Design and in vitro evaluation of 223 Ra/ 99m Tc-loaded spherical nano-hydroxyapatite in bone tumor therapy.

Aim: Nano-hydroxyapatite (nHA) is a good nanocarrier to load 223 Ra, but the low specific activity (sp.act.) of 223 Ra@nHA limits its application in medicine. Methods: We proposed a method for preparing nHA using PEG as a template, which significantly increases the sp.act of 223 Ra@nHA and a new method to loaded 99m Tc for in vivo tracking. Results: The nHA synthesized using PEG as a template was associated with higher sp.act for 223 Ra in comparison to nHA with identical particle size and without PEG. The nHA load 99m Tc-MDP was associated with higher labeling rate and stability in comparison to 99m Tc. Conclusion: All these findings suggest that using PEG as a template and 99m Tc-MDP could be the most effective of synthetic 223 Ra/ 99m Tc@nHA.