standard photon field is proposed.