Biodistribution and Radiation Dosimetry of ¹¹C-Nicotine from Whole-Body PET Imaging in Humans.

Abstract

This study assessed the in vivo distribution of ¹¹C-nicotine and the absorbed radiation dose from whole-body ¹¹C-nicotine PET imaging of 11 healthy (5 male and 6 female) subjects. <b>Methods:</b> After an initial CT attenuation scan, ¹¹C-nicotine was administered via intravenous injection. A dynamic PET scan was acquired for 90 s with the brain in the field of view, followed by a series of 13 whole-body PET scans acquired over a 90-min period. Regions of interest were drawn over organs visible in the reconstructed PET images. Time-activity curves were generated, and the residence times were calculated. The absorbed radiation dose for the whole body was calculated by entering the residence time in OLINDA/EXM 1.0 software to model the equivalent organ dose and the effective dose for a 70-kg man. <b>Results:</b> The mean residence times for ¹¹C-nicotine in the liver, red marrow, brain, and lungs were 0.048 ± 0.010, 0.031 ± 0.005, 0.021 ± 0.004, and 0.020 ± 0.005 h, respectively. The mean effective dose for ¹¹C-nicotine was 5.44 ± 0.67 μSv/MBq. The organs receiving the highest absorbed dose from the ¹¹C-nicotine injection were the urinary bladder wall (14.68 ± 8.70 μSv/MBq), kidneys (9.56 ± 2.46 μSv/MBq), liver (8.94 ± 1.67 μSv/MBq), and spleen (9.49 ± 3.89 μSv/MBq). The renal and hepatobiliary systems were the major clearance and excretion routes for radioactivity. <b>Conclusion:</b> The estimated radiation dose from ¹¹C-nicotine administration is relatively modest and would allow for multiple PET examinations on the same subject.