In-target chemistry during the production of 15O and 11C using 3He reactions

Kenneth A. Krohn, Jeanne M. Link, William G. Weitkamp

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The use of nuclear reactions that do not involve a change in element can be advantageous for radionuclide production because enriched targets are rarely required and the yield of the nuclear reactions is usually adequate. However there is a disadvantage to these reactions for medical imaging because the product radioactivity is of low specific activity. In this report we discuss the application of radiation chemistry and nucleogenic recoil chemistry to two reactions, 16O(3He,4He)15O and 12C(3He,4He)11C, to improve specific activity of the radioactive oxygen and carbon recovered from the target. For both reactions, specific activities were improved, with minimal decrease in recovered radioactivity. For the 16O → 15O reaction in water, results demonstrated that the production of [15O]-O2 followed a different reaction mechanism from that for unlabeled O2. The unlabeled yield was quantitatively predicted from classical radiation chemistry G-values for water. The radiochemical product distribution was a consequence of the combined effects of recoil chemistry and radiation chemistry. Studies with thin graphite foils demonstrated that we could irradiate sufficiently thin C foils so that a useful fraction of the recoil nucleogenic 11C atoms escaped the irradiated carbon and reacted with circulating gas to capture an appreciable fraction of the product 11C with an improvement in specific activity. Although we have shown the feasibility of producing GBq quantities of radiopharmaceuticals by recoil techniques, the advantages of even higher specific activity using enriched targets outweigh the cost of using enriched targets.

Original languageEnglish (US)
Pages (from-to)193-199
Number of pages7
JournalRadiochimica Acta
Issue number3-4/2000
StatePublished - Jan 1 2000
Externally publishedYes


  • Carbon-11
  • Hot atom chemistry
  • Oxygen-15
  • Radiation chemistry
  • Specific activity

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry


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