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

作者：Yamamoto Seiichi^*; Watabe Tadashi; Ikeda Hayato; Kanai Yasukazu; Watabe Hiroshi; Ogata Yoshimune; Kato Katsuhiko; Hatazawa Jun

来源：Annals of Nuclear Medicine, 2014, 28(10): 961-969.

DOI：10.1007/s12149-014-0892-z

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

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. %26lt;br%26gt;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 similar to 100-mu m-diameter Na-22 point source was made and imaged by the system. For applications of Cerenkov-light imaging, we conducted F-18-FDG administered in vivo, ex vivo whole brain, and sliced brain imaging of rats. %26lt;br%26gt;We obtained spatial resolution of similar to 220 mu m for a Na-22 point source with our developed imaging system. The F-18-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. %26lt;br%26gt;Even though the Cerenkov-light images showed ultrahigh resolution of similar to 220 mu m, 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.

• 出版日期2014-12