Ultrahigh-resolution Cerenkov-light imaging system for positron radionuclides: potential applications and limitations

Seiichi Yamamoto, Tadashi Watabe, Hayato Ikeda, Yasukazu Kanai, Hiroshi Watabe, Yoshimune Ogata, Katsuhiko Kato, Jun Hatazawa

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Objective: Cerenkov-light imaging provides inherently high resolution because the light is emitted near the positron radionuclide. However, the magnitude for the high spatial resolution of Cerenkov-light imaging is unclear. Its potential molecular imaging applications also remain unclear. We developed an ultrahigh-resolution Cerenkov-light imaging system, measured its spatial resolution, and explored its applications to molecular imaging research.

Methods: Our Cerenkov-light imaging system consists of a high-sensitivity charged-coupled device camera (Hamamatsu Photonics ORCA2-ER) and a bright lens (Xenon 0.95/25). An extension ring was inserted between them to magnify the subject. A ~100-μm-diameter 22Na point source was made and imaged by the system. For applications of Cerenkov-light imaging, we conducted 18F-FDG administered in vivo, ex vivo whole brain, and sliced brain imaging of rats.

Results: We obtained spatial resolution of ~220 μm for a 22Na point source with our developed imaging system. The 18F-FDG rat head images showed high light intensity in the eyes for the Cerenkov-light images, although there was no accumulation in these parts in the PET images. The sliced rat brain showed much higher spatial resolution for the Cerenkov-light images compared with CdWO4 scintillator-based autoradiography, although some contrast decrease was observed for them.

Conclusion: Even though the Cerenkov-light images showed ultrahigh resolution of ~220 μm, their distribution and contrast were sometimes different from the actual positron accumulation in the subjects. Care must be taken when evaluating positron distribution from Cerenkov-light images. However, the ultrahigh resolution of Cerenkov-light imaging will be useful for transparent subjects including phantom studies.

Original languageEnglish
Pages (from-to)961-969
Number of pages9
JournalAnnals of Nuclear Medicine
Issue number10
Publication statusPublished - 2014 Nov 27


  • CCD camera
  • Cerenkov-light imaging
  • Molecular imaging
  • Positron
  • Ultrahigh resolution


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