Biodistribution of 68Ga-DTPMP as a potential bone-seeking imaging agent in normal rats and rats with experimental model of bone callus

Abstract

Bone metastases are common in advanced stages of various cancers. Positron emission tomography (PET) with radiotracers based on phosphonates and gallium-68 is a promising method of bone metastases detection. In this work a new complex based on diethylene triamine pentamethylene phosphonate (DTPMP) labeled with 68Ga was developed and its biodistribution in normal Wistar rats and rats with experimental model of bone callus was studied. The biodistribution studies in normal rats revealed high skeletal uptake of 68Ga-DTPMP (up to 1.45 %ID/g in femur) with rapid blood clearance and minimal uptake in any other major organs, except kidneys. In rats with experimental model of bone callus the accumulation of activity in bones and soft organs and tissues was slightly lower as compared with normal rats. The amount of 68Ga-DTPMP in femur with bone callus was higher than in non-lesion bones and reached 1.90 %ID/g at 2 h p.i. Therefore, 68Ga-DTPMP could be a promising radiotracer for bone tumors imaging and could be a valuable alternative to 18F-FDG and 18F-NaF for PET centers without an onsite cyclotron.