PT - JOURNAL ARTICLE AU - Charles M. Laymon AU - N. Scott Mason AU - W. Gordon Frankle AU - Jonathan P. Carney AU - Brian J. Lopresti AU - Maralee Y. Litschge AU - Chester A. Mathis AU - James M. Mountz AU - Rajesh Narendran TI - Human Biodistribution and Dosimetry of the D<sub>2/3</sub> Agonist <sup>11</sup>C-<em>N</em>-Propylnorapomorphine (<sup>11</sup>C-NPA) Determined from PET AID - 10.2967/jnumed.108.058131 DP - 2009 May 01 TA - Journal of Nuclear Medicine PG - 814--817 VI - 50 IP - 5 4099 - http://jnm.snmjournals.org/content/50/5/814.short 4100 - http://jnm.snmjournals.org/content/50/5/814.full SO - J Nucl Med2009 May 01; 50 AB - 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 whole-body 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 (&lt;48 mCi) of 11C-NPA yields an organ dose of under 50 mSv (5 rem) to all organs.