Brain

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Brain The Final Frontier
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Lets go on a Fantastic Voyage
Gene Expression
Permeability
Transmitter Synthesis
Neurotransmission
Reuptake
Blood Flow
Metabolism
Receptor Binding
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With PET we can image at the site of thinking
Dopaminergic synapse
(18)F-FBAU
15O-H2O
18F-FDOPA
11C-raclopride, etc
11C-CFT
15O-H2O
18F-FDG
11C-raclopride
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OK.So whats the problem?
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Whats all this about models in PET?
Dopaminergic synapse
Plasma raclopride
Free raclopride
Bound raclopride
stuck raclopride
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How can we tell which radioactivity comes from
Free tracerBound tracerPlasma-borne tracer?
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Tracer in each state has a unique temporal
trajectory
which is which ?
tracer concentration
What the PET scanner sees
Bound
Free
Plasma
Time (minutes)
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Divining the shape of each curve depends on
kinetic modeling of the data.
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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.
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The modeling process
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The Modeling Process
(a)
(b)
P
F
B
N
Return
(c)
(d)