• Krohn, Kenneth (PI)

Project: Research project

Project Details


We will investigate several new radiopharmaceuticals for measurement of
regional intraorgan blood flow which could be particularly valuable for PET
imaging. These radiopharmaceutical tracers can be labeled with
generator-produced short-lived isotopes, and thus would be more convenient
to the researcher than cyclotron-produced isotopes for measuring blood
flow, principally H2150 which is produced in individual batches each time
it is needed. The proposed radiopharmaceuticals will be useful for
quantitating regional blood flow by potentially two different biological
mechanisms, and hence two different mathematical models are required for
data interpretation. The desmethylimipramine analog is a highly extracted
tracer, much like microspheres, and thus the model is simple; flow is
proportional to deposition. I-122 is the most likely label for the
imipramine derivatives. The cryptates as injected are inert,
freely-diffusible tracers much like water and butanol. We envision
cryptates labeled with Rb-82, Cs-128, and Ga-68 as possible flow tracers.
These complexes may dissociate within cells and leave the tracer metal ion
bound to cellular proteins. If so, a more complex, distributed
mathematical model for flow will be used. It allows for the transformation
of the radiopharmaceutical into one or more additional chemical species.
Thus, these experiments also provide a critical forum for comparing the
relative merit of two different approaches for measuring blood flow and,
when complete, will allow blood flow to be measured more accurately and
more conveniently than with H2150.
Effective start/end date7/1/866/30/90


  • National Institutes of Health


  • Medicine(all)


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