Elemental Mapping of Bone Strontium in Rats Treated with Strontium Ranelate and Strontium Citrate Using 2D Micro-XRF and 3D Dual Energy K-Edge Subtraction X-ray Imaging

Strontium-based medications, such as strontium ranelate, have been shown to have therapeutic effects in the treatment of osteoporosis, other strontium salts are assumed to have similar effects on bone health. The objective of this study was to compare the distribution of strontium in animal bones following administration of strontium ranelate and strontium citrate. Humerus bones were collected from female Sprague-Dawley rats that were dosed daily over ten weeks with strontium ranelate and strontium citrate, and no strontium (control). Bones were imaged using 2D micro-XRF and 3D dual energy KES X-ray imaging. The 2D imaging revealed differences in strontium and calcium levels between samples from treated and non-treated animals (푝 < 0.001). 3D images obtained showed that strontium was observed to be largely present in the trabecular regions under the epiphyseal plate with concentrations of approximately 5 to 15 mg/cm3 in the bones of both strontium treated groups. The thickness of the strontium layers below the growth plate in both the strontium ranelate and strontium citrate sample were not significantly different (푝 = 0.9201). Both imaging studies performed in this work showed that strontium from both salts is heterogeneously distributed in newly formed bone during treatment.