Experimental Study of the Biodistribution of New Bone-Seeking Compounds Based on Phosphonic Acids and Gallium-68

We investigate biodistribution of gallium-labeled hydroxyethylidenediphosphonic acid ( 68 Ga-HEDP) and diethylenetriaminepentakis(methylenephosphonic acid) ( 68 Ga-DTPMP) in intact Wistar rats. It was shown that 68 Ga-DTPMP accumulated mainly in the bone tissue providing high femur/blood and femur/muscle ratios and had high stability in vivo. In contrast, 68 Ga-HEDP was characterized by low stability and high uptake of radioactivity in blood throughout the study. So 68 Ga-DTPMP can be considered as a new prospective radiotracer in oncology for imaging bone tissue metastasis by positron emission tomography.