Postinjection L-phenylalanine increases basal ganglia contrast in PET scans of 6-18F-DOPA

Journal Article · Mon Jul 01 00:00:00 EDT 1991 · Journal of Nuclear Medicine; (United States)

OSTI ID:5462089

Doudet, D J; McLellan, C A; Aigner, T G; Wyatt, R; Adams, H R; Miyake, H; Finn, R T; Cohen, R M ^[1]

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1. Section on Clinical Brain Imaging, National Institutes of Mental Health, Bethesda, MD (USA)

The sensitivity of 18F-DOPA positron emission tomography for imaging presynaptic dopamine systems is limited by the amount of specific-to-nonspecific accumulation of radioactivity in brain. In rhesus monkeys, we have been able to increase this ratio by taking advantage of the lag time between 18F-DOPA injection and the formation of its main metabolite, the amino acid 18F-fluoromethoxydopa, the entrance of which into brain is responsible for most of the brain's nonspecific radioactivity. By infusing an unlabeled amino acid, L-phenylalanine, starting 15 min after 18F-DOPA administration, we preferentially blocked the accumulation of 18F-fluoromethoxydopa by preventing its entrance into brain through competition at the large neutral amino acid transport system of the blood-brain barrier. This method appears as reliable as the original and more sensitive, as demonstrated by the comparison of normal and MPTP-treated animals under both conditions.

• OSTI ID: 5462089
• Journal Information: Journal of Nuclear Medicine; (United States), Vol. 32:7; ISSN 0161-5505
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BRAIN
POSITRON COMPUTED TOMOGRAPHY
PHENYLALANINE
MEMBRANE TRANSPORT
SENSITIVITY ANALYSIS
BLOOD-BRAIN BARRIER
DOPA
DOPAMINE
FLUORINE 18
MACACUS
AMINES
AMINO ACIDS
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACIDS
CARDIOTONICS
CARDIOVASCULAR AGENTS
CENTRAL NERVOUS SYSTEM
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
DRUGS
EMISSION COMPUTED TOMOGRAPHY
FLUORINE ISOTOPES
HOURS LIVING RADIOISOTOPES
HYDROXY ACIDS
HYDROXY COMPOUNDS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAMMALS
MONKEYS
NANOSEC LIVING RADIOISOTOPES
NERVOUS SYSTEM
NEUROREGULATORS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PHENOLS
POLYPHENOLS
PRIMATES
RADIOISOTOPES
SYMPATHOMIMETICS
TOMOGRAPHY
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics