Preparation and biological evaluation of 99Tcm-labelled fatty acids

The aim of the present work was to develop radiolabelling fatty acids based on 99Tcm carbonyl chemistry for heart imaging. Undecanoic acids functionalised with iminodiacetatic acid and cysteine were radiolabelled with [99Tcm (CO)3(H2O)3]+ intermediates, and their radiolabelling conditions were carefully studied. Biodistribution of 99Tcm (CO)3-CYST FAC11 and 99Tcm (CO)3-IDA FAC11 were observed in normal mice. The results showed that two 99Tcm-labelled compounds had similar profile in terms of high initial radioactivity uptake and rapid washout of radiotracers in the heart. 99Tcm (CO)3-IDA FAC11 was mainly excreted via hepatobiliary system in contrast to 99Tcm (CO)3-CYST FAC11, which was excreted from urinary system. It may be in part attributed to the more lipophilicity of 99Tcm (CO)3-IDA FAC11 than 99Tcm (CO)3-CYST FAC11.