TY - JOUR
T1 - Ultrahigh-resolution Cerenkov-light imaging system for positron radionuclides
T2 - potential applications and limitations
AU - Yamamoto, Seiichi
AU - Watabe, Tadashi
AU - Ikeda, Hayato
AU - Kanai, Yasukazu
AU - Watabe, Hiroshi
AU - Ogata, Yoshimune
AU - Kato, Katsuhiko
AU - Hatazawa, Jun
N1 - Funding Information:
Acknowledgments This work was partly supported by the Japan Science and Technology Association and Ministry of Education, Science, Sports and Culture, Japan.
Publisher Copyright:
© 2014, The Japanese Society of Nuclear Medicine.
PY - 2014/11/27
Y1 - 2014/11/27
N2 - 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.
AB - 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.
KW - CCD camera
KW - Cerenkov-light imaging
KW - Molecular imaging
KW - Positron
KW - Ultrahigh resolution
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U2 - 10.1007/s12149-014-0892-z
DO - 10.1007/s12149-014-0892-z
M3 - Article
C2 - 25103137
AN - SCOPUS:84912526564
SN - 0914-7187
VL - 28
SP - 961
EP - 969
JO - Annals of Nuclear Medicine
JF - Annals of Nuclear Medicine
IS - 10
ER -