Application of carbon-11 labelled nicotine in the measurement of human cerebral blood flow and other physiological parameters.

Using positron emission tomography (PET), we measured the regional cerebral blood flow (rCBF) in five normal human subjects after intravenous injection of carbon-11 labeled (R)nicotine. The rCBF of the same subjects was measured by PET using the C15O2 inhalation steady-state method. The distribution of 11C activity in the brain after injection of 11C-(R)nicotine was almost equivalent to the CBF image obtained with the C15O2 inhalation stead-state method. The kinetics of 11C-(R)nicotine in the brain was analysed using a two-compartment model consisting of vascular and brain tissue compartments. The rCBF values obtained with 11C-(R)nicotine were higher than with C15O2 gas. The relatively long fixed distribution of 11C-(R)nicotine with a short uptake period allows stimulation studies by measurement of CBF to be performed with better photon flux and a longer imaging time than are possible with H215O.