Potential Effect of Prolonged Sevoflurane Anesthesia on the Kinetics of [(11)C]Raclopride in Non-human Primates

PURPOSE: Positron emission tomography (PET) in non-human primates (NHP) is commonly performed under anesthesia, with sevoflurane being a widely used inhaled anesthetic. PET measurement in NHP can be repeated, and a difference in radioligand kinetics has previously been observed between the first and second PET measurement on the same day using sevoflurane anesthesia. In this study, we evaluated the effect of prolonged sevoflurane anesthesia on kinetics and binding potential (BP(ND)) of [(11)C]raclopride in NHP. PROCEDURES: Three cynomolgus monkeys underwent two to three PET measurements with [(11)C]raclopride under continuous sevoflurane anesthesia on the same day. The concentration of sevoflurane was adjusted according to the general conditions and safety parameters of the NHP. Time to peak (TTP) radioactivity in the striatum was estimated from time-activity curves (TACs). The BP(ND) in the striatum was calculated by the simplified reference tissue model using the cerebellum as reference region. RESULTS: In each NHP, the TTP became shorter in the later PET measurements than in the first one. Across all measurements (n = 8), concentration of sevoflurane correlated with TTP (Spearman’s ρ = − 0.79, p = 0.03), but not with BP(ND) (ρ = − 0.25, p = 0.55). CONCLUSIONS: These data suggest that sevoflurane affects the shape of TACs but has no evident effect on BP(ND) in consecutive PET measurements.