Abstract ID: 98 Measurement of the induced neutron ambient dose equivalent during proton therapy in scanning mode

Abstract

The purpose of this study is to evaluate secondary neutron ambient dose equivalent, which simulated and measured four positions around a plastic water phantom on a couch. We compared and analyzed the secondary neutron dose during proton treatment with scanning mode of each gantry. [1] , [2] . The volume of the plastic water phantom was 30 × 30 × 60 cm 3 and was located at the isocenter. The phantom was irradiated by a proton beam at 190 MeV. Proton beams were used to irradiate a volume of 10 × 10 × 10 cm 3 centered at the isocenter in each nozzle. In addition, WENDI 2 detector was used as a neutron measuring device to measure the neutron ambient dose equivalent. We performed experiments under the same conditions as those of FLUKA simulation. The ambient dose equivalent value was normalized to the maximum value at each nozzle of scanning mode. Each normalized neutron flux in the simulation and experiment showed similar tendencies. We successfully simulated and measured the neutron ambient dose equivalents at four positions generated by the scanning mode. These results prove that the simulation data provides reliable data of the induced neutron dose. Our results provide sufficient reference for the occurrence of secondary neutron during proton therapy.