Evidence for reduced arterial plasma input, prolonged lung retention and reduced lung monoamine oxidase in smokers

The measured arterial input function values for smokers and nonsmokers are significantly different for these two tracer pairs for nonsmokers and smokers particularly for the first few minutes after radiotracer injection. Model estimates of k3 that indicate that smokers have lower lung MAO A and B activity than nonsmokers are robust and insensitive to variations in model assumptions for relative fractions of lung tissue, blood and air in the PET voxel. Although we have only investigated the behavior of [11C]clorgyline and [11C]l-deprenyl and their deuterium-substituted analogs in this report, the extent to which reduced arterial input and longer lung retention also hold for other tracers for subjects who smoke merits investigation.