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Purpose In this study, DOTA-IBA was radiolabeled with 68 Ga and we determined the optimum labelling conditions and assessed the biological properties of 68 Ga-DOTA-IBA. We investigated the biodistribution of 68 Ga-DOTA-IBA in normal animals and undertook PET/CT imaging in humans. Finally, we explored the feasibility 68 Ga-DOTA-IBA as a bone imaging agent and demonstrated its potential for the therapeutic release of 177 Lu/ 225 Ac-DOTA-IBA. Methods The controlled variables method was used to assess the impact of variables on the radiochemical purity of 68 Ga-DOTA-IBA. The biological properties of 68 Ga-DOTA-IBA were investigated. 68 Ga-DOTA-IBA micro-PET/CT imaging was performed on animals. Volunteers were recruited for 68 Ga-DOTA-IBA imaging and data were compared to 99m Tc-MDP imaging studies to calculate the target to non-target ratio (T/NT) of the lesions. Results The prepared 68 Ga-DOTA-IBA had a radiochemical purity of 97% and demonstrated good biological properties with a good safety profile in normal mice. PET/CT imaging of the animals showed rapid blood clearance with high contrast between the bone and stroma. Human imaging showed that 68 Ga-DOTA-IBA could detect more lesions compared to 99m Tc-MDP and had a higher targeted to untargeted ratio. Conclusions 68 Ga-DOTA-IBA is an osteophilic radiopharmaceutical that can be synthesized using a simple labelling method. 68 Ga-DOTA-IBA has high radiochemical purity and is stable in vitro stability. It is rapidly cleared from the blood, has low toxicity and has strong targeting to the bone with long retention times. We also found that it is rapidly cleared in non-target tissues and has high contrast on whole-body bone imaging. 68 Ga-DOTA-IBA PET/CT has potential as a novel bone imaging bone modality in patients with metastatic disease.
Wang et al. (Wed,) studied this question.