Neutron activation analysis of manganese in samples of human sternum

A compact neutron activation analysis (NAA) system utilizing a deuterium-deuterium (DD) neutron generator was developed to detect manganese (Mn) in bone in vivo. Mn was selected for study due to the elevated risk of overexposure among certain occupational groups and segments of the general population, which can result in irreversible neurotoxic effects. To improve the accuracy of DD neutron generator-based in vivo NAA (IVNAA) system, 12 human cadaver bone samples were analyzed. The system was evaluated, and good agreement was observed between its results and the conventional reactor-based NAA across six irradiated samples. The remaining samples, however, showed discrepancies-likely due to presence of residual soft tissue or the fact that some of the samples are not really bones. A major limitation in analyzing these samples was the lack of calcium (Ca) signals, which prevented Mn/Ca normalization, a critical step for correcting geometric and mass-related variations. These results emphasize the importance of proper sample preparation and verification when conducting ex vivo measurements with the laboratory system. In contrast, in vivo NAA is less affected by such inconsistencies due to a more consistent bone composition and hence the ability to normalize Mn levels to Ca. Overall, accurate application of NAA in environmental and health research requires careful consideration of sample integrity and appropriate normalization methods.