Radiation Dose of the P-Glycoprotein Tracer C-11-Laniquidar

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 wit

Comparison of HRRT and HR plus Scanners for Quantitative (R)-[C-11]verapamil, [C-11]raclopride and [C-11]flumazenil Brain Studies

Purpose: This study was conducted to directly compare the high-resolution research tomograph (HRRT) (high-resolution brain) and HR+ (standard whole-body) positron emission tomography (PET) only scanners for quantitative brain studies using three tracers with vastly different tracer distributions.Procedures: Healthy volunteers underwent successive scans on HR+ and HRRT scanners (in random order) using either (R)-[11C]verapamil (n = 6), [11C]raclopride (n = 7) or [11C]flumazenil (n = 7). For all tracers, metabolite-corrected plasma-input functions were generated.Results: After resolution matching, HRRT-derived kinetic parameter values correlated well with those of HR+ for all tracers (intraclass correlation coefficients ≥0.78), having a good absolute interscanner test-retest variability (≤15 %). However, systematic differences can be seen for HRRT-derived kinetic parameter values (range −13 to +15 %).Conclusion: Quantification of kinetic parameters based on plasma-input models leads to comparable results when spatial resolution between HRRT and HR+ data is matched. When using reference-tissue models, differences remain that are likely caused by differences in attenuation and scatter corrections and/or image reconstruction