In vivo neutron activation assembly design for quantification of trace elements using MCNP

Background: Trace and essential elements both play a crucial role in maintaining normal cellular and organ functions in human, while abnormal exposure to some of them is also potentially related to diseases, e.g.manganism. To study the association between elemental intake and health outcomes, accurate assessment of elemental uptake and storage in the human body is essential.Objective: Technology based on neutron activation analysis can be used forin vivomeasurement of the trace elements given that the measurement system guarantees a low detection limit with an acceptable dose. This study aims to design and optimize a customized and portable deuterium-deuterium neutron generator-based irradiation assembly for the NAA of trace elementsin vivo,using Monte Carlo simulations.Approach: The irradiation assembly includes a moderator, a fast neutron filter, a reflector, and shielding. The human hand phantoms doped with manganese (Mn) and potassium (K) are used to determine the respective elements' system sensitivity and detection limit.Main results: The calculated detection limit is 0.16μg Mn per gram dry bone (ppm) for Mn and 17 ppm for K, with an equivalent dose of 36 mSv to the hand for 10 min irradiation.Significance: This more sensitivein vivoneutron activation analysis system will detect trace elementsin vivo.