Human biodistribution and dosimetry of the D2/3 agonist 11C-N-propylnorapomorphine (11C-NPA) determined from PET

Abstract

We measured the whole-body distribution of intravenously injected 11C-N-propylnorapomorphine (11C-NPA), a dopamine agonist PET tracer, in human subjects and determined the resulting absorbed radiation doses. Methods: Six subjects (3 women, 3 men) were injected with 11C-NPA (nominal dose, 370 MBq). A total of 9 consecutive whole-body PET scans were obtained for each subject. In addition, time-activity curves for 12 organs were determined, and residence times were computed for each subject. Dosimetry was determined for the various body organs and the whole body. Results: The average NPA wholebody radiation dose was 3.17 × 10 -3 mSv per MBq of injected 11C-NPA. The organ receiving the highest dose was the gallbladder wall, with an average of 2.81 × 10-2 mSv·MBq-1. Conclusion: On the basis of averaged dosimetry results, an administration of less than 1,780 MBq (<48 mCi) of 11C-NPA yields an organ dose of under 50 mSv (5 rem) to all organs. Copyright © 2009 by the Society of Nuclear Medicine, Inc.