@article{oai:repo.qst.go.jp:00046723,
 author = {Matsumoto, Takahiro and Yamaya, Taiga and Yoshida, Eiji and Nishikido, Fumihiko and Inadama, Naoko and Murayama, Hideo and Suga, Mikio and 松本 貴宏 and 山谷 泰賀 and 吉田 英治 and 錦戸 文彦 and 稲玉 直子 and 村山 秀雄 and 菅 幹生},
 issue = {1},
 journal = {Radiological physics and technology},
 month = {Jan},
 note = {We are developing a novel PET detector with 3D isotropic resolution called a crystal (X'tal) cube. The X'tal cube detector consists of a crystal block all 6 surfaces of which are covered with silicon photomultipliers (SiPMs). We have developed a prototype detector with 3D isotropic 1 mm resolution. On the other hand, when the X'tal cubes are arranged to form a PET scanner, insensitive inter-detector gaps made by the SiPM arrays should not be too wide, or, better yet, they should be removed. Reduction of the number of SiPMs will also be reflected in the production costs. Therefore, reducing the number of faces to be connected to the SiPMs has become our top priority. In this study, we evaluated the effect of reducing the number of SiPMs on the positioning accuracy through numerical simulations. Simulations were performed with the X'tal cube, which was composed of a 6 × 6 × 6 array of Lu2x Gd2(1-x)SiO5:Ce crystal elements with dimensions of (3.0 mm)(3). Each surface of the crystal block was covered with a 4 × 4 array of SiPMs, each of which had a (3.0 mm)(2) active area. For material between crystal elements, we compared two: optical glue and an air gap. The air gap showed a better crystal identification performance than did the optical glue, although a good crystal identification performance was obtained even with optical glue for the 6-face photodetection. In conclusion, the number of photodetection faces could be reduced to two when the gap material was air.},
 title = {Simulation study optimizing the number of photodetection faces for the X'tal cube PET detector with separated crystal segments.},
 volume = {7},
 year = {2014}
}