NONDESTRUCTIVE BONE ALUMINUM ASSAY BY NEUTRON-ACTIVATION ANALYSIS

A non-destructive method based on instrumental neutron activation analysis (INAA) for the assay of aluminum in bone samples is described. The Al-28 signal obtained upon neutron irradiation includes contributions from both the reaction Al-27(n, gamma)Al-28 and P-31(n, alpha)Al-28. The first reaction is with the thermal neutrons and the second one is with the fast neutrons. The contribution from the P-31 reaction is calculated from the fact that Ca/P ratio in bone mineral is constant and the amount of calcium can be measured from the thermal reaction Ca-48(n, gamma)Ca-49. The aluminum values obtained by the INAA procedure agreed within 10% of those obtained by atomic absorption spectrophotometry. With this assay the levels of aluminum in normal bones (< 70-mu-g g-1 apatite) cannot be determined reliably but higher aluminum levels in bone biopsies associated with Al toxicity, e.g. some patients with renal osteodystrophy, can be determined with a precision of +/- 10%.