67 Ga-labeled human fibrinogen: a new promising thrombus imaging agent.

Gallium-67 labeled fibrinogen was prepared as a new deep-vein thrombus imaging agent, using deferoxamine (DF) as a bifunctional chelating agent. Excellent physicochemical and biological properties of 67 Ga-DF-fibrinogen were obtained. The isotopic clottability was 85.3%. High stability in vivo as well as in vitro was observed. Studies carried out in rabbits with induced thrombi in the femoral vein showed thrombus to blood radioactivity ration of 11.7, comparable to the value estimated with conventional 131I-fibrinogen 24 h after injection. Remarkable visualization of these thrombi with a scintillation camera provided good evidence for the selective mechanism of this new radiopharmaceutical.