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Brain… The Final Frontier…. Lets go on a “Fantastic Voyage”. Gene Expression. Transmitter Synthesis. Permeability. Neurotransmission. Reuptake. Blood Flow. Metabolism. Receptor Binding. With PET we can image at the site of “thinking”. Dopaminergic synapse. (18)F-FBAU . 18F-FDOPA.
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Lets go on a “Fantastic Voyage” Gene Expression Transmitter Synthesis Permeability Neurotransmission Reuptake Blood Flow Metabolism Receptor Binding
With PET we can image at the site of “thinking” Dopaminergic synapse (18)F-FBAU 18F-FDOPA 15O-[H2O] 11C-raclopride, etc 11C-CFT 15O-[H2O] 18F-FDG 11C-raclopride
What’s all this about models in PET? Dopaminergic synapse Plasma raclopride Free raclopride Bound raclopride ‘stuck’ raclopride
How can we tell which radioactivity comes from Free tracerBound tracerPlasma-borne tracer?
Tracer in each state has a unique temporal trajectory which is which ? tracer concentration What the PET scanner sees Bound Free Plasma Time (minutes)
Divining the shape of each curve depends on kinetic modeling of the data.
(a) (b) P F B N (c) (d) The modeling process Imagine a living brain Consider the relevant neurochemistry Describe exchange between pools by a series of differential equations Abstract the neurochemistry into a series of connected pools Morris, E.D., C.J. Endres, K. Schmidt, B.T. Christian, R.F. Muzic, R.E. Fisher. Kinetic Modeling in PET. In Emission Tomography: The Fundamentals of PET and SPECT, ed. M. Wernick and N. Aarsvold. Academic Press. Amsterdam, Netherlands, 2004, pp. 499-540.
(a) (b) P F B N (c) (d) The modeling process