Biodistribution, safety profile, and radiation dosimetry of [18F]SYN2, a new PET perfusion tracer in healthy subjects

Aims The phase I clinical, a first-in-man, study aimed to assess safety profile, radiation dosimetry, and biodistribution of a new potential cardiac positron emission tomography (PET) perfusion tracer [18F]SYN2 (18F acridinium derivative) in healthy subjects. Methods [18F]SYN2 intravenous administration with PET imaging was performed in healthy volunteers and sequential whole-body imaging was performed for 4 hours. Blood and urine samples were collected for up to 240 min. Safety follow-up visits took place at 2, 5 and 14 days after the administration. Results 10 subjects (8 females and 2 males) completed all study procedures. The mean age was 38.1 ± 8.8 years, and the mean body mass index was 22.7 ± 3.0 kg/m2. The mean administered dose of radioactivity was 253 MBq (range: 240 – 258 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 very rapidly taken up by myocardial wall and cleared up from plasma leading to good image quality already after minutes of tracer injection. The accumulation of [18F]SYN2 to left ventricle was 2.2-2.4 %ID/organ. Conclusions Based on tracer safety profile, radiation dosimetry, and biodistribution [18F]SYN2 appears a promising agent for clinical PET myocardial perfusion imaging and further clinical studies are warranted.The PET images at each time period