title: Development of a high-resolution Si-PM-based gamma camera system.
abstract: A silicon photomultiplier (Si-PM) is a promising photodetector for PET, especially for PET/MRI combined systems, due to its high gain, small size, and lower sensitivity to static magnetic fields. However, these properties are also promising for gamma camera systems for single-photon imaging. We developed an ultra-high-resolution Si-PM-based compact gamma camera system for small animals. Y(2)SiO(5):Ce (YSO) was selected as scintillators because of its high light output and no natural radioactivity. The gamma camera consists of 0.6 mm × 0.6 mm × 6 mm YSO pixels combined with a 0.1 mm thick reflector to form a 17 × 17 matrix that was optically coupled to a Si-PM array (Hamamatsu multi-pixel photon counter S11064-050P) with a 2 mm thick light guide. The YSO block size was 12 mm × 12 mm. The YSO gamma camera was encased in a 5 mm thick gamma shield, and a parallel hole collimator was mounted in front of the camera (0.5 mm hole, 0.7 mm separation, 5 mm thick). The two-dimensional distribution for the Co-57 gamma photons (122 keV) was almost resolved. The energy resolution was 24.4% full-width at half-maximum (FWHM) for the Co-57 gamma photons. The spatial resolution at 1.5 mm from the collimator surface was 1.25 mm FWHM measured using a 1 mm diameter Co-57 point source. Phantom and small animal images were successfully obtained. We conclude that a Si-PM-based gamma camera is promising for molecular imaging research.
authors.affiliation: Kobe City College of Technology, Kobe, Japan. s-yama@kobe-kosen.ac.jp
authors.forename: Seiichi
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watabe
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Kanai
authors.forename: Masao
authors.initials: M
authors.lastname: Imaizumi
authors.forename: Tadashi
authors.initials: T
authors.lastname: Watabe
authors.forename: Eku
authors.initials: E
authors.lastname: Shimosegawa
authors.forename: Jun
authors.initials: J
authors.lastname: Hatazawa
mesh_terms: D000818:Animals; D015902:Gamma Cameras; D051379:Mice; D017785:Photons; D049268:Positron-Emission Tomography / Q000295:instrumentation*; D012588:Scintillation Counting; D012825:Silicon; D013696:Temperature
chemical_list: D012825:Silicon