Synthesis of [11C]palmitic acid for PET imaging using a single molecular sieve 13X cartridge for reagent trapping, radiolabeling and selective purification

Alejandro Amor-Coarasa, James M. Kelly, John W. Babich

Research output: Contribution to journalArticle

5 Scopus citations


Introduction: Radiolabeled fatty acids are valuable metabolic tracers for PET imaging. Carbon-11 is widely used in clinical PET studies due to the prevalence of facile techniques enabling the incorporation of [11C]CO2 and [11C]CH3 into molecules and a short half-life (20.4min) that translates into low patient dose. However, the short half-life considerably limits the time for radiosynthesis. Furthermore, the majority of the syntheses of [11C]palmitic acid in common use employ high starting [11C]CO2 activities and/or expensive equipment. Methods: [11C]CO2 was trapped with greater than 99.99% efficiency by a three stage cartridge packed with molecular sieve 13X, 100-120mesh. The labeling of n-pentadecylmagnesium bromide took place in 5min in the cartridge, and the [11C]palmitic acid product was selectively eluted in ethanol following alkaline and acidic washes of the column. Results: The system reliably produced more than 925MBq (25mCi) of [11C]palmitic acid suitable for human use from 7.4GBq (200mCi) of [11C]CO2 in 8min from end-of-bombardment. Conclusions: We have exploited the properties of the inexpensive molecular sieve 13X to develop a miniature, disposable and leak tight "gas capture" system for the rapid labeling and purification of [11C]fatty acids in good yield and >99% radiochemical purity. The rapidity of the synthesis and purification allows small [11C]CO2 starting activities to be used, and with no requirement for expensive synthesis equipment or facilities, the system can be implemented in any radiopharmaceutical center.

Original languageEnglish (US)
Pages (from-to)685-690
Number of pages6
JournalNuclear Medicine and Biology
Issue number8
Publication statusPublished - Aug 1 2015
Externally publishedYes



  • 3D printing
  • Fatty acid
  • Metabolism
  • [C]CO
  • [C]Palmitic acid

ASJC Scopus subject areas

  • Molecular Medicine
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

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