Efficient gallium-68 radiolabeling reaction of DOTA derivatives using a resonant-type microwave reactor

Yusuke Yagi, Yoichi Shimizu, Kenji Arimitsu, Yuji Nakamoto, Takahiro Higuchi, Kaori Togashi, Hiroyuki Kimura

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Gallium-68 ( 68 Ga, t 1/2  = 68 min) can be easily obtained from a 68 Ge/ 68 Ga generator, and several such systems are commercially available. The use of positron emission tomography (PET) imaging using 68 Ga-labeled radiopharmaceuticals is expected to increase in both preclinical and clinical settings. However, the chelation between a 68 Ga cation and the bifunctional macrocyclic chelates that are used for labeling bioactive substances, such as 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), requires a relatively long reaction time and high temperature to achieve a high radiochemical yield. Previously, we reported on a novel resonant-type microwave reactor that can be used for radiosynthesis and the usefulness of this reactor in the PET radiosynthesis of 18 F. In the present study, the usefulness of this resonant-type microwave reactor was evaluated for the radiolabeling of model macrocyclic chelates with 68 Ga. As a result, microwave heating of resonant-type microwave reactor notably improved the rate of the 68 Ga labeling chelate reaction in a short time period of 2 minutes, compared with the use of a conventional heating method. Additionally, it was found that the use of this reactor made it possible to decrease the amount of precursors required in the reaction and to improve the molar activity of the labeled compounds.

Original languageEnglish
Pages (from-to)132-138
Number of pages7
JournalJournal of Labelled Compounds and Radiopharmaceuticals
Issue number3
Publication statusPublished - Mar 2019
Externally publishedYes


  • Ga-chelation
  • Ga-p-Bn–NCS–DOTA
  • positron emission tomography radiochemistry
  • resonant-type microwave reactor

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Radiology Nuclear Medicine and imaging
  • Drug Discovery
  • Spectroscopy
  • Organic Chemistry


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