PhoNeS: A novel approach to BNCT with conventional radiotherapy accelerators

PhoNeS (Photo Neutron Source) is an INFN project devoted to the optimization of the neutron production and moderation in radiotherapy linear accelerators. LinAcs producing high energy (15-25 MeV) photon beams are becoming widespread. At this energy neutron photo-production is unavoidable and the neutron dose must be controlled and reduced during normal radiotherapy. A technique known as BNCT (Boron Neutron Capture Therapy) uses neutrons for radiotherapic treatments: the cells are given a drug containing B-10 which undergoes fission after neutron capture, inducing heavy damages to the DNA of the cell itself. This paper will describe the moderator developed by PhoNeS and the results in terms of neutron flux and spectrum and photon contamination of the measurements performed on several radiotherapy accelerators.