Analysis and modifications of two in vivo methods for determining fluorine content in bone

Abstract

Non-invasive techniques to measure bone fluorine levels in vivo are few and not well studied. These techniques would prove useful for longitudinal studies of fluorine accumulation and treatment optimization for patients with poor bone health. Two measurement techniques were analyzed and improvements to each technique attempted with bone samples and bone-mimicking phantoms. The first method analyzed was neutron activation analysis (NAA), a technique previously studied in our laboratory. A previous detector setup consisting of nine sodium iodide detectors was re-tested and a new detector setup consisting of two high-purity germanium detectors was also tested. The detection limit of the sodium iodide setup was found to be higher than previously reported by a factor of 4, and the new high-purity germanium detector setup was found to result in a higher detection limit by a factor of 5 compared to the sodium iodide setup. The second method analyzed was nuclear magnetic resonance (NMR). Magic angle spinning was performed on a human bone sample, and a novel probe was constructed for future in vivo measurements. MAS NMR measurement of the human bone sample showed it to have an appropriate chemical shift and shape consistent with previous research on substances similar to bone. The constructed probe successfully resonated at the appropriate frequency, however there were potential contamination problems which prevented a measurable fluorine signal from being obtained. Both the NAA and NMR techniques may be optimized further, though with the results obtained, NAA remains the more sensitive technique for measuring bone fluorine in vivo.