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 (11)C-N-propylnorapomorphine ((11)C-NPA), a dopamine agonist PET tracer, in human subjects and determined the resulting absorbed radiation doses. Six subjects (3 women, 3 men) were injected with (11)C-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. The average NPA whole-body radiation dose was 3.17 x 10(-3) mSv per MBq of injected (11)C-NPA. The organ receiving the highest dose was the gallbladder wall, with an average of 2.81 x 10(-2) mSv.MBq(-1). On the basis of averaged dosimetry results, an administration of less than 1,780 MBq (<48 mCi) of (11)C-NPA yields an organ dose of under 50 mSv (5 rem) to all organs.