A1 Refereed original research article in a scientific journal
Development of a non-radiometric method for measuring the arterial input function of a C-11-labeled PET radiotracer
Authors: H. Umesha Shetty, Sami S. Zoghbi, Cheryl L. Morse, Aneta Kowalski, Jussi Hirvonen, Robert B. Innis, Victor W. Pike
Publisher: NATURE RESEARCH
Publication year: 2020
Journal: Scientific Reports
Journal name in source: SCIENTIFIC REPORTS
Journal acronym: SCI REP-UK
Article number: ARTN 17350
Volume: 10
Issue: 1
Number of pages: 11
ISSN: 2045-2322
eISSN: 2045-2322
DOI: https://doi.org/10.1038/s41598-020-73646-4
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/50706687
Positron emission tomography (PET) uses radiotracers to quantify important biochemical parameters in human subjects. A radiotracer arterial input function (AIF) is often essential for converting brain PET data into robust output measures. For radiotracers labeled with carbon-11 (t(1/2)=20.4 min), AIF is routinely determined with radio-HPLC of blood sampled frequently during the PET experiment. There has been no alternative to this logistically demanding method, neither for regular use nor validation. A C-11-labeled tracer is always accompanied by a large excess of non-radioactive tracer known as carrier. In principle, AIF might be obtained by measuring the molar activity (A(m); ratio of radioactivity to total mass; Bq/mol) of a radiotracer dose and the time-course of carrier concentration in plasma after radiotracer injection. Here, we implement this principle in a new method for determining AIF, as shown by using [C-11]PBR28 as a representative tracer. The method uses liquid chromatography-tandem mass spectrometry for measuring radiotracer A(m) and then the carrier in plasma sampled regularly over the course of a PET experiment. A(m) and AIF were determined radiometrically for comparison. The new non-radiometric method is not constrained by the short half-life of carbon-11 and is an attractive alternative to conventional AIF measurement.
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