Biodistribution of phenylalanine labeled with gallium-68

Abstract

Abstract Positron emission tomography (PET) is modern high sensitivity method of various tumor imaging. The synthesis of new radiopharmaceuticals based on amino acids and positron emitting radionuclide 68Ga for PET imaging is of great interest. This work is devoted to study the biodistribution of a new agent based on amino acid phenylalanine and 68Ga (68Ga-phenylalanine) in Wistar rats with cholangioma RS-1 after intravenous administration. A comparative investigation of 68Ga-phenylalanine and 68GaCl3 biodistribution was also carried out. It was shown that the highest uptake of 68Ga-phenylalanine was observed in blood, liver, femur and tumor. Tumor uptake of 68Ga-phenylalanine increased 3.5 times from 0.20 ± 0.03 % ID/g to 0.70 ± 0.10 % ID/g, whereas uptake of 68GaCl3 decreased from 0.34 ± 0.07 % ID/g to 0.13 ± 0.04 % ID/g within 3 h. Blood uptake of 68Ga-phenylalanine reached 2.98 ± 0.31 % ID/g. In other organs and tissues the uptake of 68Ga-phenylalanine didn’t exceed 1 % ID/g. Kidneys and femur uptake of 68Ga-phenylalanine was lower as compared with 68GaCl3, but in other organs the uptake of 68Ga-phenylalanine was similar or slightly higher when compared with 68GaCl3.