225Ac-MTI-201, formerly 225Ac-DOTA-MC1RL, is a melanocortin 1 receptor ligand labeled with the alpha emitter 225Ac developed at the Moffit Cancer Center and Research Institute, Tampa FL, USA. 225Ac-MTI-201 is targeting the Melanocortin 1 receptor (MC1R) which is expressed in 94% of uveal melanoma metastases. This current application seeks to characterize a potential companion diagnostic imaging agent 67Ga-DOTA-MTI-201 in preclinical models.