[18F]FNDP PET neuroimaging test-retest repeatability and whole-body dosimetry in humans

PurposeSoluble epoxide hydrolase (sEH) is an enzyme that shapes immune signaling through its role in maintaining the homeostasis of polyunsaturated fatty acids and their related byproducts. [F-18]FNDP is a radiotracer developed for use with positron emission tomography (PET) to image sEH, which has been applied to imaging sEH in the brains of healthy individuals. Here, we report the test-retest repeatability of [F-18]FNDP brain PET binding and [F-18]FNDP whole-body dosimetry in healthy individuals.MethodsSeven healthy adults (4 men, 3 women, ages 40.1 & PLUSMN; 4.6 years) completed [F-18]FNDP brain PET on two occasions within a period of 14 days in a test-retest study design. [F-18]FNDP regional total distribution volume (V-T) values were derived from modeling time-activity data with a metabolite-corrected arterial input function. Test-retest variability, mean absolute deviation, and intraclass correlation coefficient (ICC) were investigated. Six other healthy adults (3 men, 3 women, ages 46.0 & PLUSMN; 7.0 years) underwent [F-18]FNDP PET/CT for whole-body dosimetry, which was acquired over 4.5 h, starting immediately after radiotracer administration. Organ-absorbed doses and the effective dose were then estimated.ResultsThe mean test-retest difference in regional V-T (& UDelta;V-T) was 0.82 & PLUSMN; 5.17%. The mean absolute difference in regional V-T was 4.01 & PLUSMN; 3.33%. The ICC across different brain regions ranged from 0.92 to 0.99. The organs with the greatest radiation-absorbed doses included the gallbladder (0.081 & PLUSMN; 0.024 mSv/MBq), followed by liver (0.077 & PLUSMN; 0.018 mSv/MBq) and kidneys (0.063 & PLUSMN; 0.006 mSv/MBq). The effective dose was 0.020 & PLUSMN; 0.003 mSv/MBq.ConclusionThese data support a favorable test-retest repeatability of [F-18]FNDP brain PET regional V-T. The radiation dose to humans from each [F-18]FNDP PET scan is similar to that of other F-18-based PET radiotracers.