RT Journal Article SR Electronic T1 Radiation Dose of the P-Glycoprotein Tracer 11C-Laniquidar JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 2101 OP 2103 DO 10.2967/jnumed.113.120857 VO 54 IS 12 A1 Andrey Postnov A1 Femke E. Froklage A1 Arthur van Lingen A1 Jaap C. Reijneveld A1 N. Harry Hendrikse A1 Albert D. Windhorst A1 Robert C. Schuit A1 Jonas Eriksson A1 Adriaan A. Lammertsma A1 Marc C. Huisman YR 2013 UL http://jnm.snmjournals.org/content/54/12/2101.abstract AB Resistance to current drug therapy is an important issue in the treatment of epilepsy. Inadequate access of central nervous system drugs to their targets in the brain may be caused by overexpression or overactivity of multidrug transporters, such as P-glycoprotein (P-gp), at the blood–brain barrier. Laniquidar, an inhibitor of P-gp, has been labeled with 11C for use in PET studies of P-gp expression in humans. Given potential interspecies differences in biodistribution, the purpose of this study was to ensure safe use of 11C-laniquidar by determining the dosimetry of 11C-laniquidar using whole-body PET studies. Methods: Six healthy volunteers were subjected to a series of 10 whole-body PET scans within approximately 70 min. Five blood samples were taken during the series. Results: High uptake of 11C-laniquidar was seen in liver, spleen, kidneys, and lung, whereas brain uptake was low. The effective dose for 11C-laniquidar was 4.76 ± 0.13 and 3.69 ± 0.01 μSv·MBq−1 for women and men, respectively. Conclusion: Biodistribution and measured effective dose indicate that 11C-laniquidar is a safe tracer for PET imaging, with a total dose of about 2 mSv for a brain PET/CT protocol.