Design and in vitro evaluation of ²²³Ra/^99mTc-loaded spherical nano-hydroxyapatite in bone tumor therapy

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