Trace elemental analysis in bone using x-ray microscopy

Following in vivo administration of gallium nitrate, the greatest concentrations of the therapeutic element gallium localized in the metaphysis and at the endosteal and periosteal surfaces of the diaphysis. These are the regions of greatest metabolic activity, where new bone formation and remodeling are occurring. The lowest levels of gallium were noted in the mid-cortical region of the diaphyseal shaft where bone turnover is least. The accumulation of gallium in the metaphysis was associated with a concomitant fall in iron and zinc. The gallium-induced change in the metaphysis may reflect a subtle modulation of metal dependent enzymes that are necessary for the active bone modeling that occurs in this bone region. X-ray microscopy has provided the first insights into the localization and possible mechanisms of action of gallium in bone.