In Vivo Neutron Activation Analysis (IVNAA) has been investigated to measure aluminum levels in bone for several years. Aluminum, being a toxic element, should be routinely monitored in both clinical and occupational environments. The non-invasisve IVNAA technique developed at the McMaster University Accelerator Lab is currently being improved for future use. New sets of hand phantoms were prepared that closely resemble spectra that were collected from the hand of healthy subject. Following the IVNAA of aluminum phantoms, the technique was applied for the first time to measure bone A1 levels in 18 healthy subjects. The mean hand bone A1 concentration was determined as 28 µg A1/g Ca. The results were achieved with a dose equivalent of 17.6 mSv. Further investigations using an enhanced detection system and applying optimazation of the irradiation protocol with radiation dose up to 50 mSv showed that minimum detectable limit was improved to 0.10 mg A1.