Biodistribution, Safety Profile, and Radiation Dosimetry of [¹⁸F]SYN2, a PET Cardiac Perfusion Tracer, in Healthy Subjects

A first-in-human phase I clinical study aimed to assess the safety profile, radiation dosimetry, and biodistribution of a potential cardiac PET myocardial perfusion imaging tracer, [¹⁸F]SYN2 (¹⁸F-labeled acridine derivative), in healthy subjects. Methods: [¹⁸F]SYN2 intravenous administration with PET imaging was performed on healthy volunteers, and sequential whole-body imaging was performed over 4 h. Blood and urine samples were collected for up to 240 min. Safety follow-up visits took place at 2, 5, and 14 d after the administration. Results: Ten subjects (8 women and 2 men) completed all study procedures. The mean age was 38.1 ± 8.8 y, and the mean body mass index was 22.7 ± 3.0 kg/m² The mean administered dose of radioactivity was 258 MBq (range, 246-272 MBq). There were no drug-related adverse events, and the tracer was well tolerated in all subjects. The mean whole-body effective radiation dose for [¹⁸F]SYN2 was 0.0195 mSv/MBq. The tracer was rapidly taken up by the myocardial wall and cleared from plasma, leading to good image quality within minutes of tracer injection. Conclusion: On the basis of the safety profile, radiation dosimetry, and biodistribution of [¹⁸F]SYN2, it appears to be a promising agent for clinical PET myocardial perfusion imaging and to warrant further clinical studies.