Non-destructive analysis of copper in human brain tissue by neutron activation analysis using coincidence and anti-coincidence techniques

Copper (Cu) is an essential element and is incorporated in many biomolecules that are involved in protecting the brain from oxidative damage. Many blain regions strongly affected by neurodegenerative diseases are small. A sensitive nondestructive procedure to determine Cu is desirable to preserve samples for additional studies. Copper is not easily determined by instrumental neutron activation analysis (INAA) due to high activity levels produced by major abundance elements such as sodium (Na) and chlorine (Cl), which produce a high Compton background. An INAA method involving a short epithermal neutron irradiation and counting with a Compton suppression system was developed to determine Cu in brain, via 5.1-min Cu-66. These short irradiation results are compared to those based on coincidence spectrometry of annihilation photons from positron emitting 12.7-h Cu-64, after a long irradiation.