Novel synthesis and initial preclinical evaluation of ¹⁸F-[FDG] labeled rhodamine: a potential PET myocardial perfusion imaging agent

Myocardial perfusion imaging is one of the most commonly performed investigations in nuclear medicine studies. Due to the clinical importance of [¹⁸F]-fluoro-2-deoxy-D-glucose ([¹⁸F]-FDG) and its availability in almost every PET center, a new radiofluorinated [¹⁸F]-FDG-rhodamine conjugate was synthesized using [¹⁸F]-FDG as a prosthetic group. In a convenient and simple one-step radiosynthesis, [¹⁸F]-FDG-rhodamine conjugate was prepared in quantitative radiochemical yields, with total synthesis time of nearly 20 min and radiochemical purity of greater than 98%, without the need for HPLC purification, which make these approaches amenable for automation. Biodistribution studies in normal rats at 60 min post-injection demonstrated a high uptake in the heart (> 11% ID/g) and favorable pharmacokinetics. Additionally, [¹⁸F]-FDG-rhodamine showed an extraction value of 27.63% ± 5.12% in rat hearts. These results demonstrate that [¹⁸F]-FDG-rhodamine conjugate may be useful as an imaging agent for the positron emission tomography evaluation of myocardial perfusion. - Highlights: • Division of Nuclear Medicine and Molecular Imaging, Boston Children's Hospital, Boston • Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston • Harvard Medical School, Boston