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Ann Nucl Med. 2014 Dec;28(10):961-9. doi: 10.1007/s12149-014-0892-z. Epub 2014 Aug 8.

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

Author information

1
Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, 461-8673, Japan, s-yama@met.nagoya-u.ac.jp.

Abstract

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 (22)Na point source was made and imaged by the system. For applications of Cerenkov-light imaging, we conducted (18)F-FDG administered in vivo, ex vivo whole brain, and sliced brain imaging of rats.

RESULTS:

We obtained spatial resolution of ~220 μm for a (22)Na point source with our developed imaging system. The (18)F-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.

PMID:
25103137
PMCID:
PMC4483184
DOI:
10.1007/s12149-014-0892-z
[Indexed for MEDLINE]
Free PMC Article

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