An improved method for rapid and efficient radioiodination of iodine-123-IQNB

Kan Sam Lee, Xiao Shu He, Douglas W. Jones, Richard Coppola, Julia G. Gorey, Michael B. Knable, Brian R. DeCosta, Kenner C. Rice, Daniel R. Weinberger

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The SPECT radioligand, 3-quinuclidinyl-4-[123I]iodobenzilate ([123I]IQNB), binds to muscarinic receptors and has generated interest as a potential agent for clinical SPECT. Unfortunately, cumbersome and inefficient radioiodination procedures have limited the practicality of [123I]IQNB SPECT imaging. Methods: We report a rapid (5 min) and simple radioiodination procedure for preparing [123I]IQNB from a tri-n-butylstannyl precursor in a no-carrier-added reaction that yields high specific activity with radiochemical yield exceeding 60%. The radiochemical purity of the final product exceeds 95%. Results: We have used this procedure to radioiodinate the four stereoisomers of [123I]IQNB. The procedure is highly reliable and reproducible. SPECT studies on a healthy human volunteer at 1, 2, 6 and 24 hr after injection of each of the four stereoisomers reveal expected differences in the kinetic and binding characteristics of the four stereoisomers. (R,S)-[123I]IQNB appears to be the SPECT agent of choice. Conclusion: Radioiodination of [123I]IQNB from our tri-n-butylstannyl precursor is simpler, more efficient and less expensive than previous techniques. The potential exists for a "kit" which would be practical in a typical clinical setting.

Original languageEnglish (US)
Pages (from-to)2021-2024
Number of pages4
JournalJournal of Nuclear Medicine
Issue number12
StatePublished - Dec 1 1996
Externally publishedYes


  • Diastereomers
  • Iodine-123-IQNB
  • Muscarinic receptors

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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