Abstract
Background: Myocardial perfusion imaging (MPI) is one of the most commonly performed investigations in nuclear medicine procedures. Due to the longer half-life of the emerging positron emitter copper-64 and its availability from low energy cyclotron, together with its well-known coordination chemistry, we have synthesized Cu-64-labeled NOTA- and Cu-64-NOTAM-rhodamine conjugates as potential cardiac imaging agents using PET.
Results:Cu- 64-NOTA- and Cu-64-NOTAM-rhodamine conjugates were synthesized using a traightforward and one-step simple reaction. Radiochemical yields were greater than 97% (decay corrected), with a total synthesis time of less than 25 min. Radiochemical purities were always greater than 98% as assessed by TLC and HPLC. These synthetic approaches hold considerable promise as a simple method for Cu-64-rhodamine conjugates synthesis, with high radiochemical yield and purity. Biodistribution studies in normal Fischer rats at 60 min post-injection, demonstrated significant heart uptake and a good biodistribution profile for both the radioconjugates. However, the Cu-64-NOTA-Mrhodamine conjugate has shown more heart uptake (similar to 10% ID/g) over the Cu-64-NOTArhodamine conjugate (5.6% ID/g).
Conclusions: These results demonstrate that these radioconjugates may be useful probes for the PET evaluation of MPI.