Evaluation of (/sup 123/I)isopropyliodoamphetamine as a tracer for local cerebral blood flow using direct autoradiographic comparison

Journal Article · Fri Jan 01 04:00:00 EST 1982 · J. Cereb. Blood Flow Metab.; (United States)

DOI:https://doi.org/10.1038/jcbfm.1982.17· OSTI ID:6782887

Lear, J L; Ackermann, R F; Kameyama, M; Kuhl, D E

We investigated (/sup 123/I)isopropyliodoamphetamine (IMP) for potential use in the autoradiographic determination of local cerebral blood flow (LCBF) in animals. The technique of direct autoradiographic comparison, derived from double radionuclide autoradiography, was used to compare the simultaneous uptakes of IMP and (/sup 14/C)iodoantipyrine (IAP), a reference tracer, in awake and anesthetized rats. This new technique offers several advantages over the previously developed methods of comparing tracers, brain uptake index and first pass extraction ratio. These include the avoidance of disrupting normal cerebral blood-brain tracer exchange and the ability to compare uptakes at substructural levels, whereas the other methods are limited to larger areas. Mean values of LCBF obtained with IMP agreed closely with those using IAP, from 20 to 300 ml/100 g/min. Because IMP was found to have an extremely high effective brain:blood partition coefficient, approximately 25:1, a linear uptake tracer model could be used for IMP yielding more precise values than could IAP for LCBF values above 150. IMP was found to measure choroid plexus flows much more accurately than IAP, values being greater than 500 for IMP compared to approximately 200 for IAP. Because the mechanism of the extremely high partition coefficient of IMP is not yet defined, however, care must be used in measuring LCBF with IMP where the trapping mechanisms of normal vessels may be disrupted.

• Research Organization: Laboratory of Nuclear Medicine, UCLA School of Medicine, Los Angeles, California
• OSTI ID: 6782887
• Journal Information: J. Cereb. Blood Flow Metab.; (United States), Journal Name: J. Cereb. Blood Flow Metab.; (United States) Vol. 2:2; ISSN JCBMD
• Country of Publication: United States
• Language: English

Related Subjects

550601 -- Medicine-- Unsealed Radionuclides in Diagnostics
551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINES
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
BENZEDRINE
BETA DECAY RADIOISOTOPES
BLOOD FLOW
BODY
BRAIN
CARBON 14 COMPOUNDS
CENTRAL NERVOUS SYSTEM
CEREBRUM
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE 123
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PHYSIOLOGY
RADIOISOTOPES
RADIOPHARMACEUTICALS
RATS
RODENTS
SYMPATHOMIMETICS
UPTAKE
VERTEBRATES