Development of a high-resolution YSO gamma camera system that employs 0.8-mm pixels

Seiichi Yamamoto*, Hiroshi Watabe, Yasukazu Kanai, Katsuhiko Kato, Jun Hatazawa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Objective: YSO (Ce-doped Y2SiO5) is a promising scintillator for a single-photon imaging system since it has relatively high light output and does not contain any natural radioactivity. Since YSO is not hygroscopic, it may be possible to fabricate a block with small pixels for a high-resolution system. For this purpose, we developed a high-resolution gamma camera system that employs smaller than 1-mm YSO pixels. Methods: The gamma camera's detector used 0.8 × 0.8 × 7-mm YSO pixels. All the surfaces of these YSO pixels were mechanically polished, combined with a 0.1-mm-thick BaSO4 reflector to form a 48 × 48 matrix, and optically coupled to a high quantum efficiency, 2-inch square position sensitive photomultiplier tube (Hamamatsu Photonics H10966 A-100). The YSO block was 43.2 × 43.2 mm. The YSO gamma camera was encased in a 5-mm-thick tungsten container, and a parallel collimator was mounted on its front. The parallel hole collimator was made of a 3-layer (each layer was 5-mm thick) tungsten plate, and each plate had 48 × 48, 0.6-mm holes that were positioned by one-to-one coupling with the YSO pixels. Results: Even with the 0.8-mm YSO pixels, we clearly resolved most of the pixels in a 2-dimensional histogram with a peak-to-valley ratio of 2.9 for the 122-keV gamma photons. The energy resolution was 20.4 % FWHM. The spatial resolutions with a parallel hole collimator 2 mm from the collimator surface were 0.7- and 1.3-mm FWHM for the 122- and ∼35-keV gamma photons, respectively. We successfully obtained phantoms and small animal images with our YSO gamma camera system. Conclusion: Our high-resolution system has a potential to be useful for molecular imaging research.

Original languageEnglish
Pages (from-to)232-240
Number of pages9
JournalAnnals of Nuclear Medicine
Issue number3
Publication statusPublished - 2014 Apr
Externally publishedYes


  • Gamma camera
  • High resolution
  • Tungsten collimator
  • YSO

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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