Synthesis and Evaluation of a 48V- TPPS Complex as a prospective Long-lived radiotracer for PET Imaging

Abstract

Positron emission tomography (PET) faces limitations including short half-lives of conventional radionuclides, which restrict its use in long-term biological tracking. This thesis explores vanadium-48 (48V), an emerging long-lived radioisotope, and evaluates a 48V-5,10,15,20-Tetraphenyl-21H, 23H-porphine- p,p′,p,p′′′-tetrasulfonic acid tetrasodium hydrate (TPPS) complex as a novel radiotracer for PET imaging. Both a non-radioactive vanadyl-TPPS model and a radioactive 48V-TPPS complex were synthesized. The non-radioactive version was characterized via FT-IR, UV-Vis, and Mass spectrometry, suggesting successful chelation. The radioactive complex was analyzed by radio-TLC, providing preliminary evidence of the radiotracer formation. In vitro studies showed efficient cell labeling with the 48V-TPPS complex at high concentrations for up to two weeks and no cytotoxicity observed. Appreciable cell retention of 47% of the initial radioactivity was observed at high concentration of the tracer. These promising results provide an initial proof-of- concept for 48V-TPPS complex as prospective PET tracer for cell tracking.