Selected68Ga-siderophores versus68Ga-colloid and68Ga-citrate: Biodistribution and small animal imaging in mice

Abstract

Background.68Ga-triacetylfusarinine C (TAFC) and68Ga-ferrioxamine E (FOXE) show great potential to be used as highly sensitive and selective tracers for Aspergillus infection imaging. Here we report on a comparison of the ex vivo biodistribution and small animal imaging of68Ga-TAFC and68Ga-FOXE versus68Ga-colloid and68Ga-citrate as unspecific control in mice. Methods. The radiochemical purity of tested68Ga labelled tracers was determined by RP-HPLC or ITLC-SG. Ex vivo biodistribution was studied in normal DBA/2 mice 30 min and 90 min p.i. Static and dynamic imaging were performed using μPET/CT. Results.68Ga-TAFC and68Ga-FOXE showed rapid renal excretion and low blood values even 90 min p.i.68Ga-TAFC showed almost no retention in other organs while68Ga-FOXE displayed some uptake in gastrointestinal tract.68Ga-colloid and68Ga-citrate revealed significantly different ex vivo biodistribution.68Ga-colloid showed pronounced radioactivity retention in the liver, while68Ga-citrate displayed high blood values and significant retention of radioactivity in highly perfused organs. Conclusions. From the results, both68Ga-TAFC and68Ga-FOXE have excellent and significantly different in vivo behaviour compared to68Ga-colloid and68Ga-citrate.68Ga-TAFC in particular confirmed its great potential use as a specific tracer for Aspergillus infection imaging.