Background: (S,S)-[F]FMeNER-D2 is a recently developed norepinephrine transporter ligand which is a potentially useful radiotracer for mapping the brain and heart norepinephrine transporter in vivo using positron emission tomography. In this work, we quantified the biodistribution over time and radiation exposure to multiple organs with (S,S)-[F]FMeNER-D2.
Methods: Whole-body images were acquired for 21 time points in two cynomolgus monkeys for approximately 270 min after injection of radioligand. Compressed 3-D to 2-D planar images were used to identify organs with the highest radiation exposure at each time point. Estimates of the absorbed dose of radiation were calculated using the MIRDOSE 3.1 software program performed with the dynamic bladder and ICRP 30 gastrointestinal tract models.
Results: In planar images, peak values of the percent injected dose (%ID) at a time after radioligand injection were calculated for the lungs (26.76% ID at 1.42 min), kidneys (13.55% ID at 2.18 min), whole brain (5.65% ID at 4.48 min), liver (7.20% ID at 2 min), red bone marrow (5.02% ID at 2.06 min), heart (2.36% ID at 1.42 min) and urinary bladder (23% ID at 250 min). Assuming a urine voiding interval of 2.4 h, the four organs with highest exposures in microGy . MBq ( mrad . mCi) were kidneys 126 (468), heart wall 108 (399), lungs 88.4 (327) and urinary bladder 114 (422). The effective doses were estimated with and without urine voiding at a range of 123 (33) and to 131 (35.5) microGy . MBq ( mrad . mCi).
Conclusion: The estimated radiation burden of (S,S)-[F]FMeNER-D2 is comparable to that of other F radioligands.