Neutron dose from prostheses material during radiotherapy with protons and photons

The purpose of this investigation is to measure the impact of Ti-alloy-prostheses on the neutron dose during proton and photon radiotherapy. Such unwanted neutron dose to the patient should be kept as low as possible (ALARA principle), as such additional dose can create secondary malignancies. For this purpose we performed neutron dose measurements using etch track detectors under the same conditions on a proton and a photon beam line used for radiotherapy. We found no influence of the prostheses material on the neutron dose both for proton and photon treatment.